idA name idP first_author confjournal idEidV title abstract
0 a57218202833 Gautam A. p0 True Conference 0 Self-assessment of Proficiency of Intelligent Systems: Challenges and Opportunities Autonomous systems, although capable of performing complicated tasks much faster than humans, are brittle due to uncertainties encountered in most real-time applications. People supervising these systems often rely on information relayed by the system to make any decisions, which places a burden on the system to self-assess its proficiency and communicate the relevant information. Proficiency self-assessment benefits from an understanding of how well the models and decision mechanisms used by robot align with the world and a problem holder’s goals. This paper makes three contributions: (1) Identifying the importance of goal, system, and environment for proficiency assessment; (2) Completing the phrase “proficient ‹preposition›” using an understanding of proficiency span; and (3) Proposing the proficiency dependency graph to represent causal relationships that contribute to failures, which highlights how one can reason about their own proficiency given alterations in goal, system, and environment. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
1 a7004904337 Crandall J.W. p0 False Conference 0 Self-assessment of Proficiency of Intelligent Systems: Challenges and Opportunities Autonomous systems, although capable of performing complicated tasks much faster than humans, are brittle due to uncertainties encountered in most real-time applications. People supervising these systems often rely on information relayed by the system to make any decisions, which places a burden on the system to self-assess its proficiency and communicate the relevant information. Proficiency self-assessment benefits from an understanding of how well the models and decision mechanisms used by robot align with the world and a problem holder’s goals. This paper makes three contributions: (1) Identifying the importance of goal, system, and environment for proficiency assessment; (2) Completing the phrase “proficient ‹preposition›” using an understanding of proficiency span; and (3) Proposing the proficiency dependency graph to represent causal relationships that contribute to failures, which highlights how one can reason about their own proficiency given alterations in goal, system, and environment. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
1 a7004904337 Crandall J.W. p155 False Conference 27 Moderating operator influence in human-swarm systems In human-swarm systems, human input to a robot swarm can both inhibit desirable swarm behaviors and allow the operator to properly guide the swarm to achieve mission goals. Indeed, the way that control is shared between the human operator and the inherent collective robot behaviors determines in large part the success of the human-swarm system. In this paper, we seek to understand how to design human-swarm systems that effectively moderate human influence over a robot swarm. To do this, we implement a simulated swarm system based on honeybees, and study how interacting with this swarm using various methods of moderating human influence impacts the success of the resulting human-swarm system. Our results demonstrate that moderating human influence is essential to achieving effective human-swarm systems, and highlight the need for future work in determining how to better moderate human influence in human-swarm systems. © 2019 IEEE.
1 a7004904337 Crandall J.W. p298 True Conference 80 Cooperating in long-term relationships with time-varying structure Extended interactions between agents have commonly been studied in the context of repeated games (RGs), in which the same players repeatedly interact in the same scenario. However, such interactions are uncommon in practice. Typically, the players' goals, action sets, and payoffs change from encounter to encounter, often in ways the players cannot easily model or control. These more realistic interactions, which we model as a form of stochastic game called interaction games (IGs), have attributes which prohibit the straightforward application of many often-used algorithms developed for RGs. In this paper, we generalize several algorithms previously designed for RGs, and explore their behavior and performance in IGs. Our results suggest that at least some of the methodologies designed for RGs can, with some modifications, be extended to IGs. © 2019 International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.
1 a7004904337 Crandall J.W. p630 False Conference 265 Information design in crowdfunding under thresholding policies Crowdfundmg has emerged as a prominent way for entrepreneurs to secure funding without sophisticated intermediation. In crowd- funding, an entrepreneur often has to decide how to disclose the campaign status in order to collect as many contributions as poss ible. Such decisions are difficult to make primarily due to incomp lete information. We propose information design as a tool to help the entrepreneur to improve revenue by influencing backers' bel iefs. We introduce a heuristic algorithm to dynamically compute information-disclosure policies for the entrepreneur, followed by an empirical evaluation to demonstrate its competitiveness over the widely-adopted immediate-disclosure policy. Our results demons trate that the immediate-disclosure policy is not optimal when backers follow thresholding policies despite its ease of implementat ion. With appropriate heuristics, an entrepreneur can benefit from dynamic information disclosure. Our work sheds light on inform ation design in a dynamic setting where agents make decisions using thresholding policies. © 2018 International Foundation for Autonomous Agents and Multiagent Systems.
2 a7005513246 Goodrich M.A. p0 False Conference 0 Self-assessment of Proficiency of Intelligent Systems: Challenges and Opportunities Autonomous systems, although capable of performing complicated tasks much faster than humans, are brittle due to uncertainties encountered in most real-time applications. People supervising these systems often rely on information relayed by the system to make any decisions, which places a burden on the system to self-assess its proficiency and communicate the relevant information. Proficiency self-assessment benefits from an understanding of how well the models and decision mechanisms used by robot align with the world and a problem holder’s goals. This paper makes three contributions: (1) Identifying the importance of goal, system, and environment for proficiency assessment; (2) Completing the phrase “proficient ‹preposition›” using an understanding of proficiency span; and (3) Proposing the proficiency dependency graph to represent causal relationships that contribute to failures, which highlights how one can reason about their own proficiency given alterations in goal, system, and environment. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
2 a7005513246 Goodrich M.A. p155 False Conference 27 Moderating operator influence in human-swarm systems In human-swarm systems, human input to a robot swarm can both inhibit desirable swarm behaviors and allow the operator to properly guide the swarm to achieve mission goals. Indeed, the way that control is shared between the human operator and the inherent collective robot behaviors determines in large part the success of the human-swarm system. In this paper, we seek to understand how to design human-swarm systems that effectively moderate human influence over a robot swarm. To do this, we implement a simulated swarm system based on honeybees, and study how interacting with this swarm using various methods of moderating human influence impacts the success of the resulting human-swarm system. Our results demonstrate that moderating human influence is essential to achieving effective human-swarm systems, and highlight the need for future work in determining how to better moderate human influence in human-swarm systems. © 2019 IEEE.
2 a7005513246 Goodrich M.A. p156 False Conference 28 Intent-based robotic path-replanning: When to adapt new paths in dynamic environments For goal-based robot navigation in a dynamic environment, human intent includes expectations about what performance objectives are satisfied by a planned path in terms of objectives to be met. If the planned path drifts from the human's intent as a result of environment changes, the path needs to be replanned. This paper presents a replanning framework with three elements: (a) the integration of fast online path-planning algorithms that generate trajectories conforming to the given intent; (b) a mathematical model that says when replanning must happen; and (c) an evaluation of events that trigger replanning. An interactive graphical user interface enables a human to accept or reject replanned paths when a trigger happens. A study of 50 MTurk participants is used to assess what replanning triggers best enable a human-robot collaboration to persistently satisfy intent? © 2019 IEEE.
2 a7005513246 Goodrich M.A. p174 False Journal 118 Transparency: Transitioning From Human–Machine Systems to Human-Swarm Systems Swarm robotic systems are gaining in interest with the prospect of their use for various applications, including monitoring, tracking, infrastructure support, and protection. Prior human-swarm system research investigated transparency for these systems, but assumed perfect communication scenarios. Real-world human-swarm systems will not have perfect communication due to human processing limitations caused by a large number of individual entities, emergent behavior due to varying environments, and bandwidth issues. Factors that affect transparency or are influenced by transparency were identified from various human–machine system domains; however, understanding the relationship between factors can help designers identify what criteria can be implemented to achieve transparency for swarms. Challenges that may arise based on transparency criteria from human–machine systems are examined to identify improvements for spatial swarm systems. © 2019, Human Factors and Ergonomics Society.
2 a7005513246 Goodrich M.A. p302 False Conference 83 Designing emergent swarm behaviors using behavior trees and grammatical evolution Results show that a recursively defined BT-based grammar, built from common agent behaviors, can be used by the GEESE algorithm to evolve solutions to single-source foraging task. Because of the difficulty of solving the credit assignment problem, bootstrapping methods must be added to the fitness function to find solutions in reasonable time. © 2019 International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.
2 a7005513246 Goodrich M.A. p534 False Conference 193 Swarm Transparency A key element of system transparency is allowing humans to calibrate their trust in a system, given the implicit inherent uncertainty, emergent behaviors, etc. As robotic swarms progress towards real-world missions, such transparency becomes increasingly necessary in order to reduce the disuse, misuse and errors humans make when influencing and directing the swarm. However,achieving this objective requires addressing the complex challenges associated with providing transparency. Two swarm transparency challenge categories, with exemplar challenges, are provided. © 2018 Authors.
2 a7005513246 Goodrich M.A. p567 False Conference 216 GEESE: Grammatical evolution algorithm for evolution of swarm behaviors [No abstract available]
2 a7005513246 Goodrich M.A. p592 False Conference 235 When does a human replan? Exploring intent-based replanning in multi-objective path planning In goal-based tasks such as navigating a robot from location A to location B in a dynamic environment, human intent can mean to choose a specific trade-off between multiple competing objectives. For example, intent can mean to find a path that balances between "Go quickly" and "Go stealthily". Given human expectations about how a path balances such tradeoffs, the path should match the human's intent throughout the entire execution of the path even if the environment changes. If the path drifts from the human's intent because the environment changes, then a new robotic-path needs to be planned - referred to as path-replanning. We discuss here three system-initiated triggers (prompts) for path-replanning. The objective is to create an interactive replanning system that yields paths that consistently match human intent. The triggers are to replan (a) at regular time intervals, (b) when the current robotic path deviates from the user intent, and (c) when a better path can be obtained from a different homotopy class. Further, we consider one user-generated replanning trigger that allows the user to stop the robot anytime to put the robot onto a new route. These four trigger variants seek to answer two fundamental critical questions: When is a re-planned path acceptable to a human? and How should a planner involve a human in replanning? © 2018 SPIE.
2 a7005513246 Goodrich M.A. p765 False Conference 321 Design and Evaluation of Adverb Palette: A GUI for Selecting Tradeoffs in Multi-objective Optimization Problems An important part of expressing human intent is identifying acceptable tradeoffs among competing performance objectives. We present and evaluate a set of graphical user interfaces (GUIs), that are designed to allow a human to express intent by expressing desirable tradeoffs. The GUIs require an algorithm that identifies the set of Pareto optimal solutions to the multi-objective decision problem, which means that all the solutions are equally good in the sense that there are no other solutions better for every objective. Given the Pareto set, the GUIs provide different ways for a human to express intent by exploring tradeoffs between objectives; once a tradeoff is selected, the solution is chosen. The GUI designs are applied to interactive human-robot path-selection for a robot in an urban environment, but they can be applied to other tradeoff problems. A user study evaluates GUI designs by requiring users to select a tradeoff that satisfies a specified mission intent. Results of the user study suggest that GUIs designed to support an artist's palette-metaphor can be used to express intent without incurring unacceptable levels of human workload. © 2017 ACM.
2 a7005513246 Goodrich M.A. p766 False Conference 322 Haptic Shape-Based Management of Robot Teams in Cordon and Patrol There is a growing need to develop effective interaction methods that enable a single operator to manage a team of multiple robots. This paper presents a novel approach that involves treating the team as a moldable volume, in which deformations of the volume correspond to changes in team shape. The team possesses a level of autonomy that allows the team to travel to and surround buildings of interest in a patrol and cordon scenario. During surround mode, the operator explores or manipulates the team shape to create desired formations around a building. A spacing interaction method also allows the operator to adjust how robots are spaced within the current shape. Separate haptic feedback is developed for each method to allow the operator to "feel" the shape or spacing manipulation. During travel mode, the operator chooses desired travel locations and receives feedback to help identify how and where the team travels. Results from a user study suggest that haptic feedback significantly improves operator performance in a reconnaissance task when task demand is higher, but may slightly increase operator workload. In the context of the experimental setup, these results suggest that haptic feedback may contribute to heads-up control of a team of autonomous robots. There were no significant differences in levels of situation awareness due to haptic feedback in this study. © 2017 ACM.
2 a7005513246 Goodrich M.A. p868 False Conference 389 Effect of leader placement on robotic swarm control Human control of a robotic swarm entails selecting a few influential leaders who can steer the collective efficiently and robustly. However, a clear measure of influence with respect to leader position is not adequately studied. Studies with animal systems have shown that leaders who exert strong couplings may be located in front, where they provide energy benefits, or in the middle, where they can be seen by a larger section of the group. In this paper, we systematically vary number of leaders and leader positions in simulated robotic swarms of two different sizes, and assess their effect on steering effectiveness and energy expenditure. In particular, we analyze the effect of placing leaders in the front, middle, and periphery, on the time to converge and lateral acceleration of a swarm of robotic agents as it performs a single turn to reach the desired goal direction. Our results show that swarms with leaders in the middle and periphery take less time to converge than swarms with leaders in the front, while the lateral acceleration between the three placement strategies is not different. We also find that the time to converge towards the goal direction reduces with the increase in percentage of leaders in the swarm, although this value decays slowly beyond the percentage of leaders at 30%. As the swarm size is increased, we find that the leaders in the periphery become less effective in reducing the time to converge. Finally, closer analysis of leader placement and coverage reveals that front leaders within the swarm tend to expand their coverage and move towards the center as the maneuver is performed. Results from this study are expected to inform leader placement strategies towards more effective human swarm interaction systems. © Copyright 2017, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.
3 a6508306234 de Moura Oliveira P.B. p1 True Conference 1 Bridging theory to practice: Feedforward and cascade control with tclab arduino kit Practice is of the essence in Engineering courses. A relevant question in control engineering education is: How to close the gap between theory and practice? Once subjects are introduced in theoretical classes, students want to know about its practical use. Thus, it is important to introduce theoretical control concepts with practical experiments, enabling students to easily test and validate the theory. An Arduino based temperature control laboratory (TCLab) is deployed in this study as a portable kit providing students with a simple and effective means to test some feedback control techniques. Teaching/learning experiments are proposed involving proportional, integral and derivative controllers with Feedforward and Cascade control structures. Preliminary results achieved in a Portuguese university are presented. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021.
3 a6508306234 de Moura Oliveira P.B. p176 True Conference 38 An APMonitor Temperature Lab PID Control Experiment for Undergraduate Students Students born in a digital era require adjusted teaching and learning methodologies incorporating new technologies. A common difficulty found by students is how to test their controller designs in a real system. Thus, the development of affordable, portable and easy to use feedback control kits is highly desirable. The idea is that both lecturers and students can perform simple practical experiments anytime and anywhere. The APMonitor temperature control lab is an Arduino based control kit which fulfils these requirements. Proportional, integrative and derivative control is in operation in the vast majority of industrial process control loops. Thus, it is a mandatory topic in most undergraduate introductory feedback control courses. A teaching/learning PID control experiment for undergraduate Biomedical Engineering student's based on the temperature control lab is reported here. Results received from students are presented. © 2019 IEEE.
4 a9277159100 Hedengren J.D. p1 False Conference 1 Bridging theory to practice: Feedforward and cascade control with tclab arduino kit Practice is of the essence in Engineering courses. A relevant question in control engineering education is: How to close the gap between theory and practice? Once subjects are introduced in theoretical classes, students want to know about its practical use. Thus, it is important to introduce theoretical control concepts with practical experiments, enabling students to easily test and validate the theory. An Arduino based temperature control laboratory (TCLab) is deployed in this study as a portable kit providing students with a simple and effective means to test some feedback control techniques. Teaching/learning experiments are proposed involving proportional, integral and derivative controllers with Feedforward and Cascade control structures. Preliminary results achieved in a Portuguese university are presented. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021.
4 a9277159100 Hedengren J.D. p116 False Journal 84 Model predictive control and estimation of managed pressure drilling using a real-time high fidelity flow model When drilling an oil or gas well, well pressures may be controlled using a technology called managed pressure drilling. This technology often relies on model predictive control schemes; however, practical limitations have generally led to the use of simplified controller models that do not optimally handle certain perturbations in the physical system. The present work reports on the first implementation of a highly accurate system model that has been adapted for real-time use in a controller. This real-time high-fidelity model approximates the results of offline high-fidelity models without requiring operation by model experts. The effectiveness of the model is demonstrated through simulation studies of controller behavior under various drilling conditions, including an evaluation of the impact of sparse downhole feedback measurements. © 2020
4 a9277159100 Hedengren J.D. p176 False Conference 38 An APMonitor Temperature Lab PID Control Experiment for Undergraduate Students Students born in a digital era require adjusted teaching and learning methodologies incorporating new technologies. A common difficulty found by students is how to test their controller designs in a real system. Thus, the development of affordable, portable and easy to use feedback control kits is highly desirable. The idea is that both lecturers and students can perform simple practical experiments anytime and anywhere. The APMonitor temperature control lab is an Arduino based control kit which fulfils these requirements. Proportional, integrative and derivative control is in operation in the vast majority of industrial process control loops. Thus, it is a mandatory topic in most undergraduate introductory feedback control courses. A teaching/learning PID control experiment for undergraduate Biomedical Engineering student's based on the temperature control lab is reported here. Results received from students are presented. © 2019 IEEE.
4 a9277159100 Hedengren J.D. p210 False Journal 142 Achieving tiered model quality in 3D structure from motion models using a multi-scale view-planning algorithm for automated targeted inspection This study presents a novel multi-scale view-planning algorithm for automated targeted inspection using unmanned aircraft systems (UAS). In industrial inspection, it is important to collect the most relevant data to keep processing demands, both human and computational, to a minimum. This study investigates the viability of automated targeted multi-scale image acquisition for Structure from Motion (SfM)-based infrastructure modeling. A traditional view-planning approach for SfM is extended to a multi-scale approach, planning for targeted regions of high, medium, and low priority. The unmanned aerial vehicle (UAV) can traverse the entire aerial space and facilitates collection of an optimized set of views, both close to and far away from areas of interest. The test case for field validation is the Tibble Fork Dam in Utah. Using the targeted multi-scale flight planning, a UAV automatically flies a tiered inspection using less than 25% of the number of photos needed to model the entire dam at high-priority level. This results in approximately 75% reduced flight time and model processing load, while still maintaining high model accuracy where needed. Models display stepped improvement in visual clarity and SfM reconstruction integrity by priority level, with the higher priority regions more accurately modeling smaller and finer features. A resolution map of the final tiered model is included. While this study focuses on multi-scale view planning for optical sensors, the methods potentially extend to other remote sensors, such as aerial LiDAR. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
4 a9277159100 Hedengren J.D. p211 False Journal 143 Disaster reconnaissance using multiple small unmanned aerial vehicles" [No abstract available]
4 a9277159100 Hedengren J.D. p224 False Journal 147 Dynamic optimization of a district energy system with storage using a novel mixed-integer quadratic programming algorithm As more renewable energy is integrated into the power grid, it is increasingly important to exploit variable electricity pricing structures to minimize commercial utility costs and enable more intermittent renewables on the grid through proactive management of energy storage. Using data from a large campus district energy system, equipped with centralized chilled water plants and a thermal energy storage tank, a novel technique is proposed to optimize this system in real-time, formulated as a mixed-integer quadratic programming problem. This method, titled Quadratic Programming Hybrid with Augmented Constraints, is sufficiently fast to be computed in real-time for a district chiller system. This method is compared to both Branch and Bound and a simple logical decision algorithm in both speed and optimality. The proposed method for solving this mixed-integer quadratic programming problem proves very successful at achieving a near-optimal solution when compared to a standard Branch and Bound (BnB) algorithm. Although suboptimal, the proposed algorithm takes 99.96–99.99% less computational time than the standard BnB and computes an answer to within 29.9% of the BnB objective function. When compared to a simple logical decision algorithm, which represents an operator manually controlling the plant, the proposed method is estimated to yield 8.10–33.7% in savings on chiller energy costs. The Quadratic Programming Hybrid with Augmented Constraints algorithm shows potential for use in a real-time optimization application to exploit variable electricity pricing and significantly reduce the costs of running a chiller plant with thermal energy storage. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
4 a9277159100 Hedengren J.D. p286 False Conference 69 Combined trajectory, propulsion and battery mass optimization for solar-regenerative high-altitude long endurance unmanned aircraft Combined optimization of propulsion system design, flight trajectory planning and battery mass optimization for solar-regenerative high-altitude long endurance (SRHALE) aircraft through a sequential iterative approach yields an increase of 20.2% in the end-of-day energy available on the winter solstice at 35°N latitude, resulting in an increase in flight time of 2.36 hours. The optimized flight path is obtained by using nonlinear model predictive control to solve flight and energy system dynamics over a 24 hour period with a 15 second time resolution. The optimization objective is to maximize the total energy in the system while flying a station-keeping mission, staying within a 3 km radius and above 60,000 ft. The propulsion system design optimization minimizes the total energy required to fly the optimal path. It uses a combination of blade element momentum theory, blade composite structures, empirical motor and motor controller mass data, as well as a first order motor performance model. The battery optimization seeks to optimally size the battery for a circular orbit. Fixed point iteration between these optimization frameworks yields a flight path and propulsion system that slightly decreases solar capture, but signif-icantly decreases power expended. Fully coupling the trajectory and design optimizations with this level of accuracy is infeasible with current computing resources. These efforts show the benefits of combining design and trajectory optimization to enable the feasibility of SRHALE flight. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
4 a9277159100 Hedengren J.D. p327 False Journal 189 Dynamic optimization of high-altitude solar aircraft trajectories under station-keeping constraints This paper demonstrates the use of nonlinear dynamic optimization to calculate energy-optimal trajectories for a high-altitude, solar-powered unmanned aerial vehicle (UAV). The objective is to maximize the total energy in the system while staying within a 3 km mission radius and meeting other system constraints. Solar energy capture is modeled using the vehicle orientation and solar position, and energy isstored both in batteries and in potential energy through elevation gain. Energy capture is maximized by optimally adjusting the angle of the aircraft surface relative to the sun. The UAV flight and energy system dynamics are optimized over a 24h period at an 8s time resolution using nonlinear model predictive control. Results of the simulated flights are presented for all four seasons, showing an 8.2% increase in end-of-day battery energy for the most limiting flight condition of the winter solstice. © 2018 by R. Abraham Martin, Nathaniel S. Gates, Andrew Ning, and John D. Hedengren.
4 a9277159100 Hedengren J.D. p338 False Conference 114 Evaluation and demonstration of take home laboratory kit This paper discusses some of the reasons for producing take home laboratory kits. This is then supplemented by detailed presentation of three different types of take home kit, alongside the motivations for their design and an evaluation of their efficacy with students. © 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
4 a9277159100 Hedengren J.D. p356 False Conference 126 Closed-Loop PID Re-Tuning in a Digital Twin by Re-Playing Past Setpoint and Load Disturbance Data [No abstract available]
4 a9277159100 Hedengren J.D. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
4 a9277159100 Hedengren J.D. p431 False Journal 239 Performance comparison of low temperature and chemical absorption carbon capture processes in response to dynamic electricity demand and price profiles Current projections to the year 2050 reveal that fossil fuels will remain the main source of energy generation. To achieve the target limits of carbon dioxide emission, set by national and international policies, carbon capture will play a key role. Modeling and optimization of various carbon capture technologies such as pre-combustion, oxy-fuel, and post-combustion, when integrated with coal-fired power plants, have been researched extensively in literature. Research on the integration of power generation with capture technologies regarding comparisons between the different schemes in response to dynamic inputs is lacking. This work provides a comparison between a low temperature carbon capture and a chemical absorption process in response to a dynamic electricity demand and price profile and in the presence of an intermittent wind power supply. The objective in this work is to meet the overall electricity demand of residential users and the carbon capture process while the total operating cost associated with the integrated system of power generation and carbon capture is minimized. This comparison includes scenarios with and without energy storage associated with each capture technology. It is observed that in both integrated systems, with and without energy storage, the overall electricity demanded by the capture process and residential users is supplied by a combination of coal and wind power. For the case without energy storage, the total operating cost and energy demand of the low temperature carbon capture, based on a similar amount of captured carbon dioxide, are 4.3% and 20.5% less than that of chemical absorption, respectively. For the scenario with energy storage, the low temperature carbon capture requires 32.34% less energy to capture similar amounts of carbon dioxide while incurring 9.09% less overall operational cost. © 2018 Elsevier Ltd
4 a9277159100 Hedengren J.D. p622 False Conference 258 Targeted 3D modeling from UAV imagery Reconstruction of 3D objects from UAV EO imagery yields useful information, but can be time consuming and computationally expensive. View planning reduces processing time by selecting the optimal image set needed to reconstruct a scene. This paper demonstrates how view planning is used in a targeted manner to select a subset of images from a large existing image set to model specific vehicles or structures. Potential applications of the method include enabling 3D target classification algorithms and rapid geo-location. The method could also facilitate on-board reconstruction. The view planning algorithm is tested on five different targets, and is shown to reduce processing time for target models by up to a factor of 50 with little decrease in accuracy. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
4 a9277159100 Hedengren J.D. p629 True Conference 264 New flow assurance system with high speed subsea fiber optic monitoring of pressure and temperature Subsea production control systems are instrumented to constantly monitor flowline pressure and temperature at key locations to prevent plugging and introduce mitigating control strategies. New fiber optic sensors with ruggedized construction and non-electrical components are subjected to accelerated aging tests and deployed in several installations with long service life. An overview of current progress with fiber optic technology is provided for fatigue monitoring, temperature, pressure, and strain sensing. Recent developments include improved service life, novel bonding methods, pipeline sensor station improvements, sensor calibration, and long-term fatigue analysis. The latest advancements are validated on multiple installations on a subsea tieback in the deepwater Mississippi Canyon of the Gulf of Mexico at 6, 500 ft depth. A prior third-party sensor design experienced multiple non-recoverable sensor failures. A new sensor station design is employed on two Flowline Terminations to monitor pressure and temperature at a rate of 100 Hz. Subsea tiebacks are susceptible to flow assurance issues caused by plugging events such as hydrate formation. The system was originally designed to track pig location but transitioned to pressure and temperature sensing. An issue with the transition was the lack of calibration relating the fiber Bragg grating (FBG) strain levels to the actual process conditions. A novel method is presented for in situ adjustment of the sensor array calibration. During the calibration procedure, the sensors produced unanticipated results during pipeline flow shut-in and later startup operations. The sensors helped uncover a configuration of the flowline and sensor locations that is valuable for detecting hydrate forming conditions at a key junction location. The sensors are located before and after the junction of two flowlines in the mixing zone of the pipeline streams. The novel contributions of this study are the high speed data collection, in situ fiber optic calibration, review of advancements in fiber optic sensing technology, and a field case study with multiple sensing arrays. The developments are part of the Clear Gulf study, a collaboration between the offshore energy industry and NASA that was formed in 2010. The objective of the Clear Gulf study is to employ space technology and testing facilities for use in the upstream industry to advance subsea sensor technology. The highly sensitive monitoring systems developed as part of this study are used to give early warnings for flow assurance issues, structural failures, or catastrophic events. Copyright © 2018 ASME.
4 a9277159100 Hedengren J.D. p647 False Conference 279 Development and testing of a friction-based post-installable fiber-optic monitoring system for subsea applications This paper continues to document the design, development, and test of a friction-based (non-adhesive) post-installable fiberoptic strain sensing system for oil and gas applications - especially those that require deployment on existing subsea structures. (Ref: OMAE2017-61494 Development and Testing of a Friction-Based Post-Installable Sensor for Subsea FiberOptic Monitoring Systems [1]). The prototype fiber-optic monitoring system collects a wide range of real-time data, which can be used to determine structural loading, fatigue, temperature, pressure, and flow assurance on operational platforms. The primary challenge of a post-installed instrumentation monitoring system is to ensure secure coupling between the sensors and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome installation challenges caused by marine growth and soil contamination on subsea structures, flowlines, or risers. This particular design solution is compatible with structures that are suspended in the water column and those that are resting on the seabed. In addition, the system can be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. Operational limitations of the initial design concept were identified in the previous series of tests (2016-2017), and several innovative enhancements have been implemented which resulted in significant improvements in sensor system coupling and strain measurement correlation with traditional strain measuring devices. This paper provides a summary of the notable prototype design changes, full-scale test article buildup, and detailed performance data recorded during tension and compression loading that simulated representative offshore conditions. The test results were positive and demonstrated the effectiveness of the design enhancements. Compromises made during mounting of the sensing elements resulted in better performance in tension than compression. These effects are well understood and are fully discussed, and do not influence the viability of the design changes. This study is part of a continuing collaboration between the Houston-based NASA-Johnson Space Center and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries. Copyright © 2018 ASME.
4 a9277159100 Hedengren J.D. p686 False Journal 332 A comparison of model predictive control and PID temperature control in friction stir welding Temperature control of friction stir welding (FSW) via model predictive control (MPC) is investigated in Al 7075-T7. Two MPC controllers are compared against two well-tuned PID controllers to obtain a direct comparison of MPC and current FSW controllers. One MPC controller uses a first-order plus dead-time (FOPDT) model derived from a simplified conduction-advection view of the stir zone. The other MPC controller uses the Hybrid Heat Source model that describes heat conduction in the plate and tool. At quasi steady-state conditions, all four controllers can easily hold temperature within 2 °C of the setpoint in the absence of large disturbances. Once the weld is past the initial traverse, the FOPDT controller is superior to the Hybrid Heat Source controller with regards to modeled-disturbance rejection and setpoint changes. The FOPDT controller is competitive with well-tuned PID controllers in this region of the weld. During the initial traverse, the Hybrid Heat Source controller and PID controller with regulator gains were able to control temperature within 5 °C of the setpoint, compared to a typical deviation of 20–30 °C when uncontrolled. During this period, the FOPDT controller and PID controller with servo gains could not maintain satisfactory temperature control. MPC is demonstrated to be a viable control method for FSW. Temperature control before reaching steady state for both MPC and PID is shown to be feasible, but more difficult than for steady state. Recommendations are given for when each controller might be preferred in various circumstances, based upon the results shown herein. © 2017 The Society of Manufacturing Engineers
4 a9277159100 Hedengren J.D. p768 True Journal 375 Overview of estimation methods for industrial dynamic systems Measurement technology is advancing in the oil and gas industry. Factors such as wireless transmitters, reduced cost of measurement technology, and increased regulations that require active monitoring tend to increase the number of available measurements. There is a clear opportunity to distill the recent flood of measurements into relevant and actionable information. Common methods to do this include a filtered bias update, implicit dynamic feedback, Kalman filtering, and moving horizon estimation. The purpose of these techniques is to validate measurements and align imperfect mathematical models to the actual process. Additionally, they can determine a best-estimate of the current state of the process and any potential disturbances. These methods allow potential improvements in earlier detection of disturbances, process equipment faults, and improved state estimates for optimization and control. © 2015, Springer Science+Business Media New York.
4 a9277159100 Hedengren J.D. p834 False Conference 362 Improved bottomhole pressure control with wired drillpipe and physics-based models Wired Drillpipe (WDP) technology provides two-way and high speed measurements from bottom hole and along-string sensors. The data offered by WDP technology has maximum benefit when applied in an automation system or as a real-time advisory tool. Improved control is demonstrated for Managed Pressure Drilling (MPD) with the use of high-speed telemetry and physics-based models. Stabilizing and minimizing pressure within an acceptable bound leads to higher and more consistent Rate of Penetration (ROP). MPD control is challenging due to tight pressure windows and the nonlinearity of the choke and pump response on Bottom Hole Pressure (BHP). This work demonstrates a new Hammerstein-Wiener nonlinear model predictive controller for BHP regulation in drilling. Hammerstein-Wiener models employ input and output static nonlinear blocks before and after linear dynamics blocks and thereby simplify the controller design. The control performance is evaluated in scenarios such as drilling, pipe connections, and kick attenuation. A physics-based drilling simulator, WeMod, is used for model identification and control performance evaluation. The control performance of the new nonlinear controller is compared to conventional controllers in various scenarios. Because of the interconnected multivariable and nonlinear nature of the drilling operation, conventional controllers show severe limitations. In a first scenario, the performance of set point tracking during normal drilling operation is compared. By changing the set point of the BHP, the conventional controller manipulates only the choke valve opening while the nonlinear controller moves choke valve opening, mud pump, and back pressure pump simultaneously. In a second scenario, a pipe connection of a typical drillpipe stand is demonstrated. The conventional controller is not able to regulate the BHP by adjusting the choke valve only. Although a linear version of the controller is able to exploit multivariable relationships, absence of the nonlinear relationships results in severe oscillation when the operational range is shifted outside of the training region. The nonlinear controller maintains a BHP within ±1 bar of the requested set point. A third scenario investigates the kick attenuation performance of conventional and nonlinear control algorithms. The nonlinear controller attenuates the kick within well control conditions, without requiring a well shut-in procedure. Recent advances in drilling simulators and the reliability of the WDP data highway have enabled tighter BHP control. This study presents a robust method to control BHP by applying Hammerstein-Wiener models in an efficient model predictive controller. The proposed methods have been validated in the downstream industry, but are applied for the first time to drilling with nonlinear control functionality. The multivariable control adjusts three main manipulated variables in MPD simultaneously. Copyright © 2017, SPE/IADC Drilling Conference and Exhibition.
4 a9277159100 Hedengren J.D. p844 False Journal 398 Optimal combined long-term facility design and short-term operational strategy for CHP capacity investments This work presents a detailed case study for the optimization of the expansion of a district energy system evaluating the investment decision timing, type of capacity expansion, and fine-scale operational modes. The study develops an optimization framework to find the investment schedule over 30 years with options of investing in traditional heating sources (boilers) or a next-generation combined heat and power (CHP) plant that provides heat and electricity. In district energy systems, the selected capacity and type of system is dependent on demand-side requirements, energy prices, and environmental costs. This work formulates capacity planning over a time horizon as a dynamic optimal control problem considering both operational modes and capital investment decisions. The initial plant is modified by the dynamic optimization throughout the 30 years to maximize profitability. The combined optimal controller and capital investment planner solves a large scale mixed integer nonlinear programming problem to provide the timing and size of the capacity investment (30 year outlook) and also guidance on the mode of operation (1 h time intervals). The optimizer meets optimal economic, environmental, and regulatory constraints with the suggested design and operational guidance with daily cyclical load following of heat and electricity demand. © 2016 Elsevier Ltd
4 a9277159100 Hedengren J.D. p859 False Conference 381 Automatic model calibration for drilling automation Physics-based hydraulic models are essential for proceeding to a high level of automation in drilling. Mathematical models can facilitate process understanding and problem detection, and determine appropriate actions in case of mismatch between model and data. Furthermore, calculations may replace measurements where and when the latter are not available, as normally occurs during connections or when instruments or signal transmissions fail. However, advanced hydraulic models rely on a large set of inputs, such as pipe and wellbore geometry, various tuning parameters and fluid properties. The models are therefore time-consuming and difficult to configure in the field, where third-party experts may be needed at each well, to properly initiate the automation system and adjust it during the drilling process. Although the methods described in this paper are relevant to any critical drilling operation, they are applied to Managed Pressure Drilling (MPD) as a widely deployed example of drilling automation. In MPD, hydraulic models predict downhole conditions and determine the requisite choke pressure for automatic adjustment. A new method for automatic configuration of key model parameters simplifies the tedious job of setting up the model and ensures that the automation system remains tuned to the well, even without onsite model tuning expertise. The proposed scheme is based on a simple method for separating inaccuracies due to co-linearity in frictional pressure losses and static mud weight. The search for optimal correction factors is based on a sequence of small oscillations of pump rate that can be applied during drilling without interrupting the operation. A massively parallel computing architecture improves the speed of the calibration algorithm proportional to the number of available CPU cores. A set of hydraulic model instances runs in parallel, allowing for efficient testing of changes in input signals within ranges of uncertainty. A method for selecting a subset of the best models that more accurately represent a given well is proposed. Computer simulations demonstrate how the novel calibration scheme allows automatic tuning of the friction factor and density correction factor, giving accurate prediction of the bottom hole pressure (BHP). The tuning scheme is run with a parallel architecture to demonstrate that correct values of unknown configuration parameters can be automatically determined sufficiently fast for real-time drilling control or as an advisory tool. The deployment of automation systems in drilling is hampered by the need for dedicated expert personnel to maintain systems that could have reduced the personnel needed on the rig. The proposed automated physics-based model tuning contributes to removing this roadblock, aiming at making automation systems a more cost-efficient option for drilling operations. Copyright 2017, Society of Petroleum Engineers.
4 a9277159100 Hedengren J.D. p879 False Conference 395 The use of unmanned aerial vehicles and structures from motion to measure the volume change at a deep dynamic compaction site A small unmanned aerial vehicle (sUAV) is used with structure from motion (SfM) computer vision (Marr and Nishihara 1978; Snavely et al. 2008) to measure the amount of settlement that is induced by deep dynamic compaction at a site of a new casino near Lake Havasu City, AZ. Details of the project and field operations are provided, and comparisons are made between induced settlement measurements from traditional techniques and induced settlement measurements from the new sUAV/SfM approach. Results of the study show that the sUAV/SfM approach estimates an average induced settlement of 38 cm across the site, which straddles within 2.5 cm of the average induced settlements that were measured with other traditional techniques. Additionally, the sUAV/SfM technique is shown to provide significant detail of the distribution of induced settlements across the site. This distribution of settlements could be indicative of the distribution of subsurface soils that were more affected by the DDC such as looser or cleaner sands. Implications of the findings of this study are briefly discussed. © ASCE.
5 a6507358470 Boaventura-Cunha J. p1 False Conference 1 Bridging theory to practice: Feedforward and cascade control with tclab arduino kit Practice is of the essence in Engineering courses. A relevant question in control engineering education is: How to close the gap between theory and practice? Once subjects are introduced in theoretical classes, students want to know about its practical use. Thus, it is important to introduce theoretical control concepts with practical experiments, enabling students to easily test and validate the theory. An Arduino based temperature control laboratory (TCLab) is deployed in this study as a portable kit providing students with a simple and effective means to test some feedback control techniques. Teaching/learning experiments are proposed involving proportional, integral and derivative controllers with Feedforward and Cascade control structures. Preliminary results achieved in a Portuguese university are presented. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021.
6 a53879700900 Hajimirzaie S.M. p2 True Journal 0 Development of sediment management guidelines for small to medium reservoirs Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal. © 2020 American Society of Civil Engineers.
7 a26642910500 Hotchkiss R.H. p2 False Journal 0 Development of sediment management guidelines for small to medium reservoirs Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal. © 2020 American Society of Civil Engineers.
7 a26642910500 Hotchkiss R.H. p415 False Journal 225 Submerged hydraulic jump remediation at low-head dams: Partial width deflector design Low-head dams are capable of creating dangerous countercurrents just downstream from the structure. These dangerous countercurrents are known as submerged hydraulic jumps and are responsible for hundreds of fatalities at numerous low-head dams across the United States. The countercurrent creates high upstream-directed surface velocities across the width of the channel, making it nearly impossible for a trapped individual to escape. This submerged jump can occur for a range of upstream and downstream conditions. A multiple partial width deflector design for the downstream side of the dam was tested in the laboratory to determine effectiveness in completely or partially eliminating the submerged hydraulic jump. The results demonstrate that a dramatic reduction in upstream-directed surface velocities over a wide range of headwater and tailwater conditions is possible. The dam modification is relatively inexpensive, simple to install, and designed such that an individual will likely escape the submerged jump without severe injury or harm. The design is ready for prototype testing. © 2018 American Society of Civil Engineers.
7 a26642910500 Hotchkiss R.H. p477 False Journal 225 Comparison of calibrated empirical and semi-empirical methods for bedload transport rate prediction in gravel bed streams The performance of seven sediment transport equations for bedload transport is compared using almost 2,600 of more than 8,000 measurements from a recent compilation. Named equations tested include the Meyer-Peter Muller, Barry, Pagosa good condition, Wilcock, Parker (both calibrated and uncalibrated), Recking, and that of Elhakeem and Imran. The purpose of the tests was to evaluate the performance of several empirical and semiempirical formulae using a single calibration point relative to three uncalibrated equations. The seven equations were included because they either have a calibration procedure already developed, are used frequently in practice, are historically foundational in the field, or have recently been proposed. Results are expressed in the root mean square error of the logarithms (RMSEL) and the relative mean error (RME) and show that the Pagosa good and Barry equations best predict bedload sediment transport (RMSEL of 0.02 and 0.02, respectively). The Pagosa good equation requires a data point for bankfull discharge and the corresponding bedload transport. The uncalibrated Recking (2013) equation resulted in lower errors than two of the calibrated formulae (Wilcock 2001 and Parker 1990) and was not far behind the calibrated Elhakeem and Imran (2016) formula. The Meyer-Peter Muller and uncalibrated Parker (1990) equations performed the worst (RMSEL of up to 0.85 and 0.86, respectively). The results herein demonstrate: (1) empirical formulae were more successful at predicting bedload transport than semiempirical alternatives, (2) a single calibration point significantly improves the predictive accuracy of any formula, and (3) calibration cannot compensate for all the shortcomings of a model. © 2018 American Society of Civil Engineers.
7 a26642910500 Hotchkiss R.H. p559 True Conference 208 Sediment management in U.S. reservoirs: Challenges and progress [Gestion des sédiments dans les retenues américaines: Défis et progrès] Managing reservoir sediments in the United States is becoming increasingly important as many projects now exceed their so-called design life. Environmental regulations, enacted without knowing that someday deposited sediments would need to be moved downstream, make the permitting process difficult and time consuming. The U.S. Army Corps of Engineers and the U.S. Bureau of Reclamation, recognizing the growing need for sediment management, are completing a Reservoir Sediment Information database for all of their projects and are training their employees on how to permit sediment management operations at dams and reservoirs. The Subcommittee on Sedimentation, part of the Advisory Committee on Water Information, has published a progressive resolution encouraging federal agencies to develop sediment management plans for all of their projects by the year 2020. They are also in the process of publishing a white paper on the permitting aspects of reservoir sediment management. An ongoing sediment management project at Millsite Dam on Ferron Creek in Utah, although not passing significant volumes of sediment downstream, can serve as an example of meeting the complex permit requirements associated with such activities. © 2018 ICOLD/CIGB, Paris, France.
7 a26642910500 Hotchkiss R.H. p769 False Journal 376 Reservoir sustainability and sediment management Despite mounting demand for a more sustainable worldwide water supply system, available reservoir capacity is relentlessly diminishing due to sedimentation. Neither sustainable reservoir life spans nor intergenerational equity is achieved through conventional cost-benefit analyses (CBAs), which render all benefits and costs projected to occur more than several decades into a project as negligible. Consequently, future costs, including dam decommissioning or retrofitting with sediment management facilities, would be regarded as nonfactors in an analysis. CBAs have also historically failed to account for infrastructure and environmental impacts of sedimentation over time. Alternatives to the traditional application of the CBA do exist, however, such as dam owners instituting retirement funds or insurance policies, beneficiaries paying for rehabilitation or maintenance, and economists incorporating infrastructure damages and potentially logistic discount rates into their analyses. A brief case study of Gavins Point Dam shows that available information on damages due to a lack of sediment management account for 70% of the actual construction cost and would likely exceed construction costs if all damage information were available. By integrating these alternatives, economic analyses for reservoirs will be more accurate, reservoir life spans will be more sustainable, profits will be extended indefinitely, and the economic burdens placed on future generations will be lessened. © 2016 American Society of Civil Engineers.
7 a26642910500 Hotchkiss R.H. p783 False Journal 387 Comprehensive and quality-controlled bedload transport database The processes involved in bed-load sediment transport are complex and difficult to quantify. Field measurements provide insight and a chance to improve predictive methods. A comprehensive database is described that contains more than 15,000 observations from nearly 500 data sets of bed-load sediment transport. Observations are compiled from published sources, author responses to queries, and personal visits to offices. Each entry has been checked twice for accuracy against the original data and converted to a common set of units. The database contains sections for sample descriptions, discharge and transport data, channel and bankfull characteristics, surface and subsurface grain size distributions, and, where possible, stream classification descriptors. Discharges range from far below to several times bankfull values. The database is freely available to the public and may be accessed via direct download and through WaterML based web services from the BYU World Water Data Sediment Transport Database portal at http://worldwater.byu.edu/app/index.php/sediment. The intent of this database is to provide useful data to researchers as they continue to investigate bed-load transport processes. Data can be added to the database by contacting the authors. © 2016 American Society of Civil Engineers.
8 a57204031131 Bunnell S. p3 True Journal 1 Structural design space exploration using principal component analysis Design space exploration (DSE) is the process whereby a designer seeks to understand some results across a set of design variations. Structural DSE of turbomachinery compressor blades is often challenging because the large number of design variables make it difficult to learn the effect that each variable has upon the stress contours. Principal component analysis (PCA) of the stress contours is used as a way to understand how the stress contours change over the design space. Two methods are introduced to address the challenge of understanding how the stress changes over a large number of variables. First, a two-point correlation is applied to relate the design variables to the scores of each principal component. Second, a coupling of the stress and coordinate location of each node in PCA is developed which also indicates how the stress variations relate to geometric variations. These provide insight to how design variables influence the stress. It is shown how these methods use PCA as DSE tools to better explore the structural design space of compressor blades. Better DSE can improve compressor blades and the computational cost needed for their design. Copyright © 2020 by ASME
8 a57204031131 Bunnell S. p550 True Conference 200 Rapid visualization of compressor blade finite element models using surrogate modeling The design process for compressor blades is a highly iterative and often slow process. This research applied and measured the impact of using surrogates to quickly model the stresses on a compressor blade. By modeling distinct points on a finite element (FE) model with unique surrogates, the stress field of the entire FE model was quickly predicted. This required that the distinct points remain in the same relative location on each blade used in training the surrogate. This research studied the ability of mesh morphing, and using the surface nodes as those distinct points, to satisfy this requirement. The results show that mesh morphing performed well on the tested compressor blades. The research also found that the surrogate accuracy depended not only on the number of training samples, but also the number and types of parameters being emulated. The surrogate models achieved less than 5% error on all the tested blades. Finally, the method provided a 96% decrease in time required for a structural iteration of a compressor blade. Such speeds eliminate bottlenecks that may occur in the structural design process. The combination of mesh morphing and surrogate modeling in compressor blade analysis enables exploration of various geometric parameters and their effect on structural responses. Application of this process would produce a more thoroughly refined and understood compressor blade design. Copyright © 2018 by ASME.
9 a6602649851 Gorrell S. p3 False Journal 1 Structural design space exploration using principal component analysis Design space exploration (DSE) is the process whereby a designer seeks to understand some results across a set of design variations. Structural DSE of turbomachinery compressor blades is often challenging because the large number of design variables make it difficult to learn the effect that each variable has upon the stress contours. Principal component analysis (PCA) of the stress contours is used as a way to understand how the stress contours change over the design space. Two methods are introduced to address the challenge of understanding how the stress changes over a large number of variables. First, a two-point correlation is applied to relate the design variables to the scores of each principal component. Second, a coupling of the stress and coordinate location of each node in PCA is developed which also indicates how the stress variations relate to geometric variations. These provide insight to how design variables influence the stress. It is shown how these methods use PCA as DSE tools to better explore the structural design space of compressor blades. Better DSE can improve compressor blades and the computational cost needed for their design. Copyright © 2020 by ASME
9 a6602649851 Gorrell S. p93 False Conference 13 Analysis of distortion phase shift in a highly loaded fan stage Full annulus URANS simulations are presented to investigate distortion phase shift in a single stage transonic fan. The fan is subject to a 90°sector inlet total pressure distortion. Simulation results are presented for choke, design, and near-stall operating conditions. Circumferential profiles of swirl, total pressure, total temperature, power, and phase shift are analyzed at 10%, 30%, 50%, 70%, and 90% span. Phase shift is a measure of the rotational translation of a distortion profile and is valuable for understanding the translational motion of distortion as it passes through the fan. At choke and design operating conditions the phase shift is positive in the direction of rotor rotation. At near-stall the phase shift is negative opposite rotor rotation for the outer 30% span. Local power reaches a maximum value, resulting in the generation of a uniform pressure region. This region causes increased distortion content in the near-stall case over a wide circumferential extent resulting in a negative phase shift. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
9 a6602649851 Gorrell S. p137 False Journal 96 Contributions of Tip Leakage and Inlet Diffusion on Inducer Backflow Inducers are used as a first stage in pumps to minimize cavitation and allow the pump to operate at lower inlet head conditions. Inlet flow recirculation or backflow in the inducer occurs at low flow conditions and can lead to instabilities and cavitation-induced head breakdown. Backflow of an inducer with a tip clearance (TC) of τ = 0.32% and with no tip clearance (NTC) is examined with a series of computational fluid dynamics simulations. Removing the TC eliminates tip leakage flow; however, backflow is still observed. In fact, the NTC case showed a 37% increase in the length of the upstream backflow penetration. Tip leakage flow does instigate a smaller secondary leading edge tip vortex that is separate from the much larger backflow structure. A comprehensive analysis of these simulations suggests that blade inlet diffusion, not tip leakage flow, is the fundamental mechanism leading to the formation of backflow. © 2019 by ASME.
9 a6602649851 Gorrell S. p288 False Conference 71 Simulating stall inception in a high-performance fan using createt m-av kestrel The presented research uses a CFD code developed as part of the Computational Research and Engineering Acquisition Tools and Environment (CREATE), Kestrel, to evaluate a single stage compressor at various operating conditions. Time-accurate, full annulus simulations were carried out to capture and analyze the processes leading to stall inception for uniform inlet conditions. Unsteady interaction between tip clearance flow and the detached normal shock inside of the blade passages became more prevalent at flow rates close to stall, and this unsteadiness likely provides a way for leading edge spillage to occur and initiate the stall process. Although reversed flow at the trailing edge plane was not observed to be more prevalent in simulations near stall than in simulations away from stall, the phenomenon was shown to occur in blade passages that were approaching a stall cell. Understanding the physical processes that lead to stall inception allows fan designers to design more robust fans that can safely take advantage of the better performance associated with operating closer to stall. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
9 a6602649851 Gorrell S. p337 False Conference 113 Radial variation in distortion transfer and generation in a highly loaded fan stage from near-stall to choke Understanding distortion transfer and generation through fan and compressor blade rows is able to assist in blade design and performance prediction. Using full annulus URANS simulations, the effects of distortion as it passes through the rotor of a transonic fan at five radial locations (10%, 30%, 50%, 70%, and 90% span) are analyzed. The inlet distortion profile is a 90-degree sector with a 15% total pressure deficit. Fourier distortion descriptors are used in this study to quantitatively describe distortion transfer and generation. Results are presented and compared for three operating points (near-stall, design, and choke). These results are used to explain the relationship between inlet total pressure distortion, pressure-induced swirl, total pressure distortion transfer, total temperature distortion generation, and circumferential rotor power variation. It is shown that very large changes in pressure-induced swirl and distortion transfer and generation occur between near-stall and design, but only small changes are seen between design and choke. The greatest changes are shown to be near the tip. Local power variations are shown to correlate with total pressure distortion transfer and total temperature distortion generation. Copyright © 2019 ASME.
9 a6602649851 Gorrell S. p340 False Journal 96 Increasing Inducer Stability and Suction Performance With a Stability Control Device An inducer is used as the first stage of high suction performance pump. It pressurizes the fluid to delay the onset of cavitation, which can adversely affect performance in a centrifugal pump. In this paper, the performance of a water pump inducer has been explored with and without the implementation of a stability control device (SCD). This device is an inlet cover bleed system that removes high-energy fluid near the blade leading edge and reinjects it back upstream. The research was conducted by running multiphase, time-accurate computational fluid dynamic (CFD) simulations at the design flow coefficient and at low, off-design flow coefficients. The suction performance and stability for the same inducer with and without the implementation of the SCD has been explored. An improvement in stability and suction performance was observed when the SCD was implemented. Without the SCD, the inducer developed backflow at the blade tip, which led to rotating cavitation and larger rotordynamic forces. With the SCD, no significant cavitation instabilities developed, and the rotordynamic forces remained small. The lack of cavitation instabilities also allowed the inducer to operate at lower inlet pressures, increasing the suction performance of the inducer. Copyright © 2018 by ASME.
9 a6602649851 Gorrell S. p550 False Conference 200 Rapid visualization of compressor blade finite element models using surrogate modeling The design process for compressor blades is a highly iterative and often slow process. This research applied and measured the impact of using surrogates to quickly model the stresses on a compressor blade. By modeling distinct points on a finite element (FE) model with unique surrogates, the stress field of the entire FE model was quickly predicted. This required that the distinct points remain in the same relative location on each blade used in training the surrogate. This research studied the ability of mesh morphing, and using the surface nodes as those distinct points, to satisfy this requirement. The results show that mesh morphing performed well on the tested compressor blades. The research also found that the surrogate accuracy depended not only on the number of training samples, but also the number and types of parameters being emulated. The surrogate models achieved less than 5% error on all the tested blades. Finally, the method provided a 96% decrease in time required for a structural iteration of a compressor blade. Such speeds eliminate bottlenecks that may occur in the structural design process. The combination of mesh morphing and surrogate modeling in compressor blade analysis enables exploration of various geometric parameters and their effect on structural responses. Application of this process would produce a more thoroughly refined and understood compressor blade design. Copyright © 2018 by ASME.
9 a6602649851 Gorrell S. p555 False Conference 205 Mixing plane simulation of a high-performance fan using kestrel Kestrel is a tool developed by the Computational Research and Engineering Acquisition Tools and Environments-Air Vehicles (CREATE-AV) Program to expedite the acquisition process of fixed-wing aircraft. Kestrel’s capabilities include simulating internal flow, including within turbomachinery. Mixing plane methods are often used for modeling flow in gas turbine engine turbomachinery in order to evaluate multiple designs quickly. Because Kestrel’s mixing plane capabilities have been demonstrated in only limited cases, this research seeks to further validate the model using the Air Force Research Lab’s (AFRL) Rotor 4 fan. Extensive experimental data has been gathered for Rotor 4, allowing for in-depth comparisons to be made. Following the validation study, differences between the experimental results and the predictions from the mixing plane model are highlighted and discussed. These comparisons lead the authors to conclude that Kestrel’s mixing planes can be utilized to predict performance at various operating conditions and rotor speeds. This research serves to further Kestrel’s development and use by the Department of Defense (DoD) for aircraft acquisition. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
9 a6602649851 Gorrell S. p595 False Conference 238 Radial variation in distortion transfer and generation through a highly loaded fan stage An important consideration for fan and compressor design is quantifying distortion transfer and generation blade row by blade row. Detailed information about the magnitude of distortion and the shape of the distortion profile and how it changes through blade rows increases the understanding of flow physics and helps predict aerodynamic performance. Using full annulus URANS simulations, this paper analyzes what happens to distortion as it passes through the rotor and stator blade rows at 10%, 30%, 50%, 70%, and 90% span. Fourier distortion descriptors are used in this study to quantitatively describe distortion transfer and generation. With these descriptors, evidence of pressure-induced swirl is shown at the fan inlet. It is also shown that although there is very little distortion at the 10% span of the inlet, after passing through the rotor blade row the 10% span has the greatest amount of total pressure and total temperature distortion. This radial migration of distortion is attributed to the high hade angle of the hub. The total pressure and total temperature profiles have significant circumferential phase shifts after passing through the rotor and slight phase shifts after passing through the stator. In general, the calculated phase shifts are greatest at the 10% and 90% spans, the nearest locations to the hub and the tip clearance gap, respectively. Copyright © 2018 ASME.
9 a6602649851 Gorrell S. p597 False Conference 240 Analysis of distortion transfer and generation through a compressor using the harmonic balance approach Inlet flow distortion significantly affects an engine’s overall performance. It can be difficult to predict the transfer of distortion through a compressor because traditional experimental and computational methods are very expensive and time consuming. The Harmonic Balance approach is a promising alternative which uses Fourier techniques to represent fluid flow solutions. Relatively little work has been done to assess how much Fourier information is necessary to calculate a sufficiently accurate solution with the Harmonic Balance Solver. This study focuses on analyzing the effects of varying the amount of modal content that is used in Harmonic Balance simulations. Inlet distortion profiles with varying magnitudes are used in order to analyze trends and provide insight into the distortion flow physics for various inlet conditions. The geometry is a single stage axial compressor that consists of an inlet guide vane followed by the NASA Stage 37 rotor. It is shown that simulations with greater magnitudes of distortion require more modal content in order to achieve sufficiently accurate results. Harmonic Balance simulations are shown to have significantly lower computational costs than simulations with a conventional unsteady solver. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
9 a6602649851 Gorrell S. p605 False Journal 309 Collaboration task-technology fit for student distributed engineering design teams Engineers in industry are increasingly called on to work with teammates located in multiple geographic locations (virtual teams). Engineering education has an interest in helping students learn how to best collaborate in these types of situations. Four years of multi-university, multi-disciplinary engineering capstone projects are investigated and related literature is thoroughly examined to demonstrate which collaboration tools, at different stages of the product development process, meet the needs of virtual team members for communication tasks. Student engineering design teams with team members located at various locations should, during the early, middle, and late stages of the product development process, emphasize the use of collaboration tools that will best meet the needs of each stage. In the early stages, teams should emphasize rich communication mediums, such as in-person kick-off meetings. In the middle stages, tools which allow team members to perform their individual work while staying in-sync with their remotely located teammates, such as web conferencing and shared data editing tools, become important. In the late stages, as the team shifts from digital work to physical work, tools such as texting and in-person meetings become more necessary. © 2018 TEMPUS Publications.
9 a6602649851 Gorrell S. p617 False Journal 309 Profile-based team organization in multi-university capstone engineering design teams Engineers are increasingly required to work in teams that span time zones and cultures. Engineering education has begun to attempt to prepare students for this environment. An important topic is how to best form teams of students for distributed design projects. The goals of this research were to validate a method for organizing teams to maximize team performance and identify and validate metrics for individuals that would help in the organization of distributed teams of student engineers. A review of previous, related research is provided. A description of the proposed method of team organization is given, along with methods of data collection and a comparison of the proposed method to common methods. How students were divided into teams and each team's method of organizing sub-teams are described. Use of online surveys, tests, statistical methods, and other data gathering and analysis methods are explained. Statistical analysis of survey results and qualitative results of interviews and observations suggest that a profile-based method for organizing teams results in significantly higher team satisfaction. Some methods for measuring and/or predicting individual attributes related to teamwork, such as the significance of participation in team sports, were validated. No correlation was found between which university a student attended and a student's level of satisfaction with his or her team. Team success in distributed, multi-disciplinary student design teams can be improved by gathering information about team members and using a profile-based method to organize team members into sub-teams and leadership positions. © 2018 TEMPUS Publications.
9 a6602649851 Gorrell S. p700 False Journal 339 A multi-user computer-aided design competition: Experimental findings and analysis of team-member dynamics A competition for teams of three students using a prototype multi-user computer-aided design (MUCAD) tool was held to investigate various hypotheses regarding the performance of teams in such a setting. By comparing models from the competition to the same model in a single-user CAD environment, it is seen that use of a MUCAD system can significantly increase the value-added per unit of calendar time for a modeling effort. An investigation was also made into the causes of the performance differences among the various MUCAD teams which participated in the competition. Analysis of the results shows that teams that encouraged effective forms of communication and teams whose members scored similarly on the Purdue Spatial Visualization Test: Visualization of Rotations (PSVT:R) performed better than other teams. Areas of future research in analyzing teams in MUCAD environments are suggested. Copyright © 2017 by ASME.
9 a6602649851 Gorrell S. p790 False Conference 327 Predicting efficiency of a turbine driven by pulsing flow One of the challenges of integrating pressure gain combustion into a gas turbine engine is that a turbine driven by pulsing flow experiences a decrease in efficiency. Computational fluid dynamic simulations validated with experiments showed that pulse amplitude is the driving factor for decreased turbine efficiency and not the pulsing frequency. A quadratic correlation between turbine efficiency and corrected pulse amplitude is presented. Incidence variation is shown to cause the change in turbine efficiency and a correlation between corrected incidence and corrected amplitude is shown to predict turbine efficiency. Copyright © 2017 ASME.
9 a6602649851 Gorrell S. p833 False Conference 361 Fourier descriptors for improved analysis of distortion transfer and generation For fan/compressor design, quantifying distortion transfer and generation bladerow by bladerow through a fan/compressor is important to understand the flow physics and predict performance. What is needed are descriptors capable of describing distortion profiles with both high and low distortion content and account for the reshaping of distortion profiles. Four key parameters were identified as desirable to quantitatively capture distortion transfer, generation and effects on performance: distortion magnitude, shape, severity and phase. A set of distortion descriptors based on Fourier analysis are shown to quantitatively capture distortion magnitude, shape and phase change across bladerows. These Fourier descriptors are modal amplitude, total amplitude, and phase shift. When used together, these Fourier descriptors can be used to qualitatively describe any conceivable profile shape for any parameter. Copyright © 2017 ASME.
10 a56830076500 Salmon J. p3 False Journal 1 Structural design space exploration using principal component analysis Design space exploration (DSE) is the process whereby a designer seeks to understand some results across a set of design variations. Structural DSE of turbomachinery compressor blades is often challenging because the large number of design variables make it difficult to learn the effect that each variable has upon the stress contours. Principal component analysis (PCA) of the stress contours is used as a way to understand how the stress contours change over the design space. Two methods are introduced to address the challenge of understanding how the stress changes over a large number of variables. First, a two-point correlation is applied to relate the design variables to the scores of each principal component. Second, a coupling of the stress and coordinate location of each node in PCA is developed which also indicates how the stress variations relate to geometric variations. These provide insight to how design variables influence the stress. It is shown how these methods use PCA as DSE tools to better explore the structural design space of compressor blades. Better DSE can improve compressor blades and the computational cost needed for their design. Copyright © 2020 by ASME
10 a56830076500 Salmon J. p7 False Journal 5 The effects of transition style for collaborative view sharing in immersive Virtual Reality New low-cost Virtual Reality (VR) technology is enabling large numbers of engineers and designers to be outfitted with VR tools. This, in turn, is making feasible new tools such as immersive, collaborative, design environments that reflect the collaborative environment of drafting tables while still providing all the power of modern, computer-based, design tools. However, before such an environment can be fully realized, basic issues surrounding collaboration in VR such as cybersickness and disorientation must be more fully addressed. This work presents the results of an experimental study conducted to characterize the trade-offs between different styles of transitioning collaborators to a shared view in an immersive virtual environment. The experimental task consisted of asking participants to identify in which quadrant of the car specific components were located. Quadrant identification was performed after a participant's virtual location was transitioned to a shared view location focused on the component to identify. The study was conducted with 45 participants who provided 1890 transition response datapoints. Analysis of these results suggests that, in many cases, collaborators are willing to experience some mild cybersickness in order to reduce their disorientation and improve both confidence and accuracy of component location identification. The results also support the recommendation that the best practice is to provide support for multiple transition styles and allow collaborators to select their preference. © 2020 Elsevier Ltd
10 a56830076500 Salmon J. p102 False Journal 76 Analysis and evaluation of partitioning techniques for multi-user CAD Recent advances into multi-user computer-aided design environments have enabled designers and engineers to work simultaneously on the same model in different locations. This technology enables different individuals and companies across the globe to share 3D model data in more direct ways. However, intellectual property becomes a larger issue when sharing potentially sensitive data with others in real-time. Partitioning techniques are one strategy to mitigate this risk within multi-user CAD environments. This study explores and evaluates six different partitioning techniques across various metrics identified in the literature and performed a user study to assess the methods' capabilities to hide or suppress data from others. Best practices are suggested and survey data from the participants are analyzed. Overall, the Planar Decomposition technique was found to offer the best trade between protecting data, facilitating multi-user design, and encouraging users to focus only on the relevant information for a design activity. © 2020 CAD Solutions, LLC.
10 a56830076500 Salmon J. p110 True Journal 81 Single pursuer and two cooperative evaders in the border defense differential game An interest in border defense, surveillance, and interdiction has recently increased for a variety of reasons related to issues of illegal immigration, terrorism, drug and human trafficking, and other potential threats. Unmanned aerial vehicles (UAVs) offer an attractive alternative to supporting and defending various threats at borders. This paper applies a differential game to define a border defense scenario where one UAV (pursuer) seeks to capture two intruders (evaders) before they reach a designated border. The evaders can be UAVs, marine or ground vehicles, or human agents, but they have a lower maximum speed than the pursuer throughout the game. Simple motion is assumed for the pursuer and evaders with complete state information shared across all agents. The game is played within a rectangular area with a parallel top and bottom border of length L and left and right borders with a length of W, for a game aspect ratio of L∕W. The value of the game is the minimum distance to the bottom border achieved by the evaders at any time before capture of both evaders. Within the region where the pursuer wins, the game of degree is explored and the optimal policy for both the evaders and pursuer is derived using geometric properties. © 2020 by John Salmon. Published by the American Institute of Aeronautics and Astronautics, Inc.
10 a56830076500 Salmon J. p248 False Journal 163 Deconfliction in high-density unmanned aerial vehicle systems Small unmanned aerial vehicles play increasingly important roles in many industries and organizations in the United States and around the globe. As usage becomes more widespread, airspace will become increasingly crowded. These high-density unmanned aerial vehicle (UAV) situations will pose many unique challenges, including in conflict resolution. Using agent-based models, conflict resolution and the well-clear and action-distance concepts for small multirotor UAVs in dense environments were explored. Specifically, the safety and efficiency of several collision-avoidance mechanisms under different possible densities, accelerations, and action distances were investigated. The results suggest that selecting appropriate action distances and collision-avoidance mechanisms will be vital to maintaining safety and efficiency. Interestingly, excessive action distances quickly degrade performance: using a simple method under high-density conditions (1 UAV∕km2), well-clear distances above approximately 750 m have extremely low efficiency (∼1% as many deliveries accomplished in 5000 simulation hours compared to lower distances). More advanced algorithms also suffer from low efficiency at higher (∼1 km) response distances. Different definitions for near-midair collisions and their effects on system safety and well-clear distance are discussed. © 2018 by John Salmon. Published by the American Institute of Aeronautics and Astronautics, Inc.,.
10 a56830076500 Salmon J. p291 False Conference 73 Identifying mode shapes of turbo-machinery blades using principal component analysis and support vector machines Manually identifying mode shapes generated from finite element solvers images is an expensive task. This paper proposes an automated process to identify mode shapes from gray-scale images of compressor blades within a jetengine. This work introduces mode shape identification using principal component analysis (PCA), similar to approaches in facial and other recognition tasks in computer vision. This technique calculates the projected values of potentially linearly correlated values onto P-linearly orthogonal axes, where P is the number of principal axes that define a subset space. Classification was done using support vector machines (SVM). Using the PCA and SVM algorithm, approximately 5300 training images representative of 16 different modes were used to create a classifier. The classifier achieved on average 98% accuracy when tested using a test set of approximately 2000 images given P D 70. The results suggest that using digital images to perform mode shape identification can be achieved with high accuracy. Potential generalization of this method could be applied to other engineering design and analysis applications. © The Society for Experimental Mechanics, Inc. 2019.
10 a56830076500 Salmon J. p328 False Journal 190 A neutral XML design framework for generating parametric parts in multiple CAD systems Engineering companies often require designers to work with and operate between different CAD systems. This motivates the necessity of having a neutral design standard for CAD models to facilitate generation, customization, and parameterization across multiple systems. Current standards often fail to incorporate file history, design intent, and are designed to be an intermediary format for translation. This research proposes a simplified, neutral design format based on XML that can be used to generate models in different CAD systems and versions. The format utilizes advanced features such as finding tools to address issues that arise due to directionality and selection without a user interface. To test the feasibility of the neutral format, scripts were made that generated a quadcopter and an airplane wing rib. Comparisons between the generated models in both NX and CATIA are performed to evaluate the accuracy, flexibility, and similarity of the results of the generated neutral XML design framework. © 2019 CAD Solutions, LLC.
10 a56830076500 Salmon J. p360 False Journal 190 A CAD assembly simplification approach with ray casting We present novel methods for the removal of interior bodies from complex assemblies using ray casting. These methods locate and preserve bodies that represent the high-fidelity exterior surface of an assembly while removing all interior bodies that do not contribute to the exterior assembly surface. In so doing we create parts that can accurately be used for assembly packaging and other tasks without sufiering from the ineficiencies that come from working with the full assembly. We further present an analysis of the process on assemblies of known properties and several use cases with simplification results. Finally, we present directions for future research that could enhance this work. © 2019 CAD Solutions, LLC.
10 a56830076500 Salmon J. p420 False Journal 230 Exploration and evaluation of CAD modeling in virtual reality Virtual reality (VR) technology has experienced a recent surge in popularity over the past few years and is finding more applications beyond entertainment. Three dimensional modeling is an application in which integration with VR technology is still in the development stage. The focus of this research is to evaluate the feasibility for computer-aided design in VR and to identify the best set of features for virtual reality modeling and practices in this new domain. A platform for testing CAD in VR is developed through the integration of CAD software with a game engine and compared against traditional CAD methods through testing. Modeling capabilities included previews, creating solid rectangular prisms and spheres, lock to grid, and cuts of similar shapes. User testing with four different models (i.e. chair, maze, truck, sculpture) and survey responses suggest respectively that design in virtual reality promoted greater creativity in modeling, allowed for a greater feature creation rate, and that a slight majority of test participants preferred modeling in VR compared to traditional CAD applications. © 2018, © 2018 CAD Solutions, LLC.
10 a56830076500 Salmon J. p508 False Conference 188 Systems analysis of EV adoption and criteria pollutant accumulation during inversion events Exploring the system-level interactions between vehicle exhaust criteria pollutants, human health, and natural weather patterns such as inversion events is increasingly expedient given the accelerated growth and concentration of human populations in recent years. Pollutants often accumulate to unhealthy concentrations during winter inversion events like those that commonly occur in the state of Utah and other mountainous regions. Electric vehicles (EV) are a potential solution to reduce harmful tail-pipe emissions that accumulate during inversions. This work represents a systems-level analysis of the degree to which replacing internal combustion engine vehicles (ICE) with EVs would reduce the near-road accumulation of criteria pollutants. The analysis draws on vehicle miles travelled data from major highways in Utah, vehicle fuel efficiency data, EPA-specified vehicle pollution emission standards, and local weather pattern trends. It employs two models, built in MATLAB and the agent-based modeling environment NetLogo, to determine pollutant concentrations, accumulation, and dispersion rates. These results are processed to determine changes in the Air Quality Index (AQI) caused by adjusting the percentage of EVs present within the vehicle population. The analysis concludes that replacing a significant percentage (80-100%) of the existing, fossil-fuel powered vehicle population with EVs would improve local AQI by 13 points. During extreme inversion events in Utah, these reductions would delay AQI levels from reaching 'red,' or unhealthy, status for enough time to allow local weather patterns to shift and dissipate the inversion event and accompanying pollution. Such a drastic reduction in AQI translates into better adolescent and elderly health and could minimize the risk of early onset asthma and other respiratory illnesses in regions negatively affected by high traffic pollution and winter inversion events. © 2018 IEEE.
10 a56830076500 Salmon J. p513 False Journal 282 A bi-directional interface for improved interaction with engineering models in virtual reality design reviews Leveraging virtual reality (VR) technology to enhance engineering design reviews has been an area of significant interest for researchers since the advent of modern VR. The ability to interact meaningfully with 3D computer-aided engineering models in these VR design reviews is an important, though often neglected, capability due to the difficulty of performing data translation between native computer-aided design (CAD) data and VR compatible file formats. A bi-directional interface was developed between a VR design review environment and a commercial CAD package that streamlines the data translation process. Transmitting both geometric data and selected metadata from the CAD system enabled the development of enhanced model interaction tools in a VR design review application. User experiments were performed that compared the enhanced tools developed to a baseline toolset. Participants success using these toolsets was measured as they performed tasks related to design understanding and decision making, such as counting the number of gears in a gearbox or evaluating the feasibility of a proposed design change in a four-cylinder engine. The analysis of the data from these experiments showed a statistically significant improvement in participants ability to understand the geometry of the model correctly, confidently, and quickly, as well as in participants ability to correctly and confidently understand the implications of a proposed design change when using the Enhanced Toolset. We conclude that the bi-directional interface concept developed in this work can be extended to enable advanced interaction with a diversity of engineering data in VR. © 2017, Springer-Verlag France.
10 a56830076500 Salmon J. p521 False Journal 274 Effectiveness of an Immersive Virtual Environment for Collaboration with Gesture Support Using Low-Cost Hardware Since the advent of modern computer-aided design software, engineers have been divorced from the highly collaborative environment previously enjoyed. Today's highly complex designs require modern software tools and the realities of a global economy often constrain engineers to remote collaboration. These conditions make it highly impractical to collaborate locally around physical models. Various approaches to creating new collaboration tools and software, which alleviate these issues, have been tried previously. However, past solutions either used expensive hardware, which is not widely available, or used standard two-dimensional (2D) monitors to share three-dimensional (3D) information. Recently, new low-cost virtual reality (VR) hardware has been introduced, which creates a highly immersive 3D experience at a tiny fraction of the cost of previous hardware. This work demonstrates an immersive collaborative environment built using a network of this hardware, which allows users to interact with gestures virtually and conducts a study to show its advantages over traditional video conferencing software. Copyright ©2018 by ASME.
10 a56830076500 Salmon J. p545 False Journal 230 A comparative analysis of computer-aided design team performance with collaboration software For the past several years, the BYU CAD Lab has been developing collaborative computer-aided design (CAD) software. As this software is being developed, industry seeks to better understand the differences in performance between teams using multi-user CAD and single-user CAD to make informed decisions about implementing this new software into their engineering processes. In order to better understand the differences in performance between teams, an experimental study was conducted in which four multi-user teams and four single-user teams competed to create the best model of a hand drill. Key findings of this study were that multi-user CAD increases awareness of teammates’ activities as well as communication between team members. Performance, with respect to the metrics of quality and time for completion, could be improved with increased familiarity with the multi-user CAD software. Future research directions are suggested and discussed. © 2018 CAD Solutions, LLC.
10 a56830076500 Salmon J. p548 False Journal 230 Hybrid state transactional database for product lifecycle management features in a multi-engineer synchronous heterogeneous CAD environment As interoperability between Computer Aided Design (CAD) systems becomes a possibility, a need arises for a way for the Neutral Parametric Canonical Form (NPCF), as designed at the BYU Site of the NSF Center for e-Design, to be integrated with Product Lifecycle Management (PLM). The only method currently available to users to sync with a PLM system at this time would be to choose one CAD system and create files based off of the NPCF data then save those part files in the PLM system. This database expansion to the NPCF allows the NPCF to hold the entire part history as well as enable future work revision history and configuration management. Enforcing referential integrity within the database allows for part data to never get corrupted and the NPCF allows any CAD system with the appropriate plug-ins to read the uncorrupted data. © 2017 CAD Solutions, LLC.
10 a56830076500 Salmon J. p550 False Conference 200 Rapid visualization of compressor blade finite element models using surrogate modeling The design process for compressor blades is a highly iterative and often slow process. This research applied and measured the impact of using surrogates to quickly model the stresses on a compressor blade. By modeling distinct points on a finite element (FE) model with unique surrogates, the stress field of the entire FE model was quickly predicted. This required that the distinct points remain in the same relative location on each blade used in training the surrogate. This research studied the ability of mesh morphing, and using the surface nodes as those distinct points, to satisfy this requirement. The results show that mesh morphing performed well on the tested compressor blades. The research also found that the surrogate accuracy depended not only on the number of training samples, but also the number and types of parameters being emulated. The surrogate models achieved less than 5% error on all the tested blades. Finally, the method provided a 96% decrease in time required for a structural iteration of a compressor blade. Such speeds eliminate bottlenecks that may occur in the structural design process. The combination of mesh morphing and surrogate modeling in compressor blade analysis enables exploration of various geometric parameters and their effect on structural responses. Application of this process would produce a more thoroughly refined and understood compressor blade design. Copyright © 2018 by ASME.
10 a56830076500 Salmon J. p569 False Conference 217 Exploration of three dimensional, hierarchical, large scale UAV system interactions Unmanned aerial vehicles (UAVs) have the potential to revolutionize airspaces across the world. As they increase in prevalence, how UAVs interact with each other and their environments will become increasingly important. The UAV air traffic control system will play an important role in keeping UAV-human interactions safe, effective, and efficient. The large number of automated agents, and the complex interactions between them, make this air traffic control system unusually complex. In this paper, the authors consider how the vertical distribution of UAVs affects an air traffic control system’s safety and efficiency. Several possible frameworks are examined, including a free-flight system in which UAVs are allowed to distribute themselves within the entire airspace; a stratified system where different layers are used for travel in different directions, and a compromise system where layers are specified, but vertical course deviation for conflict avoidance is permitted. Investigations are made into how prioritizing some UAVs over others in a hierarchy (for instance, giving emergency services UAVs a separate layer, independent of recreational or commercial users) could affect this system. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
10 a56830076500 Salmon J. p582 False Conference 227 Automating the design of thick-origami mechanisms Applying an origami pattern to thick, non-paper-like materials is a challenging task. Though many techniques have been developed to accommodate thickness in origami, creating 3D models of such thick-origami mechanisms is complex. The time and knowledge required to manually model an origami mechanism can impede the exploration of the design space and creation of robust designs. This work presents data structures based on origami that can be used in the automation of thick-origami mechanism design. These structures are described and an example computer program that implements them is investigated. The program automatically generates all the necessary 3D CAD part models and an assembly model for a user-specified origami crease pattern. Models resulting from the program for several crease patterns are demonstrated with a discussion of the advantages and limitations of the system. With further development of the data structures and program, this framework has the potential to help mitigate some of the barriers to more widespread use of origami-based design. Copyright © 2018 ASME
10 a56830076500 Salmon J. p696 False Journal 339 A Review of the Capabilities of Current Low-Cost Virtual Reality Technology and Its Potential to Enhance the Design Process In the past few years, there have been some significant advances in consumer virtual reality (VR) devices. Devices such as the Oculus Rift, HTC Vive, Leap Motion™ Controller, and Microsoft Kinect® are bringing immersive VR experiences into the homes of consumers with much lower cost and space requirements than previous generations of VR hardware. These new devices are also lowering the barrier to entry for VR engineering applications. Past research has suggested that there are significant opportunities for using VR during design tasks to improve results and reduce development time. This work reviews the latest generation of VR hardware and reviews research studying VR in the design process. Additionally, this work extracts the major themes from the reviews and discusses how the latest technology and research may affect the engineering design process. We conclude that these new devices have the potential to significantly improve portions of the design process. Copyright © 2017 by ASME.
10 a56830076500 Salmon J. p700 False Journal 339 A multi-user computer-aided design competition: Experimental findings and analysis of team-member dynamics A competition for teams of three students using a prototype multi-user computer-aided design (MUCAD) tool was held to investigate various hypotheses regarding the performance of teams in such a setting. By comparing models from the competition to the same model in a single-user CAD environment, it is seen that use of a MUCAD system can significantly increase the value-added per unit of calendar time for a modeling effort. An investigation was also made into the causes of the performance differences among the various MUCAD teams which participated in the competition. Analysis of the results shows that teams that encouraged effective forms of communication and teams whose members scored similarly on the Purdue Spatial Visualization Test: Visualization of Rotations (PSVT:R) performed better than other teams. Areas of future research in analyzing teams in MUCAD environments are suggested. Copyright © 2017 by ASME.
10 a56830076500 Salmon J. p715 False Journal 352 Methods for determining the optimal number of simultaneous contributors for multi-user CAD parts The development of multi-user CAD (MUCAD) tools has opened up exciting new opportunities and applications. The capability for multiple users to simultaneously model and design a CAD part has far-reaching potential. However, many basic questions remains unanswered, such as how many users should work together on a given part. This research proposes and develops a set of methods to determine the optimal number of users for a given part within a MUCAD environment, based on the characteristics of the part itself. Two candidate models are evaluated with a set of 60 experiments with design teams composed of different numbers of users. The models show modest correlations with the test data while more-refined models are explored to improve predictive power. On the other hand, highly significant correlations between the ability to predict completion time and multi-user team size were identified in the experimental data. Observations regarding the speed and quality of MUCAD teams are also made with future areas of research suggested. © 2017 CAD Solutions, LLC.
10 a56830076500 Salmon J. p723 False Journal 353 A Systems Engineering Approach to Harnessing Human Energy in Public Places: A Feasibility Study This study analyzes the feasibility of placing modified exercise equipment in public places to enable human energy harnessing. By assessing the impacts as a system-level synthesis of economic, environmental, productivity, and health benefits, it is shown that introducing human-powered equipment (HPE) in public places would be feasible and beneficial both to society in general and to the specific stakeholders investing in this technology. This study develops a framework to evaluate applications of this technology using benefits to costs analyses. The benefits and challenges for successful implementation of HPE technology are also presented and evaluated in various case studies involving public places at airports and schools. Copyright © 2017 by ASME.
10 a56830076500 Salmon J. p741 False Journal 352 Associative CAD references in the neutral parametric canonical form Due to the multiplicity of computer-aided engineering applications used in industry, interoperability between programs has become increasingly important. A 1999 study by the National Institute for Standards and Technology (NIST) estimated that inadequate interoperability between the original engineering manufacturers (OEM) and their suppliers cost the US automotive industry over $1 billion per year, with the majority spent fixing data after translations. The Neutral Parametric Canonical Form (NPCF) prototype standard developed by the BYU Site of the NSF Center for e-Design offers a solution to this problem by enabling real-time collaboration between heterogeneous systems while preserving design intent. The NPCF is implemented within a SQL database and defines the schema both for neutral features and for the parameters defining the inter-feature relationships and associations. © 2016 CAD Solutions, LLC.
10 a56830076500 Salmon J. p747 False Conference 320 Simulation and exploration of high-density unmanned aerial vehicle systems Systems of unmanned aerial vehicles (UAVs), such as the Amazon Air delivery system, will play a large part in future aerospace development. The design and implementation of these systems will be economically, transportationally, and environmentally important. In this paper, we use agent-based models to analyze the emergent behavior of several types of UAV systems with varying parameters and environments. We find that while increasing the number of UAVs initially has a more-than-linear effect on the reported separation incidents, this effect quickly levels off due to carrying capacity limitations. We also find that while different behaviors (objectives and movement patterns) of UAVs affects the locations of the separation incidents, the number of separation incidents is not strongly influenced by these changes. We then explore the implementation of separation-assurance mechanisms using varying levels of information, and examine effects on the emergent behavior. © 2017 IEEE.
11 a57204029674 Thelin C. p3 False Journal 1 Structural design space exploration using principal component analysis Design space exploration (DSE) is the process whereby a designer seeks to understand some results across a set of design variations. Structural DSE of turbomachinery compressor blades is often challenging because the large number of design variables make it difficult to learn the effect that each variable has upon the stress contours. Principal component analysis (PCA) of the stress contours is used as a way to understand how the stress contours change over the design space. Two methods are introduced to address the challenge of understanding how the stress changes over a large number of variables. First, a two-point correlation is applied to relate the design variables to the scores of each principal component. Second, a coupling of the stress and coordinate location of each node in PCA is developed which also indicates how the stress variations relate to geometric variations. These provide insight to how design variables influence the stress. It is shown how these methods use PCA as DSE tools to better explore the structural design space of compressor blades. Better DSE can improve compressor blades and the computational cost needed for their design. Copyright © 2020 by ASME
11 a57204029674 Thelin C. p550 False Conference 200 Rapid visualization of compressor blade finite element models using surrogate modeling The design process for compressor blades is a highly iterative and often slow process. This research applied and measured the impact of using surrogates to quickly model the stresses on a compressor blade. By modeling distinct points on a finite element (FE) model with unique surrogates, the stress field of the entire FE model was quickly predicted. This required that the distinct points remain in the same relative location on each blade used in training the surrogate. This research studied the ability of mesh morphing, and using the surface nodes as those distinct points, to satisfy this requirement. The results show that mesh morphing performed well on the tested compressor blades. The research also found that the surrogate accuracy depended not only on the number of training samples, but also the number and types of parameters being emulated. The surrogate models achieved less than 5% error on all the tested blades. Finally, the method provided a 96% decrease in time required for a structural iteration of a compressor blade. Such speeds eliminate bottlenecks that may occur in the structural design process. The combination of mesh morphing and surrogate modeling in compressor blade analysis enables exploration of various geometric parameters and their effect on structural responses. Application of this process would produce a more thoroughly refined and understood compressor blade design. Copyright © 2018 by ASME.
12 a57204032253 Ruoti C. p3 False Journal 1 Structural design space exploration using principal component analysis Design space exploration (DSE) is the process whereby a designer seeks to understand some results across a set of design variations. Structural DSE of turbomachinery compressor blades is often challenging because the large number of design variables make it difficult to learn the effect that each variable has upon the stress contours. Principal component analysis (PCA) of the stress contours is used as a way to understand how the stress contours change over the design space. Two methods are introduced to address the challenge of understanding how the stress changes over a large number of variables. First, a two-point correlation is applied to relate the design variables to the scores of each principal component. Second, a coupling of the stress and coordinate location of each node in PCA is developed which also indicates how the stress variations relate to geometric variations. These provide insight to how design variables influence the stress. It is shown how these methods use PCA as DSE tools to better explore the structural design space of compressor blades. Better DSE can improve compressor blades and the computational cost needed for their design. Copyright © 2020 by ASME
12 a57204032253 Ruoti C. p550 False Conference 200 Rapid visualization of compressor blade finite element models using surrogate modeling The design process for compressor blades is a highly iterative and often slow process. This research applied and measured the impact of using surrogates to quickly model the stresses on a compressor blade. By modeling distinct points on a finite element (FE) model with unique surrogates, the stress field of the entire FE model was quickly predicted. This required that the distinct points remain in the same relative location on each blade used in training the surrogate. This research studied the ability of mesh morphing, and using the surface nodes as those distinct points, to satisfy this requirement. The results show that mesh morphing performed well on the tested compressor blades. The research also found that the surrogate accuracy depended not only on the number of training samples, but also the number and types of parameters being emulated. The surrogate models achieved less than 5% error on all the tested blades. Finally, the method provided a 96% decrease in time required for a structural iteration of a compressor blade. Such speeds eliminate bottlenecks that may occur in the structural design process. The combination of mesh morphing and surrogate modeling in compressor blade analysis enables exploration of various geometric parameters and their effect on structural responses. Application of this process would produce a more thoroughly refined and understood compressor blade design. Copyright © 2018 by ASME.
13 a57217149830 Richardson M. p4 True Journal 2 Religion-focused dating apps: A Q methodology study on the uses of mutual Dating apps have become an increasingly viable option for individuals seeking interpersonal romantic relationships. While there is significant research regarding user motivation on dating apps such as Bumble, Tinder, and Match.com, there is no published research that discusses the motivations of Mutual app users. Developed as a dating app to target members of The Church of Jesus Christ of Latter-Day Saints, Mutual allows users to find potential mates who share their religious background and specify their relationship readiness (from “Into Dating I Guess” to “Ready for a Ring”). This research aims to illuminate the various motivations, attitudes, and opinions of Mutual app users through Q methodology, which identifies perceptual groups among homogeneous populations through a factor analysis of participants’ agreement with similar statements regarding Mutual use. Findings indicated four factor groups: the Relationship Readies (i.e., those serious about dating), the Swipeaholics (i.e., those looking for entertainment), the Faithless (i.e., those who felt pressured to use Mutual), and the Eligible Optimists (i.e., those who saw the app as a convenient, entertaining way to date). Different from other research on dating apps, this study indicates that people may use a niche religion-focused dating app to find individuals with similar moral values or due to external pressure from others. Results warrant further investigation into niche dating apps. © 2020 Elsevier Ltd
14 a57217149403 Cannon S. p4 False Journal 2 Religion-focused dating apps: A Q methodology study on the uses of mutual Dating apps have become an increasingly viable option for individuals seeking interpersonal romantic relationships. While there is significant research regarding user motivation on dating apps such as Bumble, Tinder, and Match.com, there is no published research that discusses the motivations of Mutual app users. Developed as a dating app to target members of The Church of Jesus Christ of Latter-Day Saints, Mutual allows users to find potential mates who share their religious background and specify their relationship readiness (from “Into Dating I Guess” to “Ready for a Ring”). This research aims to illuminate the various motivations, attitudes, and opinions of Mutual app users through Q methodology, which identifies perceptual groups among homogeneous populations through a factor analysis of participants’ agreement with similar statements regarding Mutual use. Findings indicated four factor groups: the Relationship Readies (i.e., those serious about dating), the Swipeaholics (i.e., those looking for entertainment), the Faithless (i.e., those who felt pressured to use Mutual), and the Eligible Optimists (i.e., those who saw the app as a convenient, entertaining way to date). Different from other research on dating apps, this study indicates that people may use a niche religion-focused dating app to find individuals with similar moral values or due to external pressure from others. Results warrant further investigation into niche dating apps. © 2020 Elsevier Ltd
15 a57217145377 Teichert L. p4 False Journal 2 Religion-focused dating apps: A Q methodology study on the uses of mutual Dating apps have become an increasingly viable option for individuals seeking interpersonal romantic relationships. While there is significant research regarding user motivation on dating apps such as Bumble, Tinder, and Match.com, there is no published research that discusses the motivations of Mutual app users. Developed as a dating app to target members of The Church of Jesus Christ of Latter-Day Saints, Mutual allows users to find potential mates who share their religious background and specify their relationship readiness (from “Into Dating I Guess” to “Ready for a Ring”). This research aims to illuminate the various motivations, attitudes, and opinions of Mutual app users through Q methodology, which identifies perceptual groups among homogeneous populations through a factor analysis of participants’ agreement with similar statements regarding Mutual use. Findings indicated four factor groups: the Relationship Readies (i.e., those serious about dating), the Swipeaholics (i.e., those looking for entertainment), the Faithless (i.e., those who felt pressured to use Mutual), and the Eligible Optimists (i.e., those who saw the app as a convenient, entertaining way to date). Different from other research on dating apps, this study indicates that people may use a niche religion-focused dating app to find individuals with similar moral values or due to external pressure from others. Results warrant further investigation into niche dating apps. © 2020 Elsevier Ltd
16 a57217146534 Vance A. p4 False Journal 2 Religion-focused dating apps: A Q methodology study on the uses of mutual Dating apps have become an increasingly viable option for individuals seeking interpersonal romantic relationships. While there is significant research regarding user motivation on dating apps such as Bumble, Tinder, and Match.com, there is no published research that discusses the motivations of Mutual app users. Developed as a dating app to target members of The Church of Jesus Christ of Latter-Day Saints, Mutual allows users to find potential mates who share their religious background and specify their relationship readiness (from “Into Dating I Guess” to “Ready for a Ring”). This research aims to illuminate the various motivations, attitudes, and opinions of Mutual app users through Q methodology, which identifies perceptual groups among homogeneous populations through a factor analysis of participants’ agreement with similar statements regarding Mutual use. Findings indicated four factor groups: the Relationship Readies (i.e., those serious about dating), the Swipeaholics (i.e., those looking for entertainment), the Faithless (i.e., those who felt pressured to use Mutual), and the Eligible Optimists (i.e., those who saw the app as a convenient, entertaining way to date). Different from other research on dating apps, this study indicates that people may use a niche religion-focused dating app to find individuals with similar moral values or due to external pressure from others. Results warrant further investigation into niche dating apps. © 2020 Elsevier Ltd
17 a57217147399 Kramer I. p4 False Journal 2 Religion-focused dating apps: A Q methodology study on the uses of mutual Dating apps have become an increasingly viable option for individuals seeking interpersonal romantic relationships. While there is significant research regarding user motivation on dating apps such as Bumble, Tinder, and Match.com, there is no published research that discusses the motivations of Mutual app users. Developed as a dating app to target members of The Church of Jesus Christ of Latter-Day Saints, Mutual allows users to find potential mates who share their religious background and specify their relationship readiness (from “Into Dating I Guess” to “Ready for a Ring”). This research aims to illuminate the various motivations, attitudes, and opinions of Mutual app users through Q methodology, which identifies perceptual groups among homogeneous populations through a factor analysis of participants’ agreement with similar statements regarding Mutual use. Findings indicated four factor groups: the Relationship Readies (i.e., those serious about dating), the Swipeaholics (i.e., those looking for entertainment), the Faithless (i.e., those who felt pressured to use Mutual), and the Eligible Optimists (i.e., those who saw the app as a convenient, entertaining way to date). Different from other research on dating apps, this study indicates that people may use a niche religion-focused dating app to find individuals with similar moral values or due to external pressure from others. Results warrant further investigation into niche dating apps. © 2020 Elsevier Ltd
18 a57217147006 Barter M. p4 False Journal 2 Religion-focused dating apps: A Q methodology study on the uses of mutual Dating apps have become an increasingly viable option for individuals seeking interpersonal romantic relationships. While there is significant research regarding user motivation on dating apps such as Bumble, Tinder, and Match.com, there is no published research that discusses the motivations of Mutual app users. Developed as a dating app to target members of The Church of Jesus Christ of Latter-Day Saints, Mutual allows users to find potential mates who share their religious background and specify their relationship readiness (from “Into Dating I Guess” to “Ready for a Ring”). This research aims to illuminate the various motivations, attitudes, and opinions of Mutual app users through Q methodology, which identifies perceptual groups among homogeneous populations through a factor analysis of participants’ agreement with similar statements regarding Mutual use. Findings indicated four factor groups: the Relationship Readies (i.e., those serious about dating), the Swipeaholics (i.e., those looking for entertainment), the Faithless (i.e., those who felt pressured to use Mutual), and the Eligible Optimists (i.e., those who saw the app as a convenient, entertaining way to date). Different from other research on dating apps, this study indicates that people may use a niche religion-focused dating app to find individuals with similar moral values or due to external pressure from others. Results warrant further investigation into niche dating apps. © 2020 Elsevier Ltd
19 a57210571665 King J. p4 False Journal 2 Religion-focused dating apps: A Q methodology study on the uses of mutual Dating apps have become an increasingly viable option for individuals seeking interpersonal romantic relationships. While there is significant research regarding user motivation on dating apps such as Bumble, Tinder, and Match.com, there is no published research that discusses the motivations of Mutual app users. Developed as a dating app to target members of The Church of Jesus Christ of Latter-Day Saints, Mutual allows users to find potential mates who share their religious background and specify their relationship readiness (from “Into Dating I Guess” to “Ready for a Ring”). This research aims to illuminate the various motivations, attitudes, and opinions of Mutual app users through Q methodology, which identifies perceptual groups among homogeneous populations through a factor analysis of participants’ agreement with similar statements regarding Mutual use. Findings indicated four factor groups: the Relationship Readies (i.e., those serious about dating), the Swipeaholics (i.e., those looking for entertainment), the Faithless (i.e., those who felt pressured to use Mutual), and the Eligible Optimists (i.e., those who saw the app as a convenient, entertaining way to date). Different from other research on dating apps, this study indicates that people may use a niche religion-focused dating app to find individuals with similar moral values or due to external pressure from others. Results warrant further investigation into niche dating apps. © 2020 Elsevier Ltd
20 a55611356500 Callahan C. p4 False Journal 2 Religion-focused dating apps: A Q methodology study on the uses of mutual Dating apps have become an increasingly viable option for individuals seeking interpersonal romantic relationships. While there is significant research regarding user motivation on dating apps such as Bumble, Tinder, and Match.com, there is no published research that discusses the motivations of Mutual app users. Developed as a dating app to target members of The Church of Jesus Christ of Latter-Day Saints, Mutual allows users to find potential mates who share their religious background and specify their relationship readiness (from “Into Dating I Guess” to “Ready for a Ring”). This research aims to illuminate the various motivations, attitudes, and opinions of Mutual app users through Q methodology, which identifies perceptual groups among homogeneous populations through a factor analysis of participants’ agreement with similar statements regarding Mutual use. Findings indicated four factor groups: the Relationship Readies (i.e., those serious about dating), the Swipeaholics (i.e., those looking for entertainment), the Faithless (i.e., those who felt pressured to use Mutual), and the Eligible Optimists (i.e., those who saw the app as a convenient, entertaining way to date). Different from other research on dating apps, this study indicates that people may use a niche religion-focused dating app to find individuals with similar moral values or due to external pressure from others. Results warrant further investigation into niche dating apps. © 2020 Elsevier Ltd
21 a57218886193 Stanković A.M. p5 True Journal 3 Interleaving physics- and data-driven models for power system transient dynamics The paper explores interleaved and coordinated refinement of physics- and data-driven models in describing transient phenomena in large-scale power systems. We develop and study an integrated analytical and computational data-driven gray box environment needed to achieve this aim. Main ingredients include computational differential geometry-based model reduction, optimization-based compressed sensing, and a finite approximation of the Koopman operator. The proposed two-step procedure (the model reduction by differential geometric (information geometry) tools, and data refinement by the compressed sensing and Koopman theory based dynamics prediction) is illustrated on the multi-machine benchmark example of IEEE 14-bus system with renewable sources, where the results are shown for doubly-fed induction generator (DFIG) with local measurements in the connection point. The algorithm is directly applicable to identification of other dynamic components (for example, dynamic loads). © 2020 Elsevier B.V.
21 a57218886193 Stanković A.M. p8 False Journal 6 Probabilistic extension of flexible hybrid state estimation for cyber-physical systems This paper proposes a probabilistic extension to flexible hybrid state estimation (FHSE) for cyber-physical systems (CPSs). The main goal of the algorithm is improvement of the system state tracking when realistic communications are taken into account, by optimizing information and communication technology (ICT) usage. These advancements result in: 1) coping with ICT outages and inevitable irregularities (delay, packet drop and bad measurements); 2) determining the optimized state estimation execution frequencies based on expected measurement refresh times. Additionally, information about CPSs is gathered from both the phasor measurement units (PMU) and SCADA-based measurements. This measurement transfer introduces two network observability types, which split the system into observable (White) and unobservable (Grey) areas, based on 1) deployed measuring instruments (MIs) and 2) received measurements. A two-step bad data detection (BDD) method is introduced for ICT irregularities and outages. The proposed algorithm benefits are shown on two IEEE test cases with time-varying load/generation: 14-bus and 300-bus. © 2020 Elsevier Ltd
21 a57218886193 Stanković A.M. p36 False Journal 30 Flexible hybrid state estimation for power systems with communication irregularities This study proposes a novel flexible hybrid state estimation (SE) algorithm when a realistic communication system with its irregularities is taken into account. This system is modelled by the Network Simulator 2 software tool, which is also used to calculate communication delays and packet drop probabilities. Within this setup, the system observability can be predicted, and the proposed SE can decide between using the static SE (SSE) or the discrete Kalman filter plus SSE-based measurements and time alignment (Forecasting-aided SE). Flexible hybrid SE (FHSE) incorporates both phasor measurement units and supervisory control and data acquisition-based measurements, with different time stamps. The proposed FHSE with detailed modelling of the communication system is motivated by: (i) well-known issues in SSE (time alignment of the measurements, frequent un-observability for fixed SE time stamps etc.); and (ii) the need to model a realistic communication system (calculated communication delays and packet drop probabilities are a part of the proposed FHSE). Application of the proposed algorithm is illustrated for examples with time-varying bus load/generation on two IEEE test cases: 14-bus and 300-bus. © The Institution of Engineering and Technology 2020
21 a57218886193 Stanković A.M. p161 False Conference 31 Network Reduction in Transient Stability Models using Partial Response Matching We describe a method for simultaneously identifying and reducing dynamic power systems models in the form of differential-algebraic equations. Often, these models are large and complex, containing more parameters than can be identified from the available system measurements. We demonstrate our method on transient stability models, using the IEEE 14-bus test system. Our approach uses techniques of information geometry to remove unidentifiable parameters from the model. We examine the case of a networked system with 58 parameters using full observations throughout the network. We show that greater reduction can be achieved when only partial observations are available, Including reduction of the network itself. © 2019 IEEE.
21 a57218886193 Stanković A.M. p225 False Conference 54 Data classification and parameter identification in power systems by manifold learning This paper describes a manifold learning algorithm for big data classification and parameter identification in real-time operation of power systems. We assume a black-box setting, where only SCADA-based measurements at the point of interest are available. Data classification is based on diffusion maps, where an improved data-informed metric construction for partition trees is used. Data reduction is demonstrated on an hourly measurement tensor example, collected from the power flow solutions calculated for daily load/generation profiles. Parameter identification is performed on the same example, generated via randomly selected input parameters. The proposed method is illustrated on the case of the static part (ZIP) of a detailed WECC load model, connected to a single bus of a real-world 441-bus power system. © 2019 IEEE.
21 a57218886193 Stanković A.M. p379 False Journal 207 Data-driven dynamic equivalents for power system areas from boundary measurements The paper describes an algorithm for parameter identification of a dynamic equivalent for an external subsystem, based solely on the available online measurements in boundary buses and branches. Static equivalent part is represented by equivalent impedances from boundary buses (ones that separate the internal and external subsystems) and calculated using the modified (minimum loss) radial, equivalent, and independent method. Parameter identification of synchronous generator (SG)-based equivalent (for predominantly production external areas), dynamic load (DL)-based equivalent (for predominantly load external areas), or (SG + DL)-based equivalent (for mixed external areas) in fictitious buses is performed by Levenberg-Marquardt weighted least-square nonlinear optimization, which minimizes the variances between available online measurements and transient responses of the reduced power system. The IEEE 14-bus and 441-bus real-world test systems are used to illustrate and test the proposed power system equivalent derivation technique. © 2018 IEEE.
21 a57218886193 Stanković A.M. p403 False Conference 149 Simultaneous Global Identification of Dynamic and Network Parameters in Transient Stability Studies The paper describes a global identification procedure for dynamic power system models in the form of differential and algebraic equations. Power system models have a number of features that makes their improvement challenging - they are multi-level, multi-user and multi-physics. Not surprisingly, they are nonlinear and time varying, both in terms of states (memory variables) and parameters, and discrete structures, such as graphs, are strongly blended with continuous dynamics, resulting in network dynamics. The transient stability models are used as a prototypical example. Our method is based on information geometry, and uses advances in computational differential geometry to characterize high-dimensional manifolds in the space of measurements. In the case of network parameters, a comparison is presented with circuit-theoretic techniques. The results are illustrated on the case of IEEE 14-bus test system with 58 parameters in our realization. © 2018 IEEE.
21 a57218886193 Stanković A.M. p753 False Journal 367 Measurement-Directed Reduction of Dynamic Models in Power Systems The paper describes a new model reduction procedure tailored to power systems. It uses measurement data to devise a family of reduced order nonlinear models while retaining physical interpretability of parameters and equations. The manifold boundary approximation method (MBAM) uses the Fisher information matrix calculated from measurements to identify the least relevant parameter combination in the original model. Next, it numerically constructs a geodesic on the corresponding statistical manifold originating from the initial parameters in the least relevant parameter direction until a manifold boundary is found. MBAM then identifies a limiting approximation in the mathematical form of the model and removes one parameter combination. The simplified model is recalibrated by fitting its behavior to that of the original model, and the process is repeated as appropriate. MBAM is demonstrated on the example of a synchronous generator (SG), which has been treated extensively in the literature. Implications of the proposed model reduction procedure on large power system models are illustrated on a 441-bus, 72-SG dynamical model. © 1969-2012 IEEE.
22 a57210260262 Sarić A.A. p5 False Journal 3 Interleaving physics- and data-driven models for power system transient dynamics The paper explores interleaved and coordinated refinement of physics- and data-driven models in describing transient phenomena in large-scale power systems. We develop and study an integrated analytical and computational data-driven gray box environment needed to achieve this aim. Main ingredients include computational differential geometry-based model reduction, optimization-based compressed sensing, and a finite approximation of the Koopman operator. The proposed two-step procedure (the model reduction by differential geometric (information geometry) tools, and data refinement by the compressed sensing and Koopman theory based dynamics prediction) is illustrated on the multi-machine benchmark example of IEEE 14-bus system with renewable sources, where the results are shown for doubly-fed induction generator (DFIG) with local measurements in the connection point. The algorithm is directly applicable to identification of other dynamic components (for example, dynamic loads). © 2020 Elsevier B.V.
23 a6701777223 Sarić A.T. p5 False Journal 3 Interleaving physics- and data-driven models for power system transient dynamics The paper explores interleaved and coordinated refinement of physics- and data-driven models in describing transient phenomena in large-scale power systems. We develop and study an integrated analytical and computational data-driven gray box environment needed to achieve this aim. Main ingredients include computational differential geometry-based model reduction, optimization-based compressed sensing, and a finite approximation of the Koopman operator. The proposed two-step procedure (the model reduction by differential geometric (information geometry) tools, and data refinement by the compressed sensing and Koopman theory based dynamics prediction) is illustrated on the multi-machine benchmark example of IEEE 14-bus system with renewable sources, where the results are shown for doubly-fed induction generator (DFIG) with local measurements in the connection point. The algorithm is directly applicable to identification of other dynamic components (for example, dynamic loads). © 2020 Elsevier B.V.
23 a6701777223 Sarić A.T. p8 False Journal 6 Probabilistic extension of flexible hybrid state estimation for cyber-physical systems This paper proposes a probabilistic extension to flexible hybrid state estimation (FHSE) for cyber-physical systems (CPSs). The main goal of the algorithm is improvement of the system state tracking when realistic communications are taken into account, by optimizing information and communication technology (ICT) usage. These advancements result in: 1) coping with ICT outages and inevitable irregularities (delay, packet drop and bad measurements); 2) determining the optimized state estimation execution frequencies based on expected measurement refresh times. Additionally, information about CPSs is gathered from both the phasor measurement units (PMU) and SCADA-based measurements. This measurement transfer introduces two network observability types, which split the system into observable (White) and unobservable (Grey) areas, based on 1) deployed measuring instruments (MIs) and 2) received measurements. A two-step bad data detection (BDD) method is introduced for ICT irregularities and outages. The proposed algorithm benefits are shown on two IEEE test cases with time-varying load/generation: 14-bus and 300-bus. © 2020 Elsevier Ltd
23 a6701777223 Sarić A.T. p36 False Journal 30 Flexible hybrid state estimation for power systems with communication irregularities This study proposes a novel flexible hybrid state estimation (SE) algorithm when a realistic communication system with its irregularities is taken into account. This system is modelled by the Network Simulator 2 software tool, which is also used to calculate communication delays and packet drop probabilities. Within this setup, the system observability can be predicted, and the proposed SE can decide between using the static SE (SSE) or the discrete Kalman filter plus SSE-based measurements and time alignment (Forecasting-aided SE). Flexible hybrid SE (FHSE) incorporates both phasor measurement units and supervisory control and data acquisition-based measurements, with different time stamps. The proposed FHSE with detailed modelling of the communication system is motivated by: (i) well-known issues in SSE (time alignment of the measurements, frequent un-observability for fixed SE time stamps etc.); and (ii) the need to model a realistic communication system (calculated communication delays and packet drop probabilities are a part of the proposed FHSE). Application of the proposed algorithm is illustrated for examples with time-varying bus load/generation on two IEEE test cases: 14-bus and 300-bus. © The Institution of Engineering and Technology 2020
23 a6701777223 Sarić A.T. p160 False Conference 30 Probabilistic Network Observability of a Hybrid Power System with Communication Irregularities This paper explores power system network observability while taking into account realistic communication network behavior. The overall information is obtained by combining SCADA-and phasor measurement unit-derived data, where time stamping (based on Global Positioning System or an equivalent local clock) for all measurements is assumed. Based on simulations performed in communication Network Simulator 2, empirical cumulative distribution functions can be associated with transfer times of measurement packets, which will reflect communication parameters and irregularities. This is further used to form an algorithm which maximizes the number of successful network observability checks, and thus the number of possible state estimations, in a certain time period. Application is demonstrated on the IEEE 14-bus test power system example. © 2019 IEEE.
23 a6701777223 Sarić A.T. p161 False Conference 31 Network Reduction in Transient Stability Models using Partial Response Matching We describe a method for simultaneously identifying and reducing dynamic power systems models in the form of differential-algebraic equations. Often, these models are large and complex, containing more parameters than can be identified from the available system measurements. We demonstrate our method on transient stability models, using the IEEE 14-bus test system. Our approach uses techniques of information geometry to remove unidentifiable parameters from the model. We examine the case of a networked system with 58 parameters using full observations throughout the network. We show that greater reduction can be achieved when only partial observations are available, Including reduction of the network itself. © 2019 IEEE.
23 a6701777223 Sarić A.T. p225 True Conference 54 Data classification and parameter identification in power systems by manifold learning This paper describes a manifold learning algorithm for big data classification and parameter identification in real-time operation of power systems. We assume a black-box setting, where only SCADA-based measurements at the point of interest are available. Data classification is based on diffusion maps, where an improved data-informed metric construction for partition trees is used. Data reduction is demonstrated on an hourly measurement tensor example, collected from the power flow solutions calculated for daily load/generation profiles. Parameter identification is performed on the same example, generated via randomly selected input parameters. The proposed method is illustrated on the case of the static part (ZIP) of a detailed WECC load model, connected to a single bus of a real-world 441-bus power system. © 2019 IEEE.
23 a6701777223 Sarić A.T. p284 False Conference 68 Geometrically Motivated Reparameterization for Identifiability Analysis in Power Systems Models This paper describes a geometric approach to parameter identifiability analysis in models of power systems dynamics. When a model of a power system is to be compared with measurements taken at discrete times, it can be interpreted as a mapping from parameter space into a data or prediction space. Generically, model mappings can be interpreted as manifolds with dimensionality equal to the number of structurally identifiable parameters. Empirically it is observed that model mappings often correspond to bounded manifolds. We propose a new definition of practical identifiability based the topological definition of a manifold with boundary. In many ways, our proposed definition extends the properties of structural identifiability. We construct numerical approximations to geodesics on the model manifold and use the results, combined with insights derived from the mathematical form of the equations, to identify combinations of practically identifiable and unidentifiable parameters. We give several examples of application to dynamic power systems models. © 2018 IEEE.
23 a6701777223 Sarić A.T. p379 True Journal 207 Data-driven dynamic equivalents for power system areas from boundary measurements The paper describes an algorithm for parameter identification of a dynamic equivalent for an external subsystem, based solely on the available online measurements in boundary buses and branches. Static equivalent part is represented by equivalent impedances from boundary buses (ones that separate the internal and external subsystems) and calculated using the modified (minimum loss) radial, equivalent, and independent method. Parameter identification of synchronous generator (SG)-based equivalent (for predominantly production external areas), dynamic load (DL)-based equivalent (for predominantly load external areas), or (SG + DL)-based equivalent (for mixed external areas) in fictitious buses is performed by Levenberg-Marquardt weighted least-square nonlinear optimization, which minimizes the variances between available online measurements and transient responses of the reduced power system. The IEEE 14-bus and 441-bus real-world test systems are used to illustrate and test the proposed power system equivalent derivation technique. © 2018 IEEE.
23 a6701777223 Sarić A.T. p403 False Conference 149 Simultaneous Global Identification of Dynamic and Network Parameters in Transient Stability Studies The paper describes a global identification procedure for dynamic power system models in the form of differential and algebraic equations. Power system models have a number of features that makes their improvement challenging - they are multi-level, multi-user and multi-physics. Not surprisingly, they are nonlinear and time varying, both in terms of states (memory variables) and parameters, and discrete structures, such as graphs, are strongly blended with continuous dynamics, resulting in network dynamics. The transient stability models are used as a prototypical example. Our method is based on information geometry, and uses advances in computational differential geometry to characterize high-dimensional manifolds in the space of measurements. In the case of network parameters, a comparison is presented with circuit-theoretic techniques. The results are illustrated on the case of IEEE 14-bus test system with 58 parameters in our realization. © 2018 IEEE.
23 a6701777223 Sarić A.T. p406 False Conference 152 Influence of Communication Irregularities and Co-simulation on Hybrid Power System State Estimation The paper explores the effects of sensor behavior and communication system (CS) irregularities on power system state estimation (SE). CS are modeled in Network Simulator 2 (NS-2), allowing the quantification of irregularities, including delays and dropped packets. The overall information is obtained combining SCADA measurements with phasor measurement unit (PMU) derived data, where time stamping (based on GPS or an equivalent local clock) for all measurements is assumed. To fully analyze the effects of irregularities, a detailed analysis of sensitivities to different communication system parameters is provided as well. Using the co-simulation environment PiccSIM, a SE with these irregularities is quantified for CS parameter variation, with detailed models of power and communication flows. © 2018 IEEE.
23 a6701777223 Sarić A.T. p528 True Journal 293 Information geometry for model identification and parameter estimation in renewable energy - DFIG plant case This study describes a new class of system identification procedures, tailored to electric power systems with renewable resources. The procedure described here builds on computational advances in differential geometry, and offers a new, global, and intrinsic characterisation of challenges in data-derived identification of electric power systems. The approach benefits from increased availability of high-quality measurements. The procedure is illustrated on the multi-machine benchmark example of IEEE 14-bus system with renewable resources, but it is equally applicable to identification of other components and systems (e.g. dynamic loads). The authors consider doubly-fed induction generators (DFIG) operating in a wind farm with system level proportional-integral controllers. © The Institution of Engineering and Technology 2017.
23 a6701777223 Sarić A.T. p541 False Conference 195 Hybrid power system state estimation with irregular sampling The paper proposes a power system state estimation algorithm in the presence of irregular sensor sampling and random communication delays. Our state estimator incorporates Phasor Measurement Units (PMU) and SCADA measurements. We use an Extended Kalman filter based algorithm for time alignment of measurements and state variables. Time stamps are assumed for PMU, SCADA and state estimation. Application of the proposed algorithm is illustrated for hourly/daily load/generation variations on two test examples: 14-bus and 118-bus. © 2017 IEEE.
23 a6701777223 Sarić A.T. p753 False Journal 367 Measurement-Directed Reduction of Dynamic Models in Power Systems The paper describes a new model reduction procedure tailored to power systems. It uses measurement data to devise a family of reduced order nonlinear models while retaining physical interpretability of parameters and equations. The manifold boundary approximation method (MBAM) uses the Fisher information matrix calculated from measurements to identify the least relevant parameter combination in the original model. Next, it numerically constructs a geodesic on the corresponding statistical manifold originating from the initial parameters in the least relevant parameter direction until a manifold boundary is found. MBAM then identifies a limiting approximation in the mathematical form of the model and removes one parameter combination. The simplified model is recalibrated by fitting its behavior to that of the original model, and the process is repeated as appropriate. MBAM is demonstrated on the example of a synchronous generator (SG), which has been treated extensively in the literature. Implications of the proposed model reduction procedure on large power system models are illustrated on a 441-bus, 72-SG dynamical model. © 1969-2012 IEEE.
24 a8448666000 Transtrum M.K. p5 False Journal 3 Interleaving physics- and data-driven models for power system transient dynamics The paper explores interleaved and coordinated refinement of physics- and data-driven models in describing transient phenomena in large-scale power systems. We develop and study an integrated analytical and computational data-driven gray box environment needed to achieve this aim. Main ingredients include computational differential geometry-based model reduction, optimization-based compressed sensing, and a finite approximation of the Koopman operator. The proposed two-step procedure (the model reduction by differential geometric (information geometry) tools, and data refinement by the compressed sensing and Koopman theory based dynamics prediction) is illustrated on the multi-machine benchmark example of IEEE 14-bus system with renewable sources, where the results are shown for doubly-fed induction generator (DFIG) with local measurements in the connection point. The algorithm is directly applicable to identification of other dynamic components (for example, dynamic loads). © 2020 Elsevier B.V.
24 a8448666000 Transtrum M.K. p8 False Journal 6 Probabilistic extension of flexible hybrid state estimation for cyber-physical systems This paper proposes a probabilistic extension to flexible hybrid state estimation (FHSE) for cyber-physical systems (CPSs). The main goal of the algorithm is improvement of the system state tracking when realistic communications are taken into account, by optimizing information and communication technology (ICT) usage. These advancements result in: 1) coping with ICT outages and inevitable irregularities (delay, packet drop and bad measurements); 2) determining the optimized state estimation execution frequencies based on expected measurement refresh times. Additionally, information about CPSs is gathered from both the phasor measurement units (PMU) and SCADA-based measurements. This measurement transfer introduces two network observability types, which split the system into observable (White) and unobservable (Grey) areas, based on 1) deployed measuring instruments (MIs) and 2) received measurements. A two-step bad data detection (BDD) method is introduced for ICT irregularities and outages. The proposed algorithm benefits are shown on two IEEE test cases with time-varying load/generation: 14-bus and 300-bus. © 2020 Elsevier Ltd
24 a8448666000 Transtrum M.K. p36 False Journal 30 Flexible hybrid state estimation for power systems with communication irregularities This study proposes a novel flexible hybrid state estimation (SE) algorithm when a realistic communication system with its irregularities is taken into account. This system is modelled by the Network Simulator 2 software tool, which is also used to calculate communication delays and packet drop probabilities. Within this setup, the system observability can be predicted, and the proposed SE can decide between using the static SE (SSE) or the discrete Kalman filter plus SSE-based measurements and time alignment (Forecasting-aided SE). Flexible hybrid SE (FHSE) incorporates both phasor measurement units and supervisory control and data acquisition-based measurements, with different time stamps. The proposed FHSE with detailed modelling of the communication system is motivated by: (i) well-known issues in SSE (time alignment of the measurements, frequent un-observability for fixed SE time stamps etc.); and (ii) the need to model a realistic communication system (calculated communication delays and packet drop probabilities are a part of the proposed FHSE). Application of the proposed algorithm is illustrated for examples with time-varying bus load/generation on two IEEE test cases: 14-bus and 300-bus. © The Institution of Engineering and Technology 2020
24 a8448666000 Transtrum M.K. p151 False Journal 106 Model Boundary Approximation Method as a Unifying Framework for Balanced Truncation and Singular Perturbation Approximation We show that two widely accepted model reduction techniques, balanced truncation (BT) and balanced singular perturbation approximation (BSPA), can be derived as limiting approximations of a carefully constructed parameterization of linear time invariant systems by employing the model boundary approximation method (MBAM) [1]. We also show that MBAM provides a novel way to interpolate between BT and BSPA, by exploring the set of approximations on the boundary of the 'model manifold,' which is associated with the specific choice of model parameterization and initial condition and is embedded in a sample space of measured outputs, between the elements that correspond to the two model reduction techniques. This paper suggests similar types of approximations may be obtainable in topologically similar places (i.e., on certain boundaries) on the associated model manifold of nonlinear systems if analogous parameterizations can be achieved, therefore extending these widely accepted model reduction techniques to nonlinear systems.1 © 1963-2012 IEEE.
24 a8448666000 Transtrum M.K. p160 False Conference 30 Probabilistic Network Observability of a Hybrid Power System with Communication Irregularities This paper explores power system network observability while taking into account realistic communication network behavior. The overall information is obtained by combining SCADA-and phasor measurement unit-derived data, where time stamping (based on Global Positioning System or an equivalent local clock) for all measurements is assumed. Based on simulations performed in communication Network Simulator 2, empirical cumulative distribution functions can be associated with transfer times of measurement packets, which will reflect communication parameters and irregularities. This is further used to form an algorithm which maximizes the number of successful network observability checks, and thus the number of possible state estimations, in a certain time period. Application is demonstrated on the IEEE 14-bus test power system example. © 2019 IEEE.
24 a8448666000 Transtrum M.K. p161 False Conference 31 Network Reduction in Transient Stability Models using Partial Response Matching We describe a method for simultaneously identifying and reducing dynamic power systems models in the form of differential-algebraic equations. Often, these models are large and complex, containing more parameters than can be identified from the available system measurements. We demonstrate our method on transient stability models, using the IEEE 14-bus test system. Our approach uses techniques of information geometry to remove unidentifiable parameters from the model. We examine the case of a networked system with 58 parameters using full observations throughout the network. We show that greater reduction can be achieved when only partial observations are available, Including reduction of the network itself. © 2019 IEEE.
24 a8448666000 Transtrum M.K. p225 False Conference 54 Data classification and parameter identification in power systems by manifold learning This paper describes a manifold learning algorithm for big data classification and parameter identification in real-time operation of power systems. We assume a black-box setting, where only SCADA-based measurements at the point of interest are available. Data classification is based on diffusion maps, where an improved data-informed metric construction for partition trees is used. Data reduction is demonstrated on an hourly measurement tensor example, collected from the power flow solutions calculated for daily load/generation profiles. Parameter identification is performed on the same example, generated via randomly selected input parameters. The proposed method is illustrated on the case of the static part (ZIP) of a detailed WECC load model, connected to a single bus of a real-world 441-bus power system. © 2019 IEEE.
24 a8448666000 Transtrum M.K. p284 True Conference 68 Geometrically Motivated Reparameterization for Identifiability Analysis in Power Systems Models This paper describes a geometric approach to parameter identifiability analysis in models of power systems dynamics. When a model of a power system is to be compared with measurements taken at discrete times, it can be interpreted as a mapping from parameter space into a data or prediction space. Generically, model mappings can be interpreted as manifolds with dimensionality equal to the number of structurally identifiable parameters. Empirically it is observed that model mappings often correspond to bounded manifolds. We propose a new definition of practical identifiability based the topological definition of a manifold with boundary. In many ways, our proposed definition extends the properties of structural identifiability. We construct numerical approximations to geodesics on the model manifold and use the results, combined with insights derived from the mathematical form of the equations, to identify combinations of practically identifiable and unidentifiable parameters. We give several examples of application to dynamic power systems models. © 2018 IEEE.
24 a8448666000 Transtrum M.K. p379 False Journal 207 Data-driven dynamic equivalents for power system areas from boundary measurements The paper describes an algorithm for parameter identification of a dynamic equivalent for an external subsystem, based solely on the available online measurements in boundary buses and branches. Static equivalent part is represented by equivalent impedances from boundary buses (ones that separate the internal and external subsystems) and calculated using the modified (minimum loss) radial, equivalent, and independent method. Parameter identification of synchronous generator (SG)-based equivalent (for predominantly production external areas), dynamic load (DL)-based equivalent (for predominantly load external areas), or (SG + DL)-based equivalent (for mixed external areas) in fictitious buses is performed by Levenberg-Marquardt weighted least-square nonlinear optimization, which minimizes the variances between available online measurements and transient responses of the reduced power system. The IEEE 14-bus and 441-bus real-world test systems are used to illustrate and test the proposed power system equivalent derivation technique. © 2018 IEEE.
24 a8448666000 Transtrum M.K. p403 True Conference 149 Simultaneous Global Identification of Dynamic and Network Parameters in Transient Stability Studies The paper describes a global identification procedure for dynamic power system models in the form of differential and algebraic equations. Power system models have a number of features that makes their improvement challenging - they are multi-level, multi-user and multi-physics. Not surprisingly, they are nonlinear and time varying, both in terms of states (memory variables) and parameters, and discrete structures, such as graphs, are strongly blended with continuous dynamics, resulting in network dynamics. The transient stability models are used as a prototypical example. Our method is based on information geometry, and uses advances in computational differential geometry to characterize high-dimensional manifolds in the space of measurements. In the case of network parameters, a comparison is presented with circuit-theoretic techniques. The results are illustrated on the case of IEEE 14-bus test system with 58 parameters in our realization. © 2018 IEEE.
24 a8448666000 Transtrum M.K. p406 False Conference 152 Influence of Communication Irregularities and Co-simulation on Hybrid Power System State Estimation The paper explores the effects of sensor behavior and communication system (CS) irregularities on power system state estimation (SE). CS are modeled in Network Simulator 2 (NS-2), allowing the quantification of irregularities, including delays and dropped packets. The overall information is obtained combining SCADA measurements with phasor measurement unit (PMU) derived data, where time stamping (based on GPS or an equivalent local clock) for all measurements is assumed. To fully analyze the effects of irregularities, a detailed analysis of sensitivities to different communication system parameters is provided as well. Using the co-simulation environment PiccSIM, a SE with these irregularities is quantified for CS parameter variation, with detailed models of power and communication flows. © 2018 IEEE.
24 a8448666000 Transtrum M.K. p528 False Journal 293 Information geometry for model identification and parameter estimation in renewable energy - DFIG plant case This study describes a new class of system identification procedures, tailored to electric power systems with renewable resources. The procedure described here builds on computational advances in differential geometry, and offers a new, global, and intrinsic characterisation of challenges in data-derived identification of electric power systems. The approach benefits from increased availability of high-quality measurements. The procedure is illustrated on the multi-machine benchmark example of IEEE 14-bus system with renewable resources, but it is equally applicable to identification of other components and systems (e.g. dynamic loads). The authors consider doubly-fed induction generators (DFIG) operating in a wind farm with system level proportional-integral controllers. © The Institution of Engineering and Technology 2017.
24 a8448666000 Transtrum M.K. p541 False Conference 195 Hybrid power system state estimation with irregular sampling The paper proposes a power system state estimation algorithm in the presence of irregular sensor sampling and random communication delays. Our state estimator incorporates Phasor Measurement Units (PMU) and SCADA measurements. We use an Extended Kalman filter based algorithm for time alignment of measurements and state variables. Time stamps are assumed for PMU, SCADA and state estimation. Application of the proposed algorithm is illustrated for hourly/daily load/generation variations on two test examples: 14-bus and 118-bus. © 2017 IEEE.
24 a8448666000 Transtrum M.K. p753 True Journal 367 Measurement-Directed Reduction of Dynamic Models in Power Systems The paper describes a new model reduction procedure tailored to power systems. It uses measurement data to devise a family of reduced order nonlinear models while retaining physical interpretability of parameters and equations. The manifold boundary approximation method (MBAM) uses the Fisher information matrix calculated from measurements to identify the least relevant parameter combination in the original model. Next, it numerically constructs a geodesic on the corresponding statistical manifold originating from the initial parameters in the least relevant parameter direction until a manifold boundary is found. MBAM then identifies a limiting approximation in the mathematical form of the model and removes one parameter combination. The simplified model is recalibrated by fitting its behavior to that of the original model, and the process is repeated as appropriate. MBAM is demonstrated on the example of a synchronous generator (SG), which has been treated extensively in the literature. Implications of the proposed model reduction procedure on large power system models are illustrated on a 441-bus, 72-SG dynamical model. © 1969-2012 IEEE.
24 a8448666000 Transtrum M.K. p777 False Journal 384 Theoretical estimates of maximum fields in superconducting resonant radio frequency cavities: Stability theory, disorder, and laminates Theoretical limits to the performance of superconductors in high magnetic fields parallel to their surfaces are of key relevance to current and future accelerating cavities, especially those made of new higher-T c materials such as Nb3Sn, NbN, and MgB2. Indeed, beyond the so-called superheating field , flux will spontaneously penetrate even a perfect superconducting surface and ruin the performance. We present intuitive arguments and simple estimates for , and combine them with our previous rigorous calculations, which we summarize. We briefly discuss experimental measurements of the superheating field, comparing to our estimates. We explore the effects of materials anisotropy and the danger of disorder in nucleating vortex entry. Will we need to control surface orientation in the layered compound MgB2? Can we estimate theoretically whether dirt and defects make these new materials fundamentally more challenging to optimize than niobium? Finally, we discuss and analyze recent proposals to use thin superconducting layers or laminates to enhance the performance of superconducting cavities. Flux entering a laminate can lead to so-called pancake vortices; we consider the physics of the dislocation motion and potential re-annihilation or stabilization of these vortices after their entry. © 2017 IOP Publishing Ltd.
25 a36149254500 Hackney D. p6 True Journal 4 Survivability of integrated fiber Bragg grating sensors in ballistic protection fabrics for high velocity impact testing This research demonstrates that fiber Bragg grating (FBG) strain sensors can survive and provide useful strain information when integrated into a woven fabric subjected to ballistic impact testing. In this work, FBGs were integrated into a single-layer, Kevlar® fabric, sensing mat, placed between a 30-layer Kevlar® fabric shoot pack and clay backing material, and then impacted with an 8.23 g, 12.69 mm diameter, steel ball bearing at velocities up to 285 m/s. Three different optical fiber types, with differing fiber coatings and fiber diameters, were tested. The FBG strain response was determined from the full-spectrum FBG response which was interrogated at 100 kHz throughout the impact event. The difference in FBG strain response for the different coatings and fiber diameters were compared. Additionally, the degradation of the coatings after repeated impacts were visually characterized, showing that smaller diameter fibers behaved better with a more elastic coating. © 2020 Elsevier Inc.
25 a36149254500 Hackney D. p13 True Journal 11 In-situ strain measurement of ballistic fabrics during impact using fiber Bragg gratings In previous experiments, the authors demonstrated that strain values collected from fiber Bragg gratings (FBG) integrated into a single layer of Kevlar fabric, placed between a soft armor test specimen and backing material, could be related to the time dependent back-face deformation (BFD) of the armor sample. In this paper, we investigate the specific fabric deformation and failure mechanisms that cause observed events in the FBG measured strain behavior and the FBG spectral profile throughout the impact event. For these experiments, the standard clay backing material was replaced with a 20% clear ballistic gel to provide visual access to the back-face. The test specimen was impacted by an 8.24 g steel ball bearing travelling at 248.8 m/s, during which strain was calculated from the measured full spectrum response of the FBG using a high-speed optical interrogation system. The strain response was compared to the BFD of the Kevlar sample. The BFD was measured through the clear ballistic gel using two high speed cameras recording at 100,000 fps. The results from these tests can be used for future testing using a non-transparent backing material to obtain a detailed strain–time history, back-face deformation history and an understanding of the time sequence of physical energy dissipation mechanisms in the fabric. © 2020 Elsevier Inc.
25 a36149254500 Hackney D. p645 True Conference 277 In-situ measurements of strain in soft body armor with FBG sensors during ballistic impacts The strain on a single FBG sensor, integrated into a single layer of Kevlar mounted behind a Kevlar soft body armor coupon, is measured throughout a ballistic impact event. The strain is collected through high-speed, full-spectral interrogation of the FBG during the event. The use of the wavelength shift and spectral distortion of the FBG provides a description of the strain profile and interaction between the optical fiber and Kevlar fabric. The measurements are correlated to high-speed camera images taken from the rear and side of the armor coupon. In future testing, this information can be applied to identify the sequence of energy dissipation mechanisms enacted within the armor to resist the ballistic impact. © OSA 2018 © 2018 The Author(s)
26 a57191155872 Goode T. p6 False Journal 4 Survivability of integrated fiber Bragg grating sensors in ballistic protection fabrics for high velocity impact testing This research demonstrates that fiber Bragg grating (FBG) strain sensors can survive and provide useful strain information when integrated into a woven fabric subjected to ballistic impact testing. In this work, FBGs were integrated into a single-layer, Kevlar® fabric, sensing mat, placed between a 30-layer Kevlar® fabric shoot pack and clay backing material, and then impacted with an 8.23 g, 12.69 mm diameter, steel ball bearing at velocities up to 285 m/s. Three different optical fiber types, with differing fiber coatings and fiber diameters, were tested. The FBG strain response was determined from the full-spectrum FBG response which was interrogated at 100 kHz throughout the impact event. The difference in FBG strain response for the different coatings and fiber diameters were compared. Additionally, the degradation of the coatings after repeated impacts were visually characterized, showing that smaller diameter fibers behaved better with a more elastic coating. © 2020 Elsevier Inc.
26 a57191155872 Goode T. p13 False Journal 11 In-situ strain measurement of ballistic fabrics during impact using fiber Bragg gratings In previous experiments, the authors demonstrated that strain values collected from fiber Bragg gratings (FBG) integrated into a single layer of Kevlar fabric, placed between a soft armor test specimen and backing material, could be related to the time dependent back-face deformation (BFD) of the armor sample. In this paper, we investigate the specific fabric deformation and failure mechanisms that cause observed events in the FBG measured strain behavior and the FBG spectral profile throughout the impact event. For these experiments, the standard clay backing material was replaced with a 20% clear ballistic gel to provide visual access to the back-face. The test specimen was impacted by an 8.24 g steel ball bearing travelling at 248.8 m/s, during which strain was calculated from the measured full spectrum response of the FBG using a high-speed optical interrogation system. The strain response was compared to the BFD of the Kevlar sample. The BFD was measured through the clear ballistic gel using two high speed cameras recording at 100,000 fps. The results from these tests can be used for future testing using a non-transparent backing material to obtain a detailed strain–time history, back-face deformation history and an understanding of the time sequence of physical energy dissipation mechanisms in the fabric. © 2020 Elsevier Inc.
26 a57191155872 Goode T. p188 True Journal 129 Soft body armor time-dependent back face deformation (BFD) with ballistics gel backing This paper presents a method for obtaining time dependent back face deformation (BFD) data for body armor during ballistic impact using a clear ballistics gelatin backing and high-speed cameras to capture the deformation profile. Using this method, baseline fabric characterization data was obtained for samples comprised of varying layers of 467 g/m 2 Kevlar K29 fabric impacted with 8.24 g steel ball projectile and backed with NATO standard 20% clear ballistics gelatin. For these tests, deformation depths were seen to increase with increasing impact energy and decreasing total areal density. A limited study of the various test parameters was performed by testing one additional fabric, projectile, and ballistics gelatin. From these comparisons, it was observed that 122 g/m 2 Kevlar KM2+ fabric performs better per weight than 467 g/m 2 Kevlar K29 fabric in terms of BFD, 9 mm FMJ projectiles produce deeper BFDs than 12.7 mm steel ball projectiles, and backing a sample with FBI standard 10% ballistics gel increases the BFD considerably over NATO standard 20% ballistics gel. © 2019
26 a57191155872 Goode T. p645 False Conference 277 In-situ measurements of strain in soft body armor with FBG sensors during ballistic impacts The strain on a single FBG sensor, integrated into a single layer of Kevlar mounted behind a Kevlar soft body armor coupon, is measured throughout a ballistic impact event. The strain is collected through high-speed, full-spectral interrogation of the FBG during the event. The use of the wavelength shift and spectral distortion of the FBG provides a description of the strain profile and interaction between the optical fiber and Kevlar fabric. The measurements are correlated to high-speed camera images taken from the rear and side of the armor coupon. In future testing, this information can be applied to identify the sequence of energy dissipation mechanisms enacted within the armor to resist the ballistic impact. © OSA 2018 © 2018 The Author(s)
27 a56681156600 Seng F. p6 False Journal 4 Survivability of integrated fiber Bragg grating sensors in ballistic protection fabrics for high velocity impact testing This research demonstrates that fiber Bragg grating (FBG) strain sensors can survive and provide useful strain information when integrated into a woven fabric subjected to ballistic impact testing. In this work, FBGs were integrated into a single-layer, Kevlar® fabric, sensing mat, placed between a 30-layer Kevlar® fabric shoot pack and clay backing material, and then impacted with an 8.23 g, 12.69 mm diameter, steel ball bearing at velocities up to 285 m/s. Three different optical fiber types, with differing fiber coatings and fiber diameters, were tested. The FBG strain response was determined from the full-spectrum FBG response which was interrogated at 100 kHz throughout the impact event. The difference in FBG strain response for the different coatings and fiber diameters were compared. Additionally, the degradation of the coatings after repeated impacts were visually characterized, showing that smaller diameter fibers behaved better with a more elastic coating. © 2020 Elsevier Inc.
27 a56681156600 Seng F. p13 False Journal 11 In-situ strain measurement of ballistic fabrics during impact using fiber Bragg gratings In previous experiments, the authors demonstrated that strain values collected from fiber Bragg gratings (FBG) integrated into a single layer of Kevlar fabric, placed between a soft armor test specimen and backing material, could be related to the time dependent back-face deformation (BFD) of the armor sample. In this paper, we investigate the specific fabric deformation and failure mechanisms that cause observed events in the FBG measured strain behavior and the FBG spectral profile throughout the impact event. For these experiments, the standard clay backing material was replaced with a 20% clear ballistic gel to provide visual access to the back-face. The test specimen was impacted by an 8.24 g steel ball bearing travelling at 248.8 m/s, during which strain was calculated from the measured full spectrum response of the FBG using a high-speed optical interrogation system. The strain response was compared to the BFD of the Kevlar sample. The BFD was measured through the clear ballistic gel using two high speed cameras recording at 100,000 fps. The results from these tests can be used for future testing using a non-transparent backing material to obtain a detailed strain–time history, back-face deformation history and an understanding of the time sequence of physical energy dissipation mechanisms in the fabric. © 2020 Elsevier Inc.
27 a56681156600 Seng F. p511 True Journal 280 Noise reduction techniques in fiber optic sensors Test and evaluation needs are becoming more and more demanding on the sensors being used. Fiber optic sensors are known for their ability to survive in harsh environments such as high pressure and temperature like those within oil/gas wells, or high vibration like those with electromagnetic railguns. As these sensors become commercially available, one challenge is overcoming multiple noise sources simultaneously in the sensor and its network imposed from the harsh environment. Optical amplifiers are typically used in fiber optic sensors to improve the signal-to-noise ratio (SNR). This method is suitable for boosting the signal above the floor caused by electrical noise. However, certain noise sources in fiber optic sensors directly modulate the optical signal. This can be due to other measurands being induced on the system. For example, while a slab coupled optical sensor (SCOS) is sensitive to electric field, it is also inherently sensitive to strain; therefore, any strain noise imposed on the sensor would overwhelm the electric field measurement and be considered noise. In this chapter, optical phase induced interference noise (PIIN) in a sensor network is reduced by using optical phase modulation in both a SCOS and a fiber Bragg grating (FBG). Strain induced noise on the optical fiber sensor is reduced using a differential sensor setup called a push-pull SCOS. Phase modulation and differentiation are then combined to allow for simultaneous noise reduction from different noise sources and allow for optical sensing of electric fields in harsh environments. These principles are applicable to other types of fiber optic sensors and sensors in general. © 2018 Nova Science Publishers, Inc.
27 a56681156600 Seng F. p645 False Conference 277 In-situ measurements of strain in soft body armor with FBG sensors during ballistic impacts The strain on a single FBG sensor, integrated into a single layer of Kevlar mounted behind a Kevlar soft body armor coupon, is measured throughout a ballistic impact event. The strain is collected through high-speed, full-spectral interrogation of the FBG during the event. The use of the wavelength shift and spectral distortion of the FBG provides a description of the strain profile and interaction between the optical fiber and Kevlar fabric. The measurements are correlated to high-speed camera images taken from the rear and side of the armor coupon. In future testing, this information can be applied to identify the sequence of energy dissipation mechanisms enacted within the armor to resist the ballistic impact. © OSA 2018 © 2018 The Author(s)
27 a56681156600 Seng F. p705 False Journal 346 Non-perturbing voltage measurement in a coaxial cable with slab-coupled optical sensors Voltage in a coaxial cable is measured by an electric-field optical fiber sensor exploiting the proportionality of voltage and electric field in a fixed structure. The sensor is inserted in a hole drilled through the dielectric of the RG-218 coaxial cable and sealed with epoxy to displace all air and prevent the adverse effects of charge buildup during high-voltage measurements. It is shown that the presence of the sensor in the coaxial cable does not significantly increase electrical reflections in the cable. A slab-coupled optical fiber sensor (SCOS) is used for its compact size and dielectric make. The dynamic range of 50 dB is shown experimentally with detection of signals as low as 1 V and up to 157 kV. A low corner of 0.3 Hz is demonstrated and the SCOS is shown to be able to measure 90 ns rise time. © 2017 Optical Society of America.
27 a56681156600 Seng F. p740 True Journal 346 Optical electric field sensor sensitivity direction rerouting and enhancement using a passive integrated dipole antenna This work introduces a passive dipole antenna integrated into the packaging of a slab-coupled optical sensor to enhance the directional sensitivity of electro-optic electric field measurements parallel to the fiber axis. Using the passive integrated dipole antenna described in this work, a sensor that can typically only sense fields transverse to the fiber direction is able to sense a 1.25 kV/m field along the fiber direction with a gain of 17.5. This is verified through simulation and experiment. © 2017 Optical Society of America.
28 a35088650000 Pankow M. p6 False Journal 4 Survivability of integrated fiber Bragg grating sensors in ballistic protection fabrics for high velocity impact testing This research demonstrates that fiber Bragg grating (FBG) strain sensors can survive and provide useful strain information when integrated into a woven fabric subjected to ballistic impact testing. In this work, FBGs were integrated into a single-layer, Kevlar® fabric, sensing mat, placed between a 30-layer Kevlar® fabric shoot pack and clay backing material, and then impacted with an 8.23 g, 12.69 mm diameter, steel ball bearing at velocities up to 285 m/s. Three different optical fiber types, with differing fiber coatings and fiber diameters, were tested. The FBG strain response was determined from the full-spectrum FBG response which was interrogated at 100 kHz throughout the impact event. The difference in FBG strain response for the different coatings and fiber diameters were compared. Additionally, the degradation of the coatings after repeated impacts were visually characterized, showing that smaller diameter fibers behaved better with a more elastic coating. © 2020 Elsevier Inc.
28 a35088650000 Pankow M. p13 False Journal 11 In-situ strain measurement of ballistic fabrics during impact using fiber Bragg gratings In previous experiments, the authors demonstrated that strain values collected from fiber Bragg gratings (FBG) integrated into a single layer of Kevlar fabric, placed between a soft armor test specimen and backing material, could be related to the time dependent back-face deformation (BFD) of the armor sample. In this paper, we investigate the specific fabric deformation and failure mechanisms that cause observed events in the FBG measured strain behavior and the FBG spectral profile throughout the impact event. For these experiments, the standard clay backing material was replaced with a 20% clear ballistic gel to provide visual access to the back-face. The test specimen was impacted by an 8.24 g steel ball bearing travelling at 248.8 m/s, during which strain was calculated from the measured full spectrum response of the FBG using a high-speed optical interrogation system. The strain response was compared to the BFD of the Kevlar sample. The BFD was measured through the clear ballistic gel using two high speed cameras recording at 100,000 fps. The results from these tests can be used for future testing using a non-transparent backing material to obtain a detailed strain–time history, back-face deformation history and an understanding of the time sequence of physical energy dissipation mechanisms in the fabric. © 2020 Elsevier Inc.
28 a35088650000 Pankow M. p188 False Journal 129 Soft body armor time-dependent back face deformation (BFD) with ballistics gel backing This paper presents a method for obtaining time dependent back face deformation (BFD) data for body armor during ballistic impact using a clear ballistics gelatin backing and high-speed cameras to capture the deformation profile. Using this method, baseline fabric characterization data was obtained for samples comprised of varying layers of 467 g/m 2 Kevlar K29 fabric impacted with 8.24 g steel ball projectile and backed with NATO standard 20% clear ballistics gelatin. For these tests, deformation depths were seen to increase with increasing impact energy and decreasing total areal density. A limited study of the various test parameters was performed by testing one additional fabric, projectile, and ballistics gelatin. From these comparisons, it was observed that 122 g/m 2 Kevlar KM2+ fabric performs better per weight than 467 g/m 2 Kevlar K29 fabric in terms of BFD, 9 mm FMJ projectiles produce deeper BFDs than 12.7 mm steel ball projectiles, and backing a sample with FBI standard 10% ballistics gel increases the BFD considerably over NATO standard 20% ballistics gel. © 2019
28 a35088650000 Pankow M. p645 False Conference 277 In-situ measurements of strain in soft body armor with FBG sensors during ballistic impacts The strain on a single FBG sensor, integrated into a single layer of Kevlar mounted behind a Kevlar soft body armor coupon, is measured throughout a ballistic impact event. The strain is collected through high-speed, full-spectral interrogation of the FBG during the event. The use of the wavelength shift and spectral distortion of the FBG provides a description of the strain profile and interaction between the optical fiber and Kevlar fabric. The measurements are correlated to high-speed camera images taken from the rear and side of the armor coupon. In future testing, this information can be applied to identify the sequence of energy dissipation mechanisms enacted within the armor to resist the ballistic impact. © OSA 2018 © 2018 The Author(s)
29 a7201741468 Schultz S. p6 False Journal 4 Survivability of integrated fiber Bragg grating sensors in ballistic protection fabrics for high velocity impact testing This research demonstrates that fiber Bragg grating (FBG) strain sensors can survive and provide useful strain information when integrated into a woven fabric subjected to ballistic impact testing. In this work, FBGs were integrated into a single-layer, Kevlar® fabric, sensing mat, placed between a 30-layer Kevlar® fabric shoot pack and clay backing material, and then impacted with an 8.23 g, 12.69 mm diameter, steel ball bearing at velocities up to 285 m/s. Three different optical fiber types, with differing fiber coatings and fiber diameters, were tested. The FBG strain response was determined from the full-spectrum FBG response which was interrogated at 100 kHz throughout the impact event. The difference in FBG strain response for the different coatings and fiber diameters were compared. Additionally, the degradation of the coatings after repeated impacts were visually characterized, showing that smaller diameter fibers behaved better with a more elastic coating. © 2020 Elsevier Inc.
29 a7201741468 Schultz S. p13 False Journal 11 In-situ strain measurement of ballistic fabrics during impact using fiber Bragg gratings In previous experiments, the authors demonstrated that strain values collected from fiber Bragg gratings (FBG) integrated into a single layer of Kevlar fabric, placed between a soft armor test specimen and backing material, could be related to the time dependent back-face deformation (BFD) of the armor sample. In this paper, we investigate the specific fabric deformation and failure mechanisms that cause observed events in the FBG measured strain behavior and the FBG spectral profile throughout the impact event. For these experiments, the standard clay backing material was replaced with a 20% clear ballistic gel to provide visual access to the back-face. The test specimen was impacted by an 8.24 g steel ball bearing travelling at 248.8 m/s, during which strain was calculated from the measured full spectrum response of the FBG using a high-speed optical interrogation system. The strain response was compared to the BFD of the Kevlar sample. The BFD was measured through the clear ballistic gel using two high speed cameras recording at 100,000 fps. The results from these tests can be used for future testing using a non-transparent backing material to obtain a detailed strain–time history, back-face deformation history and an understanding of the time sequence of physical energy dissipation mechanisms in the fabric. © 2020 Elsevier Inc.
29 a7201741468 Schultz S. p485 True Conference 177 Intensive mentoring and micro-electronics research for students in engineering (IMMERSE) This paper describes an undergraduate research program called IMMERSE that has been implemented in the Electrical and Computer Engineering Department at Brigham Young University. Approximately 50 students per year participate along with 12 faculty members. The objectives of the IMMERSE program are to prepare student to continue on to graduate school and to enable students to publish their research in peer-reviewed venues. The key features of the program are (1) a single point of entry, (2) long-term and authentic research experiences, (3) participation in a broader impact project, and (4) personal mentoring between students and faculty. since its inception in 2003, the program has had 251 total student participants that have published 225 peer reviewed publications and 75% have continued on to graduate school. © American Society for Engineering Education, 2018.
29 a7201741468 Schultz S. p489 True Conference 181 Designing a sustainable large-scale project-based learning (PBL) experience for juniors in electrical and computer engineering This paper presents a large-scale Project-Based Learning (PBL) curriculum that can handle 200 students per year without requiring an undue commitment of faculty or teaching-assistant time. The following strategies were used to attain the student benefits of the PBL curriculum while accommodating a large number of students and while keeping the faculty and teaching-assistant commitments to reasonable levels. (1) A top-level hardware/software specification of the system (laser-tag) is provided to the students. (2) Students must test their software and hardware using both their own methods and with provided test software and hardware fixtures. (3) How-to and demonstration videos are provided via a dedicated youTube channel. (4) Students implement the system by completing a series of scheduled milestones. (5) The same PBL project is completed every year. This large scale PBL curriculum is conducted during the junior year and has been in place for several years in the Electrical and Computer Engineering Department. © American Society for Engineering Education, 2018.
30 a7402786794 Peters K. p6 False Journal 4 Survivability of integrated fiber Bragg grating sensors in ballistic protection fabrics for high velocity impact testing This research demonstrates that fiber Bragg grating (FBG) strain sensors can survive and provide useful strain information when integrated into a woven fabric subjected to ballistic impact testing. In this work, FBGs were integrated into a single-layer, Kevlar® fabric, sensing mat, placed between a 30-layer Kevlar® fabric shoot pack and clay backing material, and then impacted with an 8.23 g, 12.69 mm diameter, steel ball bearing at velocities up to 285 m/s. Three different optical fiber types, with differing fiber coatings and fiber diameters, were tested. The FBG strain response was determined from the full-spectrum FBG response which was interrogated at 100 kHz throughout the impact event. The difference in FBG strain response for the different coatings and fiber diameters were compared. Additionally, the degradation of the coatings after repeated impacts were visually characterized, showing that smaller diameter fibers behaved better with a more elastic coating. © 2020 Elsevier Inc.
30 a7402786794 Peters K. p13 False Journal 11 In-situ strain measurement of ballistic fabrics during impact using fiber Bragg gratings In previous experiments, the authors demonstrated that strain values collected from fiber Bragg gratings (FBG) integrated into a single layer of Kevlar fabric, placed between a soft armor test specimen and backing material, could be related to the time dependent back-face deformation (BFD) of the armor sample. In this paper, we investigate the specific fabric deformation and failure mechanisms that cause observed events in the FBG measured strain behavior and the FBG spectral profile throughout the impact event. For these experiments, the standard clay backing material was replaced with a 20% clear ballistic gel to provide visual access to the back-face. The test specimen was impacted by an 8.24 g steel ball bearing travelling at 248.8 m/s, during which strain was calculated from the measured full spectrum response of the FBG using a high-speed optical interrogation system. The strain response was compared to the BFD of the Kevlar sample. The BFD was measured through the clear ballistic gel using two high speed cameras recording at 100,000 fps. The results from these tests can be used for future testing using a non-transparent backing material to obtain a detailed strain–time history, back-face deformation history and an understanding of the time sequence of physical energy dissipation mechanisms in the fabric. © 2020 Elsevier Inc.
30 a7402786794 Peters K. p188 False Journal 129 Soft body armor time-dependent back face deformation (BFD) with ballistics gel backing This paper presents a method for obtaining time dependent back face deformation (BFD) data for body armor during ballistic impact using a clear ballistics gelatin backing and high-speed cameras to capture the deformation profile. Using this method, baseline fabric characterization data was obtained for samples comprised of varying layers of 467 g/m 2 Kevlar K29 fabric impacted with 8.24 g steel ball projectile and backed with NATO standard 20% clear ballistics gelatin. For these tests, deformation depths were seen to increase with increasing impact energy and decreasing total areal density. A limited study of the various test parameters was performed by testing one additional fabric, projectile, and ballistics gelatin. From these comparisons, it was observed that 122 g/m 2 Kevlar KM2+ fabric performs better per weight than 467 g/m 2 Kevlar K29 fabric in terms of BFD, 9 mm FMJ projectiles produce deeper BFDs than 12.7 mm steel ball projectiles, and backing a sample with FBI standard 10% ballistics gel increases the BFD considerably over NATO standard 20% ballistics gel. © 2019
30 a7402786794 Peters K. p645 False Conference 277 In-situ measurements of strain in soft body armor with FBG sensors during ballistic impacts The strain on a single FBG sensor, integrated into a single layer of Kevlar mounted behind a Kevlar soft body armor coupon, is measured throughout a ballistic impact event. The strain is collected through high-speed, full-spectral interrogation of the FBG during the event. The use of the wavelength shift and spectral distortion of the FBG provides a description of the strain profile and interaction between the optical fiber and Kevlar fabric. The measurements are correlated to high-speed camera images taken from the rear and side of the armor coupon. In future testing, this information can be applied to identify the sequence of energy dissipation mechanisms enacted within the armor to resist the ballistic impact. © OSA 2018 © 2018 The Author(s)
30 a7402786794 Peters K. p678 False Conference 291 High-Speed Interrogation of Multiplexed Fiber Bragg Gratings with Spectral Distortion Fiber Bragg grating (FBG) sensors can be multiplexed in large numbers to monitor the performance of large structures. This paper addresses the collection of FBG reflection spectra from wavelength division multiplexed sensors at fast acquisition rates. The spectral and temporal resolution is first derived as a function of the tunable filter and measurement system properties. The method is applied to impact loading investigations of a stiffened composite skin panel. The reflected spectrum of each FBG in an array, embedded in the panel, is collected at 100 kHz during the impact events with a spectral resolution down to 40 pm. Visualization of the FBG responses to these impact events, including the presence of spectral distortion in some FBG spectra, is presented. Future analyses based on the full-spectral data sets can enable the assessment of the localized progression of internal damage in such structures. © 2001-2012 IEEE.
31 a57191822951 Coburn J. p7 True Journal 5 The effects of transition style for collaborative view sharing in immersive Virtual Reality New low-cost Virtual Reality (VR) technology is enabling large numbers of engineers and designers to be outfitted with VR tools. This, in turn, is making feasible new tools such as immersive, collaborative, design environments that reflect the collaborative environment of drafting tables while still providing all the power of modern, computer-based, design tools. However, before such an environment can be fully realized, basic issues surrounding collaboration in VR such as cybersickness and disorientation must be more fully addressed. This work presents the results of an experimental study conducted to characterize the trade-offs between different styles of transitioning collaborators to a shared view in an immersive virtual environment. The experimental task consisted of asking participants to identify in which quadrant of the car specific components were located. Quadrant identification was performed after a participant's virtual location was transitioned to a shared view location focused on the component to identify. The study was conducted with 45 participants who provided 1890 transition response datapoints. Analysis of these results suggests that, in many cases, collaborators are willing to experience some mild cybersickness in order to reduce their disorientation and improve both confidence and accuracy of component location identification. The results also support the recommendation that the best practice is to provide support for multiple transition styles and allow collaborators to select their preference. © 2020 Elsevier Ltd
31 a57191822951 Coburn J. p513 False Journal 282 A bi-directional interface for improved interaction with engineering models in virtual reality design reviews Leveraging virtual reality (VR) technology to enhance engineering design reviews has been an area of significant interest for researchers since the advent of modern VR. The ability to interact meaningfully with 3D computer-aided engineering models in these VR design reviews is an important, though often neglected, capability due to the difficulty of performing data translation between native computer-aided design (CAD) data and VR compatible file formats. A bi-directional interface was developed between a VR design review environment and a commercial CAD package that streamlines the data translation process. Transmitting both geometric data and selected metadata from the CAD system enabled the development of enhanced model interaction tools in a VR design review application. User experiments were performed that compared the enhanced tools developed to a baseline toolset. Participants success using these toolsets was measured as they performed tasks related to design understanding and decision making, such as counting the number of gears in a gearbox or evaluating the feasibility of a proposed design change in a four-cylinder engine. The analysis of the data from these experiments showed a statistically significant improvement in participants ability to understand the geometry of the model correctly, confidently, and quickly, as well as in participants ability to correctly and confidently understand the implications of a proposed design change when using the Enhanced Toolset. We conclude that the bi-directional interface concept developed in this work can be extended to enable advanced interaction with a diversity of engineering data in VR. © 2017, Springer-Verlag France.
31 a57191822951 Coburn J. p521 True Journal 274 Effectiveness of an Immersive Virtual Environment for Collaboration with Gesture Support Using Low-Cost Hardware Since the advent of modern computer-aided design software, engineers have been divorced from the highly collaborative environment previously enjoyed. Today's highly complex designs require modern software tools and the realities of a global economy often constrain engineers to remote collaboration. These conditions make it highly impractical to collaborate locally around physical models. Various approaches to creating new collaboration tools and software, which alleviate these issues, have been tried previously. However, past solutions either used expensive hardware, which is not widely available, or used standard two-dimensional (2D) monitors to share three-dimensional (3D) information. Recently, new low-cost virtual reality (VR) hardware has been introduced, which creates a highly immersive 3D experience at a tiny fraction of the cost of previous hardware. This work demonstrates an immersive collaborative environment built using a network of this hardware, which allows users to interact with gestures virtually and conducts a study to show its advantages over traditional video conferencing software. Copyright ©2018 by ASME.
31 a57191822951 Coburn J. p696 True Journal 339 A Review of the Capabilities of Current Low-Cost Virtual Reality Technology and Its Potential to Enhance the Design Process In the past few years, there have been some significant advances in consumer virtual reality (VR) devices. Devices such as the Oculus Rift, HTC Vive, Leap Motion™ Controller, and Microsoft Kinect® are bringing immersive VR experiences into the homes of consumers with much lower cost and space requirements than previous generations of VR hardware. These new devices are also lowering the barrier to entry for VR engineering applications. Past research has suggested that there are significant opportunities for using VR during design tasks to improve results and reduce development time. This work reviews the latest generation of VR hardware and reviews research studying VR in the design process. Additionally, this work extracts the major themes from the reviews and discusses how the latest technology and research may affect the engineering design process. We conclude that these new devices have the potential to significantly improve portions of the design process. Copyright © 2017 by ASME.
32 a57188654880 Freeman I. p7 False Journal 5 The effects of transition style for collaborative view sharing in immersive Virtual Reality New low-cost Virtual Reality (VR) technology is enabling large numbers of engineers and designers to be outfitted with VR tools. This, in turn, is making feasible new tools such as immersive, collaborative, design environments that reflect the collaborative environment of drafting tables while still providing all the power of modern, computer-based, design tools. However, before such an environment can be fully realized, basic issues surrounding collaboration in VR such as cybersickness and disorientation must be more fully addressed. This work presents the results of an experimental study conducted to characterize the trade-offs between different styles of transitioning collaborators to a shared view in an immersive virtual environment. The experimental task consisted of asking participants to identify in which quadrant of the car specific components were located. Quadrant identification was performed after a participant's virtual location was transitioned to a shared view location focused on the component to identify. The study was conducted with 45 participants who provided 1890 transition response datapoints. Analysis of these results suggests that, in many cases, collaborators are willing to experience some mild cybersickness in order to reduce their disorientation and improve both confidence and accuracy of component location identification. The results also support the recommendation that the best practice is to provide support for multiple transition styles and allow collaborators to select their preference. © 2020 Elsevier Ltd
32 a57188654880 Freeman I. p513 True Journal 282 A bi-directional interface for improved interaction with engineering models in virtual reality design reviews Leveraging virtual reality (VR) technology to enhance engineering design reviews has been an area of significant interest for researchers since the advent of modern VR. The ability to interact meaningfully with 3D computer-aided engineering models in these VR design reviews is an important, though often neglected, capability due to the difficulty of performing data translation between native computer-aided design (CAD) data and VR compatible file formats. A bi-directional interface was developed between a VR design review environment and a commercial CAD package that streamlines the data translation process. Transmitting both geometric data and selected metadata from the CAD system enabled the development of enhanced model interaction tools in a VR design review application. User experiments were performed that compared the enhanced tools developed to a baseline toolset. Participants success using these toolsets was measured as they performed tasks related to design understanding and decision making, such as counting the number of gears in a gearbox or evaluating the feasibility of a proposed design change in a four-cylinder engine. The analysis of the data from these experiments showed a statistically significant improvement in participants ability to understand the geometry of the model correctly, confidently, and quickly, as well as in participants ability to correctly and confidently understand the implications of a proposed design change when using the Enhanced Toolset. We conclude that the bi-directional interface concept developed in this work can be extended to enable advanced interaction with a diversity of engineering data in VR. © 2017, Springer-Verlag France.
32 a57188654880 Freeman I. p521 False Journal 274 Effectiveness of an Immersive Virtual Environment for Collaboration with Gesture Support Using Low-Cost Hardware Since the advent of modern computer-aided design software, engineers have been divorced from the highly collaborative environment previously enjoyed. Today's highly complex designs require modern software tools and the realities of a global economy often constrain engineers to remote collaboration. These conditions make it highly impractical to collaborate locally around physical models. Various approaches to creating new collaboration tools and software, which alleviate these issues, have been tried previously. However, past solutions either used expensive hardware, which is not widely available, or used standard two-dimensional (2D) monitors to share three-dimensional (3D) information. Recently, new low-cost virtual reality (VR) hardware has been introduced, which creates a highly immersive 3D experience at a tiny fraction of the cost of previous hardware. This work demonstrates an immersive collaborative environment built using a network of this hardware, which allows users to interact with gestures virtually and conducts a study to show its advantages over traditional video conferencing software. Copyright ©2018 by ASME.
32 a57188654880 Freeman I. p696 False Journal 339 A Review of the Capabilities of Current Low-Cost Virtual Reality Technology and Its Potential to Enhance the Design Process In the past few years, there have been some significant advances in consumer virtual reality (VR) devices. Devices such as the Oculus Rift, HTC Vive, Leap Motion™ Controller, and Microsoft Kinect® are bringing immersive VR experiences into the homes of consumers with much lower cost and space requirements than previous generations of VR hardware. These new devices are also lowering the barrier to entry for VR engineering applications. Past research has suggested that there are significant opportunities for using VR during design tasks to improve results and reduce development time. This work reviews the latest generation of VR hardware and reviews research studying VR in the design process. Additionally, this work extracts the major themes from the reviews and discusses how the latest technology and research may affect the engineering design process. We conclude that these new devices have the potential to significantly improve portions of the design process. Copyright © 2017 by ASME.
33 a57192247939 Švenda V.G. p8 True Journal 6 Probabilistic extension of flexible hybrid state estimation for cyber-physical systems This paper proposes a probabilistic extension to flexible hybrid state estimation (FHSE) for cyber-physical systems (CPSs). The main goal of the algorithm is improvement of the system state tracking when realistic communications are taken into account, by optimizing information and communication technology (ICT) usage. These advancements result in: 1) coping with ICT outages and inevitable irregularities (delay, packet drop and bad measurements); 2) determining the optimized state estimation execution frequencies based on expected measurement refresh times. Additionally, information about CPSs is gathered from both the phasor measurement units (PMU) and SCADA-based measurements. This measurement transfer introduces two network observability types, which split the system into observable (White) and unobservable (Grey) areas, based on 1) deployed measuring instruments (MIs) and 2) received measurements. A two-step bad data detection (BDD) method is introduced for ICT irregularities and outages. The proposed algorithm benefits are shown on two IEEE test cases with time-varying load/generation: 14-bus and 300-bus. © 2020 Elsevier Ltd
33 a57192247939 Švenda V.G. p36 True Journal 30 Flexible hybrid state estimation for power systems with communication irregularities This study proposes a novel flexible hybrid state estimation (SE) algorithm when a realistic communication system with its irregularities is taken into account. This system is modelled by the Network Simulator 2 software tool, which is also used to calculate communication delays and packet drop probabilities. Within this setup, the system observability can be predicted, and the proposed SE can decide between using the static SE (SSE) or the discrete Kalman filter plus SSE-based measurements and time alignment (Forecasting-aided SE). Flexible hybrid SE (FHSE) incorporates both phasor measurement units and supervisory control and data acquisition-based measurements, with different time stamps. The proposed FHSE with detailed modelling of the communication system is motivated by: (i) well-known issues in SSE (time alignment of the measurements, frequent un-observability for fixed SE time stamps etc.); and (ii) the need to model a realistic communication system (calculated communication delays and packet drop probabilities are a part of the proposed FHSE). Application of the proposed algorithm is illustrated for examples with time-varying bus load/generation on two IEEE test cases: 14-bus and 300-bus. © The Institution of Engineering and Technology 2020
33 a57192247939 Švenda V.G. p160 True Conference 30 Probabilistic Network Observability of a Hybrid Power System with Communication Irregularities This paper explores power system network observability while taking into account realistic communication network behavior. The overall information is obtained by combining SCADA-and phasor measurement unit-derived data, where time stamping (based on Global Positioning System or an equivalent local clock) for all measurements is assumed. Based on simulations performed in communication Network Simulator 2, empirical cumulative distribution functions can be associated with transfer times of measurement packets, which will reflect communication parameters and irregularities. This is further used to form an algorithm which maximizes the number of successful network observability checks, and thus the number of possible state estimations, in a certain time period. Application is demonstrated on the IEEE 14-bus test power system example. © 2019 IEEE.
33 a57192247939 Švenda V.G. p406 True Conference 152 Influence of Communication Irregularities and Co-simulation on Hybrid Power System State Estimation The paper explores the effects of sensor behavior and communication system (CS) irregularities on power system state estimation (SE). CS are modeled in Network Simulator 2 (NS-2), allowing the quantification of irregularities, including delays and dropped packets. The overall information is obtained combining SCADA measurements with phasor measurement unit (PMU) derived data, where time stamping (based on GPS or an equivalent local clock) for all measurements is assumed. To fully analyze the effects of irregularities, a detailed analysis of sensitivities to different communication system parameters is provided as well. Using the co-simulation environment PiccSIM, a SE with these irregularities is quantified for CS parameter variation, with detailed models of power and communication flows. © 2018 IEEE.
33 a57192247939 Švenda V.G. p541 False Conference 195 Hybrid power system state estimation with irregular sampling The paper proposes a power system state estimation algorithm in the presence of irregular sensor sampling and random communication delays. Our state estimator incorporates Phasor Measurement Units (PMU) and SCADA measurements. We use an Extended Kalman filter based algorithm for time alignment of measurements and state variables. Time stamps are assumed for PMU, SCADA and state estimation. Application of the proposed algorithm is illustrated for hourly/daily load/generation variations on two test examples: 14-bus and 118-bus. © 2017 IEEE.
34 a57218593962 Walker Z. p9 True Journal 7 Solid-state membranes formed on natural menisci We present a method to create robust, nanoscale solid-state membranes using the natural shape of a liquid meniscus as a template. A narrow, open channel is etched into a silicon substrate and then a photoresist polymer is introduced into the channel through spontaneous capillary action. The natural concave meniscus formed by the polymer is then covered by a thin chemical vapor deposited membrane. The polymer is removed by sacrificial etching, leaving behind a suspended membrane. Membranes as large as 20 μm by 9 mm can be fabricated with a thickness as low as 50 nm. © 2020 IOP Publishing Ltd.
35 a57218593446 Wells T. p9 False Journal 7 Solid-state membranes formed on natural menisci We present a method to create robust, nanoscale solid-state membranes using the natural shape of a liquid meniscus as a template. A narrow, open channel is etched into a silicon substrate and then a photoresist polymer is introduced into the channel through spontaneous capillary action. The natural concave meniscus formed by the polymer is then covered by a thin chemical vapor deposited membrane. The polymer is removed by sacrificial etching, leaving behind a suspended membrane. Membranes as large as 20 μm by 9 mm can be fabricated with a thickness as low as 50 nm. © 2020 IOP Publishing Ltd.
36 a57218591162 Lay K. p9 False Journal 7 Solid-state membranes formed on natural menisci We present a method to create robust, nanoscale solid-state membranes using the natural shape of a liquid meniscus as a template. A narrow, open channel is etched into a silicon substrate and then a photoresist polymer is introduced into the channel through spontaneous capillary action. The natural concave meniscus formed by the polymer is then covered by a thin chemical vapor deposited membrane. The polymer is removed by sacrificial etching, leaving behind a suspended membrane. Membranes as large as 20 μm by 9 mm can be fabricated with a thickness as low as 50 nm. © 2020 IOP Publishing Ltd.
37 a57201772566 Sampad M.J.N. p9 False Journal 7 Solid-state membranes formed on natural menisci We present a method to create robust, nanoscale solid-state membranes using the natural shape of a liquid meniscus as a template. A narrow, open channel is etched into a silicon substrate and then a photoresist polymer is introduced into the channel through spontaneous capillary action. The natural concave meniscus formed by the polymer is then covered by a thin chemical vapor deposited membrane. The polymer is removed by sacrificial etching, leaving behind a suspended membrane. Membranes as large as 20 μm by 9 mm can be fabricated with a thickness as low as 50 nm. © 2020 IOP Publishing Ltd.
38 a16422844400 Schmidt H. p9 False Journal 7 Solid-state membranes formed on natural menisci We present a method to create robust, nanoscale solid-state membranes using the natural shape of a liquid meniscus as a template. A narrow, open channel is etched into a silicon substrate and then a photoresist polymer is introduced into the channel through spontaneous capillary action. The natural concave meniscus formed by the polymer is then covered by a thin chemical vapor deposited membrane. The polymer is removed by sacrificial etching, leaving behind a suspended membrane. Membranes as large as 20 μm by 9 mm can be fabricated with a thickness as low as 50 nm. © 2020 IOP Publishing Ltd.
38 a16422844400 Schmidt H. p62 False Journal 45 3D hydrodynamic focusing in microscale optofluidic channels formed with a single sacrificial layer Optofluidic devices are capable of detecting single molecules, but greater sensitivity and specificity is desired through hydrodynamic focusing (HDF). Three-dimensional (3D) hydrodynamic focusing was implemented in 10-μm scale microchannel cross-sections made with a single sacrificial layer. HDF is achieved using buffer fluid to sheath the sample fluid, requiring four fluid ports to operate by pressure driven flow. A low-pressure chamber, or pit, formed by etching into a substrate, enables volumetric flow ratio-induced focusing at a low flow velocity. The single layer design simplifies surface micromachining and improves device yield by 1.56 times over previous work. The focusing design was integrated with optical waveguides and used in order to analyze fluorescent signals from beads in fluid flow. The implementation of the focusing scheme was found to narrow the distribution of bead velocity and fluorescent signal, giving rise to 33% more consistent signal. Reservoir effects were observed at low operational vacuum pressures and a balance between optofluidic signal variance and intensity was achieved. The implementation of the design in optofluidic sensors will enable higher detection sensitivity and sample specificity. © 2020 by the authors.
38 a16422844400 Schmidt H. p171 False Conference 35 Free Space Excitation in Optofluidic Devices for Single Particle Detection Free space top-down illumination of liquid-core waveguides in an optofluidic chip is implemented by milling slits into a metal layer covering the waveguide channel. Detection of single microbeads with excellent signal-to-noise ratio is demonstrated for different milling depths. © 2019 IEEE.
38 a16422844400 Schmidt H. p172 False Conference 36 Multiplexed Detection of Single Antibiotic Drug-Resistant Plasmids using Multimode Interference Waveguide Based Optofluidic Chip A single multimode interference waveguide is used to create distinct spectral spot patterns on two liquid-core waveguides on an optofluidic chip. This device is used for multiplexed detection of antibiotic-resistant plasmids with single nucleic acid sensitivity. © 2019 IEEE.
38 a16422844400 Schmidt H. p173 False Conference 37 Three-Dimensional Hydrodynamic Focusing Designs for Integrated Optofluidic Detection Enhancement Three-dimensional hydrodynamic focusing promises to enhance detection capabilities of optofluidic sensors, enabling low concentration interrogation with higher confidence, critical for disease diagnosis. Novel 3DHDF designs with optofluidic channel diameters in the range of ten microns are evaluated, predicting detection enhancement of up to 3.54 times. © 2019 IEEE.
38 a16422844400 Schmidt H. p235 False Conference 56 Single Particle Detection Enhancement with Wavelet-based Signal Processing Technique Chip-based single molecule detection requires ultra-sensitive devices and robust signal processing methods. A new wavelet-based signal processing method is introduced that improves detection and error rates on an optofluidic platform by 2x and 3x, respectively. © 2019 The Author(s) 2019 OSA.
38 a16422844400 Schmidt H. p239 False Conference 57 Optofluidic Platform with Integrated Optical Waveguides and Sample Preparation for Digitized Detection of Nucleic Acid Targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s) 2019 OSA.
38 a16422844400 Schmidt H. p347 False Conference 119 Single particle detection enhancement with wavelet-based signal processing technique Chip-based single molecule detection requires ultra-sensitive devices and robust signal processing methods. A new wavelet-based signal processing method is introduced that improves detection and error rates on an optofluidic platform by 2x and 3x, respectively. © 2019 The Author(s)
38 a16422844400 Schmidt H. p350 False Journal 196 Enhanced Detection of Single Viruses On-Chip via Hydrodynamic Focusing Planar optofluidics provide a powerful tool for facilitating chip-scale light-matter interactions. Silicon-based liquid core waveguides have been shown to offer single molecule sensitivity for efficient detection of bioparticles. Recently, a PDMS based planar optofluidic platform was introduced that opens the way to rapid development and prototyping of unique structures, taking advantage of the positive attributes of silicon dioxide-based optofluidics and PDMS based microfluidics. Here, hydrodynamic focusing is integrated into a PDMS based optofluidic chip to enhance the detection of single H1N1 viruses on-chip. Chip-plane focusing is provided by a system of microfluidic channels to force the particles towards a region of high optical collection efficiency. Focusing is demonstrated and enhanced detection is quantified using fluorescent polystyrene beads where the coefficient of variation is found to decrease by a factor of 4 with the addition of hydrodynamic focusing. The mean signal amplitude of fluorescently tagged single H1N1 viruses is found to increase with the addition of focusing by a factor of 1.64. © 1995-2012 IEEE.
38 a16422844400 Schmidt H. p359 False Journal 200 Broadband antireflective light-blocking layer using nanoparticle suspension in photoresist with high-resolution patterning Background: Many MEMS and optical sensor devices can benefit from layers that block transmission and suppress reflection of light across the visible spectrum. Because these devices can include complicated topography, many existing methods for depositing antireflective layers are difficult, impractical, or unusable. Aim: To create a light-blocking antireflective layer that works well with complicated MEMS and sensor devices, a layer should be made that is cheap, simple, and can be deposited and patterned with high resolution at low temperatures. Approach: Light blocking is achieved using an aluminum layer. Suppressing reflection is achieved by mixing aluminum oxide nanoparticles in photoresist to create a layer that partially absorbs and partially scatters light. Results: The combination of a layer of metal and a layer of nanoparticles and photoresist completely blocks transmission of light and significantly reduces reflections across the visible spectrum, particularly for shorter wavelengths. The layer is also patternable to sizes as small as a few microns with high resolution. Conclusion: By combining a metal layer and a layer of nanoparticles in photoresist, a simple, cheap, and effective light-blocking antireflective layer can be created that is compatible with planar devices with complex topography. © 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).
38 a16422844400 Schmidt H. p378 False Conference 137 Optofluidic platform with integrated optical waveguides and sample preparation for digitized detection of nucleic acid targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s)
38 a16422844400 Schmidt H. p407 False Journal 217 Integration of sample preparation and analysis into an optofluidic chip for multi-target disease detection Detection of molecular biomarkers with high specificity and sensitivity from biological samples requires both sophisticated sample preparation and subsequent analysis. These tasks are often carried out on separate platforms which increases required sample volumes and the risk of errors, sample loss, and contamination. Here, we present an optofluidic platform which combines an optical detection section with single nucleic acid strand sensitivity, and a sample processing unit capable of on-chip, specific extraction and labeling of nucleic acid and protein targets in complex biological matrices. First, on-chip labeling and detection of individual lambda DNA molecules down to concentrations of 8 fM is demonstrated. Subsequently, we demonstrate the simultaneous capture, fluorescence tagging and detection of both Zika specific nucleic acid and NS-1 protein targets in both buffer and human serum. We show that the dual DNA and protein assay allows for successful differentiation and diagnosis of Zika against cross-reacting species like dengue. © The Royal Society of Chemistry 2018.
38 a16422844400 Schmidt H. p459 False Journal 256 Buried Rib SiO2 Multimode Interference Waveguides for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used to create wavelength-dependent spot patterns which enables simultaneous analyte detection on a single optofluidic chip, useful for disease diagnostics. The fidelity of such multi-spot patterns is important for high sensitivity and accurate target identification. Buried rib structures have been incorporated into these SiO2-based waveguides to improve environmental stability. Through experiments and simulation, this letter explores design parameters for a buried MMI rib waveguide based on anti-resonant reflecting optical waveguides in order to produce high-fidelity spot patterns. Optimal rib heights and widths are reported in the context of available microfabrication etch technology and performance for an optimized biosensor is shown. © 1989-2012 IEEE.
38 a16422844400 Schmidt H. p502 False Journal 273 Optimized ARROW-Based MMI Waveguides for High Fidelity Excitation Patterns for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used for multiplexing and de-multiplexing optical signals. High fidelity, wavelength dependent multi-spot patterns from MMI waveguides are useful for sensitive and simultaneous identification of multiple targets in multiplexed fluorescence optofluidic biosensors. Through experiments and simulation, this paper explores design parameters for an MMI rib anti-resonant reflecting optical waveguide in order to produce high fidelity spot patterns at the liquid core biomarker excitation region. Width and etch depth of the single excitation rib waveguide used to excite the MMI waveguide are especially critical because they determine the size of the input optical mode which is imaged at the MMI waveguide's output. To increase optical throughput into the MMI waveguide when light is coupled in from an optical fiber, tapers in the waveguide width can be used for better mode matching. © 2012 IEEE.
38 a16422844400 Schmidt H. p607 False Conference 245 High fidelity MMI excitation patterns for optofluidic multiplexing High fidelity interference patterns from multimode interference waveguides are needed for multiplexed optofluidic biosensors. Spot pattern fidelity can be optimized by careful design of the single-mode waveguides used to excite the multimode waveguides. © OSA 2018.
38 a16422844400 Schmidt H. p608 False Conference 246 3D hydrodynamic focusing for optofluidics using a stacked channel design We present a 3D hydrodynamic focusing design suitable for optofluidic devices allowing planar fabrication and velocity independent particle focusing. Simulations are presented and fabrication outlined with evidence that stacked SU8 layers are suitable building blocks. © OSA 2018.
38 a16422844400 Schmidt H. p706 False Journal 347 Optofluidic lab-on-a-chip fluorescence sensor using integrated buried ARROW (bARROW) waveguides Optofluidic, lab-on-a-chip fluorescence sensors were fabricated using buried anti-resonant reflecting optical waveguides (bARROWs). The bARROWs are impervious to the negative water absorption effects that typically occur in waveguides made using hygroscopic, plasma-enhanced chemical vapor deposition (PECVD) oxides. These sensors were used to detect fluorescent microbeads and had an average signal-to-noise ratio (SNR) that was 81.3% higher than that of single-oxide ARROW fluorescence sensors. While the single-oxide ARROW sensors were annealed at 300 ◦ C to drive moisture out of the waveguides, the bARROW sensors required no annealing process to obtain a high SNR. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.
38 a16422844400 Schmidt H. p749 False Journal 363 Mitigating Water Absorption in Waveguides Made from Unannealed PECVD SiO2 Water absorption was studied in two types of waveguides made from unannealed plasma enhanced chemical vapor deposition (PECVD) SiO2. Standard rib anti-resonant reflecting optical waveguides (ARROWs) were fabricated with thin films of different intrinsic stress and indices of refraction. Buried ARROWs (bARROWs) with low and high refractive index differences between the core and cladding regions were also fabricated from the same types of PECVD films. All waveguides were subjected to a heated, high humidity environment and their optical throughput was tested over time. Due to water absorption in the SiO2 films, the optical throughput of all of the ARROWs decreased with time spent in the wet environment. The ARROWs with the lowest stress SiO2 had the slowest rate of throughput change. High index difference bARROWs showed no decrease in optical throughput after 40 days in the wet environment and are presented as a solution for environmentally stable waveguides made from unannealed PECVD SiO2. © 2017 IEEE.
38 a16422844400 Schmidt H. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
38 a16422844400 Schmidt H. p786 False Conference 323 MMI waveguide based multispectral detection of nucleic acids for analysis of drug-resistant bacteria A multi-mode interference waveguide is used for creating distinct temporal fluorescence patterns at multiple excitation wavelengths. This allows for identification of bacterial nucleic acids labeled with molecular beacons in two colors. © 2016 IEEE.
38 a16422844400 Schmidt H. p787 False Conference 324 Design and characterization of integrated 2D ABEL trap Design and characterization of a chip-based electro-optic single-particle trap with feedback-based confinement in two dimensions is demonstrated. Improvements over 1D confinement and integration of nanopores for gated delivery of individual nanoparticles are discussed. © 2016 IEEE.
38 a16422844400 Schmidt H. p839 False Conference 366 Preserving optical confinement in unannealed PECVD SiO2 waveguides Rib and buried channel waveguides (BCWs) made of unannealed PECVD SiO2 were studied after exposure to high humidity. Low stressed rib waveguides had lower optical throughput change, while high index difference BCWs were practically unaffected. © 2017 OSA.
38 a16422844400 Schmidt H. p840 False Conference 367 Multimodal multiplexing of single-virus detection using multi-mode interference waveguides Multi-mode interference waveguides are used to implement simultaneous spectral and spatial multiplex fluorescence analysis in liquid-core waveguide channels. A six-times multiplex identification of single influenza viruses is demonstrated with two excitation colors and threechannels. © 2017 OSA.
38 a16422844400 Schmidt H. p841 False Conference 368 Single particle fluorescence analysis on demand on electro-optofluidic chip with gated particle delivery Electronic feedback enables introduction of single microbeads and DNA molecules into a liquid-core waveguide through a micro/nanopore. Subsequent fluorescence detection from a controlled number of individual particles is demonstrated, enabling single particle analysis on demand. © 2017 OSA.
38 a16422844400 Schmidt H. p860 False Journal 402 Optofluidic bioanalysis: Fundamentals and applications Over the past decade, optofluidics has established itself as a new and dynamic research field for exciting developments at the interface of photonics, microfluidics, and the life sciences. The strong desire for developing miniaturized bioanalytic devices and instruments, in particular, has led to novel and powerful approaches to integrating optical elements and biological fluids on the same chip-scale system. Here, we review the state-of-the-art in optofluidic research with emphasis on applications in bioanalysis and a focus on waveguide-based approaches that represent the most advanced level of integration between optics and fluidics. We discuss recent work in photonically reconfigurable devices and various application areas. We show how optofluidic approaches have been pushing the performance limits in bioanalysis, e.g. in terms of sensitivity and portability, satisfying many of the key requirements for point-of-care devices. This illustrates how the requirements for bianalysis instruments are increasingly being met by the symbiotic integration of novel photonic capabilities in a miniaturized system. © 2017, Holger Schmidt et al.
39 a7102975249 Hawkins A. p9 False Journal 7 Solid-state membranes formed on natural menisci We present a method to create robust, nanoscale solid-state membranes using the natural shape of a liquid meniscus as a template. A narrow, open channel is etched into a silicon substrate and then a photoresist polymer is introduced into the channel through spontaneous capillary action. The natural concave meniscus formed by the polymer is then covered by a thin chemical vapor deposited membrane. The polymer is removed by sacrificial etching, leaving behind a suspended membrane. Membranes as large as 20 μm by 9 mm can be fabricated with a thickness as low as 50 nm. © 2020 IOP Publishing Ltd.
39 a7102975249 Hawkins A. p21 False Conference 2 Low-Noise, Low-Power Pulse Shaper for Particle Detection (Invited Paper) Pulse shapers are widely used in particle detector applications to reduce the rise and fall times of the pulse signal and to remove noise from the frontend amplifiers. We demonstrate a low-noise, low-power pulse shaper employing an active lowpass Salley-Key biquad filter, passive highpass filter, and input/output buffers. The design process is described to generate the desired transfer characteristic while incorporating tuning knobs to adapt the shaper characteristic to the needs of different applications. Utilizing only a single 1.8-V supply, the shaper consumes 1.5 mW and achieves an input-referred noise of 17 µVrms, both the lowest among state-of-the-art. The power efficiency normalized to bandwidth and noise is nearly 1.7× better than the next best design. © 2020 IEEE.
39 a7102975249 Hawkins A. p47 False Journal 37 Direct macro-to-micro interface method for microfluidics The macro-to-micro interface method presented here meets many of the requirements for an ideal interconnect by sealing a short length of plastic tubing directly to a microfluidic chip. The adaptability and low-temperature processing make it compatible with a wide range of device materials. The method was validated on silicon, acrylic (polymethyl methacrylate), printed circuit board and glass substrates with high-pressure integrity to over 300 psi (2 MPa). Fluid interfaces created with this method were used for pressure tests on microfluidic channels constructed on silicon. © 2020 IOP Publishing Ltd.
39 a7102975249 Hawkins A. p62 False Journal 45 3D hydrodynamic focusing in microscale optofluidic channels formed with a single sacrificial layer Optofluidic devices are capable of detecting single molecules, but greater sensitivity and specificity is desired through hydrodynamic focusing (HDF). Three-dimensional (3D) hydrodynamic focusing was implemented in 10-μm scale microchannel cross-sections made with a single sacrificial layer. HDF is achieved using buffer fluid to sheath the sample fluid, requiring four fluid ports to operate by pressure driven flow. A low-pressure chamber, or pit, formed by etching into a substrate, enables volumetric flow ratio-induced focusing at a low flow velocity. The single layer design simplifies surface micromachining and improves device yield by 1.56 times over previous work. The focusing design was integrated with optical waveguides and used in order to analyze fluorescent signals from beads in fluid flow. The implementation of the focusing scheme was found to narrow the distribution of bead velocity and fluorescent signal, giving rise to 33% more consistent signal. Reservoir effects were observed at low operational vacuum pressures and a balance between optofluidic signal variance and intensity was achieved. The implementation of the design in optofluidic sensors will enable higher detection sensitivity and sample specificity. © 2020 by the authors.
39 a7102975249 Hawkins A. p99 False Journal 37 Nanofluidic peristaltic pumps made from silica thin films We present theory for operation and experimental results for a nanoscale pump implemented in silica thin films that uses electrostatic actuation. The devices were implemented on silicon substrates using standard microfabrication recipes. Using pressures induced by capillary forces, the pressures exerted on pump membranes through electrostatic forces, and the approximate displacement per stroke we predict the pump speed operating the device over a range of frequencies and voltages. For membranes 100 nm thick, 170 V was required for pump actuation, providing exquisite control of pumping rates of less than 1 fl s-1 per nanochannel. © 2019 IOP Publishing Ltd.
39 a7102975249 Hawkins A. p171 False Conference 35 Free Space Excitation in Optofluidic Devices for Single Particle Detection Free space top-down illumination of liquid-core waveguides in an optofluidic chip is implemented by milling slits into a metal layer covering the waveguide channel. Detection of single microbeads with excellent signal-to-noise ratio is demonstrated for different milling depths. © 2019 IEEE.
39 a7102975249 Hawkins A. p172 False Conference 36 Multiplexed Detection of Single Antibiotic Drug-Resistant Plasmids using Multimode Interference Waveguide Based Optofluidic Chip A single multimode interference waveguide is used to create distinct spectral spot patterns on two liquid-core waveguides on an optofluidic chip. This device is used for multiplexed detection of antibiotic-resistant plasmids with single nucleic acid sensitivity. © 2019 IEEE.
39 a7102975249 Hawkins A. p173 False Conference 37 Three-Dimensional Hydrodynamic Focusing Designs for Integrated Optofluidic Detection Enhancement Three-dimensional hydrodynamic focusing promises to enhance detection capabilities of optofluidic sensors, enabling low concentration interrogation with higher confidence, critical for disease diagnosis. Novel 3DHDF designs with optofluidic channel diameters in the range of ten microns are evaluated, predicting detection enhancement of up to 3.54 times. © 2019 IEEE.
39 a7102975249 Hawkins A. p235 False Conference 56 Single Particle Detection Enhancement with Wavelet-based Signal Processing Technique Chip-based single molecule detection requires ultra-sensitive devices and robust signal processing methods. A new wavelet-based signal processing method is introduced that improves detection and error rates on an optofluidic platform by 2x and 3x, respectively. © 2019 The Author(s) 2019 OSA.
39 a7102975249 Hawkins A. p239 False Conference 57 Optofluidic Platform with Integrated Optical Waveguides and Sample Preparation for Digitized Detection of Nucleic Acid Targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s) 2019 OSA.
39 a7102975249 Hawkins A. p347 False Conference 119 Single particle detection enhancement with wavelet-based signal processing technique Chip-based single molecule detection requires ultra-sensitive devices and robust signal processing methods. A new wavelet-based signal processing method is introduced that improves detection and error rates on an optofluidic platform by 2x and 3x, respectively. © 2019 The Author(s)
39 a7102975249 Hawkins A. p350 False Journal 196 Enhanced Detection of Single Viruses On-Chip via Hydrodynamic Focusing Planar optofluidics provide a powerful tool for facilitating chip-scale light-matter interactions. Silicon-based liquid core waveguides have been shown to offer single molecule sensitivity for efficient detection of bioparticles. Recently, a PDMS based planar optofluidic platform was introduced that opens the way to rapid development and prototyping of unique structures, taking advantage of the positive attributes of silicon dioxide-based optofluidics and PDMS based microfluidics. Here, hydrodynamic focusing is integrated into a PDMS based optofluidic chip to enhance the detection of single H1N1 viruses on-chip. Chip-plane focusing is provided by a system of microfluidic channels to force the particles towards a region of high optical collection efficiency. Focusing is demonstrated and enhanced detection is quantified using fluorescent polystyrene beads where the coefficient of variation is found to decrease by a factor of 4 with the addition of hydrodynamic focusing. The mean signal amplitude of fluorescently tagged single H1N1 viruses is found to increase with the addition of focusing by a factor of 1.64. © 1995-2012 IEEE.
39 a7102975249 Hawkins A. p359 False Journal 200 Broadband antireflective light-blocking layer using nanoparticle suspension in photoresist with high-resolution patterning Background: Many MEMS and optical sensor devices can benefit from layers that block transmission and suppress reflection of light across the visible spectrum. Because these devices can include complicated topography, many existing methods for depositing antireflective layers are difficult, impractical, or unusable. Aim: To create a light-blocking antireflective layer that works well with complicated MEMS and sensor devices, a layer should be made that is cheap, simple, and can be deposited and patterned with high resolution at low temperatures. Approach: Light blocking is achieved using an aluminum layer. Suppressing reflection is achieved by mixing aluminum oxide nanoparticles in photoresist to create a layer that partially absorbs and partially scatters light. Results: The combination of a layer of metal and a layer of nanoparticles and photoresist completely blocks transmission of light and significantly reduces reflections across the visible spectrum, particularly for shorter wavelengths. The layer is also patternable to sizes as small as a few microns with high resolution. Conclusion: By combining a metal layer and a layer of nanoparticles in photoresist, a simple, cheap, and effective light-blocking antireflective layer can be created that is compatible with planar devices with complex topography. © 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).
39 a7102975249 Hawkins A. p378 False Conference 137 Optofluidic platform with integrated optical waveguides and sample preparation for digitized detection of nucleic acid targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s)
39 a7102975249 Hawkins A. p407 False Journal 217 Integration of sample preparation and analysis into an optofluidic chip for multi-target disease detection Detection of molecular biomarkers with high specificity and sensitivity from biological samples requires both sophisticated sample preparation and subsequent analysis. These tasks are often carried out on separate platforms which increases required sample volumes and the risk of errors, sample loss, and contamination. Here, we present an optofluidic platform which combines an optical detection section with single nucleic acid strand sensitivity, and a sample processing unit capable of on-chip, specific extraction and labeling of nucleic acid and protein targets in complex biological matrices. First, on-chip labeling and detection of individual lambda DNA molecules down to concentrations of 8 fM is demonstrated. Subsequently, we demonstrate the simultaneous capture, fluorescence tagging and detection of both Zika specific nucleic acid and NS-1 protein targets in both buffer and human serum. We show that the dual DNA and protein assay allows for successful differentiation and diagnosis of Zika against cross-reacting species like dengue. © The Royal Society of Chemistry 2018.
39 a7102975249 Hawkins A. p459 False Journal 256 Buried Rib SiO2 Multimode Interference Waveguides for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used to create wavelength-dependent spot patterns which enables simultaneous analyte detection on a single optofluidic chip, useful for disease diagnostics. The fidelity of such multi-spot patterns is important for high sensitivity and accurate target identification. Buried rib structures have been incorporated into these SiO2-based waveguides to improve environmental stability. Through experiments and simulation, this letter explores design parameters for a buried MMI rib waveguide based on anti-resonant reflecting optical waveguides in order to produce high-fidelity spot patterns. Optimal rib heights and widths are reported in the context of available microfabrication etch technology and performance for an optimized biosensor is shown. © 1989-2012 IEEE.
39 a7102975249 Hawkins A. p485 False Conference 177 Intensive mentoring and micro-electronics research for students in engineering (IMMERSE) This paper describes an undergraduate research program called IMMERSE that has been implemented in the Electrical and Computer Engineering Department at Brigham Young University. Approximately 50 students per year participate along with 12 faculty members. The objectives of the IMMERSE program are to prepare student to continue on to graduate school and to enable students to publish their research in peer-reviewed venues. The key features of the program are (1) a single point of entry, (2) long-term and authentic research experiences, (3) participation in a broader impact project, and (4) personal mentoring between students and faculty. since its inception in 2003, the program has had 251 total student participants that have published 225 peer reviewed publications and 75% have continued on to graduate school. © American Society for Engineering Education, 2018.
39 a7102975249 Hawkins A. p502 False Journal 273 Optimized ARROW-Based MMI Waveguides for High Fidelity Excitation Patterns for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used for multiplexing and de-multiplexing optical signals. High fidelity, wavelength dependent multi-spot patterns from MMI waveguides are useful for sensitive and simultaneous identification of multiple targets in multiplexed fluorescence optofluidic biosensors. Through experiments and simulation, this paper explores design parameters for an MMI rib anti-resonant reflecting optical waveguide in order to produce high fidelity spot patterns at the liquid core biomarker excitation region. Width and etch depth of the single excitation rib waveguide used to excite the MMI waveguide are especially critical because they determine the size of the input optical mode which is imaged at the MMI waveguide's output. To increase optical throughput into the MMI waveguide when light is coupled in from an optical fiber, tapers in the waveguide width can be used for better mode matching. © 2012 IEEE.
39 a7102975249 Hawkins A. p522 False Journal 262 Antireflective light-blocking layers using a liquid top matte coating Methods exist for the creation of antireflective thin film layers; however, many of these methods depend on the use of high temperatures, harsh chemical etches, or are made with difficult pattern materials, rendering them unusable for many applications. In addition, most methods of light blocking are specifically designed to increase light coupling and absorption in the substrate, making them incompatible with some applications that also require blocking transmission of light. A method of forming a simple, patternable light-blocking layer that drastically reduces both transmission and reflection of light without dependence on processes that could damage underlying structures using a light scattering matte coating over a partially antireflective thin film light-blocking layer is presented. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
39 a7102975249 Hawkins A. p607 False Conference 245 High fidelity MMI excitation patterns for optofluidic multiplexing High fidelity interference patterns from multimode interference waveguides are needed for multiplexed optofluidic biosensors. Spot pattern fidelity can be optimized by careful design of the single-mode waveguides used to excite the multimode waveguides. © OSA 2018.
39 a7102975249 Hawkins A. p608 False Conference 246 3D hydrodynamic focusing for optofluidics using a stacked channel design We present a 3D hydrodynamic focusing design suitable for optofluidic devices allowing planar fabrication and velocity independent particle focusing. Simulations are presented and fabrication outlined with evidence that stacked SU8 layers are suitable building blocks. © OSA 2018.
39 a7102975249 Hawkins A. p706 False Journal 347 Optofluidic lab-on-a-chip fluorescence sensor using integrated buried ARROW (bARROW) waveguides Optofluidic, lab-on-a-chip fluorescence sensors were fabricated using buried anti-resonant reflecting optical waveguides (bARROWs). The bARROWs are impervious to the negative water absorption effects that typically occur in waveguides made using hygroscopic, plasma-enhanced chemical vapor deposition (PECVD) oxides. These sensors were used to detect fluorescent microbeads and had an average signal-to-noise ratio (SNR) that was 81.3% higher than that of single-oxide ARROW fluorescence sensors. While the single-oxide ARROW sensors were annealed at 300 ◦ C to drive moisture out of the waveguides, the bARROW sensors required no annealing process to obtain a high SNR. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.
39 a7102975249 Hawkins A. p749 False Journal 363 Mitigating Water Absorption in Waveguides Made from Unannealed PECVD SiO2 Water absorption was studied in two types of waveguides made from unannealed plasma enhanced chemical vapor deposition (PECVD) SiO2. Standard rib anti-resonant reflecting optical waveguides (ARROWs) were fabricated with thin films of different intrinsic stress and indices of refraction. Buried ARROWs (bARROWs) with low and high refractive index differences between the core and cladding regions were also fabricated from the same types of PECVD films. All waveguides were subjected to a heated, high humidity environment and their optical throughput was tested over time. Due to water absorption in the SiO2 films, the optical throughput of all of the ARROWs decreased with time spent in the wet environment. The ARROWs with the lowest stress SiO2 had the slowest rate of throughput change. High index difference bARROWs showed no decrease in optical throughput after 40 days in the wet environment and are presented as a solution for environmentally stable waveguides made from unannealed PECVD SiO2. © 2017 IEEE.
39 a7102975249 Hawkins A. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
39 a7102975249 Hawkins A. p786 False Conference 323 MMI waveguide based multispectral detection of nucleic acids for analysis of drug-resistant bacteria A multi-mode interference waveguide is used for creating distinct temporal fluorescence patterns at multiple excitation wavelengths. This allows for identification of bacterial nucleic acids labeled with molecular beacons in two colors. © 2016 IEEE.
39 a7102975249 Hawkins A. p787 False Conference 324 Design and characterization of integrated 2D ABEL trap Design and characterization of a chip-based electro-optic single-particle trap with feedback-based confinement in two dimensions is demonstrated. Improvements over 1D confinement and integration of nanopores for gated delivery of individual nanoparticles are discussed. © 2016 IEEE.
39 a7102975249 Hawkins A. p839 False Conference 366 Preserving optical confinement in unannealed PECVD SiO2 waveguides Rib and buried channel waveguides (BCWs) made of unannealed PECVD SiO2 were studied after exposure to high humidity. Low stressed rib waveguides had lower optical throughput change, while high index difference BCWs were practically unaffected. © 2017 OSA.
39 a7102975249 Hawkins A. p840 False Conference 367 Multimodal multiplexing of single-virus detection using multi-mode interference waveguides Multi-mode interference waveguides are used to implement simultaneous spectral and spatial multiplex fluorescence analysis in liquid-core waveguide channels. A six-times multiplex identification of single influenza viruses is demonstrated with two excitation colors and threechannels. © 2017 OSA.
39 a7102975249 Hawkins A. p841 False Conference 368 Single particle fluorescence analysis on demand on electro-optofluidic chip with gated particle delivery Electronic feedback enables introduction of single microbeads and DNA molecules into a liquid-core waveguide through a micro/nanopore. Subsequent fluorescence detection from a controlled number of individual particles is demonstrated, enabling single particle analysis on demand. © 2017 OSA.
39 a7102975249 Hawkins A. p860 False Journal 402 Optofluidic bioanalysis: Fundamentals and applications Over the past decade, optofluidics has established itself as a new and dynamic research field for exciting developments at the interface of photonics, microfluidics, and the life sciences. The strong desire for developing miniaturized bioanalytic devices and instruments, in particular, has led to novel and powerful approaches to integrating optical elements and biological fluids on the same chip-scale system. Here, we review the state-of-the-art in optofluidic research with emphasis on applications in bioanalysis and a focus on waveguide-based approaches that represent the most advanced level of integration between optics and fluidics. We discuss recent work in photonically reconfigurable devices and various application areas. We show how optofluidic approaches have been pushing the performance limits in bioanalysis, e.g. in terms of sensitivity and portability, satisfying many of the key requirements for point-of-care devices. This illustrates how the requirements for bianalysis instruments are increasingly being met by the symbiotic integration of novel photonic capabilities in a miniaturized system. © 2017, Holger Schmidt et al.
40 a57193338296 Wu F. p10 True Journal 8 Assessing the environmental impact and payback of carbon nanotube supported CO2 capture technologies using LCA methodology Climate change caused by excessive CO2 emissions in the atmosphere has attracted widespread public concern in recent years. Current industrial methods generally utilize monoethanolamine for CO2 capture; however, the CO2 regeneration requires a high temperature and energy demand during every adsorption/desorption process, along with material losses. Many solid amines with high capture capacity and stability are developed as adsorbents to overcome the limitations. However, the environmental impacts caused by adsorbents themselves are not holistically considered and discussed; meanwhile, material syntheses and consumptions are also associated with CO2 emission. To determine the environmental impacts and identify hotspots of novel CO2 capture adsorbents, two carbon nanotube supported polyethyleneimine, physically adsorbed and covalently bonded, were compared with traditional monoethanolamine method using life cycle assessment. The carbon payback periods were also analyzed to gain understanding on whether the currently evaluated novel materials are suitable for industrial application. Results suggest that, material usage, especially carbon nanotubes, contributes the majority of the overall environmental impacts for both types of carbon nanotube supported polyethyleneimine. Meanwhile, their carbon payback periods are over 40 times longer than monoethanolamine during the synthesis phase. However, the energy consumption of physically adsorbed polyethyleneimine saves up to 60% compared to monoethanolamine in every adsorption/desorption cycle due to its lower heat capacity. In addition, the rate of cumulative CO2 remission for carbon nanotube supported polyethyleneimine is twice higher than monoethanolamine, indicating the potential application for industrial CO2 capture. Overall, our study indicates that current status of solid amine has a potential in CO2 capture, but requires much improvements. Future research should pay attention on decreasing the initial material synthesis and increasing the product life time due to their high environmental tradeoffs. Meanwhile, our study highlights that unilateral emphasis of the CO2 capture efficiency by novel materials may not be adequate, comprehensive considerations should be focused on the comparison throughout material life cycles including use and preparation phases. © 2020 Elsevier Ltd
41 a57194692502 Zhou Z. p10 False Journal 8 Assessing the environmental impact and payback of carbon nanotube supported CO2 capture technologies using LCA methodology Climate change caused by excessive CO2 emissions in the atmosphere has attracted widespread public concern in recent years. Current industrial methods generally utilize monoethanolamine for CO2 capture; however, the CO2 regeneration requires a high temperature and energy demand during every adsorption/desorption process, along with material losses. Many solid amines with high capture capacity and stability are developed as adsorbents to overcome the limitations. However, the environmental impacts caused by adsorbents themselves are not holistically considered and discussed; meanwhile, material syntheses and consumptions are also associated with CO2 emission. To determine the environmental impacts and identify hotspots of novel CO2 capture adsorbents, two carbon nanotube supported polyethyleneimine, physically adsorbed and covalently bonded, were compared with traditional monoethanolamine method using life cycle assessment. The carbon payback periods were also analyzed to gain understanding on whether the currently evaluated novel materials are suitable for industrial application. Results suggest that, material usage, especially carbon nanotubes, contributes the majority of the overall environmental impacts for both types of carbon nanotube supported polyethyleneimine. Meanwhile, their carbon payback periods are over 40 times longer than monoethanolamine during the synthesis phase. However, the energy consumption of physically adsorbed polyethyleneimine saves up to 60% compared to monoethanolamine in every adsorption/desorption cycle due to its lower heat capacity. In addition, the rate of cumulative CO2 remission for carbon nanotube supported polyethyleneimine is twice higher than monoethanolamine, indicating the potential application for industrial CO2 capture. Overall, our study indicates that current status of solid amine has a potential in CO2 capture, but requires much improvements. Future research should pay attention on decreasing the initial material synthesis and increasing the product life time due to their high environmental tradeoffs. Meanwhile, our study highlights that unilateral emphasis of the CO2 capture efficiency by novel materials may not be adequate, comprehensive considerations should be focused on the comparison throughout material life cycles including use and preparation phases. © 2020 Elsevier Ltd
41 a57194692502 Zhou Z. p449 False Journal 253 Synthesis of high-specific volume carbon nanotube structures for gas-phase applications A novel and efficient gas-phase method has been developed for synthesizing carbon nanotube (CNT) structures with very high specific volume, high surface area and high porosity. The resulting material has potential application as a catalyst and adsorbent support for gas-phase chemical processes and has several advantages over the conventional liquid-phase approach that involves multiple steps and takes many hours to days resulting in a dense mat of CNTs. Multi-walled CNTs were initially nucleated and grown on alumina nanoparticles using a liquid precursor of ferrocene dissolved in xylene. The CNT seeds were extended using ethylene as the gas precursor. Forces generated by CNT growth separated the alumina support clusters to result in a porous entangled structure with a 60 times gain in weight and a 1300 times gain in volume, compared to the original alumina particles. Effects of ferrocene injection rate, alumina particle sizes, and CNT growth parameters on the volume of the structure were analyzed and it was determined that high ferrocene input, moderate temperatures, and small alumina particles all favor the synthesis of high-volume CNT structures. © 2018 Elsevier B.V.
42 a57202017958 Temizel-Sekeryan S. p10 False Journal 8 Assessing the environmental impact and payback of carbon nanotube supported CO2 capture technologies using LCA methodology Climate change caused by excessive CO2 emissions in the atmosphere has attracted widespread public concern in recent years. Current industrial methods generally utilize monoethanolamine for CO2 capture; however, the CO2 regeneration requires a high temperature and energy demand during every adsorption/desorption process, along with material losses. Many solid amines with high capture capacity and stability are developed as adsorbents to overcome the limitations. However, the environmental impacts caused by adsorbents themselves are not holistically considered and discussed; meanwhile, material syntheses and consumptions are also associated with CO2 emission. To determine the environmental impacts and identify hotspots of novel CO2 capture adsorbents, two carbon nanotube supported polyethyleneimine, physically adsorbed and covalently bonded, were compared with traditional monoethanolamine method using life cycle assessment. The carbon payback periods were also analyzed to gain understanding on whether the currently evaluated novel materials are suitable for industrial application. Results suggest that, material usage, especially carbon nanotubes, contributes the majority of the overall environmental impacts for both types of carbon nanotube supported polyethyleneimine. Meanwhile, their carbon payback periods are over 40 times longer than monoethanolamine during the synthesis phase. However, the energy consumption of physically adsorbed polyethyleneimine saves up to 60% compared to monoethanolamine in every adsorption/desorption cycle due to its lower heat capacity. In addition, the rate of cumulative CO2 remission for carbon nanotube supported polyethyleneimine is twice higher than monoethanolamine, indicating the potential application for industrial CO2 capture. Overall, our study indicates that current status of solid amine has a potential in CO2 capture, but requires much improvements. Future research should pay attention on decreasing the initial material synthesis and increasing the product life time due to their high environmental tradeoffs. Meanwhile, our study highlights that unilateral emphasis of the CO2 capture efficiency by novel materials may not be adequate, comprehensive considerations should be focused on the comparison throughout material life cycles including use and preparation phases. © 2020 Elsevier Ltd
43 a57205128747 Ghamkhar R. p10 False Journal 8 Assessing the environmental impact and payback of carbon nanotube supported CO2 capture technologies using LCA methodology Climate change caused by excessive CO2 emissions in the atmosphere has attracted widespread public concern in recent years. Current industrial methods generally utilize monoethanolamine for CO2 capture; however, the CO2 regeneration requires a high temperature and energy demand during every adsorption/desorption process, along with material losses. Many solid amines with high capture capacity and stability are developed as adsorbents to overcome the limitations. However, the environmental impacts caused by adsorbents themselves are not holistically considered and discussed; meanwhile, material syntheses and consumptions are also associated with CO2 emission. To determine the environmental impacts and identify hotspots of novel CO2 capture adsorbents, two carbon nanotube supported polyethyleneimine, physically adsorbed and covalently bonded, were compared with traditional monoethanolamine method using life cycle assessment. The carbon payback periods were also analyzed to gain understanding on whether the currently evaluated novel materials are suitable for industrial application. Results suggest that, material usage, especially carbon nanotubes, contributes the majority of the overall environmental impacts for both types of carbon nanotube supported polyethyleneimine. Meanwhile, their carbon payback periods are over 40 times longer than monoethanolamine during the synthesis phase. However, the energy consumption of physically adsorbed polyethyleneimine saves up to 60% compared to monoethanolamine in every adsorption/desorption cycle due to its lower heat capacity. In addition, the rate of cumulative CO2 remission for carbon nanotube supported polyethyleneimine is twice higher than monoethanolamine, indicating the potential application for industrial CO2 capture. Overall, our study indicates that current status of solid amine has a potential in CO2 capture, but requires much improvements. Future research should pay attention on decreasing the initial material synthesis and increasing the product life time due to their high environmental tradeoffs. Meanwhile, our study highlights that unilateral emphasis of the CO2 capture efficiency by novel materials may not be adequate, comprehensive considerations should be focused on the comparison throughout material life cycles including use and preparation phases. © 2020 Elsevier Ltd
44 a55829396600 Hicks A.L. p10 False Journal 8 Assessing the environmental impact and payback of carbon nanotube supported CO2 capture technologies using LCA methodology Climate change caused by excessive CO2 emissions in the atmosphere has attracted widespread public concern in recent years. Current industrial methods generally utilize monoethanolamine for CO2 capture; however, the CO2 regeneration requires a high temperature and energy demand during every adsorption/desorption process, along with material losses. Many solid amines with high capture capacity and stability are developed as adsorbents to overcome the limitations. However, the environmental impacts caused by adsorbents themselves are not holistically considered and discussed; meanwhile, material syntheses and consumptions are also associated with CO2 emission. To determine the environmental impacts and identify hotspots of novel CO2 capture adsorbents, two carbon nanotube supported polyethyleneimine, physically adsorbed and covalently bonded, were compared with traditional monoethanolamine method using life cycle assessment. The carbon payback periods were also analyzed to gain understanding on whether the currently evaluated novel materials are suitable for industrial application. Results suggest that, material usage, especially carbon nanotubes, contributes the majority of the overall environmental impacts for both types of carbon nanotube supported polyethyleneimine. Meanwhile, their carbon payback periods are over 40 times longer than monoethanolamine during the synthesis phase. However, the energy consumption of physically adsorbed polyethyleneimine saves up to 60% compared to monoethanolamine in every adsorption/desorption cycle due to its lower heat capacity. In addition, the rate of cumulative CO2 remission for carbon nanotube supported polyethyleneimine is twice higher than monoethanolamine, indicating the potential application for industrial CO2 capture. Overall, our study indicates that current status of solid amine has a potential in CO2 capture, but requires much improvements. Future research should pay attention on decreasing the initial material synthesis and increasing the product life time due to their high environmental tradeoffs. Meanwhile, our study highlights that unilateral emphasis of the CO2 capture efficiency by novel materials may not be adequate, comprehensive considerations should be focused on the comparison throughout material life cycles including use and preparation phases. © 2020 Elsevier Ltd
45 a57201634652 Larsen B. p11 True Journal 9 Investigating steel tool life in the RFSSW process Refill Friction Stir Spot Welding (RFSSW) has demonstrated capability in joining thin sheets of aluminum with dissimilar thickness, alloy, and composition. The process remains to be implemented on a wide scale in the automotive and aerospace industries, partially due to the relatively short number of welds producible by a toolset, prior to needing cleaning. In the following work, an investigation was conducted to better understand this limitation. First, the effective tool life of a steel toolset was quantified. Experiments showed that less than 60 consecutive welds could be made before the toolset seized and required cleaning. To better understand the conditions contributing so such a short tool life, thermocouples were used in subsequent experiments, to measure the temperatures achieved at various locations in the weld. Peak weld temperature increased with longer cycle times and decreased with shorter cycle times. During the experiments, it was noted that weld temperatures in excess of 500 °C were observed at weld center. At these high temperatures, the authors anticipate that intermetallic compounds (IMCs) are able to grow on tool surfaces. A rough, existing model of IMC growth in an Fe-Al system predicted IMC growth on the same order of magnitude of the tool clearances, supporting the anticipation that IMC growth is a factor in the observed, short tool life between cleanings. Following this analysis, future evaluation of less re-active tool materials is recommended. © 2020 The Society of Manufacturing Engineers
45 a57201634652 Larsen B. p58 True Conference 10 Reducing Cycle Times of Refill Friction Stir Spot Welding in Automotive Aluminum Alloys A major barrier, preventing RFSSW from use by manufacturers, is the long cycle time that has been historically associated with making a weld. In order for RFSSW to become a readily implementable welding solution, cycle times must be reduced to an acceptable level, similar to that of well developed, competing spot joining processes. In the present work, an investigation of the RFSSW process is conducted to evaluate factors that have traditionally prevented the process from achieving fast cycle times. Within this investigation, the relationship between cycle time and joint quality is explored, as is the meaning and measurement of cycle time in the RFSSW process. Claims and general sentiment found in prior literature are challenged regarding the potential for high-speed RFSSW joints to be made. The RFSSW weld design-as described by process parameters such as tool feed rate, tool rotational velocity, and plunge depth-is shown through experimentation to affect the loads and torques placed on RFSSW tooling and machines during the welding process. As cycle time is decreased, the load and torque on the toolset are shown to increase. Similarly, as tool rotational velocity is decreased, the load and torque on the toolset is shown to increase. The relationship between machine design limitations and cycle time is also explored. It is demonstrated that welds with cycle times below one second can be produced without compromising material properties, suggesting that high speed RFSSW can be enabled through informed efforts. © 2020 SAE International. All Rights Reserved.
45 a57201634652 Larsen B. p615 False Conference 253 Initial Comparisons of Friction Stir Spot Welding and Self Piercing Riveting of Ultra-Thin Steel Sheet Due to the limitations on resistance spot welding of ultra-thin steel sheet (thicknesses below 0.5 mm) in high-volume automotive manufacturing, a comparison of friction stir spot welding and self-piercing riveting was performed to determine which process may be more amenable to enabling assembly of ultra-thin steel sheet. Statistical comparisons between mechanical properties of lap-shear tensile and T-peel were made in sheet thickness below 0.5 mm and for dissimilar thickness combinations. An evaluation of energy to fracture, fracture mechanisms, and joint consistency is presented. © 2018 SAE International; Ford Motor Company; General Motors LLC.
46 a57218685929 Hunt J. p11 False Journal 9 Investigating steel tool life in the RFSSW process Refill Friction Stir Spot Welding (RFSSW) has demonstrated capability in joining thin sheets of aluminum with dissimilar thickness, alloy, and composition. The process remains to be implemented on a wide scale in the automotive and aerospace industries, partially due to the relatively short number of welds producible by a toolset, prior to needing cleaning. In the following work, an investigation was conducted to better understand this limitation. First, the effective tool life of a steel toolset was quantified. Experiments showed that less than 60 consecutive welds could be made before the toolset seized and required cleaning. To better understand the conditions contributing so such a short tool life, thermocouples were used in subsequent experiments, to measure the temperatures achieved at various locations in the weld. Peak weld temperature increased with longer cycle times and decreased with shorter cycle times. During the experiments, it was noted that weld temperatures in excess of 500 °C were observed at weld center. At these high temperatures, the authors anticipate that intermetallic compounds (IMCs) are able to grow on tool surfaces. A rough, existing model of IMC growth in an Fe-Al system predicted IMC growth on the same order of magnitude of the tool clearances, supporting the anticipation that IMC growth is a factor in the observed, short tool life between cleanings. Following this analysis, future evaluation of less re-active tool materials is recommended. © 2020 The Society of Manufacturing Engineers
47 a18535712500 Hovanski Y. p11 False Journal 9 Investigating steel tool life in the RFSSW process Refill Friction Stir Spot Welding (RFSSW) has demonstrated capability in joining thin sheets of aluminum with dissimilar thickness, alloy, and composition. The process remains to be implemented on a wide scale in the automotive and aerospace industries, partially due to the relatively short number of welds producible by a toolset, prior to needing cleaning. In the following work, an investigation was conducted to better understand this limitation. First, the effective tool life of a steel toolset was quantified. Experiments showed that less than 60 consecutive welds could be made before the toolset seized and required cleaning. To better understand the conditions contributing so such a short tool life, thermocouples were used in subsequent experiments, to measure the temperatures achieved at various locations in the weld. Peak weld temperature increased with longer cycle times and decreased with shorter cycle times. During the experiments, it was noted that weld temperatures in excess of 500 °C were observed at weld center. At these high temperatures, the authors anticipate that intermetallic compounds (IMCs) are able to grow on tool surfaces. A rough, existing model of IMC growth in an Fe-Al system predicted IMC growth on the same order of magnitude of the tool clearances, supporting the anticipation that IMC growth is a factor in the observed, short tool life between cleanings. Following this analysis, future evaluation of less re-active tool materials is recommended. © 2020 The Society of Manufacturing Engineers
47 a18535712500 Hovanski Y. p58 False Conference 10 Reducing Cycle Times of Refill Friction Stir Spot Welding in Automotive Aluminum Alloys A major barrier, preventing RFSSW from use by manufacturers, is the long cycle time that has been historically associated with making a weld. In order for RFSSW to become a readily implementable welding solution, cycle times must be reduced to an acceptable level, similar to that of well developed, competing spot joining processes. In the present work, an investigation of the RFSSW process is conducted to evaluate factors that have traditionally prevented the process from achieving fast cycle times. Within this investigation, the relationship between cycle time and joint quality is explored, as is the meaning and measurement of cycle time in the RFSSW process. Claims and general sentiment found in prior literature are challenged regarding the potential for high-speed RFSSW joints to be made. The RFSSW weld design-as described by process parameters such as tool feed rate, tool rotational velocity, and plunge depth-is shown through experimentation to affect the loads and torques placed on RFSSW tooling and machines during the welding process. As cycle time is decreased, the load and torque on the toolset are shown to increase. Similarly, as tool rotational velocity is decreased, the load and torque on the toolset is shown to increase. The relationship between machine design limitations and cycle time is also explored. It is demonstrated that welds with cycle times below one second can be produced without compromising material properties, suggesting that high speed RFSSW can be enabled through informed efforts. © 2020 SAE International. All Rights Reserved.
47 a18535712500 Hovanski Y. p154 False Journal 109 Identifying the relative importance of predictive variables in artificial neural networks based on data produced through a discrete event simulation of a manufacturing environment This research used a discrete event simulation to create data on a shipment receiving process instead of using historical records on the process. The simulation was used to create records with different inputs and operating conditions and the resulting overall elapsed time for the overall process. The resulting records were used to create a set of predictive artificial neural network models that predicted elapsed time based on the process characteristics. Then, the connection weight approach was used to determine the relative importance of the input variables. The connection weight approach was applied in three different steps: (1) on all input variables to identify predictive and non-predictive inputs, (2) on all predictive inputs, and (3) after removal of a dominating predictive input. This produced a clearer picture of the relative importance of input variables on the outcome variable than applying the connection weight approach once. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
47 a18535712500 Hovanski Y. p187 False Journal 128 Evaluation of intermetallic compound layer at aluminum/steel interface joined by friction stir scribe technology Heat input and high strain rate deformation during friction stir welding of aluminum and steel resulted in the diffusion-based formation of a Fe x Al y intermetallic compound (IMC) layer. Compared with conventional friction stir welding tools, a friction stir scribe tool can reduce heat input significantly limiting the IMC layer thickness (~100–750 nm). Friction stir scribe joined lap joints fractured either through the welded interface or within the base aluminum alloy on the loading side, depending on IMC layer thickness during tensile lap shear testing. In addition, a modified effective heat of formation model predicted that Al 13 Fe 4 formed first at aluminum/steel interface and, during welding process, was substituted by Al 5 Fe 2 with local silicon enrichment, which was verified via microstructural characterization. © 2019 The Authors
47 a18535712500 Hovanski Y. p396 True Journal 214 Preface [No abstract available]
47 a18535712500 Hovanski Y. p506 False Journal 277 Shaping and Forming of Advanced High Strength Steels [No abstract available]
47 a18535712500 Hovanski Y. p572 False Journal 303 A review of friction stir welding of steels: Tool, material flow, microstructure, and properties Considerable progress has been achieved in friction stir welding (FSW) of steels in every aspect of tool fabrication, microstructure control and properties evaluation in the past two decades. With the development of reliable welding tools and precise control systems, FSW of steels has reached a new level of technical maturity. High-quality, long welds can be produced in many engineering steels. Compared to traditional fusion welding, FSW exhibits unique advantages producing joints with better properties. As a result of active control of the welding temperature and/or cooling rate, FSW has the capability of fabricating steel joints with excellent toughness and strength. For example, unfavorable phase transformations that usually occur during traditional welding can be avoided and favorable phase fractions in advanced steels can be maintained in the weld zone thus avoiding the typical property degradations associated with fusion welding. If phase transformations do occur during FSW of thick steels, optimization of microstructure and properties can be attained by controlling the heat input and post-weld cooling rate. © 2017
47 a18535712500 Hovanski Y. p615 True Conference 253 Initial Comparisons of Friction Stir Spot Welding and Self Piercing Riveting of Ultra-Thin Steel Sheet Due to the limitations on resistance spot welding of ultra-thin steel sheet (thicknesses below 0.5 mm) in high-volume automotive manufacturing, a comparison of friction stir spot welding and self-piercing riveting was performed to determine which process may be more amenable to enabling assembly of ultra-thin steel sheet. Statistical comparisons between mechanical properties of lap-shear tensile and T-peel were made in sheet thickness below 0.5 mm and for dissimilar thickness combinations. An evaluation of energy to fracture, fracture mechanisms, and joint consistency is presented. © 2018 SAE International; Ford Motor Company; General Motors LLC.
47 a18535712500 Hovanski Y. p637 False Conference 271 Local texture evolution and mechanical performance of ultra-high-speed friction stir weld of AA 6111-T4 sheets Friction stir welding has gained wide interest in industry and drawn large research attention due to its high level of automation and superior joint performance. In this study we further expand the welding parameters to be of magnitudes higher than those previously reported to lower the cost and enable high volume joint production. Sound butt-joints were produced with aluminum alloy 6111-T4 blanks with welding speeds up to 6000, mm/min. Tensile tests of the joint pieces show >97% joint efficiency in terms of ultimate tensile strength. The T4 natural aging and grain refinement is found to contribute to the superior joint properties. Electron backscatter diffraction (EBSD) analysis is used to qualitatively study the local shear texture inside the nugget zones of the welds. The shear texture result is a good indicator of the material flow directions in the nugget zones. The flow directions behind the rotation tool are found to be flattened towards the top surface of the workpiece when the welding speed is increased, suggesting intense material mixing and transportation along the longitudinal welding direction (WD). © The Minerals, Metals & Materials Society 2018.
47 a18535712500 Hovanski Y. p638 False Journal 227 High-Speed Friction Stir Welding of AA7075-T6 Sheet: Microstructure, Mechanical Properties, Micro-texture, and Thermal History Friction stir welding (FSW) is a cost-effective and high-quality joining process for aluminum alloys (especially heat-treatable alloys) that is historically operated at lower joining speeds (up to hundreds of millimeters per minute). In this study, we present a microstructural analysis of friction stir welded AA7075-T6 blanks with high welding speeds up to 3 M/min. Textures, microstructures, mechanical properties, and weld quality are analyzed using TEM, EBSD, metallographic imaging, and Vickers hardness. The higher welding speed results in narrower, stronger heat-affected zones (HAZs) and also higher hardness in the nugget zones. The material flow direction in the nugget zone is found to be leaning towards the welding direction as the welding speed increases. Results are coupled with welding parameters and thermal history to aid in the understanding of the complex material flow and texture gradients within the welds in an effort to optimize welding parameters for high-speed processing. © 2017, The Minerals, Metals & Materials Society and ASM International.
47 a18535712500 Hovanski Y. p746 True Journal 361 Enabling Dissimilar Material Joining Using Friction Stir Scribe Technology One challenge in adapting welding processes to dissimilar material joining is the diversity of melting temperatures of the different materials. Although the use of mechanical fasteners and adhesives have mostly paved the way for near-term implementation of dissimilar material systems, these processes only accentuate the need for low-cost welding processes capable of impartially joining dissimilar material components regardless of alloy, properties, or melting temperature. Friction stir scribe technology was developed to overcome the challenges of joining dissimilar material components where melting temperatures vary greatly, and properties and/or chemistry are not compatible with more traditional welding processes. Although the friction stir scribe process is capable of joining dissimilar metals and metal/polymer systems, a more detailed evaluation of several aluminum/steel joints is presented herein to demonstrate the ability to both chemically and mechanically join dissimilar materials. © 2017, The Minerals, Metals & Materials Society.
47 a18535712500 Hovanski Y. p754 False Journal 361 Behavior of Sheet Metal Under Multiaxial Deformation Paths [No abstract available]
47 a18535712500 Hovanski Y. p872 False Journal 404 Predicting Lap Shear Strength for Friction Stir Scribe Joining of Dissimilar Materials Friction stir scribe technology has been developed to join materials with vastly different properties, most importantly different melting regimes. Specifically lighter, lower temperature materials such as aluminum or magnesium can be joined to higher temperature materials such as steel and titanium. The scribe portion of the modified friction stir welding pin tool creates in situ mechanical interlocks at the material interface. This mechanical interlocking, or hook-like interface morphology, has shown promising joint strength. However, this morphology can vary along a weld length and is sensitive to joining and tooling parameters. The current work seeks to determine the sensitivity of joint strength to the morphology of the hook interface and predict joint strength based on key morphology parameters. Key morphology features of the hooks extracted from joined samples are varied to quantify their impact on simulated lap shear strength. Predictable joint strength is key to wide spread use of this technique. © 2017, The Minerals, Metals & Materials Society.
47 a18535712500 Hovanski Y. p873 False Journal 405 High-Speed FSW Aluminum Alloy 7075 Microstructure and Corrosion Properties High-speed friction stir welding provides an opportunity to enable high-volume aluminum joining, thus lowering the expense of the process. To better understand this important industrial process the properties of the welds must be fully characterized. In this study we examined the microstructures of AA7075 butt welds with welding speeds of 1, 2 and 3 m/min. The welds were also tested for their corrosion resistance in a diluted EXCO solution at room temperature. The welds with higher speeds had a smaller corrosion sensitive area along with smaller HAZs, but the nugget zone became more corrosion susceptible. Their microstructure features were used to explain the non-uniform corrosion behavior across the weld. Both constituent particles and precipitate distribution were altered by the friction stir process and resulted in an overall sensitized weld affected region compared to the base material. © 2017, The Minerals, Metals & Materials Society.
47 a18535712500 Hovanski Y. p885 True Journal 411 Preface [No abstract available]
47 a18535712500 Hovanski Y. p887 False Journal 412 Joining Dissimilar Material Using Friction Stir Scribe Technique The ability to effectively join materials with vastly different melting points, like aluminum to steel, and polymer composites to metals, has been one of the roadblocks to realizing multi-material components for lightweighting efforts. The friction stir scribe (FSS) technique is a promising method that produces continuous overlap joints between materials with vastly different melting regimes and high-temperature flow characteristics. FSS uses an offset cutting tool at the tip of the friction stir welding pin to create an in situ mechanical interlock between material interfaces. With investments from the U.S. Department of Energy Vehicle Technologies Office and several automotive manufacturers and suppliers, Pacific Northwest National Laboratory is developing the FSS process and has demonstrated the viability of joining several material combinations. Details of welding trials, unique challenges, and mitigation strategies in different material combinations will be discussed. Joint characterization, including mechanical tests and joint performance, will also be presented. © 2017, The Minerals, Metals & Materials Society.
48 a56248593800 Peterson C.K. p12 True Journal 10 Persistent intelligence, surveillance, and reconnaissance using multiple autonomous vehicles with asynchronous route updates Providing persistent intelligence, reconnaissance, and surveillance of targets is a challenging, but important task when time-critical information is required. In this letter, we provide a decentralized routing algorithm for coordinating multiple autonomous vehicles as they visit a discrete set of pre-defined targets with weighted revisit priorities. The algorithm utilizes a block coordinate ascent algorithm combined with a Monte Carlo tree search to tractably decide each vehicle's route. The result is a non-myopic algorithm for multiple vehicles that is decentralized, computationally tractable, and allows for target prioritization. Guarantees are provided that all targets will have finite revisit times and that the block coordinate ascent algorithm will converge to a block optimal solution. Numerical simulations illustrate the utility of this method by showing that the results are comparable to those of a centralized exhaustive search and that they degrade gracefully with limited communication and scale under increasing numbers of targets and vehicles. © 2016 IEEE.
48 a56248593800 Peterson C.K. p192 False Conference 42 Tracking multiple vehicles constrained to a road network from a uav with sparse visual measurements Many multiple target tracking algorithms operate in the local frame of the sensor and have difficulty with track reallocation when targets move in and out of the sensor field of view. This poses a problem when an unmanned aerial vehicle (UAV) is tracking multiple ground targets on a road network larger than its field of view. We propose a Rao-Blackwellized Particle Filter (RBPF) to maintain individual target tracks and to perform probabilistic data association when the targets are constrained to a road network. This is particularly useful when a target leaves then re-enters the UAV's field of view. The RBPF is structured as a particle filter of particle filters. The top level filter handles data association and each of its particles maintains a bank of particle filters to handle target tracking. The tracking particle filters incorporate both positive and negative information when a measurement is received. We then implement a receding horizon controller to improve the filter certainty of multiple target locations. The controller prioritizes searching for targets based on the entropy of each target's estimate. © 2019 American Automatic Control Council.
48 a56248593800 Peterson C.K. p214 False Conference 49 Encirclement of moving targets using relative range and bearing measurements This paper presents a controller that uses relative range and bearing measurements to steer unmanned aerial vehicles (UAVs) to circular trajectories around a constant velocity target. Estimates of the range rate and angular rate to the target are used to improve the error in the range and bearing. For moving targets, their velocity is also estimated and used in the control law. Theoretical proofs using Lyapunov theory for stationary targets and feedback linearization for moving targets are provided. Numerical simulations show vehicles converging to circular formations around both stationary and moving targets. © 2019 IEEE.
48 a56248593800 Peterson C.K. p221 False Conference 53 Gesture commands for controlling high-level UAV behavior In this paper, an accelerometer and gyroscope are used to sense gesture commands, which are then classified using a logistic regression model. Seven gestures were chosen and mapped to specific behaviors that a fixed wing unmanned air vehicle could accomplish. These behaviors specified various searching, following, and tracking patterns that could be used in a dynamic environment. The system was trained to recognize the seven gestures and then tested in a hardware-in-the-loop simulation. The system was able to identify all gestures with an overall accuracy of 90% and with five of the seven gestures being accurately identified at least 94% of the time. Each of the behaviors associated with the gestures was tested in simulation and the ability to dynamically switch between behaviors was proven. The results show that the system can be used as a natural interface to assist an operator in directing an unmanned air vehicle's behaviors. © 2019 IEEE.
48 a56248593800 Peterson C.K. p453 False Conference 159 Learned Search Parameters for Cooperating Vehicles using Gaussian Process Regressions Unmanned vehicles are capable of working as teams to accomplish a wide variety of mission objectives, such as searching for and tracking targets. In this paper, vehicle search paths are dictated by a joint cost function which maximizes the reward earned from partitioned sections across the search area. In previous work, these rewards were assigned based on the elapsed time since the section had last been searched. This approach is effective in rewarding vehicles to search out areas which haven't been visited in a long time, yet it lacks the ability to weight grid cells differently based on the probability that targets will be in that section. This paper proposes a method of using accumulated knowledge of the average density of targets within an area, along with a Gaussian process regression to assign rewards. Vehicles then choose paths that are more likely to find targets rather than seeking areas which have not been searched recently. Through numerical simulations we show that this method increases the number of targets seen by cooperating UAVs and provides an accurate estimate of target density within a search area. © 2018 IEEE.
48 a56248593800 Peterson C.K. p664 False Conference 290 Bias estimation for angle-only sensors in distributed multi-target tracking systems This paper describes a method of automatic sensor bias calculation for angle only sensor models in a target tracking scenario. It is assumed that separate Kalman filters are employed by each sensor and no measurements of known landmarks are available. Accurate bias estimation is achieved through the use of pseudo measurements of slant range from each sensor to the target and pseudo measurements of each sensor's bias. The covariance intersection (CI) algorithm is used to produce a pseudo measurement of slant range. This pseudo measurement of range allows pseudo measurements of sensor bias to be calculated based on each sensor's residuals and Kalman gains. Substantially improved tracking performance is demonstrated when estimating and accounting for constant biases on each sensor. © 2017 IEEE.
48 a56248593800 Peterson C.K. p681 True Conference 293 Dynamic grouping of cooperating vehicles using a receding horizon controller for ground target search and track missions Teams of unmanned vehicles are capable of accomplishing a wide variety of mission objectives, such as searching for and tracking targets. In this paper, a receding horizon control is utilized with information based reward measures to accomplish these two competing mission objectives. This approach for cooperatively searching and tracking has proven to be effective in past work. However, it is not generally scalable for large numbers of vehicles due to the computational expense required when generating joint path decisions. This paper proposes a method to dynamically group vehicles with neighbors that have intersecting decision spaces, thus reducing computational cost while still maintaining reasonable performance. Each vehicle also decides its ideal event horizon based upon inferred knowledge of the operational environment, further reducing cost. © 2017 IEEE.
49 a10640480600 Casbeer D.W. p12 False Journal 10 Persistent intelligence, surveillance, and reconnaissance using multiple autonomous vehicles with asynchronous route updates Providing persistent intelligence, reconnaissance, and surveillance of targets is a challenging, but important task when time-critical information is required. In this letter, we provide a decentralized routing algorithm for coordinating multiple autonomous vehicles as they visit a discrete set of pre-defined targets with weighted revisit priorities. The algorithm utilizes a block coordinate ascent algorithm combined with a Monte Carlo tree search to tractably decide each vehicle's route. The result is a non-myopic algorithm for multiple vehicles that is decentralized, computationally tractable, and allows for target prioritization. Guarantees are provided that all targets will have finite revisit times and that the block coordinate ascent algorithm will converge to a block optimal solution. Numerical simulations illustrate the utility of this method by showing that the results are comparable to those of a centralized exhaustive search and that they degrade gracefully with limited communication and scale under increasing numbers of targets and vehicles. © 2016 IEEE.
49 a10640480600 Casbeer D.W. p110 False Journal 81 Single pursuer and two cooperative evaders in the border defense differential game An interest in border defense, surveillance, and interdiction has recently increased for a variety of reasons related to issues of illegal immigration, terrorism, drug and human trafficking, and other potential threats. Unmanned aerial vehicles (UAVs) offer an attractive alternative to supporting and defending various threats at borders. This paper applies a differential game to define a border defense scenario where one UAV (pursuer) seeks to capture two intruders (evaders) before they reach a designated border. The evaders can be UAVs, marine or ground vehicles, or human agents, but they have a lower maximum speed than the pursuer throughout the game. Simple motion is assumed for the pursuer and evaders with complete state information shared across all agents. The game is played within a rectangular area with a parallel top and bottom border of length L and left and right borders with a length of W, for a game aspect ratio of L∕W. The value of the game is the minimum distance to the bottom border achieved by the evaders at any time before capture of both evaders. Within the region where the pursuer wins, the game of degree is explored and the optimal policy for both the evaders and pursuer is derived using geometric properties. © 2020 by John Salmon. Published by the American Institute of Aeronautics and Astronautics, Inc.
50 a24923036100 Manyam S.G. p12 False Journal 10 Persistent intelligence, surveillance, and reconnaissance using multiple autonomous vehicles with asynchronous route updates Providing persistent intelligence, reconnaissance, and surveillance of targets is a challenging, but important task when time-critical information is required. In this letter, we provide a decentralized routing algorithm for coordinating multiple autonomous vehicles as they visit a discrete set of pre-defined targets with weighted revisit priorities. The algorithm utilizes a block coordinate ascent algorithm combined with a Monte Carlo tree search to tractably decide each vehicle's route. The result is a non-myopic algorithm for multiple vehicles that is decentralized, computationally tractable, and allows for target prioritization. Guarantees are provided that all targets will have finite revisit times and that the block coordinate ascent algorithm will converge to a block optimal solution. Numerical simulations illustrate the utility of this method by showing that the results are comparable to those of a centralized exhaustive search and that they degrade gracefully with limited communication and scale under increasing numbers of targets and vehicles. © 2016 IEEE.
51 a7201675107 Rasmussen S. p12 False Journal 10 Persistent intelligence, surveillance, and reconnaissance using multiple autonomous vehicles with asynchronous route updates Providing persistent intelligence, reconnaissance, and surveillance of targets is a challenging, but important task when time-critical information is required. In this letter, we provide a decentralized routing algorithm for coordinating multiple autonomous vehicles as they visit a discrete set of pre-defined targets with weighted revisit priorities. The algorithm utilizes a block coordinate ascent algorithm combined with a Monte Carlo tree search to tractably decide each vehicle's route. The result is a non-myopic algorithm for multiple vehicles that is decentralized, computationally tractable, and allows for target prioritization. Guarantees are provided that all targets will have finite revisit times and that the block coordinate ascent algorithm will converge to a block optimal solution. Numerical simulations illustrate the utility of this method by showing that the results are comparable to those of a centralized exhaustive search and that they degrade gracefully with limited communication and scale under increasing numbers of targets and vehicles. © 2016 IEEE.
52 a56330168500 Zou Z. p14 True Journal 12 An isogeometric Reissner–Mindlin shell element based on Bézier dual basis functions: Overcoming locking and improved coarse mesh accuracy We develop a mixed geometrically nonlinear isogeometric Reissner–Mindlin shell element for the analysis of thin-walled structures that leverages Bézier dual basis functions to address both shear and membrane locking and to improve the quality of computed stresses. The accuracy of computed solutions over coarse meshes, that have highly non-interpolatory control meshes, is achieved through the application of a continuous rotational approach. The starting point of the formulation is the modified Hellinger–Reissner variational principle with independent displacement, membrane, and shear strains as the unknown fields. To overcome locking, the strain variables are interpolated with lower-order spline bases while the variations of the strain variables are interpolated with the corresponding Bézier dual bases. Leveraging the orthogonality property of the Bézier dual basis, the strain variables are condensed out of the system with only a slight increase in the bandwidth of the resulting linear system. The condensed approach preserves the accuracy of the non-condensed mixed approach but with fewer degrees of freedom. From a practical point of view, since the Bézier dual basis is completely specified through Bézier extraction, any spline space that admits Bézier extraction can utilize the proposed approach directly. © 2020 Elsevier B.V.
52 a56330168500 Zou Z. p52 False Journal 41 Isogeometric Bézier dual mortaring: The enriched Bézier dual basis with application to second- and fourth-order problems In this paper, we present an algorithm to construct enriched Bézier dual basis functions that can reproduce higher-order polynomials. Our construction is unique in that it is based on Bézier extraction and projection, allowing it to be used for tensor product and unstructured polynomial spline spaces, is well-conditioned, and is quadrature-free. When used as a basis for dual mortar methods, optimal approximations are achieved for both second- and fourth-order problems. In the context of fourth-order problems, both C0 and C1 continuity constraints must be applied at each intersection. We develop a novel geometry-independent C1 continuity constraint that also preserves the sparsity of the coupled problem. The performance of the proposed formulation is verified through several challenging second- and fourth-order problems. © 2020 Elsevier B.V.
52 a56330168500 Zou Z. p515 True Journal 284 Isogeometric Bézier dual mortaring: Refineable higher-order spline dual bases and weakly continuous geometry In this paper we develop the isogeometric Bézier dual mortar method. It is based on Bézier extraction and projection and is applicable to any spline space which can be represented in Bézier form (i.e., NURBS, T-splines, LR-splines, etc.). The approach weakly enforces the continuity of the solution at patch interfaces and the error can be adaptively controlled by leveraging the refineability of the underlying slave dual spline basis without introducing any additional degrees of freedom. As a consequence, optimal higher-order convergence rates can be achieved without the need for an expensive shared master/slave segmentation step. We also develop weakly continuous geometry as a particular application of isogeometric Bézier dual mortaring. Weakly continuous geometry is a geometry description where the weak continuity constraints are built into properly modified Bézier extraction operators. As a result, multi-patch models can be processed in a solver directly without having to employ a mortaring solution strategy. We demonstrate the utility of the approach on several challenging benchmark problems. © 2018 Elsevier B.V.
52 a56330168500 Zou Z. p764 True Journal 373 A Geometrically Exact Isogeometric Blended Shell: Formulation, Benchmarking, and Automotive Application We present a geometrically exact isogeometric blended shell formulation. In other words, all geometric quantities appearing in the blended theory are evaluated exactly and no approximations are employed. The blended approach allows higher-order shell theories, like Kirchhoff-Love, to be combined with Reissner-Mindlin shell formulations, which have rotational degrees of freedom. In this way, rotations can be employed only where needed to simplify shell modeling such as at kinks and intersections. Away from these regions shear locking free formulations can be employed to improve robustness, accuracy, and efficiency. We compare our approach to standard shell elements commonly used in industry on several benchmarks to explore the behavior of the element. We then model an inner car hood to demonstrate our ability to handle complex CAD geometry in a simple manner without geometry cleanup and mesh generation steps. This shell element forms the basis of the newly developed Isogeometrx structural solver. © 2017 SAE International.
53 a9942259800 Scott M.A. p14 False Journal 12 An isogeometric Reissner–Mindlin shell element based on Bézier dual basis functions: Overcoming locking and improved coarse mesh accuracy We develop a mixed geometrically nonlinear isogeometric Reissner–Mindlin shell element for the analysis of thin-walled structures that leverages Bézier dual basis functions to address both shear and membrane locking and to improve the quality of computed stresses. The accuracy of computed solutions over coarse meshes, that have highly non-interpolatory control meshes, is achieved through the application of a continuous rotational approach. The starting point of the formulation is the modified Hellinger–Reissner variational principle with independent displacement, membrane, and shear strains as the unknown fields. To overcome locking, the strain variables are interpolated with lower-order spline bases while the variations of the strain variables are interpolated with the corresponding Bézier dual bases. Leveraging the orthogonality property of the Bézier dual basis, the strain variables are condensed out of the system with only a slight increase in the bandwidth of the resulting linear system. The condensed approach preserves the accuracy of the non-condensed mixed approach but with fewer degrees of freedom. From a practical point of view, since the Bézier dual basis is completely specified through Bézier extraction, any spline space that admits Bézier extraction can utilize the proposed approach directly. © 2020 Elsevier B.V.
53 a9942259800 Scott M.A. p52 False Journal 41 Isogeometric Bézier dual mortaring: The enriched Bézier dual basis with application to second- and fourth-order problems In this paper, we present an algorithm to construct enriched Bézier dual basis functions that can reproduce higher-order polynomials. Our construction is unique in that it is based on Bézier extraction and projection, allowing it to be used for tensor product and unstructured polynomial spline spaces, is well-conditioned, and is quadrature-free. When used as a basis for dual mortar methods, optimal approximations are achieved for both second- and fourth-order problems. In the context of fourth-order problems, both C0 and C1 continuity constraints must be applied at each intersection. We develop a novel geometry-independent C1 continuity constraint that also preserves the sparsity of the coupled problem. The performance of the proposed formulation is verified through several challenging second- and fourth-order problems. © 2020 Elsevier B.V.
53 a9942259800 Scott M.A. p141 False Journal 99 Isogeometric boundary element methods and patch tests for linear elastic problems: Formulation, numerical integration, and applications An Isogeometric Boundary Element Method for solving three-dimensional boundary-value problems of classical linear elasticity theory is proposed. The method is developed as a generalization of the author's earlier work on Laplace's equation to Navier's equations. As a result the proposed method features (i) proper basis functions for approximating Dirichlet and Neumann data, (ii) high-order collocation schemes for weakly singular, singular, and hyper-singular integral operators, (iii) state-of-the-art numerical integration schemes capable of handling geometries with disparate dimensions, (iv) well-conditioned linear algebraic systems, with the condition number independent of the mesh size. Boundary Element Patch Tests, as extensions of concepts widely used for finite element methods, are also introduced. It is shown how these tests can be used to assess the veracity of boundary element formulations and numerical integration schemes, implementations, and geometric precision of Computer Aided Design models. The method is applied to two challenging case studies, representative of industrial applications. © 2019 Elsevier B.V.
53 a9942259800 Scott M.A. p274 False Journal 180 Dynamics of a capsule flowing in a tube under pulsatile flow We analyze numerically the behavior of a deformable micro-capsule confined in a pipe under a pulsatile flow. The capsule moves and is deformed by the action of a pulsatile flow inside the tube with a non-null mean velocity. This configuration can be found in the nature and in many bioengineering systems where artificial capsules are driven by micro-pumps through micro-channels. The capsule is considered as a thin hyperelastic membrane, which encloses an internal fluid. As it has been demonstrated in the literature, this model represents a wide range of artificial capsules, for example, the alginate-based capsules, typically used in bioengineering applications. A hybrid isogeometric finite element method and boundary element method based on a T-spline discretization and formulated in the time domain is used to solve the mechanical and hydrodynamical equations. The influence of the relative rigidity of the membrane, frequency and amplitude of the pulsatile flow is studied. Results show that the behavior of the capsule differs from steady flows and it depends strongly on the frequency of the flow and mechanical characteristic of the capsule. © 2018 Elsevier Ltd
53 a9942259800 Scott M.A. p496 False Journal 268 Bézier B̄ projection In this paper we demonstrate the use of Bézier projection to alleviate locking phenomena in structural mechanics applications of isogeometric analysis. Interpreting the well-known B̄ projection in two different ways we develop two formulations for locking problems in beams and nearly incompressible elastic solids. One formulation leads to a sparse symmetric system and the other leads to a sparse non-symmetric system. To demonstrate the utility of Bézier projection for both geometry and material locking phenomena we focus on transverse shear locking in Timoshenko beams and volumetric locking in nearly compressible linear elasticity although the approach can be applied generally to other types of locking phenomena as well. Bézier projection is a local projection technique with optimal approximation properties, which in many cases produces solutions that are comparable to global L2 projection. In the context of B̄ methods, the use of Bézier projection produces sparse stiffness matrices with only a slight increase in bandwidth when compared to standard displacement-based methods. Of particular importance is that the approach is applicable to any spline representation that can be written in Bézier form like NURBS, T-splines, LR-splines, etc. We discuss in detail how to integrate this approach into an existing finite element framework with minimal disruption through the use of Bézier extraction operators and a newly introduced dual basis for the Bézier projection operator. We then demonstrate the behavior of the two proposed formulations through several challenging benchmark problems. © 2018
53 a9942259800 Scott M.A. p515 False Journal 284 Isogeometric Bézier dual mortaring: Refineable higher-order spline dual bases and weakly continuous geometry In this paper we develop the isogeometric Bézier dual mortar method. It is based on Bézier extraction and projection and is applicable to any spline space which can be represented in Bézier form (i.e., NURBS, T-splines, LR-splines, etc.). The approach weakly enforces the continuity of the solution at patch interfaces and the error can be adaptively controlled by leveraging the refineability of the underlying slave dual spline basis without introducing any additional degrees of freedom. As a consequence, optimal higher-order convergence rates can be achieved without the need for an expensive shared master/slave segmentation step. We also develop weakly continuous geometry as a particular application of isogeometric Bézier dual mortaring. Weakly continuous geometry is a geometry description where the weak continuity constraints are built into properly modified Bézier extraction operators. As a result, multi-patch models can be processed in a solver directly without having to employ a mortaring solution strategy. We demonstrate the utility of the approach on several challenging benchmark problems. © 2018 Elsevier B.V.
53 a9942259800 Scott M.A. p677 False Journal 328 A 3D isogeometric BE–FE analysis with dynamic remeshing for the simulation of a deformable particle in shear flows A three-dimensional isogeometric coupled boundary element and finite element approach based on analysis suitable T-splines is developed for the simulation of deformable capsules suspended in shear flows. Boundary element analysis is used to solve the fluid Stokes equation whereas the hydrodynamic membrane load is computed via isogeometric analysis under the assumption that the membrane is a hyper-elastic thin shell with negligible bending resistance. The smoothness of the T-spline basis functions accommodate large deformations of the capsule without the need for additional smoothing techniques, and can be used to accurately compute the membrane load. A balanced distribution of membrane elements can be constructed using an unstructured locally refined mesh. These properties are coupled with an adaptive temporal implicit integration scheme. Several benchmark examples are solved to illustrate the accuracy and potential of the method. The approach is then applied to simulate the dynamics of a capsule in a real geometry of a brain capillary. © 2017 Elsevier B.V.
53 a9942259800 Scott M.A. p745 False Journal 360 Hierarchically refined and coarsened splines for moving interface problems, with particular application to phase-field models of prostate tumor growth Moving interface problems are ubiquitous in science and engineering. To develop an accurate and efficient methodology for this class of problems, we present algorithms for local h-adaptivity of hierarchical B-splines to be utilized in isogeometric analysis. We extend Bézier projection, an efficient quadrature-free local projection technique, to the hierarchical setting. In this case, extraction operators may not be invertible. To address this issue we develop a multi-level reconstruction operator which maintains the locality properties of the projection. We also introduce a balance parameter to control the overlap of hierarchical functions leading to improved numerical conditioning. We apply our algorithms to the simulation of localized prostate cancer growth. We model this disease using the phase-field method and a set of diffusion–reaction equations to account for the dynamics of nutrients and a key biomarker termed Prostate Specific Antigen. Our results include examples on simple 2D and 3D domains and a more compelling tissue-scale, patient-specific simulation, which is run over a prostate anatomy extracted from medical images. Our methods for local h-adaptivity efficiently capture the evolving interface between the tumor and the neighboring healthy tissue with remarkable accuracy in all cases. © 2017 Elsevier B.V.
53 a9942259800 Scott M.A. p764 False Journal 373 A Geometrically Exact Isogeometric Blended Shell: Formulation, Benchmarking, and Automotive Application We present a geometrically exact isogeometric blended shell formulation. In other words, all geometric quantities appearing in the blended theory are evaluated exactly and no approximations are employed. The blended approach allows higher-order shell theories, like Kirchhoff-Love, to be combined with Reissner-Mindlin shell formulations, which have rotational degrees of freedom. In this way, rotations can be employed only where needed to simplify shell modeling such as at kinks and intersections. Away from these regions shear locking free formulations can be employed to improve robustness, accuracy, and efficiency. We compare our approach to standard shell elements commonly used in industry on several benchmarks to explore the behavior of the element. We then model an inner car hood to demonstrate our ability to handle complex CAD geometry in a simple manner without geometry cleanup and mesh generation steps. This shell element forms the basis of the newly developed Isogeometrx structural solver. © 2017 SAE International.
53 a9942259800 Scott M.A. p870 False Journal 403 Isogeometric design and analysis [No abstract available]
54 a57201257192 Miao D. p14 False Journal 12 An isogeometric Reissner–Mindlin shell element based on Bézier dual basis functions: Overcoming locking and improved coarse mesh accuracy We develop a mixed geometrically nonlinear isogeometric Reissner–Mindlin shell element for the analysis of thin-walled structures that leverages Bézier dual basis functions to address both shear and membrane locking and to improve the quality of computed stresses. The accuracy of computed solutions over coarse meshes, that have highly non-interpolatory control meshes, is achieved through the application of a continuous rotational approach. The starting point of the formulation is the modified Hellinger–Reissner variational principle with independent displacement, membrane, and shear strains as the unknown fields. To overcome locking, the strain variables are interpolated with lower-order spline bases while the variations of the strain variables are interpolated with the corresponding Bézier dual bases. Leveraging the orthogonality property of the Bézier dual basis, the strain variables are condensed out of the system with only a slight increase in the bandwidth of the resulting linear system. The condensed approach preserves the accuracy of the non-condensed mixed approach but with fewer degrees of freedom. From a practical point of view, since the Bézier dual basis is completely specified through Bézier extraction, any spline space that admits Bézier extraction can utilize the proposed approach directly. © 2020 Elsevier B.V.
54 a57201257192 Miao D. p52 True Journal 41 Isogeometric Bézier dual mortaring: The enriched Bézier dual basis with application to second- and fourth-order problems In this paper, we present an algorithm to construct enriched Bézier dual basis functions that can reproduce higher-order polynomials. Our construction is unique in that it is based on Bézier extraction and projection, allowing it to be used for tensor product and unstructured polynomial spline spaces, is well-conditioned, and is quadrature-free. When used as a basis for dual mortar methods, optimal approximations are achieved for both second- and fourth-order problems. In the context of fourth-order problems, both C0 and C1 continuity constraints must be applied at each intersection. We develop a novel geometry-independent C1 continuity constraint that also preserves the sparsity of the coupled problem. The performance of the proposed formulation is verified through several challenging second- and fourth-order problems. © 2020 Elsevier B.V.
54 a57201257192 Miao D. p496 True Journal 268 Bézier B̄ projection In this paper we demonstrate the use of Bézier projection to alleviate locking phenomena in structural mechanics applications of isogeometric analysis. Interpreting the well-known B̄ projection in two different ways we develop two formulations for locking problems in beams and nearly incompressible elastic solids. One formulation leads to a sparse symmetric system and the other leads to a sparse non-symmetric system. To demonstrate the utility of Bézier projection for both geometry and material locking phenomena we focus on transverse shear locking in Timoshenko beams and volumetric locking in nearly compressible linear elasticity although the approach can be applied generally to other types of locking phenomena as well. Bézier projection is a local projection technique with optimal approximation properties, which in many cases produces solutions that are comparable to global L2 projection. In the context of B̄ methods, the use of Bézier projection produces sparse stiffness matrices with only a slight increase in bandwidth when compared to standard displacement-based methods. Of particular importance is that the approach is applicable to any spline representation that can be written in Bézier form like NURBS, T-splines, LR-splines, etc. We discuss in detail how to integrate this approach into an existing finite element framework with minimal disruption through the use of Bézier extraction operators and a newly introduced dual basis for the Bézier projection operator. We then demonstrate the behavior of the two proposed formulations through several challenging benchmark problems. © 2018
55 a56260937200 Bischoff M. p14 False Journal 12 An isogeometric Reissner–Mindlin shell element based on Bézier dual basis functions: Overcoming locking and improved coarse mesh accuracy We develop a mixed geometrically nonlinear isogeometric Reissner–Mindlin shell element for the analysis of thin-walled structures that leverages Bézier dual basis functions to address both shear and membrane locking and to improve the quality of computed stresses. The accuracy of computed solutions over coarse meshes, that have highly non-interpolatory control meshes, is achieved through the application of a continuous rotational approach. The starting point of the formulation is the modified Hellinger–Reissner variational principle with independent displacement, membrane, and shear strains as the unknown fields. To overcome locking, the strain variables are interpolated with lower-order spline bases while the variations of the strain variables are interpolated with the corresponding Bézier dual bases. Leveraging the orthogonality property of the Bézier dual basis, the strain variables are condensed out of the system with only a slight increase in the bandwidth of the resulting linear system. The condensed approach preserves the accuracy of the non-condensed mixed approach but with fewer degrees of freedom. From a practical point of view, since the Bézier dual basis is completely specified through Bézier extraction, any spline space that admits Bézier extraction can utilize the proposed approach directly. © 2020 Elsevier B.V.
56 a57081918700 Oesterle B. p14 False Journal 12 An isogeometric Reissner–Mindlin shell element based on Bézier dual basis functions: Overcoming locking and improved coarse mesh accuracy We develop a mixed geometrically nonlinear isogeometric Reissner–Mindlin shell element for the analysis of thin-walled structures that leverages Bézier dual basis functions to address both shear and membrane locking and to improve the quality of computed stresses. The accuracy of computed solutions over coarse meshes, that have highly non-interpolatory control meshes, is achieved through the application of a continuous rotational approach. The starting point of the formulation is the modified Hellinger–Reissner variational principle with independent displacement, membrane, and shear strains as the unknown fields. To overcome locking, the strain variables are interpolated with lower-order spline bases while the variations of the strain variables are interpolated with the corresponding Bézier dual bases. Leveraging the orthogonality property of the Bézier dual basis, the strain variables are condensed out of the system with only a slight increase in the bandwidth of the resulting linear system. The condensed approach preserves the accuracy of the non-condensed mixed approach but with fewer degrees of freedom. From a practical point of view, since the Bézier dual basis is completely specified through Bézier extraction, any spline space that admits Bézier extraction can utilize the proposed approach directly. © 2020 Elsevier B.V.
57 a55487415500 Dornisch W. p14 False Journal 12 An isogeometric Reissner–Mindlin shell element based on Bézier dual basis functions: Overcoming locking and improved coarse mesh accuracy We develop a mixed geometrically nonlinear isogeometric Reissner–Mindlin shell element for the analysis of thin-walled structures that leverages Bézier dual basis functions to address both shear and membrane locking and to improve the quality of computed stresses. The accuracy of computed solutions over coarse meshes, that have highly non-interpolatory control meshes, is achieved through the application of a continuous rotational approach. The starting point of the formulation is the modified Hellinger–Reissner variational principle with independent displacement, membrane, and shear strains as the unknown fields. To overcome locking, the strain variables are interpolated with lower-order spline bases while the variations of the strain variables are interpolated with the corresponding Bézier dual bases. Leveraging the orthogonality property of the Bézier dual basis, the strain variables are condensed out of the system with only a slight increase in the bandwidth of the resulting linear system. The condensed approach preserves the accuracy of the non-condensed mixed approach but with fewer degrees of freedom. From a practical point of view, since the Bézier dual basis is completely specified through Bézier extraction, any spline space that admits Bézier extraction can utilize the proposed approach directly. © 2020 Elsevier B.V.
57 a55487415500 Dornisch W. p515 False Journal 284 Isogeometric Bézier dual mortaring: Refineable higher-order spline dual bases and weakly continuous geometry In this paper we develop the isogeometric Bézier dual mortar method. It is based on Bézier extraction and projection and is applicable to any spline space which can be represented in Bézier form (i.e., NURBS, T-splines, LR-splines, etc.). The approach weakly enforces the continuity of the solution at patch interfaces and the error can be adaptively controlled by leveraging the refineability of the underlying slave dual spline basis without introducing any additional degrees of freedom. As a consequence, optimal higher-order convergence rates can be achieved without the need for an expensive shared master/slave segmentation step. We also develop weakly continuous geometry as a particular application of isogeometric Bézier dual mortaring. Weakly continuous geometry is a geometry description where the weak continuity constraints are built into properly modified Bézier extraction operators. As a result, multi-patch models can be processed in a solver directly without having to employ a mortaring solution strategy. We demonstrate the utility of the approach on several challenging benchmark problems. © 2018 Elsevier B.V.
58 a7202083837 Rice M. p15 True Journal 13 Physical-Layer Security for Vehicle-to-Everything Networks: Increasing Security while Maintaining Reliable Communications This article highlights the potential contribution of physical-layer security in making vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) networks more secure against eavesdropping. We showcase a set of experiments using a mobile testbed for both types of networks and demonst rate that finite block-length physical-layer security coding increases the security while maintaining reliable communications. The fundamental tradeoffs in achieving both reliability and security through physical-layer efforts are also discussed in terms of relative eavesdropper location in an urban environment. © 2020 IEEE.
58 a7202083837 Rice M. p38 False Journal 20 On the effects of channel sparsity on joint estimators in aeronautical telemetry Minimum mean-squared error (MMSE) equalizers are a viable solution to mitigate the frequency selectivity of the aeronautical telemetry channel. Because the MMSE equalizer filter coefficients are a function of the carrier frequency offset (CFO), the equivalent discrete-time channel, and the noise variance, reliable estimates of those parameters are required. The CFO is due primarily to the high velocity of the airborne transmitter. Because the equivalent discrete-time channel in aeronautical telemetry is sparse, the performance of the joint estimator based on a sparse channel estimator is superior to the performance of a traditional nonsparse maximum-likelihood-inspired joint estimator. The improvement is seen in lower estimator error variances for the parameters, particularly for the CFO and channel estimate, and in the postequalizer bit-error rate. Simulation results demonstrate that the postequalizer bit-error rate using the sparse estimator is almost as good as that using ideal estimators. © 1965-2011 IEEE.
58 a7202083837 Rice M. p85 False Journal 20 Sparse Equalization in Aeronautical Telemetry Using Two Transmit Antennas This correspondence explores the application of sparse equalizers in generalized time-reversed space-time block codes (GTR-STBCs) for a two-transmit/one-receive antenna aeronautical telemetry link. It is shown that the jointly optimum design of the sparse equalizer coefficients and the power sharing parameter \rho in GTR-STBCs is computationally challenging because the active tap ratio of the sparse equalizers is a non-convex function of \rho. A search algorithm based on a grid search followed by an interpolation is shown to yield impressive results. Our numerical results demonstrate that depending on signal-to-noise ratio and channel conditions, the number of non-zero taps of sparse equalizers for GTR-STBCs can be reduced by 53% to 86\% at the cost of 0.25 dB relaxation in the mean-squared error. © 1965-2011 IEEE.
58 a7202083837 Rice M. p148 False Conference 26 Space-Time Coded ARTM CPM for Aeronautical Telemetry This paper shows that burst-based orthogonal spacetime block-coded ARTM CPM is capable of solving the two-antenna problem in aeronautical telemetry, but detection requires a prohibitively complex trellis detector. In single-input, single-output (SISO) applications, pulse truncation and state-space partitioning reduce the computational complexity of the trellis detector with only modest bit error rate (BER) performance penalties. In this paper it is shown that layering pulse truncation and state-space partition complexity-reducing techniques with a burst-based orthogonal space-time block-code does not introduce additional BER performance losses relative to the SISO case. © 2019 IEEE.
58 a7202083837 Rice M. p159 True Journal 111 On Sparse Channel Estimation in Aeronautical Telemetry This paper examines the application of sparse estimation techniques for the estimation of a discrete-time equivalent multipath channel in the aeronautical telemetry context. The sensing matrix comprises samples of shaped offset QPSK-TG (a continuous phase modulation) based on the pilot bit sequence currently defined in the aeronautical telemetry standard. Representative algorithms from the three broad classes of sparse estimators were examined side by side using computer simulations to estimate the postequalizer bit error rate (BER). Ideal and nonideal frequency offset synchronization were assumed in the simulations. The results show that the performance of the matching pursuit (MP) algorithms seemed to be better suited to this application in the sense that no additional steps were required and the postequalizer BER of the best MP algorithm was slightly better than that of the other sparse estimation techniques. In the case of both ideal and nonideal frequency offset synchronization, the postequalizer BER achieved by the generalized orthogonal MP algorithm was approximately 1.5 dB better than that obtained using the nonsparse-constrained maximum likelihood channel estimate. © 1965-2011 IEEE.
58 a7202083837 Rice M. p232 False Conference 55 Physical-Layer Security: Does it Work in a Real Environment? This paper applies channel sounding measurements to enable physical-layer security coding. The channel measurements were acquired in an indoor environment and used to assess the secrecy capacity as a function of physical location. A variety of Reed-Muller wiretap codes were applied to the channel measurements to determine the most effective code for the environment. The results suggest that deploying physical-layer security coding is a three-point design process, where channel sounding data guides 1) the physical placement of the antennas, 2) the power settings of the transmitter, and 3) the selection of wiretap coding. © 2019 IEEE.
58 a7202083837 Rice M. p249 True Journal 111 Approximate MLSE Equalization of SOQPSK-TG in Aeronautical Telemetry An approximate maximum likelihood sequence estimator (MLSE) equalizer for shaped offset QPSK, version TG (SOQPSK-TG) is derived based on the pulse amplitude modulation (PAM) approximation of SOQPSK-TG using the two principal PAM pulses. The resulting equalizer is a generalization of the equalizer based on the Ungerboeck observation model, where the generalization is to two parallel, cross-correlated symbol streams over parallel intersymbol interference channels. The bit error rate (BER) performance and computational complexity of the approximate MLSE equalizer operating over three example channels, motivated by multipath propagation in aeronautical telemetry and with increasing selectivity, are presented. The BER performance was evaluated using computer simulations and shown to be approximately 5-8 dB better than the best frequency-domain minimum mean-squared error (MMSE) equalizers published in the open literature. The computational complexity, measured by the number of real-valued multiplications, is comparable to that of the frequency-domain MMSE equalizers. © 1965-2011 IEEE.
58 a7202083837 Rice M. p308 False Conference 88 DFT-based frequency offset estimators for 16-APSK In this paper, we analyze several DFT-based frequency offset estimators for use with the 16-APSK digital modulation scheme. Even a small frequency offset between radio transmitters and receivers can cause phase information to be lost, so a system to align the phases is required to reliably demodulate PSK signals. These estimators have been adapted for 16-APSK from methods originally intended for use with QPSK and CPM. These methods consist of a coarse search and a fine search with an optional dichotomous search to improve accuracy. We analyze the estimator error variance and bit error rate associated with several methods of frequency estimation. These estimators exhibit small estimate error and variance and can provide bit error rates close to the ideal AWGN BER. © 2019 International Foundation for Telemetering. All rights reserved.
58 a7202083837 Rice M. p309 False Conference 89 Doppler power spectra from vehicle-to-everything propagation experiments This paper presents the results of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) propagation experiments. The experimental results are summarized by Doppler power spectra. Our measurements indicate the need for a dynamic system that can handle the variable channels experienced in vehicle-to-everything communications. © 2019 International Foundation for Telemetering. All rights reserved.
58 a7202083837 Rice M. p311 True Conference 91 On carrier frequency and phase synchronization for coded 16-APSK in aeronautical mobile telemetry This paper examines the problem of carrier phase and frequency estimation for coded 16-APSK in aeronautical mobile telemetry. Given the fact that coded systems tend to operate at lower signal-to-noise ratios than uncoded systems, the synchronizer must operate at these lower signal-to-noise ratios. For a 30 kHz frequency offset and a 10 Mbit/s 16-APSK signal, the conventional phase lock loop (PLL) system does not achieve consistent lock to be a useful approach. Consequently, a blind feed-forward approach, based on the FFT, and an initialized feedback approach based on the PLL were examined. The feed-forward estimator is capable of achieving BER ideal performance for Eb/N0 ≥ 6 dB using 1024 symbols. The feedback estimator, initialized using a feed-forward estimate based on 1024 symbols is also capable of achieving BER ideal performance for Eb/N0 ≥ 6 dB. Both synchronizers require a sufficiently good blind estimate: the estimate based on 2014 symbols appears to be the minimum value to achieve good performance. © 2019 International Foundation for Telemetering. All rights reserved.
58 a7202083837 Rice M. p312 False Conference 92 Polarization diversity and equalization of frequency selective channels in telemetry environment for 16APSK Providing RHCP and LHCP outputs from the antennas vertical (V) and horizontal (H) dipoles in the resonant cavity within the antenna feeds is the current practice of ground-based station receivers in aeronautical telemetry. The equalizers on the market, operate on either LHCP or RHCP alone, or a combined signal created by co-phasing and adding the RHCP and LHCP outputs. In this paper, we show how to optimally combine the V and H dipole outputs and demonstrate that an equalizer operating on this optimally-combined signal outperforms an equalizer operating on the RHCP, LHCP, or the combined signals. Finally, we show how to optimally combine the RHCP and LHCP outputs for equalization, where this optimal combination performs as good as the optimally combined V and H signals. © 2019 International Foundation for Telemetering. All rights reserved.
58 a7202083837 Rice M. p414 True Journal 224 Spectrum allocations: The aeronautical telemetry story in the USA Aeronautical telemetry encompasses all the technologies necessary to successfully monitor airborne test articles, such as fixed and rotary wing aircraft, missiles, and drones. Aeronautical telemetry is primarily focused on the final stages of development when the test article performs the maneuvers required to operate in its deployed environment. Necessarily, the test article is 'in the air' while the flight test engineers who monitor its performance are 'on the ground.' The key enabling resource for aeronautical telemetry is spectrum: bandwidth is needed to transmit the measurements from the test article to the ground so flight test engineers can monitor the test, the safety of which is paramount. © 1986-2012 IEEE.
58 a7202083837 Rice M. p435 False Conference 156 On peak-to-average power ratio optimization for coded APSK The symmetric information rate is used to define the relationship between the APSK constellation parameters, the code rate, and the average and peak Eb=N0. Minimizing the average Eb=N0 reproduces the DVB-S2 constellation parameters for 16- And 32-APSK. Minimizing the peak Eb=N0 produces DVB-S2 constellation parameters for 16- And 32-APSK that minimize the peak-to-average power ratio. The peak-to-average power ratio gains are less than 1 dB, but when used on coded systems with very steep decoded bit error probability vs. Eb=N0 curves, the gains can be significant. © 2018 IEEE.
58 a7202083837 Rice M. p574 False Conference 219 On the performance of filter based equalizers for 16apsk in aeronautical telemetry environment 16APSK is a candidate modulation for aeronautical telemetry because it has better spectral efficiency than SOQPSK-TG, but requires a linear RF power amplifier. This paper investigates the BER performance of filter-based equalizers for 16APSK operating over multipath channels measured at Edwards AFB. The results show that decision feedback equalizers outperform the other equalizers and are capable of providing excellent multipath mitigation. © held by the author; distribution rights International Foundation for Telemetering.
58 a7202083837 Rice M. p618 False Conference 255 Unification of signal models for soqpsk This paper begins by summarizing a recent advancement in the way that shaped offset quadrature phase shift keying (SOQPSK) waveforms can be viewed. This new viewpoint succeeds in eliminating the need for SOQPSK to be thought of as a “special” kind of correlated, ternary continuous phase modulation (CPM). Instead, SOQPSK can be viewed as an ordinary, binary CPM. We provide all of the details necessary to achieve a complete unification of SOQPSK models at the waveform level, at the bit sequence level, and in terms of waveform initialization. With this information, SOQPSK users can easily mix and match SOQPSK models at the transmitter and receiver in order to make use of the advantages of each model. © held by the author; distribution rights International Foundation for Telemetering.
58 a7202083837 Rice M. p619 False Conference 256 Cfo estimation by exploiting channel sparsity in aeronautical telemetry In this paper, we explore a carrier frequency offset (CFO) estimation scheme with sparsity-constraint (SC) on the aeronautical telemetry channels. This SC CFO estimator is implemented in two steps. In the first step, channel support is recovered by combining compressed sensing techniques with the CFO estimate based on the non-sparsity constraint (NSC) on the channel. Next we use the estimated channel support to derive the SC CFO estimator. Simulations are performed to compare the performance of the SC CFO estimator against the existing NSC CFO estimators using shaped offset QPSK version TG (SOQPSK-TG) modulated iNET-formatted data over an aeronautical test channel. © held by the author; distribution rights International Foundation for Telemetering.
58 a7202083837 Rice M. p711 True Journal 350 Space-Time Coding for Aeronautical Telemetry: Part i - Estimators This paper derives and analyzes the estimators required for detection and decoding of Alamouti-encoded-shaped offset QPSK version TG (SOQPSK-TG). The joint maximum likelihood (ML) estimators for the frequency offset, channel delays, and channel gains are derived and analyzed. As a complexity-reducing technique, a sequential version of the ML estimators is developed. The Cramér-Rao bound for the parameters is derived and used to analyze the performance of the estimators to determine pilot sequence length. The complexity of the frequency estimator is reduced by applying the Zoom FFT algorithm in the coarse search. The complexity of the channel delay estimator was reduced by developing a novel version of the simplex search algorithm that operated on a discrete two-dimensional grid. These estimation algorithms were implemented in a prototype demodulator that was field tested at Edwards AFB. © 2017 IEEE.
58 a7202083837 Rice M. p712 True Journal 350 Space-Time Coding for Aeronautical Telemetry: Part II - Decoder and System Performance This paper describes the use of Alamouti-encoded-shaped offset QPSK version TG (SOQPSK-TG) to solve the two-antenna problem in aeronautical telemetry. The Alamouti space-time block code is used to encode the phase states in the complex exponential representation of SOQPSK-TG. Because SOQPSK-TG possesses memory, the Alamouti decoder is a sequence estimator. Maximum likelihood and least squares sequence decoders are derived. To reduce the number of states, the eight-waveform cross-correlated trellis-coded quadrature modulation (XTCQM) approximate representation of SOQPSK-TG is used. A prototype decoder based on the least squares decoder and the estimators described in Part I and operating at a data rate of 10 Mb/s was tested in the laboratory in test flights at the Air Force Test Center, Edwards AFB. The test flights demonstrate that Alamouti-encoded SOQPSK-TG, as described in this paper, using the least squares decoder based on the estimators described in Part I solves the two antenna problem in aeronautical telemetry. © 2017 IEEE.
58 a7202083837 Rice M. p807 True Conference 342 On if-to-baseband translation and resampling in sampled-data receivers This paper summarizes the design of a discrete-time quadrature downconversion and resampling processor that operates on samples of a 70 MHz IF signal. The unique properties of discrete-time processing-aliasing due to resampling bandpass signals and polyphase filter decompositions- are applied to create a low-complexity approach that does not require any arithmetic operations at the IF sample rate. The required tasks are performed in two stages: a downsample-by-2 operation followed by a more traditional resampler based on a polyphase filterbank.
58 a7202083837 Rice M. p847 True Conference 371 Optimizing coded 16-APSK for aeronautical mobile telemetry This paper investigates the application of 16-APSK modulation to aeronautical mobile telemetry. The peak-to-average power ratio vs. code rate tradeoffis mapped to an optimization problem involving spectral efficiency and the constellation parameters. The optimization results produce a theoretically optimum solution that is 3.95 times more spectrally efficient as uncoded SOQPSKTG. When implementation losses and the available IRIG 106 LDPC code rates are factored in, the advantage drops to 3.20 times the spectral efficiency of SOQPSK-TG.
58 a7202083837 Rice M. p848 False Conference 372 Sparse MMSE equalizer for GTR-STBC in aeronautical telemetry This paper investigates the performance of sparse minimum mean squared error (MMSE) equalizer for generalized time-reversed space-time block codes (GTR-STBC) in aeronautical telemetry. GTR-STBC equipped with MMSE equalizer performs the best trade-offbetween the signal-tonoise ratio and inter-symbol interference by allocating unequal power over aeronautical telemetry channels. However, aeronautical telemetry channels are in general consists of larger delay spreads which make the MMSE equalization of aeronautical channels with GTR-STBC computationally complex. Interestingly enough, in spite of larger delays aeronautical channels are made of few sparsely distributed multipaths and therefore their MMSE equalizers are highly compressible. In this paper, compressed sensing based greedy algorithm is used for the design of sparse MMSE equalizer and a convex curve-fitting algorithm is used to find the sub-optimum power allocation parameter at the same sparsity level for GTR-STBC. Our simulation results show that 75-90% of the non-zero equalizer taps can be reduced with a slight relaxation of the mean-squared error (or equivalently slight degradation of bit-error rate performance). It is also observed that the optimum transmitter power profile for the sparse MMSE equalizer is different than that of the non-sparse equalizer.
58 a7202083837 Rice M. p886 True Conference 398 A summary of data-aided equalizer experiments at edwards AFB This paper summarizes the analysis of bit error rate data captured during flight tests designed to compare data-aided equalizers with SOQPSK-TG to unequalized and currently available blind, adaptive equalizers with SOQPSK-TG. The number of bit errors, on a second-by-second basis, are analyzed. The results are different for each test point. Given the uncertain behavior of the preamble detector for the data-aided equalizer and the differing channel conditions between the data-aided equalizer channel and the conventional serial streaming telemetry channel, we are unable to draw any firm comparative conclusions.
59 a57210290270 Clark B. p15 False Journal 13 Physical-Layer Security for Vehicle-to-Everything Networks: Increasing Security while Maintaining Reliable Communications This article highlights the potential contribution of physical-layer security in making vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) networks more secure against eavesdropping. We showcase a set of experiments using a mobile testbed for both types of networks and demonst rate that finite block-length physical-layer security coding increases the security while maintaining reliable communications. The fundamental tradeoffs in achieving both reliability and security through physical-layer efforts are also discussed in terms of relative eavesdropper location in an urban environment. © 2020 IEEE.
59 a57210290270 Clark B. p232 False Conference 55 Physical-Layer Security: Does it Work in a Real Environment? This paper applies channel sounding measurements to enable physical-layer security coding. The channel measurements were acquired in an indoor environment and used to assess the secrecy capacity as a function of physical location. A variety of Reed-Muller wiretap codes were applied to the channel measurements to determine the most effective code for the environment. The results suggest that deploying physical-layer security coding is a three-point design process, where channel sounding data guides 1) the physical placement of the antennas, 2) the power settings of the transmitter, and 3) the selection of wiretap coding. © 2019 IEEE.
60 a57210288045 Flanary D. p15 False Journal 13 Physical-Layer Security for Vehicle-to-Everything Networks: Increasing Security while Maintaining Reliable Communications This article highlights the potential contribution of physical-layer security in making vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) networks more secure against eavesdropping. We showcase a set of experiments using a mobile testbed for both types of networks and demonst rate that finite block-length physical-layer security coding increases the security while maintaining reliable communications. The fundamental tradeoffs in achieving both reliability and security through physical-layer efforts are also discussed in terms of relative eavesdropper location in an urban environment. © 2020 IEEE.
60 a57210288045 Flanary D. p232 False Conference 55 Physical-Layer Security: Does it Work in a Real Environment? This paper applies channel sounding measurements to enable physical-layer security coding. The channel measurements were acquired in an indoor environment and used to assess the secrecy capacity as a function of physical location. A variety of Reed-Muller wiretap codes were applied to the channel measurements to determine the most effective code for the environment. The results suggest that deploying physical-layer security coding is a three-point design process, where channel sounding data guides 1) the physical placement of the antennas, 2) the power settings of the transmitter, and 3) the selection of wiretap coding. © 2019 IEEE.
61 a57210287166 Jensen B. p15 False Journal 13 Physical-Layer Security for Vehicle-to-Everything Networks: Increasing Security while Maintaining Reliable Communications This article highlights the potential contribution of physical-layer security in making vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) networks more secure against eavesdropping. We showcase a set of experiments using a mobile testbed for both types of networks and demonst rate that finite block-length physical-layer security coding increases the security while maintaining reliable communications. The fundamental tradeoffs in achieving both reliability and security through physical-layer efforts are also discussed in terms of relative eavesdropper location in an urban environment. © 2020 IEEE.
61 a57210287166 Jensen B. p232 True Conference 55 Physical-Layer Security: Does it Work in a Real Environment? This paper applies channel sounding measurements to enable physical-layer security coding. The channel measurements were acquired in an indoor environment and used to assess the secrecy capacity as a function of physical location. A variety of Reed-Muller wiretap codes were applied to the channel measurements to determine the most effective code for the environment. The results suggest that deploying physical-layer security coding is a three-point design process, where channel sounding data guides 1) the physical placement of the antennas, 2) the power settings of the transmitter, and 3) the selection of wiretap coding. © 2019 IEEE.
61 a57210287166 Jensen B. p309 False Conference 89 Doppler power spectra from vehicle-to-everything propagation experiments This paper presents the results of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) propagation experiments. The experimental results are summarized by Doppler power spectra. Our measurements indicate the need for a dynamic system that can handle the variable channels experienced in vehicle-to-everything communications. © 2019 International Foundation for Telemetering. All rights reserved.
62 a57211254337 Nelson N. p15 False Journal 13 Physical-Layer Security for Vehicle-to-Everything Networks: Increasing Security while Maintaining Reliable Communications This article highlights the potential contribution of physical-layer security in making vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) networks more secure against eavesdropping. We showcase a set of experiments using a mobile testbed for both types of networks and demonst rate that finite block-length physical-layer security coding increases the security while maintaining reliable communications. The fundamental tradeoffs in achieving both reliability and security through physical-layer efforts are also discussed in terms of relative eavesdropper location in an urban environment. © 2020 IEEE.
63 a57210292389 Norman K. p15 False Journal 13 Physical-Layer Security for Vehicle-to-Everything Networks: Increasing Security while Maintaining Reliable Communications This article highlights the potential contribution of physical-layer security in making vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) networks more secure against eavesdropping. We showcase a set of experiments using a mobile testbed for both types of networks and demonst rate that finite block-length physical-layer security coding increases the security while maintaining reliable communications. The fundamental tradeoffs in achieving both reliability and security through physical-layer efforts are also discussed in terms of relative eavesdropper location in an urban environment. © 2020 IEEE.
63 a57210292389 Norman K. p232 False Conference 55 Physical-Layer Security: Does it Work in a Real Environment? This paper applies channel sounding measurements to enable physical-layer security coding. The channel measurements were acquired in an indoor environment and used to assess the secrecy capacity as a function of physical location. A variety of Reed-Muller wiretap codes were applied to the channel measurements to determine the most effective code for the environment. The results suggest that deploying physical-layer security coding is a three-point design process, where channel sounding data guides 1) the physical placement of the antennas, 2) the power settings of the transmitter, and 3) the selection of wiretap coding. © 2019 IEEE.
63 a57210292389 Norman K. p309 True Conference 89 Doppler power spectra from vehicle-to-everything propagation experiments This paper presents the results of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) propagation experiments. The experimental results are summarized by Doppler power spectra. Our measurements indicate the need for a dynamic system that can handle the variable channels experienced in vehicle-to-everything communications. © 2019 International Foundation for Telemetering. All rights reserved.
64 a57218761022 Perrins E. p15 False Journal 13 Physical-Layer Security for Vehicle-to-Everything Networks: Increasing Security while Maintaining Reliable Communications This article highlights the potential contribution of physical-layer security in making vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) networks more secure against eavesdropping. We showcase a set of experiments using a mobile testbed for both types of networks and demonst rate that finite block-length physical-layer security coding increases the security while maintaining reliable communications. The fundamental tradeoffs in achieving both reliability and security through physical-layer efforts are also discussed in terms of relative eavesdropper location in an urban environment. © 2020 IEEE.
65 a35147940600 Harrison W.K. p15 False Journal 13 Physical-Layer Security for Vehicle-to-Everything Networks: Increasing Security while Maintaining Reliable Communications This article highlights the potential contribution of physical-layer security in making vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) networks more secure against eavesdropping. We showcase a set of experiments using a mobile testbed for both types of networks and demonst rate that finite block-length physical-layer security coding increases the security while maintaining reliable communications. The fundamental tradeoffs in achieving both reliability and security through physical-layer efforts are also discussed in terms of relative eavesdropper location in an urban environment. © 2020 IEEE.
65 a35147940600 Harrison W.K. p84 False Journal 64 Postprocessing the outputs of an interacting multiple-model Kalman filter using a Markovian trellis to estimate parameter values of aged Li-ion cells Lithium-ion battery modeling for use in battery management systems requires models that can adapt to the changing behavior of a cell as it ages. One method to enable this adaptivity is to select the most representative model from a set of “pre-aged” models that represent the characteristics of the cell as different cyclic and calendar aging processes occur. By modeling the aging of a cell as a Markovian process, an interacting multiple-model Kalman filter (IMM) can be utilized to determine a time-varying probability mass function that specifies the probability that each of the models under consideration is the best representation of the cell under observation. While the output of the IMM is useful by itself, its predictions can be improved by post-processing. In this paper, we present methods to analyze the time-series probability mass function produced by the IMM using the Viterbi and BCJR algorithms in common use in the digital-communications discipline. These algorithms seek to identify the “best path” through the space of available models over time, based on the likelihoods produced by the IMM and the Markovian transition probabilities. Through the use of these post-processing algorithms, confidence in the best-fitting model can be improved. © 2019 Elsevier Ltd
65 a35147940600 Harrison W.K. p142 False Conference 24 Irregular quadrature amplitude modulation for adaptive physical-layer security We propose adding an irregular quadrature amplitude modulation (QAM) constellation to a wireless transmission scheme in order to obtain greater control over the signal-to-noise ratio (SNR) required to successfully decode the signal. By altering the separation between adjacent symbols, the minimum required SNR is raised without degradation in the performance of the scheme. This allows the system to adapt to preferable channel conditions for the authorized user, making it harder for eavesdroppers to intercept and decode the transmission, thus making the communication safer. In addition, we show that by overlaying a coset code onto the QAM constellation, a new, stronger security gap metric can be further improved. Results show the effectiveness of this strategy with an interleaved coding for secrecy with a hidden key (ICSHK) scheme. © 2019 IEEE.
65 a35147940600 Harrison W.K. p186 True Journal 127 Generating a Binary Symmetric Channel for Wiretap Codes In this paper, we fill a void between information theoretic security and practical coding over the Gaussian wiretap channel using a three-stage encoder/decoder technique. Security is measured using Kullback-Leibler divergence and resolvability techniques along with a limited number of practical assumptions regarding the eavesdropper's decoder. The results specify a general coding recipe for obtaining both secure and reliable communications over the Gaussian wiretap channel, and one specific set of concatenated codes is presented as a test case for the sake of providing simulation-based evaluation of security and reliability over the network. It is shown that there exists a threshold in signal-to-noise ratio (SNR) over a Gaussian channel, such that receivers experiencing SNR below the threshold have no practical hope of receiving information about the message when the three-stage coding technique is applied. Results further indicate that the two innermost encoding stages successfully approximate a binary symmetric channel, allowing the outermost encoding stage (e.g., a wiretap code) to focus solely on secrecy coding over this approximated channel. © 2005-2012 IEEE.
65 a35147940600 Harrison W.K. p232 False Conference 55 Physical-Layer Security: Does it Work in a Real Environment? This paper applies channel sounding measurements to enable physical-layer security coding. The channel measurements were acquired in an indoor environment and used to assess the secrecy capacity as a function of physical location. A variety of Reed-Muller wiretap codes were applied to the channel measurements to determine the most effective code for the environment. The results suggest that deploying physical-layer security coding is a three-point design process, where channel sounding data guides 1) the physical placement of the antennas, 2) the power settings of the transmitter, and 3) the selection of wiretap coding. © 2019 IEEE.
65 a35147940600 Harrison W.K. p240 False Conference 58 Full-Duplex Jamming for Enhanced Hidden-Key Secrecy This paper presents a practical physical-layer security scheme based on coding methodologies combined with self-jamming to combat advantaged eavesdroppers, i.e., eavesdroppers that may possess an equal or even better channel than the legitimate receiver. We introduce a strengthened security gap notion, where reliability is assured by typical bit-error rate (BER) measurements, but secrecy is guaranteed by considering the entire distribution of messages upon reception, instead of average measures. Relying on this new security gap notion, we then propose a scheme that combines concatenated coding with self-jamming by the legitimate receiver for effective security and reliability even when eavesdroppers possess a channel with equal or better conditions than the legitimate receiver. © 2019 IEEE.
65 a35147940600 Harrison W.K. p241 False Conference 59 Adaptive Physical-Layer Security Through Punctured Coding for Secrecy We propose a coding methodology for physical layer security with adaptive characteristics, whereby adaptive we mean that the system must be tunable to different operational points/signal-to-noise ratio levels of both the legitimate receiver and the eavesdropper. Based on interleaving and scrambling as techniques that shuffle the original message before transmission, we consider puncturing over an interleaving/scrambling key and/or over the message as a mechanism to provide the required adaptability to channel conditions. The proposed techniques have shown suitable adaptability to different channel quality levels of the legitimate receiver and eavesdropper, while still guaranteeing the desired reliability for the legitimate receiver and secrecy against the eavesdropper. © 2019 IEEE.
65 a35147940600 Harrison W.K. p253 False Conference 60 Polar coding for physical-layer security without knowledge of the eavesdropper's channel We propose an adaptive secrecy scheme using polar codes with random frozen bits for a general wiretap channel, in which to protect the data from a potential eavesdropper, part or all of the frozen bits are randomly generated per message. To assess the secrecy level of the proposed scheme, three types of decoding strategies are evaluated: a matching decoder which knows the positions of all inserted bits inside the blocklength and tries to estimate them using the same decoding techniques, a blind decoder which treats all the frozen bits as the same value, and a random decoder which considers those dynamic bits as random at the receiver. Results are presented in terms of the system security gap, assuming an adaptive decoding strategy. It is shown that the system achieves combined secrecy and reliability. The proposed scheme does not assume knowledge of the eavesdropper's channel when defining the indices of information and frozen bits. © 2019 IEEE.
65 a35147940600 Harrison W.K. p309 False Conference 89 Doppler power spectra from vehicle-to-everything propagation experiments This paper presents the results of vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) propagation experiments. The experimental results are summarized by Doppler power spectra. Our measurements indicate the need for a dynamic system that can handle the variable channels experienced in vehicle-to-everything communications. © 2019 International Foundation for Telemetering. All rights reserved.
65 a35147940600 Harrison W.K. p434 False Conference 155 Active Topology Inference in Store, Code, and Forward Networks This paper presents a technique for active topology inference in store, code, and forward networks. Many techniques exist for topology inference and are well suited for storeand- forward and cut-through switching; however, these simpler techniques fail to capitalize on the flexibility of recoding afforded by store, code, and forward networks. This is in contrast to network coding, which recodes the data whenever possible and consequently achieves the maximum flow (and minimum cut) of throughput across a network. The technique herein utilizes a single probe message between a single source and potentially many destination nodes to achieve deterministic topology inference. © 2018 IEEE.
65 a35147940600 Harrison W.K. p435 False Conference 156 On peak-to-average power ratio optimization for coded APSK The symmetric information rate is used to define the relationship between the APSK constellation parameters, the code rate, and the average and peak Eb=N0. Minimizing the average Eb=N0 reproduces the DVB-S2 constellation parameters for 16- And 32-APSK. Minimizing the peak Eb=N0 produces DVB-S2 constellation parameters for 16- And 32-APSK that minimize the peak-to-average power ratio. The peak-to-average power ratio gains are less than 1 dB, but when used on coded systems with very steep decoded bit error probability vs. Eb=N0 curves, the gains can be significant. © 2018 IEEE.
65 a35147940600 Harrison W.K. p469 False Conference 171 A Rateless Approach to Physical-Layer Security A majority of coding constructions for physical-layer security are based on linear block codes and their cosets. One issue with these codes is that they require knowledge of channel state information (CSI) for both the friendly party and the eavesdropper in the wiretap channel prior to constructing the code. In this paper, we present a framework for rateless physical-layer security codes over the wiretap channel by introducing both fixed and adaptive variants of rateless security coding schemes. These techniques can be used to reduce the requirements on CSI prior to code construction, because the codes will either adapt to the operating parameters of the legitimate user's channel on the fly and/or target a maximum allowable probability of intercept (POI) at the eavesdropper. All channels in play are packet erasure channels (PECs), as these channels are quite pervasive in most real-world network applications. We further present the details of an actual implementation of rateless physical-layer security coding over a Wi-Fi network. © 2018 IEEE.
65 a35147940600 Harrison W.K. p470 False Conference 172 Nested QPSK Encoding for Information Theoretic Security This paper proposes a method to provide secrecy for digital communications with arbitrarily large quadrature amplitude modulation (QAM) constellations for transmission over a Gaussian fading wiretap channel. This is accomplished by breaking the constellation down into nested quadrature phase-shift keying (QPSK) symbols and randomizing the assignment between message bits and modulated symbols using channel state information (CSI). If enough random bits can be generated from CSI it becomes possible to uniquely map an arbitrary message to any symbol in the large QAM constellation. The proposed method can thereby provide perfect secrecy while maintaining high reliability by exclusively assigning minimum-distance-mapped constellations through the randomization for use by the legitimate decoder. © 2018 IEEE.
65 a35147940600 Harrison W.K. p575 True Conference 220 Physical-layer security for aeronautical telemetry In this paper, we investigate the application of physical-layer security coding for next generation aeronautical telemetry communication systems. The coding we refer to is similar to error-control coding, but the codes are deployed for two purposes: to achieve reliable communications, and to achieve secure communications. We consider a single eavesdropper on an air-to-ground aeronautical telemetry link, and show how the overhead measured by the rate of the code can be used to keep secrets from eavesdroppers over noisy channels, rather than recover from channel errors. We show simple examples that work over erasure channels to achieve a security constraint, and then consider approaches to more practical coding constructions for Gaussian channels that satisfies both reliability and security constraints on the network. © held by the author; distribution rights International Foundation for Telemetering.
66 a57201912667 Hendricks L.J. p16 True Journal 14 High-Speed Acoustic Impact-Echo Sounding of Concrete Bridge Decks Evaluation of deteriorating highway bridges requires new, rapid inspection methods to effectively guide repair in an era of limited fiscal resources. Of all the components of a bridge, the bridge deck typically deteriorates most quickly and must therefore be regularly inspected for non-visible internal cracking, called delamination, for which early detection and repair can enhance safety and performance as well as reduce long-term maintenance costs. This research demonstrates the development and deployment of a multi-channel acoustic impact-echo sounding apparatus equipped with specially-configured tire chains for acoustic excitation of the concrete, microphones, an array of sensors for establishing spatial position estimates, and a data processing architecture for accurately detecting and mapping delaminations in concrete bridge decks at high speeds. The new apparatus achieved very accurate results at speeds between 25 and 45 km/h across a bridge deck. These results demonstrate an orders-of-magnitude increase in data collection speed over all other acoustic impact-echo sounding techniques described in the literature. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.
67 a7202282831 Baxter J.S. p16 False Journal 14 High-Speed Acoustic Impact-Echo Sounding of Concrete Bridge Decks Evaluation of deteriorating highway bridges requires new, rapid inspection methods to effectively guide repair in an era of limited fiscal resources. Of all the components of a bridge, the bridge deck typically deteriorates most quickly and must therefore be regularly inspected for non-visible internal cracking, called delamination, for which early detection and repair can enhance safety and performance as well as reduce long-term maintenance costs. This research demonstrates the development and deployment of a multi-channel acoustic impact-echo sounding apparatus equipped with specially-configured tire chains for acoustic excitation of the concrete, microphones, an array of sensors for establishing spatial position estimates, and a data processing architecture for accurately detecting and mapping delaminations in concrete bridge decks at high speeds. The new apparatus achieved very accurate results at speeds between 25 and 45 km/h across a bridge deck. These results demonstrate an orders-of-magnitude increase in data collection speed over all other acoustic impact-echo sounding techniques described in the literature. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.
67 a7202282831 Baxter J.S. p103 False Journal 77 Automated sounding for concrete bridge deck inspection through a multi-channel, continuously moving platform A new multi-channel, automated, air-coupled, impact-echo sounding device was designed, constructed, and demonstrated in this work. The apparatus includes seven replicated impactor and recording units, a moving trailer platform, a distance measurement instrument, and signal processing modules. A series of computer algorithms is used to determine the presence of delamination on concrete bridge decks based on the bandlimited acoustic energy value computed from the acoustic response associated with each impact. Compared to traditional sounding methods, this device significantly decreases the required inspection time, eliminates subjectivity, and increases safety by substantially reducing the exposure of inspectors to live traffic. © 2019
67 a7202282831 Baxter J.S. p258 False Journal 169 Automated Air-Coupled Impact-Echo Testing of a Concrete Bridge Deck from a Continuously Moving Platform The objective of this work was to develop an automated air-coupled impact-echo testing device for mapping the occurrence of delamination in a concrete bridge deck from a continuously moving platform with a fast, repeatable excitation mechanism and algorithms for collecting and analyzing the acoustic data. The apparatus developed in this research included an impactor unit, a moving platform, a microphone for air-coupled sensing, a distance measurement instrument, and signal processing modules. Given the absence of an existing universal threshold for differentiating among intact and delaminated areas using the new device, a delamination detection threshold value was determined in a first field demonstration also involving chain dragging and coring of a concrete bridge deck. While the maps of the air-coupled impact-echo data and chain-dragging data exhibit a high degree of similarity and are highly consistent with the results of coring, a quantitative method of comparison also demonstrates the utility of the new device across a broad range of delamination percentages. Specifically, the results indicate that the percentage of the deck area determined to be delaminated using impact-echo testing was within 3 percentage points of that determined to be delaminated using chain dragging for 10 of the 13 deck test sections, which generally exhibited delamination percentages ranging from 7 to 21%. Finally, testing with the new device was more than seven times faster than chain dragging. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
67 a7202282831 Baxter J.S. p523 False Journal 290 Vertical electrical impedance testing of a concrete bridge deck using a rolling probe The speed of vertical electrical impedance testing of a concrete bridge deck using a new rolling probe was demonstrated in this research to be 190 m2/h, which is more than six times faster than the speed at which data were collected using the static probe utilized in earlier research. Furthermore, with impedance measurements obtained at a longitudinal spacing of approximately 0.1 m, the spatial resolution was 12 times greater than that of the static probe. Vertical electrical impedance testing was performed together with half-cell potential testing, chaining, cover depth, and chloride concentration testing, and an interpretation of these data sets was developed that synergistically incorporated the deck maintenance history. © 2018 Elsevier Ltd
68 a57218107757 Chou Y. p16 False Journal 14 High-Speed Acoustic Impact-Echo Sounding of Concrete Bridge Decks Evaluation of deteriorating highway bridges requires new, rapid inspection methods to effectively guide repair in an era of limited fiscal resources. Of all the components of a bridge, the bridge deck typically deteriorates most quickly and must therefore be regularly inspected for non-visible internal cracking, called delamination, for which early detection and repair can enhance safety and performance as well as reduce long-term maintenance costs. This research demonstrates the development and deployment of a multi-channel acoustic impact-echo sounding apparatus equipped with specially-configured tire chains for acoustic excitation of the concrete, microphones, an array of sensors for establishing spatial position estimates, and a data processing architecture for accurately detecting and mapping delaminations in concrete bridge decks at high speeds. The new apparatus achieved very accurate results at speeds between 25 and 45 km/h across a bridge deck. These results demonstrate an orders-of-magnitude increase in data collection speed over all other acoustic impact-echo sounding techniques described in the literature. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.
69 a57198832579 Thomas M. p16 False Journal 14 High-Speed Acoustic Impact-Echo Sounding of Concrete Bridge Decks Evaluation of deteriorating highway bridges requires new, rapid inspection methods to effectively guide repair in an era of limited fiscal resources. Of all the components of a bridge, the bridge deck typically deteriorates most quickly and must therefore be regularly inspected for non-visible internal cracking, called delamination, for which early detection and repair can enhance safety and performance as well as reduce long-term maintenance costs. This research demonstrates the development and deployment of a multi-channel acoustic impact-echo sounding apparatus equipped with specially-configured tire chains for acoustic excitation of the concrete, microphones, an array of sensors for establishing spatial position estimates, and a data processing architecture for accurately detecting and mapping delaminations in concrete bridge decks at high speeds. The new apparatus achieved very accurate results at speeds between 25 and 45 km/h across a bridge deck. These results demonstrate an orders-of-magnitude increase in data collection speed over all other acoustic impact-echo sounding techniques described in the literature. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.
70 a57218097969 Boekweg E. p16 False Journal 14 High-Speed Acoustic Impact-Echo Sounding of Concrete Bridge Decks Evaluation of deteriorating highway bridges requires new, rapid inspection methods to effectively guide repair in an era of limited fiscal resources. Of all the components of a bridge, the bridge deck typically deteriorates most quickly and must therefore be regularly inspected for non-visible internal cracking, called delamination, for which early detection and repair can enhance safety and performance as well as reduce long-term maintenance costs. This research demonstrates the development and deployment of a multi-channel acoustic impact-echo sounding apparatus equipped with specially-configured tire chains for acoustic excitation of the concrete, microphones, an array of sensors for establishing spatial position estimates, and a data processing architecture for accurately detecting and mapping delaminations in concrete bridge decks at high speeds. The new apparatus achieved very accurate results at speeds between 25 and 45 km/h across a bridge deck. These results demonstrate an orders-of-magnitude increase in data collection speed over all other acoustic impact-echo sounding techniques described in the literature. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.
71 a7003302831 Guthrie W.S. p16 False Journal 14 High-Speed Acoustic Impact-Echo Sounding of Concrete Bridge Decks Evaluation of deteriorating highway bridges requires new, rapid inspection methods to effectively guide repair in an era of limited fiscal resources. Of all the components of a bridge, the bridge deck typically deteriorates most quickly and must therefore be regularly inspected for non-visible internal cracking, called delamination, for which early detection and repair can enhance safety and performance as well as reduce long-term maintenance costs. This research demonstrates the development and deployment of a multi-channel acoustic impact-echo sounding apparatus equipped with specially-configured tire chains for acoustic excitation of the concrete, microphones, an array of sensors for establishing spatial position estimates, and a data processing architecture for accurately detecting and mapping delaminations in concrete bridge decks at high speeds. The new apparatus achieved very accurate results at speeds between 25 and 45 km/h across a bridge deck. These results demonstrate an orders-of-magnitude increase in data collection speed over all other acoustic impact-echo sounding techniques described in the literature. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.
71 a7003302831 Guthrie W.S. p103 False Journal 77 Automated sounding for concrete bridge deck inspection through a multi-channel, continuously moving platform A new multi-channel, automated, air-coupled, impact-echo sounding device was designed, constructed, and demonstrated in this work. The apparatus includes seven replicated impactor and recording units, a moving trailer platform, a distance measurement instrument, and signal processing modules. A series of computer algorithms is used to determine the presence of delamination on concrete bridge decks based on the bandlimited acoustic energy value computed from the acoustic response associated with each impact. Compared to traditional sounding methods, this device significantly decreases the required inspection time, eliminates subjectivity, and increases safety by substantially reducing the exposure of inspectors to live traffic. © 2019
71 a7003302831 Guthrie W.S. p258 True Journal 169 Automated Air-Coupled Impact-Echo Testing of a Concrete Bridge Deck from a Continuously Moving Platform The objective of this work was to develop an automated air-coupled impact-echo testing device for mapping the occurrence of delamination in a concrete bridge deck from a continuously moving platform with a fast, repeatable excitation mechanism and algorithms for collecting and analyzing the acoustic data. The apparatus developed in this research included an impactor unit, a moving platform, a microphone for air-coupled sensing, a distance measurement instrument, and signal processing modules. Given the absence of an existing universal threshold for differentiating among intact and delaminated areas using the new device, a delamination detection threshold value was determined in a first field demonstration also involving chain dragging and coring of a concrete bridge deck. While the maps of the air-coupled impact-echo data and chain-dragging data exhibit a high degree of similarity and are highly consistent with the results of coring, a quantitative method of comparison also demonstrates the utility of the new device across a broad range of delamination percentages. Specifically, the results indicate that the percentage of the deck area determined to be delaminated using impact-echo testing was within 3 percentage points of that determined to be delaminated using chain dragging for 10 of the 13 deck test sections, which generally exhibited delamination percentages ranging from 7 to 21%. Finally, testing with the new device was more than seven times faster than chain dragging. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
71 a7003302831 Guthrie W.S. p523 True Journal 290 Vertical electrical impedance testing of a concrete bridge deck using a rolling probe The speed of vertical electrical impedance testing of a concrete bridge deck using a new rolling probe was demonstrated in this research to be 190 m2/h, which is more than six times faster than the speed at which data were collected using the static probe utilized in earlier research. Furthermore, with impedance measurements obtained at a longitudinal spacing of approximately 0.1 m, the spatial resolution was 12 times greater than that of the static probe. Vertical electrical impedance testing was performed together with half-cell potential testing, chaining, cover depth, and chloride concentration testing, and an interpretation of these data sets was developed that synergistically incorporated the deck maintenance history. © 2018 Elsevier Ltd
72 a16066928300 Mazzeo B.A. p16 False Journal 14 High-Speed Acoustic Impact-Echo Sounding of Concrete Bridge Decks Evaluation of deteriorating highway bridges requires new, rapid inspection methods to effectively guide repair in an era of limited fiscal resources. Of all the components of a bridge, the bridge deck typically deteriorates most quickly and must therefore be regularly inspected for non-visible internal cracking, called delamination, for which early detection and repair can enhance safety and performance as well as reduce long-term maintenance costs. This research demonstrates the development and deployment of a multi-channel acoustic impact-echo sounding apparatus equipped with specially-configured tire chains for acoustic excitation of the concrete, microphones, an array of sensors for establishing spatial position estimates, and a data processing architecture for accurately detecting and mapping delaminations in concrete bridge decks at high speeds. The new apparatus achieved very accurate results at speeds between 25 and 45 km/h across a bridge deck. These results demonstrate an orders-of-magnitude increase in data collection speed over all other acoustic impact-echo sounding techniques described in the literature. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.
72 a16066928300 Mazzeo B.A. p103 False Journal 77 Automated sounding for concrete bridge deck inspection through a multi-channel, continuously moving platform A new multi-channel, automated, air-coupled, impact-echo sounding device was designed, constructed, and demonstrated in this work. The apparatus includes seven replicated impactor and recording units, a moving trailer platform, a distance measurement instrument, and signal processing modules. A series of computer algorithms is used to determine the presence of delamination on concrete bridge decks based on the bandlimited acoustic energy value computed from the acoustic response associated with each impact. Compared to traditional sounding methods, this device significantly decreases the required inspection time, eliminates subjectivity, and increases safety by substantially reducing the exposure of inspectors to live traffic. © 2019
72 a16066928300 Mazzeo B.A. p258 False Journal 169 Automated Air-Coupled Impact-Echo Testing of a Concrete Bridge Deck from a Continuously Moving Platform The objective of this work was to develop an automated air-coupled impact-echo testing device for mapping the occurrence of delamination in a concrete bridge deck from a continuously moving platform with a fast, repeatable excitation mechanism and algorithms for collecting and analyzing the acoustic data. The apparatus developed in this research included an impactor unit, a moving platform, a microphone for air-coupled sensing, a distance measurement instrument, and signal processing modules. Given the absence of an existing universal threshold for differentiating among intact and delaminated areas using the new device, a delamination detection threshold value was determined in a first field demonstration also involving chain dragging and coring of a concrete bridge deck. While the maps of the air-coupled impact-echo data and chain-dragging data exhibit a high degree of similarity and are highly consistent with the results of coring, a quantitative method of comparison also demonstrates the utility of the new device across a broad range of delamination percentages. Specifically, the results indicate that the percentage of the deck area determined to be delaminated using impact-echo testing was within 3 percentage points of that determined to be delaminated using chain dragging for 10 of the 13 deck test sections, which generally exhibited delamination percentages ranging from 7 to 21%. Finally, testing with the new device was more than seven times faster than chain dragging. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
72 a16066928300 Mazzeo B.A. p523 False Journal 290 Vertical electrical impedance testing of a concrete bridge deck using a rolling probe The speed of vertical electrical impedance testing of a concrete bridge deck using a new rolling probe was demonstrated in this research to be 190 m2/h, which is more than six times faster than the speed at which data were collected using the static probe utilized in earlier research. Furthermore, with impedance measurements obtained at a longitudinal spacing of approximately 0.1 m, the spatial resolution was 12 times greater than that of the static probe. Vertical electrical impedance testing was performed together with half-cell potential testing, chaining, cover depth, and chloride concentration testing, and an interpretation of these data sets was developed that synergistically incorporated the deck maintenance history. © 2018 Elsevier Ltd
73 a57213342768 Gardner J.W. p17 True Journal 15 Managing Production Yields and Rework through Feedback on Speed, Quality, and Quantity Balancing priorities of production speed and conformance quality is an ongoing challenge in production and operations management. Organizations may emphasize these priorities through various forms of performance feedback. However, the impacts of using feedback to emphasize speed, quality, and quantity remain unclear in production settings. This study employs controlled laboratory experiments to examine the impact of real-time feedback on production quantities, first time yield percentages, and rework percentages. Drawing on concepts from speed-accuracy tradeoffs, we study four types of feedback: speed, accuracy, joint speed and accuracy, and yields. Laboratory activities focus on the repetitive task of converting paper-based medical records to electronic data formats. These tasks are critical inputs to data analytics and are similar in nature to simple independent manufacturing and service tasks. We study feedback effects in a setting critical to practice but rarely studied in research, where workers are incentivized for both speed and quality as they perform production tasks that explicitly allow rework. The results show that production yields worsen under speed feedback but improve under each form of quality-containing feedback. Results also show that each form of quality-containing feedback increases the proportion of correctly reworked to produced errors through different mechanisms of increased error fixing, decreased error production, or both. © 2020 Production and Operations Management Society
73 a57213342768 Gardner J.W. p132 False Journal 91 When do workarounds help or hurt patient outcomes? The moderating role of operational failures Hospital providers often use workarounds to circumvent processes so that patients can receive care. Workarounds in response to operational failures enable care to continue and therefore may be indicative of workers' commitment. On the other hand, workarounds in the absence of operational failures may signal an ineffective approach associated with lower quality of care and worse patient outcomes. Working closely with healthcare providers, we developed a survey to measure workaround behaviors and operational failures on medical/surgical units. The lead author surveyed over 4,000 nurses from 63 hospitals throughout the United States. We matched this data with audit data on the incidence of pressure injuries among over 21,000 patients on 262 nursing units in 56 survey hospitals. Hospital-acquired pressure injuries are a significant risk to patient health and hospital costs. We do not find support for our hypothesis that workarounds are associated with a higher rate of hospital-acquired pressure injuries. However, when we take into account the moderating role of operational failures on the relationship between workarounds and pressure injuries, we find significant results. When nursing units have lower levels of operational failures, workarounds are associated with higher rates of hospital-acquired pressure injuries. Our results provide evidence that workarounds may be associated with negative patient outcomes, if they stem from a process-avoiding approach. The best results can be achieved by reducing both operational failures and workarounds via instilling a process-focused approach. © 2019 Association for Supply Chain Management, Inc.
74 a56584019300 Mulford R.B. p18 True Journal 16 Experimental demonstration of heat loss and turn-down ratio for a multi-panel, actively deployed radiator Origami-inspired, dynamic spacecraft radiators have been proposed which utilize an expandable/collapsible surface capable of large variations in emitting surface area. In this work, an experimental prototype of this concept is realized and its performance is analyzed. In particular, we demonstrate the capability of maintaining a spacecraft component at a desired operating temperature through the expansion and contraction of a collapsible radiator to control radiative heat loss. Four aluminum panels are connected via a flexible hinge constructed from interwoven copper wires and suspended from an actuating framework. The radiator panels are connected to a heated aluminum block. The radiator is placed in a vacuum environment with cooled surroundings (173 K) and the total radiative cooling power is determined as a function of radiator actuation position for a constant aluminum block temperature. As the radiator actuates from extended to collapsed, the heat transfer decreases and the fin efficiency increases. For a limited actuation range, the four-panel radiator exhibits a turn-down ratio (largest cooling power / smallest cooling power) of 1.31. A numerical model validated in this work predicts a turn-down ratio of 2.27 for actuation over the full range of radiator positions in surroundings at 4 K. Future revisions that exhibit an increase in panel and hinge thermal conductivities and utilizing eight panels would yield a turn-down ratio of 6.01. Assuming infinite thermal conductivity and infinite hinge conductance, the turn-down ratios for two, four and eight panel radiators, respectively, are 2.00, 3.98, and 7.92. © 2020 Elsevier Ltd
74 a56584019300 Mulford R.B. p147 True Journal 103 Heat transfer, efficiency and turn-down ratio of a dynamic radiative heat exchanger Efficient heat transfer is critical in the design and optimization of thermal control systems. Static radiative heat exchangers are often simple and reliable systems but typically cannot be adapted to environmental changes. Adaptable radiative heat exchangers can be adjusted in response to variations in the thermal environment or operating conditions and have the potential for increased efficiency and reduced cost. Dynamic control of a radiative heat exchanger is possible through geometric manipulation of a segmented, self-irradiating fin, consisting of rigid panels that are linked by thermal hinges in an accordion arrangement. In this paper, a numerical model is described to predict the temperature profile and efficiency of a radiative heat exchanger, accounting for conduction and self-irradiation. Governing equations are cast in terms of the conduction-radiation interaction parameter, surface emissivity, actuation angle, and the thermal conductance of the hinges linking the panels. Results indicate that a turn-down ratio (largest possible heat rate divided by smallest possible heat rate) of greater than three is possible for realistic panel geometries and materials. Self-irradiation decreases the turn-down ratio, and there is evidence that an optimal number of rigid panels exists for any combination of panel geometry and device temperature. The maximum efficiency occurs when the plates are in the collapsed position, but the heat rate is at a minimum in this configuration. Finally, the properties and geometry of the plates are shown to have a more significant effect on the turn-down ratio than the properties of the thermal hinges. © 2019 Elsevier Ltd
74 a56584019300 Mulford R.B. p263 True Journal 164 Control of Net Radiative Heat Transfer with a Variable-Emissivity Accordion Tessellation Origami tessellations have been proposed as a mechanism for control of radiative heat transfer through the use of the cavity effect. This work explores the impact of a changing projected surface area and varying apparent radiative properties on the net radiative heat transfer of an accordion fold comprised of V-grooves. The net radiative heat transfer of an accordion tessellation is obtained by a thermal energy balance at the cavity openings with radiative properties of the cavities given as a function of various cavity parameters. Results of the analytical model are experimentally confirmed. An accordion tessellation, constructed of stainless-steel shim stock, is positioned to achieve a specified fold angle and placed in a vacuum environment while heated by Joule heating. A thermal camera records the apparent temperature of the cavity openings for various fold angles. Results are compared to apparent temperatures predicted with the analytical model. Analytically and experimentally obtained temperatures agree within 5% and all measurements fall within experimental uncertainty. For diffusely irradiated surfaces, the decrease in projected surface area dominates, causing a continuous decrease in net radiative heat transfer for a collapsing accordion fold. Highly reflective specular surfaces exposed to diffuse irradiation experience large turn-down ratios (7.5× reduction in heat transfer) in the small angle ranges. Specular surfaces exposed to collimated irradiation achieve a turn down ratio of 3.35 between V-groove angles of 120 deg and 150 deg. The approach outlined here may be extended to modeling the net radiative heat transfer for other origami tessellations. © 2019 by ASME.
74 a56584019300 Mulford R.B. p448 True Journal 252 Total hemispherical apparent radiative properties of the infinite V-groove with specular reflection Multiple reflections in a cavity geometry augment the emission and absorption of the cavity opening relative to a flat surface in a phenomenon known as the cavity effect. The extent of the cavity effect is quantified using apparent absorptivity and apparent emissivity. Analysis of complicated thermal systems is simplified through application of apparent radiative properties to cavity geometries. The apparent radiative properties of a specularly-reflecting, gray, isothermal V-groove have been derived analytically, but these results have not been validated experimentally or numerically. Additionally, the model for apparent absorptivity of an infinite V-groove subjected to partial illumination in the presence of collimated irradiation is not available. In this work, the following existing models for a specularly-reflecting V-groove are collected into a single source: (1) the apparent absorptivity of a diffusely irradiated V-groove, (2) the apparent emissivity of an isothermal V-groove and (3) the apparent absorptivity of a V-groove subject to collimated irradiation with full-illumination. Further, a new analytical model is developed to predict the apparent absorptivity of an infinite V-groove subject to collimated irradiation with partial-illumination. A custom, Monte Carlo ray tracing solver is used to predict the apparent radiative properties for all cases as a means of numerical verification by comparing the ray tracing data with the results from the new model in this work and the previously existing models. For diffuse irradiation, the analytical model and ray tracing data show excellent agreement with an average discrepancy of 4.4 × 10−4, verifying the diffuse-irradiation analytical model. Similar agreement is found for collimated irradiation, where the full and partial illumination models indicate average discrepancies of 4.9 × 10−4 and 4.6 × 10−4 when compared with ray tracing data. © 2018 Elsevier Ltd
74 a56584019300 Mulford R.B. p579 False Conference 224 Adaptive net radiative heat transfer and thermal management with origami-structured surfaces The ability to control radiative behavior through the angular positioning of structured surfaces (e.g. the cavity effect) offers the ability to provide thermal management in dynamic radiative environments. Structures comprised of origami tessellations offer a means to achieve angular cavities that approach black-like behavior during collapse by exploiting use of the cavity effect. Expanded origami surfaces exhibit intrinsic radiative properties while collapsed surfaces exhibit increasingly black-like behavior as the cavity aspect ratio increases. Actuation of such surfaces provides the means to achieve any apparent radiative behavior between these two extremes. This work explores the use of three origami structures (finite V-groove, hinged V-groove and Miura-ori) and their respective apparent radiative properties as a function of cavity geometry using Monte Carlo ray tracing. Results are presented as a function of tessellation geometry and degree of actuation (i.e. collapse). Ray tracing models are benchmarked with V-groove geometries for which analytical models exist in the literature. Convergence for ray independence was determined to be satisfactory when the standard error of the mean for every test case was less than 0.005. Deviation in the apparent absorptivity for finite V-groove relative to the infinite V-groove is quantified. The apparent absorptivity of the Miura-ori fold exhibits sensitivity to the fold geometry when the angle of the unit cell is varied, but is relatively insensitive to the length ratio of the panel. The variable nature of the net radiative heat transfer, achievable through actuation, affords a method for thermal management of components with variable heat dissipation and/or variable radiative environments. © 2018 International Heat Transfer Conference. All rights reserved.
74 a56584019300 Mulford R.B. p589 True Journal 305 Total hemispherical apparent radiative properties of the infinite V-Groove with diffuse reflection [No abstract available]
75 a57217581937 Salt S.D. p18 False Journal 16 Experimental demonstration of heat loss and turn-down ratio for a multi-panel, actively deployed radiator Origami-inspired, dynamic spacecraft radiators have been proposed which utilize an expandable/collapsible surface capable of large variations in emitting surface area. In this work, an experimental prototype of this concept is realized and its performance is analyzed. In particular, we demonstrate the capability of maintaining a spacecraft component at a desired operating temperature through the expansion and contraction of a collapsible radiator to control radiative heat loss. Four aluminum panels are connected via a flexible hinge constructed from interwoven copper wires and suspended from an actuating framework. The radiator panels are connected to a heated aluminum block. The radiator is placed in a vacuum environment with cooled surroundings (173 K) and the total radiative cooling power is determined as a function of radiator actuation position for a constant aluminum block temperature. As the radiator actuates from extended to collapsed, the heat transfer decreases and the fin efficiency increases. For a limited actuation range, the four-panel radiator exhibits a turn-down ratio (largest cooling power / smallest cooling power) of 1.31. A numerical model validated in this work predicts a turn-down ratio of 2.27 for actuation over the full range of radiator positions in surroundings at 4 K. Future revisions that exhibit an increase in panel and hinge thermal conductivities and utilizing eight panels would yield a turn-down ratio of 6.01. Assuming infinite thermal conductivity and infinite hinge conductance, the turn-down ratios for two, four and eight panel radiators, respectively, are 2.00, 3.98, and 7.92. © 2020 Elsevier Ltd
76 a57214937519 Hyatt L.P. p18 False Journal 16 Experimental demonstration of heat loss and turn-down ratio for a multi-panel, actively deployed radiator Origami-inspired, dynamic spacecraft radiators have been proposed which utilize an expandable/collapsible surface capable of large variations in emitting surface area. In this work, an experimental prototype of this concept is realized and its performance is analyzed. In particular, we demonstrate the capability of maintaining a spacecraft component at a desired operating temperature through the expansion and contraction of a collapsible radiator to control radiative heat loss. Four aluminum panels are connected via a flexible hinge constructed from interwoven copper wires and suspended from an actuating framework. The radiator panels are connected to a heated aluminum block. The radiator is placed in a vacuum environment with cooled surroundings (173 K) and the total radiative cooling power is determined as a function of radiator actuation position for a constant aluminum block temperature. As the radiator actuates from extended to collapsed, the heat transfer decreases and the fin efficiency increases. For a limited actuation range, the four-panel radiator exhibits a turn-down ratio (largest cooling power / smallest cooling power) of 1.31. A numerical model validated in this work predicts a turn-down ratio of 2.27 for actuation over the full range of radiator positions in surroundings at 4 K. Future revisions that exhibit an increase in panel and hinge thermal conductivities and utilizing eight panels would yield a turn-down ratio of 6.01. Assuming infinite thermal conductivity and infinite hinge conductance, the turn-down ratios for two, four and eight panel radiators, respectively, are 2.00, 3.98, and 7.92. © 2020 Elsevier Ltd
76 a57214937519 Hyatt L.P. p33 True Journal 28 Developable mechanisms on right conical surfaces An approach for designing developable mechanisms on a conical surface is presented. By aligning the joint axes of spherical mechanisms to the ruling lines, the links can be created in a way that the mechanism conforms to a conical surface. Terminology is defined for mechanisms mapped onto a right cone. Models are developed to describe the motion of the mechanism with respect to the apex of the cone, and connections are made to cylindrical developable mechanisms using projected angles. The Loop Sum Method is presented as an approach to determine the geometry of the cone to which a given spherical mechanism can be mapped. A method for position analysis is presented to determine the location of any point along the link of a mechanism with respect to the conical geometry. These methods are also applied to multiloop spherical mechanisms. © 2020 Elsevier Ltd
76 a57214937519 Hyatt L.P. p94 True Journal 72 Using Cyclic Quadrilaterals to Design Cylindrical Developable Mechanisms Developable mechanisms on regular cylindrical surfaces can be described using cyclic quadrilaterals. Mechanisms can exist in either an open or crossed configuration, and these configurations correspond to convex and crossed cyclic quadrilaterals. Using equations developed for both convex and crossed cyclic quadrilaterals, the geometry of the reference surface to which a four-bar mechanism can be mapped is found. Grashof mechanisms can be mapped to two surfaces in open or crossed configurations. The only way to map a non-Grashof mechanism to a cylindrical surface is in its open configuration. Extramobile and intramobile behavior can be achieved depending on selected pairs within a cyclic quadrilateral and its position within the circumcircle. Selecting different sets of links as the ground link changes the potential behavior of the mechanism. Different cases are tabulated to represent all possibilities. A non-Grashof developable mechanism can only exhibit extramobile or intramobile behavior if all of the joints lie on one half of the circumcircle. © 2020, Springer Nature Switzerland AG.
77 a57217581770 Meaker K.S. p18 False Journal 16 Experimental demonstration of heat loss and turn-down ratio for a multi-panel, actively deployed radiator Origami-inspired, dynamic spacecraft radiators have been proposed which utilize an expandable/collapsible surface capable of large variations in emitting surface area. In this work, an experimental prototype of this concept is realized and its performance is analyzed. In particular, we demonstrate the capability of maintaining a spacecraft component at a desired operating temperature through the expansion and contraction of a collapsible radiator to control radiative heat loss. Four aluminum panels are connected via a flexible hinge constructed from interwoven copper wires and suspended from an actuating framework. The radiator panels are connected to a heated aluminum block. The radiator is placed in a vacuum environment with cooled surroundings (173 K) and the total radiative cooling power is determined as a function of radiator actuation position for a constant aluminum block temperature. As the radiator actuates from extended to collapsed, the heat transfer decreases and the fin efficiency increases. For a limited actuation range, the four-panel radiator exhibits a turn-down ratio (largest cooling power / smallest cooling power) of 1.31. A numerical model validated in this work predicts a turn-down ratio of 2.27 for actuation over the full range of radiator positions in surroundings at 4 K. Future revisions that exhibit an increase in panel and hinge thermal conductivities and utilizing eight panels would yield a turn-down ratio of 6.01. Assuming infinite thermal conductivity and infinite hinge conductance, the turn-down ratios for two, four and eight panel radiators, respectively, are 2.00, 3.98, and 7.92. © 2020 Elsevier Ltd
78 a55542008600 Dwivedi V.H. p18 False Journal 16 Experimental demonstration of heat loss and turn-down ratio for a multi-panel, actively deployed radiator Origami-inspired, dynamic spacecraft radiators have been proposed which utilize an expandable/collapsible surface capable of large variations in emitting surface area. In this work, an experimental prototype of this concept is realized and its performance is analyzed. In particular, we demonstrate the capability of maintaining a spacecraft component at a desired operating temperature through the expansion and contraction of a collapsible radiator to control radiative heat loss. Four aluminum panels are connected via a flexible hinge constructed from interwoven copper wires and suspended from an actuating framework. The radiator panels are connected to a heated aluminum block. The radiator is placed in a vacuum environment with cooled surroundings (173 K) and the total radiative cooling power is determined as a function of radiator actuation position for a constant aluminum block temperature. As the radiator actuates from extended to collapsed, the heat transfer decreases and the fin efficiency increases. For a limited actuation range, the four-panel radiator exhibits a turn-down ratio (largest cooling power / smallest cooling power) of 1.31. A numerical model validated in this work predicts a turn-down ratio of 2.27 for actuation over the full range of radiator positions in surroundings at 4 K. Future revisions that exhibit an increase in panel and hinge thermal conductivities and utilizing eight panels would yield a turn-down ratio of 6.01. Assuming infinite thermal conductivity and infinite hinge conductance, the turn-down ratios for two, four and eight panel radiators, respectively, are 2.00, 3.98, and 7.92. © 2020 Elsevier Ltd
78 a55542008600 Dwivedi V.H. p263 False Journal 164 Control of Net Radiative Heat Transfer with a Variable-Emissivity Accordion Tessellation Origami tessellations have been proposed as a mechanism for control of radiative heat transfer through the use of the cavity effect. This work explores the impact of a changing projected surface area and varying apparent radiative properties on the net radiative heat transfer of an accordion fold comprised of V-grooves. The net radiative heat transfer of an accordion tessellation is obtained by a thermal energy balance at the cavity openings with radiative properties of the cavities given as a function of various cavity parameters. Results of the analytical model are experimentally confirmed. An accordion tessellation, constructed of stainless-steel shim stock, is positioned to achieve a specified fold angle and placed in a vacuum environment while heated by Joule heating. A thermal camera records the apparent temperature of the cavity openings for various fold angles. Results are compared to apparent temperatures predicted with the analytical model. Analytically and experimentally obtained temperatures agree within 5% and all measurements fall within experimental uncertainty. For diffusely irradiated surfaces, the decrease in projected surface area dominates, causing a continuous decrease in net radiative heat transfer for a collapsing accordion fold. Highly reflective specular surfaces exposed to diffuse irradiation experience large turn-down ratios (7.5× reduction in heat transfer) in the small angle ranges. Specular surfaces exposed to collimated irradiation achieve a turn down ratio of 3.35 between V-groove angles of 120 deg and 150 deg. The approach outlined here may be extended to modeling the net radiative heat transfer for other origami tessellations. © 2019 by ASME.
79 a56714263700 Jones M.R. p18 False Journal 16 Experimental demonstration of heat loss and turn-down ratio for a multi-panel, actively deployed radiator Origami-inspired, dynamic spacecraft radiators have been proposed which utilize an expandable/collapsible surface capable of large variations in emitting surface area. In this work, an experimental prototype of this concept is realized and its performance is analyzed. In particular, we demonstrate the capability of maintaining a spacecraft component at a desired operating temperature through the expansion and contraction of a collapsible radiator to control radiative heat loss. Four aluminum panels are connected via a flexible hinge constructed from interwoven copper wires and suspended from an actuating framework. The radiator panels are connected to a heated aluminum block. The radiator is placed in a vacuum environment with cooled surroundings (173 K) and the total radiative cooling power is determined as a function of radiator actuation position for a constant aluminum block temperature. As the radiator actuates from extended to collapsed, the heat transfer decreases and the fin efficiency increases. For a limited actuation range, the four-panel radiator exhibits a turn-down ratio (largest cooling power / smallest cooling power) of 1.31. A numerical model validated in this work predicts a turn-down ratio of 2.27 for actuation over the full range of radiator positions in surroundings at 4 K. Future revisions that exhibit an increase in panel and hinge thermal conductivities and utilizing eight panels would yield a turn-down ratio of 6.01. Assuming infinite thermal conductivity and infinite hinge conductance, the turn-down ratios for two, four and eight panel radiators, respectively, are 2.00, 3.98, and 7.92. © 2020 Elsevier Ltd
79 a56714263700 Jones M.R. p147 False Journal 103 Heat transfer, efficiency and turn-down ratio of a dynamic radiative heat exchanger Efficient heat transfer is critical in the design and optimization of thermal control systems. Static radiative heat exchangers are often simple and reliable systems but typically cannot be adapted to environmental changes. Adaptable radiative heat exchangers can be adjusted in response to variations in the thermal environment or operating conditions and have the potential for increased efficiency and reduced cost. Dynamic control of a radiative heat exchanger is possible through geometric manipulation of a segmented, self-irradiating fin, consisting of rigid panels that are linked by thermal hinges in an accordion arrangement. In this paper, a numerical model is described to predict the temperature profile and efficiency of a radiative heat exchanger, accounting for conduction and self-irradiation. Governing equations are cast in terms of the conduction-radiation interaction parameter, surface emissivity, actuation angle, and the thermal conductance of the hinges linking the panels. Results indicate that a turn-down ratio (largest possible heat rate divided by smallest possible heat rate) of greater than three is possible for realistic panel geometries and materials. Self-irradiation decreases the turn-down ratio, and there is evidence that an optimal number of rigid panels exists for any combination of panel geometry and device temperature. The maximum efficiency occurs when the plates are in the collapsed position, but the heat rate is at a minimum in this configuration. Finally, the properties and geometry of the plates are shown to have a more significant effect on the turn-down ratio than the properties of the thermal hinges. © 2019 Elsevier Ltd
79 a56714263700 Jones M.R. p263 False Journal 164 Control of Net Radiative Heat Transfer with a Variable-Emissivity Accordion Tessellation Origami tessellations have been proposed as a mechanism for control of radiative heat transfer through the use of the cavity effect. This work explores the impact of a changing projected surface area and varying apparent radiative properties on the net radiative heat transfer of an accordion fold comprised of V-grooves. The net radiative heat transfer of an accordion tessellation is obtained by a thermal energy balance at the cavity openings with radiative properties of the cavities given as a function of various cavity parameters. Results of the analytical model are experimentally confirmed. An accordion tessellation, constructed of stainless-steel shim stock, is positioned to achieve a specified fold angle and placed in a vacuum environment while heated by Joule heating. A thermal camera records the apparent temperature of the cavity openings for various fold angles. Results are compared to apparent temperatures predicted with the analytical model. Analytically and experimentally obtained temperatures agree within 5% and all measurements fall within experimental uncertainty. For diffusely irradiated surfaces, the decrease in projected surface area dominates, causing a continuous decrease in net radiative heat transfer for a collapsing accordion fold. Highly reflective specular surfaces exposed to diffuse irradiation experience large turn-down ratios (7.5× reduction in heat transfer) in the small angle ranges. Specular surfaces exposed to collimated irradiation achieve a turn down ratio of 3.35 between V-groove angles of 120 deg and 150 deg. The approach outlined here may be extended to modeling the net radiative heat transfer for other origami tessellations. © 2019 by ASME.
79 a56714263700 Jones M.R. p448 False Journal 252 Total hemispherical apparent radiative properties of the infinite V-groove with specular reflection Multiple reflections in a cavity geometry augment the emission and absorption of the cavity opening relative to a flat surface in a phenomenon known as the cavity effect. The extent of the cavity effect is quantified using apparent absorptivity and apparent emissivity. Analysis of complicated thermal systems is simplified through application of apparent radiative properties to cavity geometries. The apparent radiative properties of a specularly-reflecting, gray, isothermal V-groove have been derived analytically, but these results have not been validated experimentally or numerically. Additionally, the model for apparent absorptivity of an infinite V-groove subjected to partial illumination in the presence of collimated irradiation is not available. In this work, the following existing models for a specularly-reflecting V-groove are collected into a single source: (1) the apparent absorptivity of a diffusely irradiated V-groove, (2) the apparent emissivity of an isothermal V-groove and (3) the apparent absorptivity of a V-groove subject to collimated irradiation with full-illumination. Further, a new analytical model is developed to predict the apparent absorptivity of an infinite V-groove subject to collimated irradiation with partial-illumination. A custom, Monte Carlo ray tracing solver is used to predict the apparent radiative properties for all cases as a means of numerical verification by comparing the ray tracing data with the results from the new model in this work and the previously existing models. For diffuse irradiation, the analytical model and ray tracing data show excellent agreement with an average discrepancy of 4.4 × 10−4, verifying the diffuse-irradiation analytical model. Similar agreement is found for collimated irradiation, where the full and partial illumination models indicate average discrepancies of 4.9 × 10−4 and 4.6 × 10−4 when compared with ray tracing data. © 2018 Elsevier Ltd
79 a56714263700 Jones M.R. p579 False Conference 224 Adaptive net radiative heat transfer and thermal management with origami-structured surfaces The ability to control radiative behavior through the angular positioning of structured surfaces (e.g. the cavity effect) offers the ability to provide thermal management in dynamic radiative environments. Structures comprised of origami tessellations offer a means to achieve angular cavities that approach black-like behavior during collapse by exploiting use of the cavity effect. Expanded origami surfaces exhibit intrinsic radiative properties while collapsed surfaces exhibit increasingly black-like behavior as the cavity aspect ratio increases. Actuation of such surfaces provides the means to achieve any apparent radiative behavior between these two extremes. This work explores the use of three origami structures (finite V-groove, hinged V-groove and Miura-ori) and their respective apparent radiative properties as a function of cavity geometry using Monte Carlo ray tracing. Results are presented as a function of tessellation geometry and degree of actuation (i.e. collapse). Ray tracing models are benchmarked with V-groove geometries for which analytical models exist in the literature. Convergence for ray independence was determined to be satisfactory when the standard error of the mean for every test case was less than 0.005. Deviation in the apparent absorptivity for finite V-groove relative to the infinite V-groove is quantified. The apparent absorptivity of the Miura-ori fold exhibits sensitivity to the fold geometry when the angle of the unit cell is varied, but is relatively insensitive to the length ratio of the panel. The variable nature of the net radiative heat transfer, achievable through actuation, affords a method for thermal management of components with variable heat dissipation and/or variable radiative environments. © 2018 International Heat Transfer Conference. All rights reserved.
79 a56714263700 Jones M.R. p589 False Journal 305 Total hemispherical apparent radiative properties of the infinite V-Groove with diffuse reflection [No abstract available]
80 a8608718200 Iverson B.D. p18 False Journal 16 Experimental demonstration of heat loss and turn-down ratio for a multi-panel, actively deployed radiator Origami-inspired, dynamic spacecraft radiators have been proposed which utilize an expandable/collapsible surface capable of large variations in emitting surface area. In this work, an experimental prototype of this concept is realized and its performance is analyzed. In particular, we demonstrate the capability of maintaining a spacecraft component at a desired operating temperature through the expansion and contraction of a collapsible radiator to control radiative heat loss. Four aluminum panels are connected via a flexible hinge constructed from interwoven copper wires and suspended from an actuating framework. The radiator panels are connected to a heated aluminum block. The radiator is placed in a vacuum environment with cooled surroundings (173 K) and the total radiative cooling power is determined as a function of radiator actuation position for a constant aluminum block temperature. As the radiator actuates from extended to collapsed, the heat transfer decreases and the fin efficiency increases. For a limited actuation range, the four-panel radiator exhibits a turn-down ratio (largest cooling power / smallest cooling power) of 1.31. A numerical model validated in this work predicts a turn-down ratio of 2.27 for actuation over the full range of radiator positions in surroundings at 4 K. Future revisions that exhibit an increase in panel and hinge thermal conductivities and utilizing eight panels would yield a turn-down ratio of 6.01. Assuming infinite thermal conductivity and infinite hinge conductance, the turn-down ratios for two, four and eight panel radiators, respectively, are 2.00, 3.98, and 7.92. © 2020 Elsevier Ltd
80 a8608718200 Iverson B.D. p79 False Journal 59 Closed-Loop, Axial Temperature Control of Etched Silicon Microcolumn for Tunable Thermal Gradient Gas Chromatography Combining the resolution of conventional gas chromatography systems with the size factor of microGC systems is important for improving the affordability and portability of high performance gas analysis. Recent work has demonstrated the feasibility of high resolution separation of gases in a benchtopscale short column system by controlling thermal gradients through the column. This work reports a microfabricated thermally controllable gas chromatographic column with a small footprint (approximately 6.25 cm2). The design of the 20 cm column utilizes 21 individually controllable thin film heaters and conduction cooling to produce a desired temperature profile. The reported device is capable of heating and cooling rates exceeding 8000 °C/min and can reach temperatures of 350 °C. The control methods allow for excellent disturbance rejection and precision to within +/- 1 °C. Each length of the column between heaters was demonstrated to be individually controllable and displayed quadratic temperature profiles. This paper focuses on the fabrication process and implementation of the thermal control strategy. [2019-0113] © 1992-2012 IEEE.
80 a8608718200 Iverson B.D. p147 False Journal 103 Heat transfer, efficiency and turn-down ratio of a dynamic radiative heat exchanger Efficient heat transfer is critical in the design and optimization of thermal control systems. Static radiative heat exchangers are often simple and reliable systems but typically cannot be adapted to environmental changes. Adaptable radiative heat exchangers can be adjusted in response to variations in the thermal environment or operating conditions and have the potential for increased efficiency and reduced cost. Dynamic control of a radiative heat exchanger is possible through geometric manipulation of a segmented, self-irradiating fin, consisting of rigid panels that are linked by thermal hinges in an accordion arrangement. In this paper, a numerical model is described to predict the temperature profile and efficiency of a radiative heat exchanger, accounting for conduction and self-irradiation. Governing equations are cast in terms of the conduction-radiation interaction parameter, surface emissivity, actuation angle, and the thermal conductance of the hinges linking the panels. Results indicate that a turn-down ratio (largest possible heat rate divided by smallest possible heat rate) of greater than three is possible for realistic panel geometries and materials. Self-irradiation decreases the turn-down ratio, and there is evidence that an optimal number of rigid panels exists for any combination of panel geometry and device temperature. The maximum efficiency occurs when the plates are in the collapsed position, but the heat rate is at a minimum in this configuration. Finally, the properties and geometry of the plates are shown to have a more significant effect on the turn-down ratio than the properties of the thermal hinges. © 2019 Elsevier Ltd
80 a8608718200 Iverson B.D. p263 False Journal 164 Control of Net Radiative Heat Transfer with a Variable-Emissivity Accordion Tessellation Origami tessellations have been proposed as a mechanism for control of radiative heat transfer through the use of the cavity effect. This work explores the impact of a changing projected surface area and varying apparent radiative properties on the net radiative heat transfer of an accordion fold comprised of V-grooves. The net radiative heat transfer of an accordion tessellation is obtained by a thermal energy balance at the cavity openings with radiative properties of the cavities given as a function of various cavity parameters. Results of the analytical model are experimentally confirmed. An accordion tessellation, constructed of stainless-steel shim stock, is positioned to achieve a specified fold angle and placed in a vacuum environment while heated by Joule heating. A thermal camera records the apparent temperature of the cavity openings for various fold angles. Results are compared to apparent temperatures predicted with the analytical model. Analytically and experimentally obtained temperatures agree within 5% and all measurements fall within experimental uncertainty. For diffusely irradiated surfaces, the decrease in projected surface area dominates, causing a continuous decrease in net radiative heat transfer for a collapsing accordion fold. Highly reflective specular surfaces exposed to diffuse irradiation experience large turn-down ratios (7.5× reduction in heat transfer) in the small angle ranges. Specular surfaces exposed to collimated irradiation achieve a turn down ratio of 3.35 between V-groove angles of 120 deg and 150 deg. The approach outlined here may be extended to modeling the net radiative heat transfer for other origami tessellations. © 2019 by ASME.
80 a8608718200 Iverson B.D. p271 False Journal 178 Influence of micro-structured superhydrophobic surfaces on nucleation and natural convection in a heated pool This work experimentally explores sub-boiling pool nucleation on micro-structured superhydrophobic surfaces. All surfaces tested were submerged in a 20 mm deep pool of water and heated from below to maintain a constant surface temperature, while the side walls of the pool were insulated, and the top was covered. Three thermocouples positioned in the pool obtain the average pool temperature. A heat flux sensor is placed directly beneath the surface to measure the heat flux supplied to the pool. Free convection heat transfer coefficients are obtained for the sub-boiling temperature range of 40–90 °C. Six surface types are studied: smooth hydrophilic, smooth hydrophobic, superhydrophobic with rib/cavity structures, superhydrophobic with rib/cavity structures and additional sparsely spaced ribs to close off the cavities, circular posts, and circular holes. It is found that structured superhydrophobic surfaces provide cavities for nucleation to occur. More dissolved air effervesces from the water as the surface temperature increases due to an increased level of supersaturation and convection. The nucleation leads to large air bubble formations that reduce the overall convection coefficient when compared to the smooth surfaces. For the rib/cavity structured surfaces, the bubbles form in an anisotropic manner and are aligned with the surface structure. More bubbles are observed on the superhydrophobic surfaces where the cavities are bounded. Since water's ability to dissolve air is dependent on temperature, heat and mass transfer cannot be treated independently on any of the superhydrophobic surfaces studied here. © 2018 Elsevier Ltd
80 a8608718200 Iverson B.D. p433 False Journal 241 CIP2A immunosensor comprised of vertically-aligned carbon nanotube interdigitated electrodes towards point-of-care oral cancer screening Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered significant attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDEs were functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—an oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant label-free immunosensor was capable of detecting CIP2A across a wide linear sensing range (1−100 pg/mL) with a detection limit of 0.24 pg/mL within saliva supernatant—a range that is more sensitive than the corresponding CIP2A enzyme linked immunosorbent assay (ELISA). These results help pave the way for rapid cancer screening tests at the point-of-care (POC) such as for the early-stage diagnosis of oral cancer at a dentist's office. © 2018 Elsevier B.V.
80 a8608718200 Iverson B.D. p448 False Journal 252 Total hemispherical apparent radiative properties of the infinite V-groove with specular reflection Multiple reflections in a cavity geometry augment the emission and absorption of the cavity opening relative to a flat surface in a phenomenon known as the cavity effect. The extent of the cavity effect is quantified using apparent absorptivity and apparent emissivity. Analysis of complicated thermal systems is simplified through application of apparent radiative properties to cavity geometries. The apparent radiative properties of a specularly-reflecting, gray, isothermal V-groove have been derived analytically, but these results have not been validated experimentally or numerically. Additionally, the model for apparent absorptivity of an infinite V-groove subjected to partial illumination in the presence of collimated irradiation is not available. In this work, the following existing models for a specularly-reflecting V-groove are collected into a single source: (1) the apparent absorptivity of a diffusely irradiated V-groove, (2) the apparent emissivity of an isothermal V-groove and (3) the apparent absorptivity of a V-groove subject to collimated irradiation with full-illumination. Further, a new analytical model is developed to predict the apparent absorptivity of an infinite V-groove subject to collimated irradiation with partial-illumination. A custom, Monte Carlo ray tracing solver is used to predict the apparent radiative properties for all cases as a means of numerical verification by comparing the ray tracing data with the results from the new model in this work and the previously existing models. For diffuse irradiation, the analytical model and ray tracing data show excellent agreement with an average discrepancy of 4.4 × 10−4, verifying the diffuse-irradiation analytical model. Similar agreement is found for collimated irradiation, where the full and partial illumination models indicate average discrepancies of 4.9 × 10−4 and 4.6 × 10−4 when compared with ray tracing data. © 2018 Elsevier Ltd
80 a8608718200 Iverson B.D. p500 False Journal 271 Bubble nucleation in superhydrophobic microchannels due to subcritical heating This work experimentally studies the effects of single wall heating on laminar flow in a high-aspect ratio superhydrophobic microchannel. When water that is saturated with air is used as the working liquid, the non-wetted cavities on the superhydrophobic surfaces act as nucleation sites and allow air to effervesce out of the water and onto the surface when heated. Previous works in the literature have only considered the opposite case where the water is undersaturated and absorbs air out the cavities for a microchannel setting. The microchannel considered in this work consists of a rib/cavity structured superhydrophobic surface and a glass surface separated by spacers. The microchannel is 60 mm long by 14 mm wide and two channel heights of nominally 183 μm and 366 μm are explored. The superhydrophobic side is in contact with a heated aluminum block and a camera is used to visualize the flow through the glass side. Thermocouples are embedded in the aluminum to record the temperature profile along the length of the channel. Temperatures are maintained below the boiling temperature of the working liquid. The friction factor-Reynolds product (fRe) is obtained via pressure drop and volumetric flow-rate measurements. Five surface types/configurations are investigated: smooth hydrophilic, smooth hydrophobic, superhydrophobic with ribs perpendicular to the flow, superhydrophobic with ribs parallel to the flow, and superhydrophobic with ribs parallel to the flow with several breaker ridges perpendicular to the flow. The surface type/configuration has a significant impact on the mass transport dynamics. For surfaces with closed cell micro-structures, large bubbles eventually form and adversely affect fRe and lead to higher temperatures along the channel. When degassed water is used, no bubble nucleation is observed and the air initially trapped in the superhydrophobic cavities is quickly absorbed by the water. © 2018 Elsevier Ltd
80 a8608718200 Iverson B.D. p579 True Conference 224 Adaptive net radiative heat transfer and thermal management with origami-structured surfaces The ability to control radiative behavior through the angular positioning of structured surfaces (e.g. the cavity effect) offers the ability to provide thermal management in dynamic radiative environments. Structures comprised of origami tessellations offer a means to achieve angular cavities that approach black-like behavior during collapse by exploiting use of the cavity effect. Expanded origami surfaces exhibit intrinsic radiative properties while collapsed surfaces exhibit increasingly black-like behavior as the cavity aspect ratio increases. Actuation of such surfaces provides the means to achieve any apparent radiative behavior between these two extremes. This work explores the use of three origami structures (finite V-groove, hinged V-groove and Miura-ori) and their respective apparent radiative properties as a function of cavity geometry using Monte Carlo ray tracing. Results are presented as a function of tessellation geometry and degree of actuation (i.e. collapse). Ray tracing models are benchmarked with V-groove geometries for which analytical models exist in the literature. Convergence for ray independence was determined to be satisfactory when the standard error of the mean for every test case was less than 0.005. Deviation in the apparent absorptivity for finite V-groove relative to the infinite V-groove is quantified. The apparent absorptivity of the Miura-ori fold exhibits sensitivity to the fold geometry when the angle of the unit cell is varied, but is relatively insensitive to the length ratio of the panel. The variable nature of the net radiative heat transfer, achievable through actuation, affords a method for thermal management of components with variable heat dissipation and/or variable radiative environments. © 2018 International Heat Transfer Conference. All rights reserved.
80 a8608718200 Iverson B.D. p589 False Journal 305 Total hemispherical apparent radiative properties of the infinite V-Groove with diffuse reflection [No abstract available]
80 a8608718200 Iverson B.D. p822 False Journal 392 Two-phase flow pressure drop in superhydrophobic channels Superhydrophobic surfaces have been shown to reduce drag in single-phase channel flow; however, little work has been done to characterize their drag-reducing ability found in two-phase flows. Adiabatic, air-water mixtures were used to explore the influence of hydrophobicity on two-phase flows and the hydrodynamics which might be present in flow condensation environments. Pressure drop measurements in a rectangular channel with one superhydrophobic wall (cross-section approximately 0.37 × 10 mm) and three transparent hydrophilic walls were obtained. Data for air/water mixtures with superficial Reynolds numbers ranging from 22–215 and 55–220, respectively, were obtained for superhydrophobic surfaces with three different cavity fractions. Agreement between experimentally obtained two-phase pressure drop data and correlations in the literature for conventional smooth control surfaces was better than 20 percent, which is within the accuracy of the correlations. The data reveal a reduction in the pressure drop for two-phase flow in a channel with a single superhydrophobic wall compared to a control scenario. The observed reduction is approximately 10 percent greater than the reduction that is observed for single-phase flow (relative to a classical channel). © 2017 Elsevier Ltd
80 a8608718200 Iverson B.D. p858 False Journal 401 Improving sensitivity of electrochemical sensors with convective transport in free-standing, carbon nanotube structures High-aspect-ratio, porous membrane of vertically-aligned carbon nanotubes (CNTs) were developed through a templated microfabrication approach for electrochemical sensing. Nanostructured platinum (Pt) catalyst was deposited onto the CNTs with a facile, electroless deposition method, resulting in a Pt-nanowire-coated, CNT sensor (PN-CNT). Convective mass transfer enhancement was shown to improve PN-CNT sensor performance in the non‐enzymatic, amperometric sensing of hydrogen peroxide (H2O2). In particular, convective enhancement was achieved through the use of high surface area to fluid volume structures and concentration boundary layer confinement in a channel. Stir speed and sensor orientation especially influenced the measured current in stirred environments for sensors with through-channel diameters of 16 μm. Through-flow sensing produced drastically higher signals than stirred sensing with over 90% of the H2O2being oxidized as it passed through the PN-CNT sensor, even for low concentrations in the range of 50 nM to 500 μM. This effective utilization of the analyte in detection demonstrates the utility of exploiting convection in electrochemical sensing. For through‐flow at 100 μL s−1, a sensitivity of 24,300 μA mM−1 cm−2was achieved based on the frontal projected area (871 μA mM−1cm−2based on the nominal microchannel surface area), with a 0.03 μM limit of detection and a linear sensing range of 0.03–500 μM. © 2017 Elsevier B.V.
81 a17341858700 Chowdhury S. p19 True Journal 17 Quantum Materials for Energy-Efficient Computing [No abstract available]
82 a42062742100 Zhuang H. p19 False Journal 17 Quantum Materials for Energy-Efficient Computing [No abstract available]
83 a55802018400 Coleman S. p19 False Journal 17 Quantum Materials for Energy-Efficient Computing [No abstract available]
84 a36515506800 Patala S. p19 False Journal 17 Quantum Materials for Energy-Efficient Computing [No abstract available]
85 a56735940800 Bair J. p19 False Journal 17 Quantum Materials for Energy-Efficient Computing [No abstract available]
85 a56735940800 Bair J. p56 False Journal 17 Cryogenic Stress-Driven Grain Growth Observed via Microcompression with in situ Electron Backscatter Diffraction The deformation of materials at cryogenic temperature is of interest for space, arctic, and fundamental science applications. In this work, a custom-built cooling system attached to a commercial picoindenter was used for in situ cryogenic microcompression testing of equal-channel angular-pressed copper with real-time electron backscatter diffraction. Stress-driven grain growth at cryogenic temperatures was observed during a series of elastic and plastic deformations. These results provide direct evidence for the previously predicted phenomenon, whereas previous ex situ examinations demonstrated coarsening after cryogenic loading when samples were not maintained at cryogenic temperatures between deformation and characterization. © 2020, The Minerals, Metals & Materials Society.
86 a57194874146 Lu W. p20 True Journal 18 A new approach of reduction of carbon dioxide emission and optimal use of carbon and hydrogen content for the desired syngas production from coal This research is designed to make progress in overcoming the challenges through the development of a two-stage coal processing. Specifically, a two-stage process was used to maximize the use of the carbon in coal or increase the carbon monoxide yield or lower carbon dioxide and methane yields. Carbon dioxide-char gasification in the absence of water can generate carbon monoxide with near-zero methane, which is desired to produce high-carbon and low-hydrogen chemicals such as oxalic acid through catalytic carbon monoxide coupling and hydrolysis. The technology is applicable to any coal, although Power River Basin (PRB) coal is used as an example feedstock in this research Also, the sodium-iron catalyst can accelerate not only the reaction kinetics in both stages but also increase the hydrogen/carbon monoxide ratio in the syngas produced in the second stage. In other words, the catalyst is a multifunctional agent, which can not only intensify the overall coal process efficiency but also improve the qualities of the desired syngas products and reduce carbon dioxide emission. Thus, In the 1st stage, the catalysts can significantly reduce the CO2-char gasification by as high as 75.00%. In the 2nd stage, the H2/CO ratio of ideal syngas is ∼2:1 with near-0 CH4 generation and the CH4 production can be reduced as high as 61.29% for the CO2–H2O-Char coal gasification. The activation energy for the 2nd stage is reduced by as high as 35.43% than that of raw coal without use Na–Fe catalyst. The overall carbon footprint reduction for the study is reduced by 87.33% in the 1st stage and 96.77% compared to the direct coal combustion. © 2020 Elsevier Ltd
87 a8935141300 Cao Q. p20 False Journal 18 A new approach of reduction of carbon dioxide emission and optimal use of carbon and hydrogen content for the desired syngas production from coal This research is designed to make progress in overcoming the challenges through the development of a two-stage coal processing. Specifically, a two-stage process was used to maximize the use of the carbon in coal or increase the carbon monoxide yield or lower carbon dioxide and methane yields. Carbon dioxide-char gasification in the absence of water can generate carbon monoxide with near-zero methane, which is desired to produce high-carbon and low-hydrogen chemicals such as oxalic acid through catalytic carbon monoxide coupling and hydrolysis. The technology is applicable to any coal, although Power River Basin (PRB) coal is used as an example feedstock in this research Also, the sodium-iron catalyst can accelerate not only the reaction kinetics in both stages but also increase the hydrogen/carbon monoxide ratio in the syngas produced in the second stage. In other words, the catalyst is a multifunctional agent, which can not only intensify the overall coal process efficiency but also improve the qualities of the desired syngas products and reduce carbon dioxide emission. Thus, In the 1st stage, the catalysts can significantly reduce the CO2-char gasification by as high as 75.00%. In the 2nd stage, the H2/CO ratio of ideal syngas is ∼2:1 with near-0 CH4 generation and the CH4 production can be reduced as high as 61.29% for the CO2–H2O-Char coal gasification. The activation energy for the 2nd stage is reduced by as high as 35.43% than that of raw coal without use Na–Fe catalyst. The overall carbon footprint reduction for the study is reduced by 87.33% in the 1st stage and 96.77% compared to the direct coal combustion. © 2020 Elsevier Ltd
88 a57194231165 Xu B. p20 False Journal 18 A new approach of reduction of carbon dioxide emission and optimal use of carbon and hydrogen content for the desired syngas production from coal This research is designed to make progress in overcoming the challenges through the development of a two-stage coal processing. Specifically, a two-stage process was used to maximize the use of the carbon in coal or increase the carbon monoxide yield or lower carbon dioxide and methane yields. Carbon dioxide-char gasification in the absence of water can generate carbon monoxide with near-zero methane, which is desired to produce high-carbon and low-hydrogen chemicals such as oxalic acid through catalytic carbon monoxide coupling and hydrolysis. The technology is applicable to any coal, although Power River Basin (PRB) coal is used as an example feedstock in this research Also, the sodium-iron catalyst can accelerate not only the reaction kinetics in both stages but also increase the hydrogen/carbon monoxide ratio in the syngas produced in the second stage. In other words, the catalyst is a multifunctional agent, which can not only intensify the overall coal process efficiency but also improve the qualities of the desired syngas products and reduce carbon dioxide emission. Thus, In the 1st stage, the catalysts can significantly reduce the CO2-char gasification by as high as 75.00%. In the 2nd stage, the H2/CO ratio of ideal syngas is ∼2:1 with near-0 CH4 generation and the CH4 production can be reduced as high as 61.29% for the CO2–H2O-Char coal gasification. The activation energy for the 2nd stage is reduced by as high as 35.43% than that of raw coal without use Na–Fe catalyst. The overall carbon footprint reduction for the study is reduced by 87.33% in the 1st stage and 96.77% compared to the direct coal combustion. © 2020 Elsevier Ltd
89 a6601976036 Adidharma H. p20 False Journal 18 A new approach of reduction of carbon dioxide emission and optimal use of carbon and hydrogen content for the desired syngas production from coal This research is designed to make progress in overcoming the challenges through the development of a two-stage coal processing. Specifically, a two-stage process was used to maximize the use of the carbon in coal or increase the carbon monoxide yield or lower carbon dioxide and methane yields. Carbon dioxide-char gasification in the absence of water can generate carbon monoxide with near-zero methane, which is desired to produce high-carbon and low-hydrogen chemicals such as oxalic acid through catalytic carbon monoxide coupling and hydrolysis. The technology is applicable to any coal, although Power River Basin (PRB) coal is used as an example feedstock in this research Also, the sodium-iron catalyst can accelerate not only the reaction kinetics in both stages but also increase the hydrogen/carbon monoxide ratio in the syngas produced in the second stage. In other words, the catalyst is a multifunctional agent, which can not only intensify the overall coal process efficiency but also improve the qualities of the desired syngas products and reduce carbon dioxide emission. Thus, In the 1st stage, the catalysts can significantly reduce the CO2-char gasification by as high as 75.00%. In the 2nd stage, the H2/CO ratio of ideal syngas is ∼2:1 with near-0 CH4 generation and the CH4 production can be reduced as high as 61.29% for the CO2–H2O-Char coal gasification. The activation energy for the 2nd stage is reduced by as high as 35.43% than that of raw coal without use Na–Fe catalyst. The overall carbon footprint reduction for the study is reduced by 87.33% in the 1st stage and 96.77% compared to the direct coal combustion. © 2020 Elsevier Ltd
90 a35547089300 Gasem K. p20 False Journal 18 A new approach of reduction of carbon dioxide emission and optimal use of carbon and hydrogen content for the desired syngas production from coal This research is designed to make progress in overcoming the challenges through the development of a two-stage coal processing. Specifically, a two-stage process was used to maximize the use of the carbon in coal or increase the carbon monoxide yield or lower carbon dioxide and methane yields. Carbon dioxide-char gasification in the absence of water can generate carbon monoxide with near-zero methane, which is desired to produce high-carbon and low-hydrogen chemicals such as oxalic acid through catalytic carbon monoxide coupling and hydrolysis. The technology is applicable to any coal, although Power River Basin (PRB) coal is used as an example feedstock in this research Also, the sodium-iron catalyst can accelerate not only the reaction kinetics in both stages but also increase the hydrogen/carbon monoxide ratio in the syngas produced in the second stage. In other words, the catalyst is a multifunctional agent, which can not only intensify the overall coal process efficiency but also improve the qualities of the desired syngas products and reduce carbon dioxide emission. Thus, In the 1st stage, the catalysts can significantly reduce the CO2-char gasification by as high as 75.00%. In the 2nd stage, the H2/CO ratio of ideal syngas is ∼2:1 with near-0 CH4 generation and the CH4 production can be reduced as high as 61.29% for the CO2–H2O-Char coal gasification. The activation energy for the 2nd stage is reduced by as high as 35.43% than that of raw coal without use Na–Fe catalyst. The overall carbon footprint reduction for the study is reduced by 87.33% in the 1st stage and 96.77% compared to the direct coal combustion. © 2020 Elsevier Ltd
91 a7004479819 Argyle M. p20 False Journal 18 A new approach of reduction of carbon dioxide emission and optimal use of carbon and hydrogen content for the desired syngas production from coal This research is designed to make progress in overcoming the challenges through the development of a two-stage coal processing. Specifically, a two-stage process was used to maximize the use of the carbon in coal or increase the carbon monoxide yield or lower carbon dioxide and methane yields. Carbon dioxide-char gasification in the absence of water can generate carbon monoxide with near-zero methane, which is desired to produce high-carbon and low-hydrogen chemicals such as oxalic acid through catalytic carbon monoxide coupling and hydrolysis. The technology is applicable to any coal, although Power River Basin (PRB) coal is used as an example feedstock in this research Also, the sodium-iron catalyst can accelerate not only the reaction kinetics in both stages but also increase the hydrogen/carbon monoxide ratio in the syngas produced in the second stage. In other words, the catalyst is a multifunctional agent, which can not only intensify the overall coal process efficiency but also improve the qualities of the desired syngas products and reduce carbon dioxide emission. Thus, In the 1st stage, the catalysts can significantly reduce the CO2-char gasification by as high as 75.00%. In the 2nd stage, the H2/CO ratio of ideal syngas is ∼2:1 with near-0 CH4 generation and the CH4 production can be reduced as high as 61.29% for the CO2–H2O-Char coal gasification. The activation energy for the 2nd stage is reduced by as high as 35.43% than that of raw coal without use Na–Fe catalyst. The overall carbon footprint reduction for the study is reduced by 87.33% in the 1st stage and 96.77% compared to the direct coal combustion. © 2020 Elsevier Ltd
91 a7004479819 Argyle M. p82 False Journal 62 The effects of doping alumina with silica in alumina-supported NiO catalysts for oxidative dehydrogenation of ethane The production of ethylene via the oxidative dehydrogenation of ethane is well-documented as an energy efficient process. Alumina-supported NiO catalysts make the oxidative dehydrogenation of ethane more selective to ethylene and operate at low reaction temperatures (<500 °C). The addition of silica to the alumina supports of these NiO catalysts formed higher amounts of the NiAl2O4 spinel phase and had adjustable acidities and surface areas with calcination temperature, leading to increases in ethylene productivity. A 5 wt% silica-doped alumina support calcined at 1100 °C with 16 wt% NiO exhibited low acidity and a stable, low surface area, resulting in an ethylene productivity of 13.6 μmolethylene/s·gnickel or 1.32 × 10−2 μmolethylene/s·m2 at 500 °C. © 2019
91 a7004479819 Argyle M. p419 False Journal 229 A cost-effective approach to realization of the efficient methane chemical-looping combustion by using coal fly ash as a support for oxygen carrier Developing highly reactive, durable and low-cost oxygen carrier (OC) is the key to the advancement of the chemical looping combustion (CLC) technology that is regarded as the most energy-efficient way for the capture of CO2 emitted from fossil fuel combustion. In this study, the byproduct from coal power plant, coal fly ash (FA) was utilized as the support for Cu-based OC in methane CLC. Its performance was investigated with a thermogravimetric analyzer and a lab-scale fixed bed reactor. The results showed the FA is better as a support of OC than the most commonly used Al2O3 in anti-carbon deposition and thus beneficial to the importance of the stability of FA supported OCs. Among all the tested OCs, the Cu-based OC synthesized with FA support and impregnation method demonstrated the best performance, with CH4 conversion of 94–100% and CO2 selectivity of 91–94% in ten cycles at 800–850 °C, and minor deactivation. The characterization of the fresh and spent OCs revealed that the FA support itself could provide 1.0–2.9 wt% active oxygen for fuel combustion, which is enabled by the iron oxide in FA. In addition, the distribution of Cu on the FA support became more uniform on spent OC than on the fresh one. Also, the partially irreversible CuO decomposition into Cu2O during cyclic tests was the main reason for the deactivation of OC. Thus, Use of FA as an OC support is conducive to both development of cost-effective CLC and an environmental-friendly utilization of waste FA. © 2018 Elsevier Ltd
91 a7004479819 Argyle M. p518 False Journal 287 Low Temperature Oxidative Dehydrogenation of Ethane by Ce-Modified NiNb Catalysts Low temperature oxidative dehydrogenation catalysts are becoming a viable material for drastically altering the production of small chain alkenes. Among materials used, bimetallic and trimetallic nickel catalysts have shown great promise. In this study, we report a 38% increase in the rate of ethylene production with the addition of Ce to NiNb catalysts. Oxidative dehydrogenation of ethane was performed in the temperature range of 250-350 °C. At 300 °C, the rate of ethylene production was maximized with a rate of 6.91 × 10-4 mmol gcat-1 s-1. At higher temperatures, the rate of deep oxidation to CO2 outcompeted the rate of ethylene formation. The improved rate due to the addition of Ce is attributed to ceria's ability to rapidly transport oxygen to the NiO active sites. © 2018 American Chemical Society.
92 a55413647400 Zhang F. p20 False Journal 18 A new approach of reduction of carbon dioxide emission and optimal use of carbon and hydrogen content for the desired syngas production from coal This research is designed to make progress in overcoming the challenges through the development of a two-stage coal processing. Specifically, a two-stage process was used to maximize the use of the carbon in coal or increase the carbon monoxide yield or lower carbon dioxide and methane yields. Carbon dioxide-char gasification in the absence of water can generate carbon monoxide with near-zero methane, which is desired to produce high-carbon and low-hydrogen chemicals such as oxalic acid through catalytic carbon monoxide coupling and hydrolysis. The technology is applicable to any coal, although Power River Basin (PRB) coal is used as an example feedstock in this research Also, the sodium-iron catalyst can accelerate not only the reaction kinetics in both stages but also increase the hydrogen/carbon monoxide ratio in the syngas produced in the second stage. In other words, the catalyst is a multifunctional agent, which can not only intensify the overall coal process efficiency but also improve the qualities of the desired syngas products and reduce carbon dioxide emission. Thus, In the 1st stage, the catalysts can significantly reduce the CO2-char gasification by as high as 75.00%. In the 2nd stage, the H2/CO ratio of ideal syngas is ∼2:1 with near-0 CH4 generation and the CH4 production can be reduced as high as 61.29% for the CO2–H2O-Char coal gasification. The activation energy for the 2nd stage is reduced by as high as 35.43% than that of raw coal without use Na–Fe catalyst. The overall carbon footprint reduction for the study is reduced by 87.33% in the 1st stage and 96.77% compared to the direct coal combustion. © 2020 Elsevier Ltd
93 a55739722900 Zhang Y. p20 False Journal 18 A new approach of reduction of carbon dioxide emission and optimal use of carbon and hydrogen content for the desired syngas production from coal This research is designed to make progress in overcoming the challenges through the development of a two-stage coal processing. Specifically, a two-stage process was used to maximize the use of the carbon in coal or increase the carbon monoxide yield or lower carbon dioxide and methane yields. Carbon dioxide-char gasification in the absence of water can generate carbon monoxide with near-zero methane, which is desired to produce high-carbon and low-hydrogen chemicals such as oxalic acid through catalytic carbon monoxide coupling and hydrolysis. The technology is applicable to any coal, although Power River Basin (PRB) coal is used as an example feedstock in this research Also, the sodium-iron catalyst can accelerate not only the reaction kinetics in both stages but also increase the hydrogen/carbon monoxide ratio in the syngas produced in the second stage. In other words, the catalyst is a multifunctional agent, which can not only intensify the overall coal process efficiency but also improve the qualities of the desired syngas products and reduce carbon dioxide emission. Thus, In the 1st stage, the catalysts can significantly reduce the CO2-char gasification by as high as 75.00%. In the 2nd stage, the H2/CO ratio of ideal syngas is ∼2:1 with near-0 CH4 generation and the CH4 production can be reduced as high as 61.29% for the CO2–H2O-Char coal gasification. The activation energy for the 2nd stage is reduced by as high as 35.43% than that of raw coal without use Na–Fe catalyst. The overall carbon footprint reduction for the study is reduced by 87.33% in the 1st stage and 96.77% compared to the direct coal combustion. © 2020 Elsevier Ltd
94 a7201970805 Fan M. p20 False Journal 18 A new approach of reduction of carbon dioxide emission and optimal use of carbon and hydrogen content for the desired syngas production from coal This research is designed to make progress in overcoming the challenges through the development of a two-stage coal processing. Specifically, a two-stage process was used to maximize the use of the carbon in coal or increase the carbon monoxide yield or lower carbon dioxide and methane yields. Carbon dioxide-char gasification in the absence of water can generate carbon monoxide with near-zero methane, which is desired to produce high-carbon and low-hydrogen chemicals such as oxalic acid through catalytic carbon monoxide coupling and hydrolysis. The technology is applicable to any coal, although Power River Basin (PRB) coal is used as an example feedstock in this research Also, the sodium-iron catalyst can accelerate not only the reaction kinetics in both stages but also increase the hydrogen/carbon monoxide ratio in the syngas produced in the second stage. In other words, the catalyst is a multifunctional agent, which can not only intensify the overall coal process efficiency but also improve the qualities of the desired syngas products and reduce carbon dioxide emission. Thus, In the 1st stage, the catalysts can significantly reduce the CO2-char gasification by as high as 75.00%. In the 2nd stage, the H2/CO ratio of ideal syngas is ∼2:1 with near-0 CH4 generation and the CH4 production can be reduced as high as 61.29% for the CO2–H2O-Char coal gasification. The activation energy for the 2nd stage is reduced by as high as 35.43% than that of raw coal without use Na–Fe catalyst. The overall carbon footprint reduction for the study is reduced by 87.33% in the 1st stage and 96.77% compared to the direct coal combustion. © 2020 Elsevier Ltd
94 a7201970805 Fan M. p419 False Journal 229 A cost-effective approach to realization of the efficient methane chemical-looping combustion by using coal fly ash as a support for oxygen carrier Developing highly reactive, durable and low-cost oxygen carrier (OC) is the key to the advancement of the chemical looping combustion (CLC) technology that is regarded as the most energy-efficient way for the capture of CO2 emitted from fossil fuel combustion. In this study, the byproduct from coal power plant, coal fly ash (FA) was utilized as the support for Cu-based OC in methane CLC. Its performance was investigated with a thermogravimetric analyzer and a lab-scale fixed bed reactor. The results showed the FA is better as a support of OC than the most commonly used Al2O3 in anti-carbon deposition and thus beneficial to the importance of the stability of FA supported OCs. Among all the tested OCs, the Cu-based OC synthesized with FA support and impregnation method demonstrated the best performance, with CH4 conversion of 94–100% and CO2 selectivity of 91–94% in ten cycles at 800–850 °C, and minor deactivation. The characterization of the fresh and spent OCs revealed that the FA support itself could provide 1.0–2.9 wt% active oxygen for fuel combustion, which is enabled by the iron oxide in FA. In addition, the distribution of Cu on the FA support became more uniform on spent OC than on the fresh one. Also, the partially irreversible CuO decomposition into Cu2O during cyclic tests was the main reason for the deactivation of OC. Thus, Use of FA as an OC support is conducive to both development of cost-effective CLC and an environmental-friendly utilization of waste FA. © 2018 Elsevier Ltd
95 a57217041570 Webb D. p21 True Conference 2 Low-Noise, Low-Power Pulse Shaper for Particle Detection (Invited Paper) Pulse shapers are widely used in particle detector applications to reduce the rise and fall times of the pulse signal and to remove noise from the frontend amplifiers. We demonstrate a low-noise, low-power pulse shaper employing an active lowpass Salley-Key biquad filter, passive highpass filter, and input/output buffers. The design process is described to generate the desired transfer characteristic while incorporating tuning knobs to adapt the shaper characteristic to the needs of different applications. Utilizing only a single 1.8-V supply, the shaper consumes 1.5 mW and achieves an input-referred noise of 17 µVrms, both the lowest among state-of-the-art. The power efficiency normalized to bandwidth and noise is nearly 1.7× better than the next best design. © 2020 IEEE.
96 a57200117690 Song Y. p21 False Conference 2 Low-Noise, Low-Power Pulse Shaper for Particle Detection (Invited Paper) Pulse shapers are widely used in particle detector applications to reduce the rise and fall times of the pulse signal and to remove noise from the frontend amplifiers. We demonstrate a low-noise, low-power pulse shaper employing an active lowpass Salley-Key biquad filter, passive highpass filter, and input/output buffers. The design process is described to generate the desired transfer characteristic while incorporating tuning knobs to adapt the shaper characteristic to the needs of different applications. Utilizing only a single 1.8-V supply, the shaper consumes 1.5 mW and achieves an input-referred noise of 17 µVrms, both the lowest among state-of-the-art. The power efficiency normalized to bandwidth and noise is nearly 1.7× better than the next best design. © 2020 IEEE.
96 a57200117690 Song Y. p69 False Conference 12 A 0.2-V 10-bit 5-kHz SAR ADC with Dynamic Bulk Biasing and Ultra-Low-Supply-Voltage Comparator This paper describes a 10-bit 5-kHz SAR ADC under an ultra-low-supply-voltage of 0.2 V for low-power applications. To tolerate the severe variations in the subthreshold regime, a novel dynamic bulk biasing circuit senses the NMOS/PMOS strength ratio in the background and applies feedback to recover the circuit functionality. A new comparator relaxes the stringent speed-noise trade-off under the 0.2-V supply. Employing ac-coupling, stacked input pairs, and voltage-boosted load capacitors, the comparator achieves more than threefold improvement in speed with little noise penalty. The measured ADC consumes 22 nW and exhibits an SNDR of 52.8 dB at Nyquist, yielding an FoM of 12.3 fJ/conv.-step. Measurements of multiple chips show the proposed dynamic bulk biasing successfully improves the yield by nearly twofold in the presence of supply variations. © 2020 IEEE.
96 a57200117690 Song Y. p175 False Journal 119 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW, yielding an FoM of 37 fJ/conv.-step, the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2018 IEEE.
96 a57200117690 Song Y. p177 False Conference 39 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW,yielding an FoM of 37 fJ/conv.-step,the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2019 IEEE.
96 a57200117690 Song Y. p498 False Journal 269 Direct Measurement of High-Gain and Complementary Charge-Steering Amplifiers This brief presents direct measurement of two novel dynamic amplifiers utilizing the 'charge-steering' topology. Employing a delayed clocking scheme, a four-stage charge-steering amplifier achieves the highest gain of any reported charge-steering topology. A complementary charge-steering amplifier exploits both charging and discharging cycles to double the throughput while reducing power consumption by 22%. Fabricated in 180-nm technology, this brief presents, for the first time, direct measurement results of charge-steering amplifiers, including gain, noise, linearity, common-mode response, and power supply rejection ratio. © 2004-2012 IEEE.
97 a57207689986 Rozsa J. p21 False Conference 2 Low-Noise, Low-Power Pulse Shaper for Particle Detection (Invited Paper) Pulse shapers are widely used in particle detector applications to reduce the rise and fall times of the pulse signal and to remove noise from the frontend amplifiers. We demonstrate a low-noise, low-power pulse shaper employing an active lowpass Salley-Key biquad filter, passive highpass filter, and input/output buffers. The design process is described to generate the desired transfer characteristic while incorporating tuning knobs to adapt the shaper characteristic to the needs of different applications. Utilizing only a single 1.8-V supply, the shaper consumes 1.5 mW and achieves an input-referred noise of 17 µVrms, both the lowest among state-of-the-art. The power efficiency normalized to bandwidth and noise is nearly 1.7× better than the next best design. © 2020 IEEE.
97 a57207689986 Rozsa J. p577 True Conference 222 Byu mars rover at the 2018 university rover challenge This paper describes the design and performance of the BYU mars rover with an emphasis on the wireless communications system and the transmission and reception of data vital to the performance of the rover. © held by the author; distribution rights International Foundation for Telemetering.
98 a57200699937 Gustafson E. p21 False Conference 2 Low-Noise, Low-Power Pulse Shaper for Particle Detection (Invited Paper) Pulse shapers are widely used in particle detector applications to reduce the rise and fall times of the pulse signal and to remove noise from the frontend amplifiers. We demonstrate a low-noise, low-power pulse shaper employing an active lowpass Salley-Key biquad filter, passive highpass filter, and input/output buffers. The design process is described to generate the desired transfer characteristic while incorporating tuning knobs to adapt the shaper characteristic to the needs of different applications. Utilizing only a single 1.8-V supply, the shaper consumes 1.5 mW and achieves an input-referred noise of 17 µVrms, both the lowest among state-of-the-art. The power efficiency normalized to bandwidth and noise is nearly 1.7× better than the next best design. © 2020 IEEE.
99 a7202316035 Austin D.E. p21 False Conference 2 Low-Noise, Low-Power Pulse Shaper for Particle Detection (Invited Paper) Pulse shapers are widely used in particle detector applications to reduce the rise and fall times of the pulse signal and to remove noise from the frontend amplifiers. We demonstrate a low-noise, low-power pulse shaper employing an active lowpass Salley-Key biquad filter, passive highpass filter, and input/output buffers. The design process is described to generate the desired transfer characteristic while incorporating tuning knobs to adapt the shaper characteristic to the needs of different applications. Utilizing only a single 1.8-V supply, the shaper consumes 1.5 mW and achieves an input-referred noise of 17 µVrms, both the lowest among state-of-the-art. The power efficiency normalized to bandwidth and noise is nearly 1.7× better than the next best design. © 2020 IEEE.
100 a35209941000 Chiang S.-H.W. p21 False Conference 2 Low-Noise, Low-Power Pulse Shaper for Particle Detection (Invited Paper) Pulse shapers are widely used in particle detector applications to reduce the rise and fall times of the pulse signal and to remove noise from the frontend amplifiers. We demonstrate a low-noise, low-power pulse shaper employing an active lowpass Salley-Key biquad filter, passive highpass filter, and input/output buffers. The design process is described to generate the desired transfer characteristic while incorporating tuning knobs to adapt the shaper characteristic to the needs of different applications. Utilizing only a single 1.8-V supply, the shaper consumes 1.5 mW and achieves an input-referred noise of 17 µVrms, both the lowest among state-of-the-art. The power efficiency normalized to bandwidth and noise is nearly 1.7× better than the next best design. © 2020 IEEE.
100 a35209941000 Chiang S.-H.W. p24 False Conference 4 A Two-Step Multi-Stage Noise-Shaping Incremental Analog-to-Digital Converter (Invited Paper) High resolution wide bandwidth applications require power-efficient high-accuracy data converters. Multi-Stage Noise-Shaping (MASH) is a useful technique for the design of stable high-order ?S modulators. In this paper, we propose a two-step MASH incremental ADC (IADC). In the first step it performs a third-order coarse quantization. Re-using the same hardware, in the second step the circuit performs fine quantization as a second-order IADC. Thus, it achieves fifth-order noise shaping with only three amplifiers. For a low oversampling ratio OSR = 32, the signal-to-noise ratio can be boosted by about 30 dB. The scheme is suitable for wide bandwidth applications. © 2020 IEEE.
100 a35209941000 Chiang S.-H.W. p69 False Conference 12 A 0.2-V 10-bit 5-kHz SAR ADC with Dynamic Bulk Biasing and Ultra-Low-Supply-Voltage Comparator This paper describes a 10-bit 5-kHz SAR ADC under an ultra-low-supply-voltage of 0.2 V for low-power applications. To tolerate the severe variations in the subthreshold regime, a novel dynamic bulk biasing circuit senses the NMOS/PMOS strength ratio in the background and applies feedback to recover the circuit functionality. A new comparator relaxes the stringent speed-noise trade-off under the 0.2-V supply. Employing ac-coupling, stacked input pairs, and voltage-boosted load capacitors, the comparator achieves more than threefold improvement in speed with little noise penalty. The measured ADC consumes 22 nW and exhibits an SNDR of 52.8 dB at Nyquist, yielding an FoM of 12.3 fJ/conv.-step. Measurements of multiple chips show the proposed dynamic bulk biasing successfully improves the yield by nearly twofold in the presence of supply variations. © 2020 IEEE.
100 a35209941000 Chiang S.-H.W. p128 False Journal 90 A Low-Profile High-Efficiency Fast Battery Charger With Unifiable Constant-Current and Constant-Voltage Regulation Present universal serial bus (USB) battery chargers often suffer from limitations to meet the increasing demand for quick charging due to compromised power efficiency and complicated hardware implementation. In this paper, we propose a charge unifiable (QU) control scheme that enables a battery charger to improve power efficiency in a low-profile hardware manner. This scheme features fully soft-switching (vis-à-vis hard switching) and single control scheme (vis-à-vis multiple) for distinct constant current (CC) and constant voltage (CV) charging modes. To the best of authors' knowledge, the proposed QU control scheme is the first to simultaneously offer fully soft-switching, innate CC-and-CV regulation, and seamless CC-to-CV transition. To verify the proposed design, we monolithically realize a low-profile high-efficiency fast battery charger based on this scheme. The prototype embodying a tiny 470-nH output inductor supports a maximum input voltage of 16V, output voltage of 2.2-4.2 V, output current of 0.1-2 A, and peak power efficiency of 96.2%. When benchmarked against state-of-the-art counterparts, the proposed charger features at least 2.1x smaller inductor and 7.2% higher power efficiency at both the maximum and the minimum output power charging scenarios. Further, this charger is the only design that features ≥ 91% power efficiency in the whole load range. IEEE
100 a35209941000 Chiang S.-H.W. p175 False Journal 119 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW, yielding an FoM of 37 fJ/conv.-step, the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2018 IEEE.
100 a35209941000 Chiang S.-H.W. p177 False Conference 39 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW,yielding an FoM of 37 fJ/conv.-step,the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2019 IEEE.
100 a35209941000 Chiang S.-H.W. p277 False Journal 182 A 9-Bit 10-MHz 28-μW SAR ADC Using Tapered Bit Periods and a Partially Interdigitated DAC A successive-approximation-register (SAR) analogto- digital converter (ADC) incorporates "tapered bit periods" to reduce power consumption by minimizing the digital-to-analog converter (DAC) timing overhead. Utilizing a variable delay line and the standard SAR logic, the proposed technique reduces power by downsizing the DAC drivers and digital logic without decreasing the sampling rate. A detailed analysis derives, for the first time, a closed-form solution of the capacitive DAC settling time accounting for parasitics, and determines the time savings of the proposed design. In addition, this brief proposes a "partially interdigitated" DAC layout to reduce the bottom-plate parasitic capacitance to minimize the DAC power. A 9-bit prototype fabricated in 180-nm technology achieves a signal-to-noise-distortion ratio (SNDR) of 55.5 dB at a 10-MHz sampling rate while consuming 28 μW, yielding a figure-of-merit of 5.7 fJ/conversionstep, the lowest among published ADCs at similar speeds and resolutions. © 2004-2012 IEEE.
100 a35209941000 Chiang S.-H.W. p475 False Journal 262 Design and characterization of a package-less hybrid PDMS-CMOS-FR4 contact-imaging system for microfluidic integration We demonstrate a hybrid "package-less" polydimethylsiloxane (PDMS)-complementary metal-oxide-semiconductor (CMOS)-FR4 system for contact imaging. The system embeds the CMOS image sensor directly in a PDMS layer instead of the standard chip package to support microfluidic structures much larger and more complex than those in prior art. The CMOS/PDMS layer is self-aligned to form a continuous, flat surface to provide structural support for upper microfluidic layers. The system consists of five layers of PDMS implementing fluid channels, valves, chambers, and inlets/outlets. A custom CMOS image sensor with integrated signal conditioning circuits directly captures light from sample fluid for high optical collection efficiency. Owing to the flexibility afforded by the integration process, the system demonstrates, for the first time, integrated valves in contact imaging. Moreover, we present the first direct comparison of the optical performance of a CMOS image sensor and a photomultiplier tube (PMT) in identical contact-imaging conditions. Measurements show that our CMOS sensor achieves 17 dB better signal-to-noise ratio (SNR) compared with a commercial PMT across a broad range of integration times, with a maximum SNR of 47 dB. Chemiluminescent testing successfully shows signal detection for different analyte concentrations and integration times. The contact-imaging system demonstrates a detection limit of 25 μM of a 9,10-diphenylanthracene-based solution. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
100 a35209941000 Chiang S.-H.W. p676 False Journal 327 High-Precision, Mixed-Signal Mismatch Measurement of Metal-Oxide-Metal Capacitors This brief presents a high-precision, mixed-signal mismatch measurement technique for metal-oxide-metal capacitors. The proposed technique incorporates a switched-capacitor op amp within the measurement circuit to significantly improve the measurement precision while relaxing the resolution requirement on the backend analog-to-digital converter (ADC). The proposed technique is also robust against multiple types of errors. A detailed analysis is presented to quantify the sensitivity improvement of the proposed technique over the conventional one. In addition, this brief proposes a multiplexing technique to measure a large number of capacitors in a single chip and a new layout to improve matching. A prototype fabricated in 180 nm technology demonstrates the ability to sense capacitor mismatch standard deviation as low as 0.045% with excellent repeatability, all without the need of a high-resolution ADC. © 2004-2012 IEEE.
100 a35209941000 Chiang S.-H.W. p742 False Journal 357 Design of low-power ultra-high voltage gain differential cascode stages The conventional cascode circuit has long been used as the basis for the differential input stage to an op amp. The voltage gain of this stage can be maximised by operating the MOS devices in the moderate inversion region rather than the strong inversion region. In so doing, the voltage gains of the differential stage can reach values of over 120 dB and the power dissipation is minimised due to the low currents required. Harmonic distortion is also minimised by moderate inversion operation. Although the composite cascode or self-cascode has been successfully used as an op-amp differential stage, the conventional cascode differential circuit offers additional advantages and is compared to the composite cascode differential circuit in this work. A design procedure is also reported in this work for low-power, high voltage gain differential stages. © 2017 Informa UK Limited, trading as Taylor & Francis Group.
101 a57219312906 Lam S.-H. p22 True Conference 3 Using a Deep Learning Model, Content Features, and Author Metadata to Recommend Research Papers According to the Canadian Science Publishing, there are approximately 2.5 million scientific papers published each year. The huge volume of publications can be contributed to a substantial increase in the total number of academic journals, including the increasing number of predatory or fake scientific journals, which yield high volumes of poor-quality research work. The effect of this scenario is that there is an obsolete jungle of journals to flip through in searching for high-quality and relevant references for researchers, ranging from the ones who simply look for citations to cite or latest development and knowledge in a specific scientific area of study. Querying existing web search engines and research paper archived websites is not the solution to the problem, since they are m-equipped to suggest high quality publications to meet the users' information needs. In solving this problem, we propose an elegant research paper recommender, which is unique compared with existing ones, since besides considering the topics and contents of related publications, it also examines the authority and popularity of each publication to ensure its quality. Conducted empirical study shows that our recommender outperforms existing research paper recommenders and contributes to the design of searching relevant publications. © 2020 IEEE.
102 a57215534774 Brewer E. p22 False Conference 3 Using a Deep Learning Model, Content Features, and Author Metadata to Recommend Research Papers According to the Canadian Science Publishing, there are approximately 2.5 million scientific papers published each year. The huge volume of publications can be contributed to a substantial increase in the total number of academic journals, including the increasing number of predatory or fake scientific journals, which yield high volumes of poor-quality research work. The effect of this scenario is that there is an obsolete jungle of journals to flip through in searching for high-quality and relevant references for researchers, ranging from the ones who simply look for citations to cite or latest development and knowledge in a specific scientific area of study. Querying existing web search engines and research paper archived websites is not the solution to the problem, since they are m-equipped to suggest high quality publications to meet the users' information needs. In solving this problem, we propose an elegant research paper recommender, which is unique compared with existing ones, since besides considering the topics and contents of related publications, it also examines the authority and popularity of each publication to ensure its quality. Conducted empirical study shows that our recommender outperforms existing research paper recommenders and contributes to the design of searching relevant publications. © 2020 IEEE.
103 a35303536900 Ng Y.-K. p22 False Conference 3 Using a Deep Learning Model, Content Features, and Author Metadata to Recommend Research Papers According to the Canadian Science Publishing, there are approximately 2.5 million scientific papers published each year. The huge volume of publications can be contributed to a substantial increase in the total number of academic journals, including the increasing number of predatory or fake scientific journals, which yield high volumes of poor-quality research work. The effect of this scenario is that there is an obsolete jungle of journals to flip through in searching for high-quality and relevant references for researchers, ranging from the ones who simply look for citations to cite or latest development and knowledge in a specific scientific area of study. Querying existing web search engines and research paper archived websites is not the solution to the problem, since they are m-equipped to suggest high quality publications to meet the users' information needs. In solving this problem, we propose an elegant research paper recommender, which is unique compared with existing ones, since besides considering the topics and contents of related publications, it also examines the authority and popularity of each publication to ensure its quality. Conducted empirical study shows that our recommender outperforms existing research paper recommenders and contributes to the design of searching relevant publications. © 2020 IEEE.
103 a35303536900 Ng Y.-K. p464 False Conference 169 Movie recommendations using the deep learning approach Recommendation systems are an important part of suggesting items especially in streaming services. For streaming movie services like Netflix, recommendation systems are essential for helping users find new movies to enjoy. In this paper, we propose a deep learning approach based on autoencoders to produce a collaborative filtering system which predicts movie ratings for a user based on a large database of ratings from other users. Using the MovieLens dataset, we explore the use of deep learning to predict users' ratings on new movies, thereby enabling movie recommendations. To verify the novelty and accuracy of our deep learning approach, we compare our approach to standard collaborative filtering techniques: k-nearest-neighbor and matrix-factorization. The experimental results show that our recommendation system outperforms a user-based neighborhood baseline both in terms of root mean squared error on predicted ratings and in a survey in which users judge between recommendations from both systems. © 2018 IEEE.
103 a35303536900 Ng Y.-K. p465 False Conference 170 A graduate school recommendation system using the multi-class support vector machine and KNN approaches With the advancement in technology and increased demand on skilled workers these days, education becomes a stepping stone in securing jobs with long-term perspective. As competition for admission into higher education increases, it becomes even more important for applicants to find graduate schools that fit their requirements and expectation. Selecting appropriate schools to apply, however, is a time-consuming process, especially when looking for schools at graduate level due to the various factors in decision making imposed by the schools and applicants. In this paper, we propose a recommendation system that suggests appealing graduate programs to students based on the Support Vector Machine and K-Nearest Neighbor approaches. As graduate programs make decisions based on applicants' qualification, our recommender considers user's personal data and data of various graduate programs obtained from online education portals to make suggestions. We conduct an empirical study using data of current graduate schools and former graduate school applicants, and the performance evaluation validates the merit of our suggestions. © 2018 IEEE.
103 a35303536900 Ng Y.-K. p530 True Conference 191 CrsRecs: A personalized course recommendation system for college students Every college student has different needs when it comes to learning. It can be difficult to decide which course is best to take on the road to graduation, and which professor will best suit the student's learning style. CrsRecs, our proposed course/professor recommendation system, makes that process much easier. Using topic analysis, tag analysis, sentiment analysis, predicted course/professor ratings, and survey data revealing student priorities with respect to classes (i.e., easy A, quality of the class, etc.), CrsRecs ranks potential courses in order of perceived preference for the student based on a hybrid technique combining the analysis results of a course. Empirical studies conducted to evaluate the performance of CrsRecs have revealed that CrsRecs not only suggests relevant courses to users by considering all the features of a course, but also outperforms existing state-of-the-art course recommendation approaches. © 2017 IEEE.
103 a35303536900 Ng Y.-K. p531 False Conference 192 Using tripartite graphs to make long tail recommendations While current state-of-the-art recommendation systems perform fairly well, they generally do better at recommending the popular subset of all products available rather than matching consumers with the vast amount of niche products in what has been termed the "Long Tail". In their seminal work, "Challenging the Long Tail Recommendation", Yin et al. make an eloquent argument that the long tail is where organizations can create the most value for their consumers. They also argue that existing recommender systems operate fundamentally different for long tail products than for mainstream goods. While matrix factorization, nearest-neighbors, and clustering work well for the "head" market, the long tail is better represented by a graph; specifically a bipartite graph that connects a set of users to a set of goods. In this paper, we show the algorithms presented by Yin et al., as well as a set of similar algorithms proposed by Shang et al., which traverse the bipartite graphs through a random walker in order to identify similar users and products. We build on elements from each work, as well as elements from a Markov process, to facilitate the random walker's traversal of the graph into the long tail regions. This method specifically constructs paths into regions of the long tail that are favorable to users. © 2017 IEEE.
104 a57216811262 Erickson H.C. p23 True Journal 19 Insights into grain boundary energy structure-property relationships by examining computed [1 0 0] disorientation axis grain boundaries in Nickel A study of 346 computed [1 0 0] disorientation axis grain boundaries provides insight into grain boundary energy structure-property relationships. The grain boundaries come from 6 coincidence site lattice misorientations at regularly spaced disorientation angles, and cover the full range of boundary plane orientations. The computed energy has clear trends in disorientation angle and boundary plane orientation. The data are used to reexamine the ‘special’ attribute frequently applied to low Σ coincidence site lattice misorientations and low-angle boundaries and to assess the accuracy of a face-centered cubic grain boundary energy function developed by Bulatov, Reed, and Kumar (Acta Mater. 65 (2014) 161-175). © 2020 Acta Materialia Inc.
105 a8705255200 Homer E.R. p23 False Journal 19 Insights into grain boundary energy structure-property relationships by examining computed [1 0 0] disorientation axis grain boundaries in Nickel A study of 346 computed [1 0 0] disorientation axis grain boundaries provides insight into grain boundary energy structure-property relationships. The grain boundaries come from 6 coincidence site lattice misorientations at regularly spaced disorientation angles, and cover the full range of boundary plane orientations. The computed energy has clear trends in disorientation angle and boundary plane orientation. The data are used to reexamine the ‘special’ attribute frequently applied to low Σ coincidence site lattice misorientations and low-angle boundaries and to assess the accuracy of a face-centered cubic grain boundary energy function developed by Bulatov, Reed, and Kumar (Acta Mater. 65 (2014) 161-175). © 2020 Acta Materialia Inc.
105 a8705255200 Homer E.R. p56 False Journal 17 Cryogenic Stress-Driven Grain Growth Observed via Microcompression with in situ Electron Backscatter Diffraction The deformation of materials at cryogenic temperature is of interest for space, arctic, and fundamental science applications. In this work, a custom-built cooling system attached to a commercial picoindenter was used for in situ cryogenic microcompression testing of equal-channel angular-pressed copper with real-time electron backscatter diffraction. Stress-driven grain growth at cryogenic temperatures was observed during a series of elastic and plastic deformations. These results provide direct evidence for the previously predicted phenomenon, whereas previous ex situ examinations demonstrated coarsening after cryogenic loading when samples were not maintained at cryogenic temperatures between deformation and characterization. © 2020, The Minerals, Metals & Materials Society.
105 a8705255200 Homer E.R. p80 False Journal 60 Grain boundary structure–property model inference using polycrystals: the overdetermined case Efforts to construct predictive grain boundary (GB) structure–property models have historically relied on property measurements or calculations made on bicrystals. Experimental bicrystals can be difficult or expensive to fabricate, and computational constraints limit atomistic bicrystal simulations to high-symmetry GBs (i.e., those with small enough GB periodicity). Although the use of bicrystal property data to construct GB structure–property models is more direct, in many experimental situations the only type of data available may be measurements of the effective properties of polycrystals. In this work, we investigate the possibility of inferring GB structure–property models from measurements of the homogenized effective properties of polycrystals when the form of the structure–property model is unknown. We present an idealized case study in which GB structure–property models for diffusivity are inferred from noisy simulation results of two-dimensional microstructures, under the assumption that the number of polycrystal measurements available is larger than the number of parameters in the inferred model. We also demonstrate how uncertainty quantification for the inferred structure–property models is easily performed within this framework. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
105 a8705255200 Homer E.R. p88 False Journal 67 An investigation of geometrically necessary dislocations and back stress in large grained tantalum via EBSD and CPFEM This study explores the evolution of GNDs and their effects on back stress through experimental and computational methods. Four large-grained tantalum tensile specimens were strained in uniaxial tension, electron backscatter diffraction (EBSD) data were collected, and geometrically necessary dislocation (GND) maps of the four specimens in the unloaded state were produced. EBSD-based GND maps revealed several types of features with high GND content which caused back stress in the specimens. Correlations between five geometrically-based grain boundary (GB) transmission factors and the GB GND content were evaluated, and statistically significant correlations were found for transmission factors based on Livingston and Chalmer's N factor, Werner and Prantl's slip transfer number, and GB misorientation. The sign of individual components of the Nye tensor were used to visually and quantitatively identify clustering of GNDs of the same sign, thus giving additional evidence of increasing back stress due to deformation. Deformation of one of the specimens was simulated using multiple CPFEM based modeling approaches and predicted stress-strain responses are compared. The super dislocation model (SD model) — a crystal plasticity finite element method (CPFEM) which incorporates elastic dislocation interactions — was able to isolate impact of back stress on the overall flow stress. The SD model predicted correct stresses when compared with experimental data; however, when the elastic interactions in the SD model were turned off, stress predictions were 25% too low. Thus, demonstrating the importance of incorporating back stress into the model. © 2019 Elsevier B.V.
105 a8705255200 Homer E.R. p208 False Journal 141 Atomistic survey of grain boundary-dislocation interactions in FCC nickel It is well known that grain boundaries (GBs) have a strong influence on mechanical properties of polycrystalline materials. Not as well-known is how different GBs interact with dislocations to influence dislocation movement. This work presents a molecular dynamics study of 33 different FCC Ni bicrystals, each subjected to four different loading conditions to induce incident dislocation-GB interactions in 132 unique configurations. The resulting simulations produce 189 dislocation-GB interactions. Each interaction is analyzed to determine properties that affect the likelihood of transmission, reflection, or absorption of the dislocation at the GB of interest. The results confirm the ability to predict the slip system of a transmitted dislocation using common geometric criteria. Furthermore, machine learning reveals that geometric properties, such as the minimum residual Burgers vector (RBV) and the disorientation angle between the two grains, are strong indicators of whether or not a dislocation will transmit through a GB. © 2019 Elsevier B.V.
105 a8705255200 Homer E.R. p243 True Journal 159 High-throughput simulations for insight into grain boundary structure-property relationships and other complex microstructural phenomena High-throughput simulations can be a powerful tool in the discovery of new materials and behaviors. As part of a special issue on Rising Stars in Computational Materials Science, this article uses the work of the author to show how high-throughput simulations have had an impact in grain boundary structure-property relationships and other complex microstructural phenomena. The work demonstrates how new tools designed to analyze large datasets produced by high-throughput simulations are enabling comprehensive grain boundary structure-property relationships to be obtained. High-throughput simulations are also used to demonstrate the impact descriptive and inferential statistics has had in extracting key aspects of deformation in metallic glasses. Finally, several different examples are used to show a balanced approach between simulations designed to survey and simulations designed for detailed analysis. Together, the two approaches provide a comprehensive picture of the variety of behaviors that exist, while ensuring that the physics underlying the behaviors are thoroughly understood. © 2019 Elsevier B.V.
105 a8705255200 Homer E.R. p417 False Journal 227 Simulated Microstructural and Compositional Evolution of U-Pu-Zr Alloys Using the Potts-Phase Field Modeling Technique U-Pu-Zr alloys are considered ideal metallic fuels for experimental breeder reactors because of their superior material properties and potential for increased burnup performance. However, significant constituent redistribution has been observed in these alloys when irradiated, or subject to a thermal gradient, resulting in inhomogeneity of both composition and phase, which, in turn, alters the fuel performance. The hybrid Potts-phase field method is reformulated for ternary alloys in a thermal gradient and utilized to simulate and predict constituent redistribution and phase transformations in the U-Pu-Zr nuclear fuel system. Simulated evolution profiles for the U-16Pu-23Zr (at. pct) alloy show concentric zones that are compared with published experimental results; discrepancies in zone size are attributed to thermal profile differences and assumptions related to the diffusivity values used. Twenty-one alloys, over the entire ternary compositional spectrum, are also simulated to investigate the effects of alloy composition on constituent redistribution and phase transformations. The U-40Pu-20Zr (at. pct) alloy shows the most potential for compositional uniformity and phase homogeneity, throughout a thermal gradient, while remaining in the compositional range of feasible alloys. © 2018, The Minerals, Metals & Materials Society and ASM International.
105 a8705255200 Homer E.R. p445 False Journal 249 Effect of strain path on forming limits and retained austenite transformation in Q&P 1180 steel Forming limits and retained austenite (RA) transformation in Q&P 1180 steel are quantified as a function of plastic strain levels for three different strain paths. In-plane uniaxial tension testing was performed in a standard test frame, while limiting dome height tooling was employed for out-of-plane biaxial and plane strain tension experiments. Sheet specimens were tested incrementally for each strain path, and the RA content at each level of strain was measured using electron backscatter diffraction (EBSD). The biaxial tension strain path resulted in the greatest effective strain prior to necking at 0.355, compared to 0.123 for plane strain and 0.142 for uniaxial tension. EBSD measurements for various levels of plastic strain reveal a clear dependence of RA rate of transformation on strain path for the three linear strain paths that were employed in this work. Thinning strains appear to provide a slightly better correlation to RA transformation than effective strain levels, where biaxial tension achieved the greatest level just prior to necking, followed by plane-strain tension, and then uniaxial tension. © 2018 Elsevier B.V.
105 a8705255200 Homer E.R. p495 False Conference 186 Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lath Martensitic Steel The study of post-transformation microstructures and their properties can be greatly enhanced by studying their dependence on the grain boundary content of parent microstructures. Recent work has extended the crystallographic reconstruction of parent austenite in steels to include the reconstruction of special boundaries, such as annealing twins. These reconstructions present unique challenges, as twinned austenite grains share a subset of possible daughter variant orientations. This gives rise to regions of ambiguity in a reconstruction. A technique for the reconstruction of twin boundaries is presented here that is capable of reconstructing 60° <1 1 1> twins, even in the case where twin regions are comprised entirely of variants that are common between the twin and the parent. This technique is demonstrated in the reconstruction of lath martensitic steels. The reconstruction method utilizes a delayed decision-making approach, where a chosen orientation relationship is used to define all possible groupings of daughter grains into possible parents before divisive decisions are made. These overlapping, inclusive groupings (called clusters) are compared to each other individually using their calculated parent austenite orientations and the topographical nature of the overlapping region. These comparisons are used to uncover possible locations of twin boundaries present in the parent austenite. This technique can be applied to future studies on the dependence of post-transformation microstructures on the special grain boundary content of parent microstructures. © 2018 Institute of Physics Publishing. All rights reserved.
105 a8705255200 Homer E.R. p668 False Journal 322 Discovering the building blocks of atomic systems using machine learning: Application to grain boundaries Machine learning has proven to be a valuable tool to approximate functions in high-dimensional spaces. Unfortunately, analysis of these models to extract the relevant physics is never as easy as applying machine learning to a large data set in the first place. Here we present a description of atomic systems that generates machine learning representations with a direct path to physical interpretation. As an example, we demonstrate its usefulness as a universal descriptor of grain boundary systems. Grain boundaries in crystalline materials are a quintessential example of a complex, high-dimensional system with broad impact on many physical properties including strength, ductility, corrosion resistance, crack resistance, and conductivity. In addition to modeling such properties, the method also provides insight into the physical "building blocks" that influence them. This opens the way to discover the underlying physics behind behaviors by understanding which building blocks map to particular properties. Once the structures are understood, they can then be optimized for desirable behaviors. © 2017 The Author(s).
105 a8705255200 Homer E.R. p748 False Journal 362 An RVE procedure for micromechanical prediction of mechanical behavior of dual-phase steel A “bottom-up” representative volume element (RVE) for a dual phase steel was constructed based on measured microstructural properties (“microproperties”). This differs from the common procedure of inferring hypothetical microproperties by fitting to macroscopic behavior using an assumed micro-to-macrolaw. The bottom-up approach allows the assessment of the law itself by comparing RVE-predicted mechanical behavior with independent macroscopic measurements, thus revealing the nature of the controlling micromechanisms. An RVE for DP980 steel was constructed using actual microproperties. Finite element (FE) simulations of elastic-plastic transitions were compared with independent loading-unloading-loading and compression-tension experiments. Constitutive models of three types were utilized: 1) a standard continuum model, 2) a standard Crystal Plasticity (CP) model, and 3) a SuperDislocation (SD) model similar to CP but including the elastic interactions of discrete dislocations. These comparisons led to following conclusions: 1) While a constitutive model that ignores elastic interaction of defects can be fit to macroscopic or microscopic behavior, it cannot represent both accurately, 2) Elastic interactions among dislocations are the predominant source of nonlinearity in the nominally-elastic region (i.e. at stresses below the standard yield stress), and 3) Continuum stress inhomogeneity arising from the hard martensite / soft ferrite microstructure has a minor role in the observed transitional nonlinearity in the absence of discrete dislocation interactions. © 2017 Elsevier B.V.
106 a57218879246 Huang J.-S. p24 True Conference 4 A Two-Step Multi-Stage Noise-Shaping Incremental Analog-to-Digital Converter (Invited Paper) High resolution wide bandwidth applications require power-efficient high-accuracy data converters. Multi-Stage Noise-Shaping (MASH) is a useful technique for the design of stable high-order ?S modulators. In this paper, we propose a two-step MASH incremental ADC (IADC). In the first step it performs a third-order coarse quantization. Re-using the same hardware, in the second step the circuit performs fine quantization as a second-order IADC. Thus, it achieves fifth-order noise shaping with only three amplifiers. For a low oversampling ratio OSR = 32, the signal-to-noise ratio can be boosted by about 30 dB. The scheme is suitable for wide bandwidth applications. © 2020 IEEE.
107 a57218883196 Huang Y.-C. p24 False Conference 4 A Two-Step Multi-Stage Noise-Shaping Incremental Analog-to-Digital Converter (Invited Paper) High resolution wide bandwidth applications require power-efficient high-accuracy data converters. Multi-Stage Noise-Shaping (MASH) is a useful technique for the design of stable high-order ?S modulators. In this paper, we propose a two-step MASH incremental ADC (IADC). In the first step it performs a third-order coarse quantization. Re-using the same hardware, in the second step the circuit performs fine quantization as a second-order IADC. Thus, it achieves fifth-order noise shaping with only three amplifiers. For a low oversampling ratio OSR = 32, the signal-to-noise ratio can be boosted by about 30 dB. The scheme is suitable for wide bandwidth applications. © 2020 IEEE.
108 a57218883472 Kao C.-W. p24 False Conference 4 A Two-Step Multi-Stage Noise-Shaping Incremental Analog-to-Digital Converter (Invited Paper) High resolution wide bandwidth applications require power-efficient high-accuracy data converters. Multi-Stage Noise-Shaping (MASH) is a useful technique for the design of stable high-order ?S modulators. In this paper, we propose a two-step MASH incremental ADC (IADC). In the first step it performs a third-order coarse quantization. Re-using the same hardware, in the second step the circuit performs fine quantization as a second-order IADC. Thus, it achieves fifth-order noise shaping with only three amplifiers. For a low oversampling ratio OSR = 32, the signal-to-noise ratio can be boosted by about 30 dB. The scheme is suitable for wide bandwidth applications. © 2020 IEEE.
109 a57218875152 Hsu C.-W. p24 False Conference 4 A Two-Step Multi-Stage Noise-Shaping Incremental Analog-to-Digital Converter (Invited Paper) High resolution wide bandwidth applications require power-efficient high-accuracy data converters. Multi-Stage Noise-Shaping (MASH) is a useful technique for the design of stable high-order ?S modulators. In this paper, we propose a two-step MASH incremental ADC (IADC). In the first step it performs a third-order coarse quantization. Re-using the same hardware, in the second step the circuit performs fine quantization as a second-order IADC. Thus, it achieves fifth-order noise shaping with only three amplifiers. For a low oversampling ratio OSR = 32, the signal-to-noise ratio can be boosted by about 30 dB. The scheme is suitable for wide bandwidth applications. © 2020 IEEE.
110 a36444802300 Chen C.-H. p24 False Conference 4 A Two-Step Multi-Stage Noise-Shaping Incremental Analog-to-Digital Converter (Invited Paper) High resolution wide bandwidth applications require power-efficient high-accuracy data converters. Multi-Stage Noise-Shaping (MASH) is a useful technique for the design of stable high-order ?S modulators. In this paper, we propose a two-step MASH incremental ADC (IADC). In the first step it performs a third-order coarse quantization. Re-using the same hardware, in the second step the circuit performs fine quantization as a second-order IADC. Thus, it achieves fifth-order noise shaping with only three amplifiers. For a low oversampling ratio OSR = 32, the signal-to-noise ratio can be boosted by about 30 dB. The scheme is suitable for wide bandwidth applications. © 2020 IEEE.
111 a7402967162 Wallace J.W. p25 True Journal 20 Cooperative Relative UAV Attitude Estimation Using DoA and RF Polarization Relative unmanned aerial vehicle attitude is estimated using only on-board radio-frequency signaling. The method uses a direction-of-arrival (DoA) vector estimate to determine two degrees-of-freedom (DoFs), a polarimetric narrowband multiple-input multiple-output (MIMO) channel estimate to specify the third DoF to within a 180^\circ ambiguity, and one of the several potential methods for ambiguity resolution. Simulation results demonstrate that the method accurately determines aircraft attitude, with errors proportional to DoA and MIMO channel estimate errors. This approach is useful for cooperative navigation when external navigation aids are not available, such as in GPS-denied environments. © 1965-2011 IEEE.
111 a7402967162 Wallace J.W. p476 False Journal 263 Secure Array Synthesis in Multipath Channels While conventional antenna array synthesis determines the beamforming weights that create a specified antenna radiation pattern, secure array synthesis formulates the beamforming weights that enhance security for wireless transmission of sensitive data. This paper focuses on creating beamformers that improve the generation of secret encryption keys based on bidirectional estimation of the reciprocal electromagnetic propagation channel between two radios. The technique uses semidefinite programming to determine the array weights that maximize the average secure key rate under a constraint on the total transmit power. The numerical implementation of the technique incorporates array mutual coupling, and the results demonstrate that the technique outperforms a conventional beamforming solution, with the improvement becoming significant for certain channel correlation conditions. © 1963-2012 IEEE.
111 a7402967162 Wallace J.W. p669 True Journal 319 A Comparison of Indoor MIMO Measurements and Ray-Tracing at 24 and 2.55 GHz Colocated 4× 4 multiple-input multiple-output measurements at 2.55 and 24 GHz are presented for two university buildings consisting of classrooms and offices. Link gain in hallways and connected laboratories looks similar at the two frequencies when the effect of lower effective receive antenna aperture with increasing frequency is removed. Non-line-of-sight (NLOS) propagation through a wall or around hallway corners exhibits approximately 5-20 dB (11 dB on average) greater loss beyond the 20 dB aperture loss at 24 GHz compared to that at 2.55 GHz. Fixed directional antennas increase path loss (PL) by an average of 13 dB when misaligned. Capacity for normalized signal-to-noise ratio is very similar in the two bands and is close to that for the optimal independent identically distributed case, indicating sufficient multipath for spatial multiplexing at 24 GHz. A ray-tracing study suggests that material loss must increase from 2.55 to 24 GHz to correctly predict the higher PL at 24 GHz in severely obstructed scenarios, indicating a need for future material characterization in high microwave bands. The results suggest that 24 GHz is a viable option to replace medium-range (10-30 m) NLOS wireless services currently operating at 2.4 GHz. © 1963-2012 IEEE.
112 a56196521900 Mahmood A. p25 False Journal 20 Cooperative Relative UAV Attitude Estimation Using DoA and RF Polarization Relative unmanned aerial vehicle attitude is estimated using only on-board radio-frequency signaling. The method uses a direction-of-arrival (DoA) vector estimate to determine two degrees-of-freedom (DoFs), a polarimetric narrowband multiple-input multiple-output (MIMO) channel estimate to specify the third DoF to within a 180^\circ ambiguity, and one of the several potential methods for ambiguity resolution. Simulation results demonstrate that the method accurately determines aircraft attitude, with errors proportional to DoA and MIMO channel estimate errors. This approach is useful for cooperative navigation when external navigation aids are not available, such as in GPS-denied environments. © 1965-2011 IEEE.
112 a56196521900 Mahmood A. p145 True Journal 101 Nonreciprocal Radio System Calibration for Propagation-Based Key Generation Propagation-based secret key generation (SKG) is a physical layer method for establishing encryption keys based on two radios observing a reciprocal propagation channel. However, nonreciprocal contributions to the channel introduced by the radio circuitry significantly degrade the ability to reliably generate keys using such methods, necessitating the development of calibration methods for removing the impact of channel nonreciprocity. This paper uses a total least squares (TLS) algorithm coupled with a detailed model of the multiple-input multiple-output radio frequency circuitry and propagation for the radio system to achieve such a calibration. Simulations show that the method is highly effective in removing the impact of nonreciprocal circuit contributions over a range of operational parameters. © 1963-2012 IEEE.
112 a56196521900 Mahmood A. p593 True Conference 236 A compact low-cost direction finding system for unmanned aerial vehicles This paper considers the application where a small unmanned aerial vehicle (UAV) must determine the bearing to another UAV already in flight in an environment where GPS is denied through malicious jamming. The development therefore presents the design of a compact and low-power circuit architecture for radio frequency direction finding. The system uses switches to sequentially connect the elements of a circular array antenna to the receive circuitry. While simple architecturally, this causes phase differences between estimates that must be calibrated through use of a reference receive channel. A MUSIC-based bearing estimator developed on a small on-board processor shows the ability to accurately estimate the azimuth and elevation angles to the remote UAV during experimental flight tests. © Institution of Engineering and Technology.All Rights Reserved.
113 a35597296700 Jensen M.A. p25 False Journal 20 Cooperative Relative UAV Attitude Estimation Using DoA and RF Polarization Relative unmanned aerial vehicle attitude is estimated using only on-board radio-frequency signaling. The method uses a direction-of-arrival (DoA) vector estimate to determine two degrees-of-freedom (DoFs), a polarimetric narrowband multiple-input multiple-output (MIMO) channel estimate to specify the third DoF to within a 180^\circ ambiguity, and one of the several potential methods for ambiguity resolution. Simulation results demonstrate that the method accurately determines aircraft attitude, with errors proportional to DoA and MIMO channel estimate errors. This approach is useful for cooperative navigation when external navigation aids are not available, such as in GPS-denied environments. © 1965-2011 IEEE.
113 a35597296700 Jensen M.A. p145 False Journal 101 Nonreciprocal Radio System Calibration for Propagation-Based Key Generation Propagation-based secret key generation (SKG) is a physical layer method for establishing encryption keys based on two radios observing a reciprocal propagation channel. However, nonreciprocal contributions to the channel introduced by the radio circuitry significantly degrade the ability to reliably generate keys using such methods, necessitating the development of calibration methods for removing the impact of channel nonreciprocity. This paper uses a total least squares (TLS) algorithm coupled with a detailed model of the multiple-input multiple-output radio frequency circuitry and propagation for the radio system to achieve such a calibration. Simulations show that the method is highly effective in removing the impact of nonreciprocal circuit contributions over a range of operational parameters. © 1963-2012 IEEE.
113 a35597296700 Jensen M.A. p259 False Journal 101 The Effect of Antenna Mutual Coupling on MIMO Radar System Performance Multiple-input multiple-output (MIMO) radar systems use orthogonal signaling to enable combined transmit and receive beamforming through signal processing on the received signals. Because of the combined role of transmit and receive arrays in this processing for monostatic MIMO radar, mutual coupling present in these arrays impacts the beamforming in a unique way. This paper presents a mathematical model of a MIMO radar with coupled antennas and appropriate radio frequency circuitry. Application of the model to evaluate radar detection of a single target demonstrates that coupling can result in target detection angles that are in error by as much as 12° and increase beamformer response sidelobe levels by as much as 8 dB. The results also show that a simple matching network can improve detection performance, particularly when array mutual coupling is high. © 1963-2012 IEEE.
113 a35597296700 Jensen M.A. p476 False Journal 263 Secure Array Synthesis in Multipath Channels While conventional antenna array synthesis determines the beamforming weights that create a specified antenna radiation pattern, secure array synthesis formulates the beamforming weights that enhance security for wireless transmission of sensitive data. This paper focuses on creating beamformers that improve the generation of secret encryption keys based on bidirectional estimation of the reciprocal electromagnetic propagation channel between two radios. The technique uses semidefinite programming to determine the array weights that maximize the average secure key rate under a constraint on the total transmit power. The numerical implementation of the technique incorporates array mutual coupling, and the results demonstrate that the technique outperforms a conventional beamforming solution, with the improvement becoming significant for certain channel correlation conditions. © 1963-2012 IEEE.
113 a35597296700 Jensen M.A. p549 False Conference 199 Moment method analysis of a reconfigurable OTA reverberation chamber While determining modes in a rectangular cavity is a straightforward analytical exercise, fully understanding the behavior of the fields in a large over-moded cavity whose walls are lined with antennas, such as the reconfigurable over-the-air chamber, is a more complicated undertaking. This paper uses the Moment Method to analyze such a chamber, where each wall is lined with 9 monopole antennas. The evaluation of the cavity Green's function used in the numerical computation is accelerated through the use of Ewald's method. A comparison of scattering parameters between monopoles on the walls obtained both by the Moment Method analysis and experimental measurements shows that the technique is highly accurate in predicting the chamber field behavior. © 2018 Institution of Engineering and Technology.All Rights Reserved.
113 a35597296700 Jensen M.A. p593 False Conference 236 A compact low-cost direction finding system for unmanned aerial vehicles This paper considers the application where a small unmanned aerial vehicle (UAV) must determine the bearing to another UAV already in flight in an environment where GPS is denied through malicious jamming. The development therefore presents the design of a compact and low-power circuit architecture for radio frequency direction finding. The system uses switches to sequentially connect the elements of a circular array antenna to the receive circuitry. While simple architecturally, this causes phase differences between estimates that must be calibrated through use of a reference receive channel. A MUSIC-based bearing estimator developed on a small on-board processor shows the ability to accurately estimate the azimuth and elevation angles to the remote UAV during experimental flight tests. © Institution of Engineering and Technology.All Rights Reserved.
113 a35597296700 Jensen M.A. p669 False Journal 319 A Comparison of Indoor MIMO Measurements and Ray-Tracing at 24 and 2.55 GHz Colocated 4× 4 multiple-input multiple-output measurements at 2.55 and 24 GHz are presented for two university buildings consisting of classrooms and offices. Link gain in hallways and connected laboratories looks similar at the two frequencies when the effect of lower effective receive antenna aperture with increasing frequency is removed. Non-line-of-sight (NLOS) propagation through a wall or around hallway corners exhibits approximately 5-20 dB (11 dB on average) greater loss beyond the 20 dB aperture loss at 24 GHz compared to that at 2.55 GHz. Fixed directional antennas increase path loss (PL) by an average of 13 dB when misaligned. Capacity for normalized signal-to-noise ratio is very similar in the two bands and is close to that for the optimal independent identically distributed case, indicating sufficient multipath for spatial multiplexing at 24 GHz. A ray-tracing study suggests that material loss must increase from 2.55 to 24 GHz to correctly predict the higher PL at 24 GHz in severely obstructed scenarios, indicating a need for future material characterization in high microwave bands. The results suggest that 24 GHz is a viable option to replace medium-range (10-30 m) NLOS wireless services currently operating at 2.4 GHz. © 1963-2012 IEEE.
114 a55649569259 Mehmood R. p25 False Journal 20 Cooperative Relative UAV Attitude Estimation Using DoA and RF Polarization Relative unmanned aerial vehicle attitude is estimated using only on-board radio-frequency signaling. The method uses a direction-of-arrival (DoA) vector estimate to determine two degrees-of-freedom (DoFs), a polarimetric narrowband multiple-input multiple-output (MIMO) channel estimate to specify the third DoF to within a 180^\circ ambiguity, and one of the several potential methods for ambiguity resolution. Simulation results demonstrate that the method accurately determines aircraft attitude, with errors proportional to DoA and MIMO channel estimate errors. This approach is useful for cooperative navigation when external navigation aids are not available, such as in GPS-denied environments. © 1965-2011 IEEE.
114 a55649569259 Mehmood R. p476 True Journal 263 Secure Array Synthesis in Multipath Channels While conventional antenna array synthesis determines the beamforming weights that create a specified antenna radiation pattern, secure array synthesis formulates the beamforming weights that enhance security for wireless transmission of sensitive data. This paper focuses on creating beamformers that improve the generation of secret encryption keys based on bidirectional estimation of the reciprocal electromagnetic propagation channel between two radios. The technique uses semidefinite programming to determine the array weights that maximize the average secure key rate under a constraint on the total transmit power. The numerical implementation of the technique incorporates array mutual coupling, and the results demonstrate that the technique outperforms a conventional beamforming solution, with the improvement becoming significant for certain channel correlation conditions. © 1963-2012 IEEE.
114 a55649569259 Mehmood R. p593 False Conference 236 A compact low-cost direction finding system for unmanned aerial vehicles This paper considers the application where a small unmanned aerial vehicle (UAV) must determine the bearing to another UAV already in flight in an environment where GPS is denied through malicious jamming. The development therefore presents the design of a compact and low-power circuit architecture for radio frequency direction finding. The system uses switches to sequentially connect the elements of a circular array antenna to the receive circuitry. While simple architecturally, this causes phase differences between estimates that must be calibrated through use of a reference receive channel. A MUSIC-based bearing estimator developed on a small on-board processor shows the ability to accurately estimate the azimuth and elevation angles to the remote UAV during experimental flight tests. © Institution of Engineering and Technology.All Rights Reserved.
114 a55649569259 Mehmood R. p669 False Journal 319 A Comparison of Indoor MIMO Measurements and Ray-Tracing at 24 and 2.55 GHz Colocated 4× 4 multiple-input multiple-output measurements at 2.55 and 24 GHz are presented for two university buildings consisting of classrooms and offices. Link gain in hallways and connected laboratories looks similar at the two frequencies when the effect of lower effective receive antenna aperture with increasing frequency is removed. Non-line-of-sight (NLOS) propagation through a wall or around hallway corners exhibits approximately 5-20 dB (11 dB on average) greater loss beyond the 20 dB aperture loss at 24 GHz compared to that at 2.55 GHz. Fixed directional antennas increase path loss (PL) by an average of 13 dB when misaligned. Capacity for normalized signal-to-noise ratio is very similar in the two bands and is close to that for the optimal independent identically distributed case, indicating sufficient multipath for spatial multiplexing at 24 GHz. A ray-tracing study suggests that material loss must increase from 2.55 to 24 GHz to correctly predict the higher PL at 24 GHz in severely obstructed scenarios, indicating a need for future material characterization in high microwave bands. The results suggest that 24 GHz is a viable option to replace medium-range (10-30 m) NLOS wireless services currently operating at 2.4 GHz. © 1963-2012 IEEE.
115 a55849071700 Koch D.P. p26 True Journal 21 Relative multiplicative extended Kalman filter for observable GPS-denied navigation This work presents a multiplicative extended Kalman filter (MEKF) for estimating the relative state of a multirotor vehicle operating in a GPS-denied environment. The filter fuses data from an inertial measurement unit and altimeter with relative-pose updates from a keyframe-based visual odometry or laser scan-matching algorithm. Because the global position and heading states of the vehicle are unobservable in the absence of global measurements such as GPS, the filter in this article estimates the state with respect to a local frame that is colocated with the odometry keyframe. As a result, the odometry update provides nearly direct measurements of the relative vehicle pose, making those states observable. Recent publications have rigorously documented the theoretical advantages of such an observable parameterization, including improved consistency, accuracy, and system robustness, and have demonstrated the effectiveness of such an approach during prolonged multirotor flight tests. This article complements this prior work by providing a complete, self-contained, tutorial derivation of the relative MEKF, which has been thoroughly motivated but only briefly described to date. This article presents several improvements and extensions to the filter while clearly defining all quaternion conventions and properties used, including several new useful properties relating to error quaternions and their Euler-angle decomposition. Finally, this article derives the filter both for traditional dynamics defined with respect to an inertial frame, and for robocentric dynamics defined with respect to the vehicle’s body frame, and provides insights into the subtle differences that arise between the two formulations. © The Author(s) 2020.
115 a55849071700 Koch D.P. p466 False Journal 257 Relative Navigation: A Keyframe-Based Approach for Observable GPS-Degraded Navigation As relevant technologies become smaller and less expensive, micro air vehicles (MAVs) are transitioning from predominantly military and hobbyist applications to mainstream use. Exciting new applications include the delivery of medical supplies to remote areas, infrastructure inspection, environmental change detection, precision agriculture, survelliance of visible satellites. These issues are particularly prevalent when flying near the ground, where safety and reliability are especially important. © 1991-2012 IEEE.
116 a57190404271 Wheeler D.O. p26 False Journal 21 Relative multiplicative extended Kalman filter for observable GPS-denied navigation This work presents a multiplicative extended Kalman filter (MEKF) for estimating the relative state of a multirotor vehicle operating in a GPS-denied environment. The filter fuses data from an inertial measurement unit and altimeter with relative-pose updates from a keyframe-based visual odometry or laser scan-matching algorithm. Because the global position and heading states of the vehicle are unobservable in the absence of global measurements such as GPS, the filter in this article estimates the state with respect to a local frame that is colocated with the odometry keyframe. As a result, the odometry update provides nearly direct measurements of the relative vehicle pose, making those states observable. Recent publications have rigorously documented the theoretical advantages of such an observable parameterization, including improved consistency, accuracy, and system robustness, and have demonstrated the effectiveness of such an approach during prolonged multirotor flight tests. This article complements this prior work by providing a complete, self-contained, tutorial derivation of the relative MEKF, which has been thoroughly motivated but only briefly described to date. This article presents several improvements and extensions to the filter while clearly defining all quaternion conventions and properties used, including several new useful properties relating to error quaternions and their Euler-angle decomposition. Finally, this article derives the filter both for traditional dynamics defined with respect to an inertial frame, and for robocentric dynamics defined with respect to the vehicle’s body frame, and provides insights into the subtle differences that arise between the two formulations. © The Author(s) 2020.
116 a57190404271 Wheeler D.O. p254 False Journal 166 Direct Relative Edge Optimization, A Robust Alternative for Pose Graph Optimization Pose graph optimization is a common problem in robotics and associated fields. Most commonly, pose graph optimization is performed by finding the set of pose estimates which are the most likely for a given set of measurements. In some situations, arbitrarily large errors in pose graph initialization are unavoidable and can cause these pose-based methods to diverge or fail especially in cases where global inputs become available after some time after initialization. This letter details the parameterization of the classic pose graph problem in a relative context, optimizing directly over relative edge constraints between vertices in the pose graph and not on the poses themselves. Unlike previous literature on relative optimization, this letter details relative optimization over an entire pose graph, instead of a subset of edges, resulting in greater robustness to arbitrarily large errors than the classic pose-based or prior relative edge-based methods. Several small-scale simulation comparison studies, along with single and multi-agent hardware experiments, are presented. Results point to relative edge optimization as a strong candidate for solving real-world pose graph optimization problems that contain large heading propagation or initialization errors. © 2016 IEEE.
116 a57190404271 Wheeler D.O. p466 True Journal 257 Relative Navigation: A Keyframe-Based Approach for Observable GPS-Degraded Navigation As relevant technologies become smaller and less expensive, micro air vehicles (MAVs) are transitioning from predominantly military and hobbyist applications to mainstream use. Exciting new applications include the delivery of medical supplies to remote areas, infrastructure inspection, environmental change detection, precision agriculture, survelliance of visible satellites. These issues are particularly prevalent when flying near the ground, where safety and reliability are especially important. © 1991-2012 IEEE.
117 a35562442700 Beard R.W. p26 False Journal 21 Relative multiplicative extended Kalman filter for observable GPS-denied navigation This work presents a multiplicative extended Kalman filter (MEKF) for estimating the relative state of a multirotor vehicle operating in a GPS-denied environment. The filter fuses data from an inertial measurement unit and altimeter with relative-pose updates from a keyframe-based visual odometry or laser scan-matching algorithm. Because the global position and heading states of the vehicle are unobservable in the absence of global measurements such as GPS, the filter in this article estimates the state with respect to a local frame that is colocated with the odometry keyframe. As a result, the odometry update provides nearly direct measurements of the relative vehicle pose, making those states observable. Recent publications have rigorously documented the theoretical advantages of such an observable parameterization, including improved consistency, accuracy, and system robustness, and have demonstrated the effectiveness of such an approach during prolonged multirotor flight tests. This article complements this prior work by providing a complete, self-contained, tutorial derivation of the relative MEKF, which has been thoroughly motivated but only briefly described to date. This article presents several improvements and extensions to the filter while clearly defining all quaternion conventions and properties used, including several new useful properties relating to error quaternions and their Euler-angle decomposition. Finally, this article derives the filter both for traditional dynamics defined with respect to an inertial frame, and for robocentric dynamics defined with respect to the vehicle’s body frame, and provides insights into the subtle differences that arise between the two formulations. © The Author(s) 2020.
117 a35562442700 Beard R.W. p30 False Journal 25 An iterative pose estimation algorithm based on epipolar geometry with application to multi-target tracking This paper introduces a new algorithm for estimating the relative pose of a moving camera using consecutive frames of a video sequence. State-of-the-art algorithms for calculating the relative pose between two images use matching features to estimate the essential matrix. The essential matrix is then decomposed into the relative rotation and normalized translation between frames. To be robust to noise and feature match outliers, these methods generate a large number of essential matrix hypotheses from randomly selected minimal subsets of feature pairs, and then score these hypotheses on all feature pairs. Alternatively, the algorithm introduced in this paper calculates relative pose hypotheses by directly optimizing the rotation and normalized translation between frames, rather than calculating the essential matrix and then performing the decomposition. The resulting algorithm improves computation time by an order of magnitude. If an inertial measurement unit (IMU) is available, it is used to seed the optimizer, and in addition, we reuse the best hypothesis at each iteration to seed the optimizer thereby reducing the number of relative pose hypotheses that must be generated and scored. These advantages greatly speed up performance and enable the algorithm to run in real-time on low cost embedded hardware. We show application of our algorithm to visual multi-target tracking (MTT) in the presence of parallax and demonstrate its real-time performance on a 640 480 video sequence captured on a UAV. © 2014 Chinese Association of Automation.
117 a35562442700 Beard R.W. p34 False Conference 5 State-Dependent LQR Control for a Tilt-Rotor UAV This paper develops a control scheme capable of controlling a tilt-rotor unmanned aerial vehicle during nominal hover and fixed-wing flight as well as through transitions between flight modes. The control scheme consists of two parts: a low-level angular rate controller and variable mixer, and a trajectory tracking state-dependent LQR controller. In developing this controller we also present an aerodynamic model of a tilt-rotor with parameters for the Convergence aircraft by E-Flite. Finally we present simulation results for a representative trajectory consisting of vertical takeoff and landing as well as fixed-wing flight. © 2020 AACC.
117 a35562442700 Beard R.W. p190 False Conference 40 Relative moving target tracking and circumnavigation This paper develops observers and controllers for relative estimation and circumnavigation of a moving ground target using bearing-only measurements or range with bearing measurements. A bearing-only observer, range with bearing observer, a general circumnavigation velocity command for an arbitrary aircraft, and nonlinear velocity-based multirotor controller are developed. The observers are designed in the body-fixed reference frame, while the velocity command and multirotor controller are developed in the body-level frame, independent of aircraft heading. This enables target circumnavigation in GPS-denied environments when only a camera-IMU estimator is used for state estimation and ensures observable conditions for the estimator. Simulation results demonstrate the effectiveness of the observers, velocity command, and multirotor controller under various target motions. © 2019 American Automatic Control Council.
117 a35562442700 Beard R.W. p192 False Conference 42 Tracking multiple vehicles constrained to a road network from a uav with sparse visual measurements Many multiple target tracking algorithms operate in the local frame of the sensor and have difficulty with track reallocation when targets move in and out of the sensor field of view. This poses a problem when an unmanned aerial vehicle (UAV) is tracking multiple ground targets on a road network larger than its field of view. We propose a Rao-Blackwellized Particle Filter (RBPF) to maintain individual target tracks and to perform probabilistic data association when the targets are constrained to a road network. This is particularly useful when a target leaves then re-enters the UAV's field of view. The RBPF is structured as a particle filter of particle filters. The top level filter handles data association and each of its particles maintains a bank of particle filters to handle target tracking. The tracking particle filters incorporate both positive and negative information when a measurement is received. We then implement a receding horizon controller to improve the filter certainty of multiple target locations. The controller prioritizes searching for targets based on the entropy of each target's estimate. © 2019 American Automatic Control Council.
117 a35562442700 Beard R.W. p341 False Journal 194 Relative Heading Estimation and Its Application in Target Handoff in GPS-Denied Environments In this paper, we address the problem of target handoff between two fixed wing aircrafts that do not have access to Global Positioning Systems. The problem requires estimating the relative pose between the vehicles. We assume that onboard inertial measurement units can provide roll and pitch estimates of the aircraft attitude. We examine the observability of other relative states needed to do the handoff problem. In particular, we consider two different scenarios. In the first scenario, we assume that the relative position between the aircrafts is measured, as would be the case for a radar or a lidar sensor. We assume that the two aircrafts do not exchange their airspeed and turn rate information. Under mild assumptions, we show that the relative heading between the two aircrafts is observable. In the second scenario, we assume that only the bearing angle between the two aircrafts is measured, as would be the case for a vision sensor. We prove state observability for maneuvers that are relevant to target tracking and handoff. We also present an estimation algorithm that uses a bank of extended Kalman filters to estimate the relative states. Simulation results with full vehicle dynamics demonstrate the feasibility of the proposed approach. © 1993-2012 IEEE.
117 a35562442700 Beard R.W. p346 False Journal 195 Safe2Ditch: Emergency landing for small unmanned aircraft systems Emergency landing is a critical safety feature for the expected increase of autonomous vehicles in the airspace. This paper presents Safe2Ditch, an autonomous crash management system for landing small unmanned aerial vehicles in populated environments. Using a prepopulated database, the highest-rated landing site is selected. As the vehicle progresses toward the selected landing site, a camera is used to image the area around the landing site. Using a recently developed visual multiple target tracker, moving ground obstacles are tracked and geolocated using a flat Earth model. These inertial target estimates are used to revise the landing site and allow the vehicle to land quickly in the presence of non-cooperative obstacles. The complete system is demonstrated through 2000 Monte Carlo simulations and 16 hardware flight tests. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
117 a35562442700 Beard R.W. p369 False Conference 131 Adaptive control of large-scale soft robot manipulators with unknown payloads The compliance and other nonlinear dynamics of large-scale soft robots makes effective control difficult. This is especially true when working with unknown payloads or when the system dynamics change over time which is likely to happen for soft robots. In this paper, we present a novel method of coupling model reference adaptive control (MRAC) with model predictive control (MPC) for platforms with antagonistic pneumatic actuators. We demonstrate its utility on a fully inflatable, six degreeof-freedom pneumatically actuated soft robot manipulator that is over two meters long. Specifically, we compare control performance with no integral controller, with an integral controller, and with MRAC when running a nominal model predictive controller with significant weight attached to the end effector. © 2019 ASME.
117 a35562442700 Beard R.W. p452 False Conference 158 Autonomous target following with monocular camera on UAS using Recursive-RANSAC tracker This paper presents a vision-based target tracking and following system using a monocular camera on an Unmanned Aerial System (UAS). The R-RANSAC tracker tracks multiple moving objects in the camera field of view and the proposed controller is capable of following a particular target selected by a user while keeping the target in the center of the image. The main contribution of this paper is that multiple objects can be tracked without imposing restrictions such as color, shape, etc. Also, the hardware test shows that the system is able to follow a target autonomously in a real-world outdoor environment. The proposed algorithm is validated on a 3DR X-8 multirotor platform using a downward facing camera. © 2018 IEEE.
117 a35562442700 Beard R.W. p460 False Conference 165 Improved Track Continuity in Multi Target Tracking by Fusing Multiple Input Sources Reliable track continuity is an important characteristic of multiple target tracking (MTT) algorithms. In the specific case of tracking multiple ground targets from an aerial platform, challenges arise due to realistic operating environments such as imperfections in the measurement source. Some popular visual detection techniques include Kanade-Lucas-Tomasi (KLT)-based motion detection, difference imaging, and object feature matching. Each of these algorithmic detectors has fundamental limitations in regard to providing consistent measurements. In this paper we present a scalable detection framework that leverages multiple measurement sources. We also present the recursive random sample consensus (R-RANSAC) algorithm in a data fusion architecture that can simultaneously accommodate multiple measurement sources. We demonstrate robust track continuity using post-processed flight data and show real-time computational performance. © 2018 AACC.
117 a35562442700 Beard R.W. p461 False Conference 166 Visual Multiple Target Tracking from a Descending Aerial Platform A real-time visual multiple target tracker is demonstrated onboard a descending multirotor. Measurements of moving ground targets are generated using the Kanade-Lucas-Tomasi (KLT) tracking method. Homography-based image registration is used to align the measurements into the same coordinate frame, allowing for the detection of independently moving objects. The recently developed Recursive-RANSAC algorithm uses the visual measurements to estimate targets in clutter. Altitude-dependent tuning increases track continuity and coverage during the descent of the vehicle. The algorithm requires no operator interaction and increases the situation awareness of the unmanned aerial system. Real-time tracking efficiency is analyzed on GPUs and CPUs. Tracking results are presented and discussed using the MOTA and MOTP metrics. © 2018 AACC.
117 a35562442700 Beard R.W. p463 False Conference 168 Extending Motion Detection to Track Stopped Objects in Visual Multi-Target Tracking Various solutions to visual multi-target tracking have been proposed, but many of them are not capable of running in real time from a moving camera on an unmanned aerial vehicle (UAV). We present a tracker that runs in real time and tracks multiple objects while accounting for camera motion on a UAV. Our algorithm is capable of processing over 10 frames per second on a 1280x720 video sequence. We utilize Recursive-RANSAC, an efficient algorithm for tracking multiple objects in clutter. Our work combines motion detection with optical flow and feature matching to allow stationary objects to be tracked. We use a feature prioritization algorithm to reduce computational complexity and spatial redundancy. We also present a ghost track reduction method which prevents tracking non-existent objects when true objects are no longer visible. We demonstrate the performance of our tracker on a moving camera video sequence. Video results are available at https://youtu.be/6bXjKb-6qY. © 2018 AACC.
117 a35562442700 Beard R.W. p466 False Journal 257 Relative Navigation: A Keyframe-Based Approach for Observable GPS-Degraded Navigation As relevant technologies become smaller and less expensive, micro air vehicles (MAVs) are transitioning from predominantly military and hobbyist applications to mainstream use. Exciting new applications include the delivery of medical supplies to remote areas, infrastructure inspection, environmental change detection, precision agriculture, survelliance of visible satellites. These issues are particularly prevalent when flying near the ground, where safety and reliability are especially important. © 1991-2012 IEEE.
117 a35562442700 Beard R.W. p651 False Journal 314 Ground-based sense-and-avoid system for small unmanned aircraft In this Paper, we present a complete, proof-of-concept sense-and-avoid solution for small unmanned aircraft systems, including a small low-cost ground-based radar system, multitarget tracking and estimation, collision detection, and an avoidance planner. We describe the development of a small frequency-modulated continuous-wave phased-array radar system that provides a three-dimensional surveillance volume. The radar measurements are processed using the recursive random sample consensus algorithm, producing tracks for the intruders and the ownship. We propose a collision-detection algorithm based on the geometric relationship between encountering aircraft. If a collision threat is detected, a collision-free new path is generated for the ownship using a two-step path-planning algorithm. In the first step, an initial suboptimal path is generated using an A search. In the second step, the path is refined using a variant of the potential fields technique, adapted to the sense-and-avoid scenario. The performance of the complete system is demonstrated with flight-test experiments. © 2018 American Institute of Aeronautics and Astronautics Inc.. All rights reserved.
117 a35562442700 Beard R.W. p716 False Conference 300 Counter UAS using a formation controlled dragnet Rapidly developing UAS technology necessitates reliable counter UAS systems. This paper proposes a formation controlled dragnet as a possible solution and compares potential intercept algorithms that can be used in this scenario. Proportional navigation and target-predictive path planning, both existing algorithms, are explored and an original approach, Adaptive Radius Optimal Defense (AROD), is introduced. Simulation results are given and the strengths and weaknesses of each approach are discussed. Based on the simulation results, some advantages that AROD offers over other existing algorithms are listed. Possible improvements and future research directions are also suggested. © 2017 IEEE.
117 a35562442700 Beard R.W. p781 False Journal 350 Comparison and Analysis of Recursive-RANSAC for Multiple Target Tracking In both simulated and real experiments, the recursive random sample consensus (R-RANSAC) algorithm has shown promise as an efficient multiple target tracking (MTT) filter. In this paper, we introduce a generalized and modular framework for the R-RANSAC algorithm, analyze the sensitivity of the R-RANSAC tuning parameters, and compare R-RANSAC to five well-known MTT algorithms. We show that R-RANSAC offers a unique balance between low computational complexity, excellent track continuity, and good performance in cluttered environments. © 1965-2011 IEEE.
117 a35562442700 Beard R.W. p794 False Conference 331 Relative target estimation using a cascade of extended Kalman filters This paper presents a method of tracking multiple ground targets from an unmanned aerial vehicle (UAV) in a 3D reference frame. The tracking method uses a monocular camera and makes no assumptions on the shape of the terrain or the target motion. The UAV runs two cascaded estimators. The first is an Extended Kalman Filter (EKF), which is responsible for tracking the UAV's state, such as position and velocity relative to a fixed frame. The second estimator is an EKF that is responsible for estimating a fixed number of landmarks within the camera's field of view. Landmarks are parameterized by a quaternion associated with bearing from the camera's optical axis and an inverse distance parameter. The bearing quaternion allows for a minimal representation of each landmark's direction and distance, a filter with no singularities, and a fast update rate due to few trigonometric functions. Three methods for estimating the ground target positions are demonstrated: the first uses the landmark estimator directly on the targets, the second computes the target depth with a weighted average of converged landmark depths, and the third extends the target's measured bearing vector to intersect a ground plane approximated from the landmark estimates. Simulation results show that the third target estimation method yields the most accurate results. © 2017, Institute of Navigation.
117 a35562442700 Beard R.W. p827 True Journal 395 Foreword [No abstract available]
117 a35562442700 Beard R.W. p837 False Journal 397 Minimum required detection range for detect and avoid of unmanned aircraft systems For unmanned aircraft systems to gain full access to the National Airspace System, they must have the capability to detect and avoid other aircraft. To safely avoid another aircraft, an unmanned aircraft must detect the intruder aircraft with ample time and distance to allow the ownship to track the intruder, perform risk assessment, plan an avoidance path, and execute the maneuver. This paper describes two analytical methods for finding the minimum detection range to ensure that these detection and avoidance steps can be carried out. The first method, time-based geometric velocity vectors, includes the bank-angle dynamics of the ownship; whereas the second, geometric velocity vectors, assumes an instantaneous bank-angle maneuver. The solution using the first method must be found numerically, whereas the second has a closed-form analytical solution. These methods are compared to two existing methods. The results show the time-based geometric velocity vectors approach is precise, the geometric velocity vectors approach is a good approximation under many conditions, and the two existing approaches are good approximations at large ownship speeds relative to the intruder speed, fast ownship bank-angle transients, and small ownship bank angles. Copyright © 2017 by Brigham Young University.
118 a7006542177 McLain T.W. p26 False Journal 21 Relative multiplicative extended Kalman filter for observable GPS-denied navigation This work presents a multiplicative extended Kalman filter (MEKF) for estimating the relative state of a multirotor vehicle operating in a GPS-denied environment. The filter fuses data from an inertial measurement unit and altimeter with relative-pose updates from a keyframe-based visual odometry or laser scan-matching algorithm. Because the global position and heading states of the vehicle are unobservable in the absence of global measurements such as GPS, the filter in this article estimates the state with respect to a local frame that is colocated with the odometry keyframe. As a result, the odometry update provides nearly direct measurements of the relative vehicle pose, making those states observable. Recent publications have rigorously documented the theoretical advantages of such an observable parameterization, including improved consistency, accuracy, and system robustness, and have demonstrated the effectiveness of such an approach during prolonged multirotor flight tests. This article complements this prior work by providing a complete, self-contained, tutorial derivation of the relative MEKF, which has been thoroughly motivated but only briefly described to date. This article presents several improvements and extensions to the filter while clearly defining all quaternion conventions and properties used, including several new useful properties relating to error quaternions and their Euler-angle decomposition. Finally, this article derives the filter both for traditional dynamics defined with respect to an inertial frame, and for robocentric dynamics defined with respect to the vehicle’s body frame, and provides insights into the subtle differences that arise between the two formulations. © The Author(s) 2020.
118 a7006542177 McLain T.W. p39 False Journal 32 Relative navigation of fixed-wing aircraft in GPS-denied environments This work enables GPS-denied flight on fixed-wing UAS by accounting for fixed-wing-specific sensing requirements and using a methodology called relative navigation as an overarching framework. The development of an odometry-like, front-end, EKF-based estimator that utilizes only a monocular camera and an inertial measurement unit (IMU) is presented. The filter uses the measurement model of the multi-state-constraint Kalman filter. The filter also regularly resets its origin in coordination with the declaration of keyframe images. The keyframe-to-keyframe odometry estimates and their covariances are sent to a global back end that represents the global state as a pose graph. The back end is better suited to represent nonlinear uncertainties and incorporate opportunistic global constraints. We also introduce a method to account for front-end velocity bias in the back-end optimization. The paper provides simulation and hardware flight-test results of the front-end estimator and performs several back-end optimizations on the front-end data. © 2020 Institute of Navigation
118 a7006542177 McLain T.W. p121 False Journal 81 Cooperative relative navigation of multiple aircraft in global positioning system-denied/degraded environments This paper introduces a method for enabling multiple small unmannedaircraft to improve navigational accuracy in Global Positioning System (GPS)-denied environments by cooperatively sharing information. The method uses a multilevel framework called relative navigation and visual-inertial odometry: Both of which have been used for singlevehicle GPS-denied navigation. This work modifies the relative navigation architecture by adding the necessary elements to enable decentralized, cooperative operations. The proposed framework also includes the ability to incorporate intervehicle measurements and uses a new concept called the coordinated reset, which is necessary for optimizing the cooperative odometry and improving localization. A simple communication protocol is presented, as well as flight-test results that show its effectiveness. The method is first demonstrated in simulation, including Monte Carlo testing, to show the expected improvement gained from cooperation. Finally, results from hardware testing are presented that show the ability of the system to reject initialization errors, to operate with temporary communications dropouts, and to greatly reduce the total amount of shared data compared to a naive approach. The proposed method is able to improve both global navigation accuracy and the accuracy of the relative aircraft positions for missions that require formation flying. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
118 a7006542177 McLain T.W. p191 False Conference 41 Visual servoing with feed-forward for precision shipboard landing of an autonomous multirotor In this paper the problem of performing a precision landing of an autonomous multirotor on a small barge at sea is studied. An image-based visual servoing approach, which was initially developed for landing on stationary targets, is extended to suit the shipboard landing case. The approach includes visual servoing for aligning the multirotor with a target on the vessel, and a velocity feed-forward term which is estimated online by fusing vision and GPS velocity measurements. Special considerations are made to account for the presence of wind, and the approach is validated through full-scale outdoor hardware flight tests. The hardware system is composed entirely from off-the-shelf components that are commonly used in industry. © 2019 American Automatic Control Council.
118 a7006542177 McLain T.W. p213 False Conference 48 Deep RC: Enabling remote control through deep learning Human remote-control (RC) pilots have the ability to perceive the position and orientation of an aircraft using only third-person-perspective visual sensing. While novice pilots often struggle when learning to control RC aircraft, they can sense the orientation of the aircraft with relative ease. In this paper, we hypothesize and demonstrate that deep learning methods can be used to mimic the human ability to perceive the orientation of an aircraft from monocular imagery. This work uses a neural network to directly sense the aircraft attitude. The network is combined with more conventional image processing methods for visual tracking of the aircraft. The aircraft track and attitude measurements from the convolutional neural network (CNN) are combined in a particle filter that provides a complete state estimate of the aircraft. The network topology, training, and testing results are presented as well as filter development and results. The proposed method was tested in simulation and hardware flight demonstrations. © 2019 IEEE.
118 a7006542177 McLain T.W. p215 False Conference 50 Error-state LQR control of a multirotor UAV We propose an implementation of an LQR controller for the full-state tracking of a time-dependent trajectory with a multirotor UAV. The proposed LQR formulation is based in Lie theory and linearized at each time step according to the multirotor's current state. We show experiments in both simulation and hardware that demonstrate the proposed control scheme's ability to accurately reach and track a given trajectory. The implementation is shown to run onboard at the full rate of a UAV's estimated state. © 2019 IEEE.
118 a7006542177 McLain T.W. p216 False Conference 51 Visual servoing for multirotor precision landing in daylight and after-dark conditions The problem of precision landing for autonomous multirotor UAVs operating during the day and at night is studied. A vision-based approach is proposed and consists of varying-degree-of-freedom image-based visual servoing (VDOF IBVS), and a specialized landing marker. The proposed approach is validated through extensive flight testing outdoors in both daylight and after-dark conditions, and is done using a standard off-the-shelf autopilot system. © 2019 IEEE.
118 a7006542177 McLain T.W. p254 False Journal 166 Direct Relative Edge Optimization, A Robust Alternative for Pose Graph Optimization Pose graph optimization is a common problem in robotics and associated fields. Most commonly, pose graph optimization is performed by finding the set of pose estimates which are the most likely for a given set of measurements. In some situations, arbitrarily large errors in pose graph initialization are unavoidable and can cause these pose-based methods to diverge or fail especially in cases where global inputs become available after some time after initialization. This letter details the parameterization of the classic pose graph problem in a relative context, optimizing directly over relative edge constraints between vertices in the pose graph and not on the poses themselves. Unlike previous literature on relative optimization, this letter details relative optimization over an entire pose graph, instead of a subset of edges, resulting in greater robustness to arbitrarily large errors than the classic pose-based or prior relative edge-based methods. Several small-scale simulation comparison studies, along with single and multi-agent hardware experiments, are presented. Results point to relative edge optimization as a strong candidate for solving real-world pose graph optimization problems that contain large heading propagation or initialization errors. © 2016 IEEE.
118 a7006542177 McLain T.W. p466 False Journal 257 Relative Navigation: A Keyframe-Based Approach for Observable GPS-Degraded Navigation As relevant technologies become smaller and less expensive, micro air vehicles (MAVs) are transitioning from predominantly military and hobbyist applications to mainstream use. Exciting new applications include the delivery of medical supplies to remote areas, infrastructure inspection, environmental change detection, precision agriculture, survelliance of visible satellites. These issues are particularly prevalent when flying near the ground, where safety and reliability are especially important. © 1991-2012 IEEE.
118 a7006542177 McLain T.W. p497 False Conference 187 Relative visual-inertial odometry for fixed-wing aircraft in GPS-denied environments This paper introduces an odometry-like front-end estimator for GPS-denied fixed-wing flight using a monocular camera. This development is a critical component for enabling fixed-wing aircraft to use a novel methodology called relative navigation. Relative navigation allows a single vehicle to gracefully accommodate intermittent GPS or geo-registered image updates. It can also enable communication and a computationally feasible cooperative, batch-based navigation approach for numerous vehicles. This paper presents a visual-odometry estimator that is appropriate for fixed-wing flight characteristics and sensing requirements. We propose a modification to the multi-state-constraint Kalman filter which, instead of running the filter in a single inertial/global frame, regularly resets the navigation frame to a new local origin. The vehicle operates based on the most recent keyframe and produces a marginalized change in pose (odometry) and covariance output whenever the keyframe is updated. This allows the front end to operate at the IMU rate to accommodate guidance and control inputs while sharing marginalized keyframe-to-keyframe odometry estimates with a back-end, graph optimization at a much lower rate than traditional batch navigation schemes. Results from testing the proposed method in a high-fidelity simulation of the filter is also presented. © 2018 IEEE.
118 a7006542177 McLain T.W. p651 False Journal 314 Ground-based sense-and-avoid system for small unmanned aircraft In this Paper, we present a complete, proof-of-concept sense-and-avoid solution for small unmanned aircraft systems, including a small low-cost ground-based radar system, multitarget tracking and estimation, collision detection, and an avoidance planner. We describe the development of a small frequency-modulated continuous-wave phased-array radar system that provides a three-dimensional surveillance volume. The radar measurements are processed using the recursive random sample consensus algorithm, producing tracks for the intruders and the ownship. We propose a collision-detection algorithm based on the geometric relationship between encountering aircraft. If a collision threat is detected, a collision-free new path is generated for the ownship using a two-step path-planning algorithm. In the first step, an initial suboptimal path is generated using an A search. In the second step, the path is refined using a variant of the potential fields technique, adapted to the sense-and-avoid scenario. The performance of the complete system is demonstrated with flight-test experiments. © 2018 American Institute of Aeronautics and Astronautics Inc.. All rights reserved.
118 a7006542177 McLain T.W. p662 False Conference 289 Deep visual gravity vector detection for unmanned aircraft attitude estimation This paper demonstrates a feasible method for using a deep neural network as a sensor to estimate the attitude of a flying vehicle using only flight video. A dataset of still images and associated gravity vectors was collected and used to perform supervised learning. The network builds on a previously trained network and was trained to be able to approximate the attitude of the camera with an average error of about 8 degrees. Flight test video was recorded and processed with a relatively simple visual odometry method. The aircraft attitude is then estimated with the visual odometry as the state propagation and network providing the attitude measurement in an extended Kalman filter. Results show that the proposed method of having the neural network provide a gravity vector attitude measurement from the flight imagery reduces the standard deviation of the attitude error by approximately 12 times compared to a baseline approach. © 2017 IEEE.
118 a7006542177 McLain T.W. p788 False Conference 325 A well clear recommendation for small UAS in high-density, ADS-B-enabled airspace With the growing popularity of small unmanned aircraft systems (UAS), there is a significant need to enable small UAS to detect and avoid collisions with both manned and unmanned aircraft. The capabilities of ADS-B make it an attractive sensor for detect and avoid (DAA), but it is susceptible to frequency congestion. This paper quantitatively analyzes the frequency limitations of 978 MHz ADS-B. It then uses these limitations to make a recommendation for well clear in ADS-B-equipped airspace that has a high density of small UAS operations. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
118 a7006542177 McLain T.W. p837 False Journal 397 Minimum required detection range for detect and avoid of unmanned aircraft systems For unmanned aircraft systems to gain full access to the National Airspace System, they must have the capability to detect and avoid other aircraft. To safely avoid another aircraft, an unmanned aircraft must detect the intruder aircraft with ample time and distance to allow the ownship to track the intruder, perform risk assessment, plan an avoidance path, and execute the maneuver. This paper describes two analytical methods for finding the minimum detection range to ensure that these detection and avoidance steps can be carried out. The first method, time-based geometric velocity vectors, includes the bank-angle dynamics of the ownship; whereas the second, geometric velocity vectors, assumes an instantaneous bank-angle maneuver. The solution using the first method must be found numerically, whereas the second has a closed-form analytical solution. These methods are compared to two existing methods. The results show the time-based geometric velocity vectors approach is precise, the geometric velocity vectors approach is a good approximation under many conditions, and the two existing approaches are good approximations at large ownship speeds relative to the intruder speed, fast ownship bank-angle transients, and small ownship bank angles. Copyright © 2017 by Brigham Young University.
119 a36668159600 Brink K.M. p26 False Journal 21 Relative multiplicative extended Kalman filter for observable GPS-denied navigation This work presents a multiplicative extended Kalman filter (MEKF) for estimating the relative state of a multirotor vehicle operating in a GPS-denied environment. The filter fuses data from an inertial measurement unit and altimeter with relative-pose updates from a keyframe-based visual odometry or laser scan-matching algorithm. Because the global position and heading states of the vehicle are unobservable in the absence of global measurements such as GPS, the filter in this article estimates the state with respect to a local frame that is colocated with the odometry keyframe. As a result, the odometry update provides nearly direct measurements of the relative vehicle pose, making those states observable. Recent publications have rigorously documented the theoretical advantages of such an observable parameterization, including improved consistency, accuracy, and system robustness, and have demonstrated the effectiveness of such an approach during prolonged multirotor flight tests. This article complements this prior work by providing a complete, self-contained, tutorial derivation of the relative MEKF, which has been thoroughly motivated but only briefly described to date. This article presents several improvements and extensions to the filter while clearly defining all quaternion conventions and properties used, including several new useful properties relating to error quaternions and their Euler-angle decomposition. Finally, this article derives the filter both for traditional dynamics defined with respect to an inertial frame, and for robocentric dynamics defined with respect to the vehicle’s body frame, and provides insights into the subtle differences that arise between the two formulations. © The Author(s) 2020.
119 a36668159600 Brink K.M. p39 False Journal 32 Relative navigation of fixed-wing aircraft in GPS-denied environments This work enables GPS-denied flight on fixed-wing UAS by accounting for fixed-wing-specific sensing requirements and using a methodology called relative navigation as an overarching framework. The development of an odometry-like, front-end, EKF-based estimator that utilizes only a monocular camera and an inertial measurement unit (IMU) is presented. The filter uses the measurement model of the multi-state-constraint Kalman filter. The filter also regularly resets its origin in coordination with the declaration of keyframe images. The keyframe-to-keyframe odometry estimates and their covariances are sent to a global back end that represents the global state as a pose graph. The back end is better suited to represent nonlinear uncertainties and incorporate opportunistic global constraints. We also introduce a method to account for front-end velocity bias in the back-end optimization. The paper provides simulation and hardware flight-test results of the front-end estimator and performs several back-end optimizations on the front-end data. © 2020 Institute of Navigation
119 a36668159600 Brink K.M. p121 False Journal 81 Cooperative relative navigation of multiple aircraft in global positioning system-denied/degraded environments This paper introduces a method for enabling multiple small unmannedaircraft to improve navigational accuracy in Global Positioning System (GPS)-denied environments by cooperatively sharing information. The method uses a multilevel framework called relative navigation and visual-inertial odometry: Both of which have been used for singlevehicle GPS-denied navigation. This work modifies the relative navigation architecture by adding the necessary elements to enable decentralized, cooperative operations. The proposed framework also includes the ability to incorporate intervehicle measurements and uses a new concept called the coordinated reset, which is necessary for optimizing the cooperative odometry and improving localization. A simple communication protocol is presented, as well as flight-test results that show its effectiveness. The method is first demonstrated in simulation, including Monte Carlo testing, to show the expected improvement gained from cooperation. Finally, results from hardware testing are presented that show the ability of the system to reject initialization errors, to operate with temporary communications dropouts, and to greatly reduce the total amount of shared data compared to a naive approach. The proposed method is able to improve both global navigation accuracy and the accuracy of the relative aircraft positions for missions that require formation flying. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
119 a36668159600 Brink K.M. p254 False Journal 166 Direct Relative Edge Optimization, A Robust Alternative for Pose Graph Optimization Pose graph optimization is a common problem in robotics and associated fields. Most commonly, pose graph optimization is performed by finding the set of pose estimates which are the most likely for a given set of measurements. In some situations, arbitrarily large errors in pose graph initialization are unavoidable and can cause these pose-based methods to diverge or fail especially in cases where global inputs become available after some time after initialization. This letter details the parameterization of the classic pose graph problem in a relative context, optimizing directly over relative edge constraints between vertices in the pose graph and not on the poses themselves. Unlike previous literature on relative optimization, this letter details relative optimization over an entire pose graph, instead of a subset of edges, resulting in greater robustness to arbitrarily large errors than the classic pose-based or prior relative edge-based methods. Several small-scale simulation comparison studies, along with single and multi-agent hardware experiments, are presented. Results point to relative edge optimization as a strong candidate for solving real-world pose graph optimization problems that contain large heading propagation or initialization errors. © 2016 IEEE.
119 a36668159600 Brink K.M. p497 False Conference 187 Relative visual-inertial odometry for fixed-wing aircraft in GPS-denied environments This paper introduces an odometry-like front-end estimator for GPS-denied fixed-wing flight using a monocular camera. This development is a critical component for enabling fixed-wing aircraft to use a novel methodology called relative navigation. Relative navigation allows a single vehicle to gracefully accommodate intermittent GPS or geo-registered image updates. It can also enable communication and a computationally feasible cooperative, batch-based navigation approach for numerous vehicles. This paper presents a visual-odometry estimator that is appropriate for fixed-wing flight characteristics and sensing requirements. We propose a modification to the multi-state-constraint Kalman filter which, instead of running the filter in a single inertial/global frame, regularly resets the navigation frame to a new local origin. The vehicle operates based on the most recent keyframe and produces a marginalized change in pose (odometry) and covariance output whenever the keyframe is updated. This allows the front end to operate at the IMU rate to accommodate guidance and control inputs while sharing marginalized keyframe-to-keyframe odometry estimates with a back-end, graph optimization at a much lower rate than traditional batch navigation schemes. Results from testing the proposed method in a high-fidelity simulation of the filter is also presented. © 2018 IEEE.
120 a57200206301 Amini E. p27 True Journal 22 Municipal wastewater treatment by semi-continuous and membrane algal-bacterial photo-bioreactors Conventional wastewater treatment systems demand a high cost mechanical aeration. Using algal-bacterial systems helps to reach a cost-efficient treatment method by eliminating mechanical aeration, since algae produce the oxygen needed for treatment process. In this study, two groups of experiments were performed for domestic wastewater treatment processes. For the first group, semi-continuous microalgae-bacterial photo-bioreactors were cultivated. Chlorella Vulgaris and activated sludge (AS) were used as microalgae and bacterial inoculums, respectively. The effect of different algae and AS ratios on the chemical oxygen demand (COD), N-NH4 + and P-PO4 3− removal was studied. The removal efficiency of COD was above 93 % for the three tested algae and AS inoculum ratios (5:1, 1:1, and 1:5). The reactor with algae: AS inoculum ratio of 5:1 achieved the highest final N-NH4 + and P-PO4 3− removal efficiencies (88.0 ± 1.0 % and 84.0 ± 1.0 %, respectively). Furthermore, the highest biomass concentration (1.96 g L-1 from initial amount of 0.3 g L-1) was observed in the reactor with algae: AS ratio of 5:1. The ratio of 5:1 (algae: AS) was found as the optimum ratio which promoted the cooperation between microalgae and AS for nutrient removal. For the second group of experiments, the optimum ratio of 5:1 (algae: AS) was used in a membrane bioreactor, and the results showed that this reactor enhanced the final removal efficacies from 88 to 98 % and from 84 to 89 % for N-NH4 + and P-PO4 3-, respectively. © 2020 Elsevier Ltd
120 a57200206301 Amini E. p802 False Conference 338 Investigation of merging flames in horizontal and vertical geometries One of the main needs for accurate shrub combustion modeling is the complicated flame growth pattern due to merging of flames from multiple leaves and small branches. The interactions of neighboring flames have only been studied using regularly spaced fuel sources located on a horizontal plane. Flames in a burning shrub or tree merge to form large flames from fuel arrangements, which are not described by horizontal plane geometries. A careful study of flame interactions from fuels in three-dimensional arrangements is a necessary step in strengthening operational field models in complex fuel structures. The purpose of this research is to imitate the flame merging of the solid fuels in different geometries in order to describe fire behavior in complex fuel structures, such as trees or shrubs. Ceramic felt soaked in n-heptane were used as a fuel source to conduct flame-merging experiments. Flame characteristics such as flame length and flame width were measured for both single and merged flames. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
120 a57200206301 Amini E. p809 False Conference 344 Analysis of pyrolysis products from live shrub fuels Approximately 6 million acres per year are burned by prescribed fire shrublands in the southeastern United States. Burning the understory every 2-4 years prevents fires from spreading to the canopy. However, combustion of live shrubs is not well understood, and has been shown to differ from combustion of dead biomass fuels. The purpose of this study is to investigate pyrolysis products from live shrub fuels. The pyrolysis products constitute the fuel for the gaseous flames in a fire. Amounts of pyrolyzed species depend on heating rate, temperature, fuel type, and fuel properties. In order to provide pyrolysis conditions and oxygen-free environment, a flat-flame burner (FFB) was designed and operated in a fuel-rich mode. Hot and cold traps were used to separate low and high molecular weight (tars) pyrolysis products and then analyzed in two different GC-MS systems. The data obtained help focus modeling efforts for combustion of live shrubs. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
120 a57200206301 Amini E. p810 True Conference 345 Pyrolysis of live vegetation at slow heating rates Wildland fire is an important component of many American ecosystems. Wildland fires can have necessary ecological influences in many North American ecosystems or can dangerously affect life, property and natural resources. These hazards decrease with the proper application of controlled burning. Controlled burning destroys smaller plants and also decreases combustible materials and the potential for ignition and fire propagation in the fuel bed. Fuel bed pyrolysis and ignition determine fire ignition and propagation rates in both wildland fires and prescribed burning, but the details of solid fuel reaction under wildland fire conditions remain poorly understood. The purpose of this study is to provide fundamental information about pyrolysis of live shrub fuels at slow heating rates. A programmable heater apparatus was used to study the pyrolysis products of three different kind of live shrubs from forests of the Southeastern United States. Low and high molecular weight pyrolysis products were collected in a cold trap and then analyzed using GC-MS.
120 a57200206301 Amini E. p812 False Conference 347 Investigation of merging flames in Horizontal and vertical Geometries One of the main needs for accurate shrub combustion modeling is the complicated flame growth pattern due to merging of flames from multiple leaves and small branches. A careful study of flame interactions from fuels in three-dimensional arrangements is a necessary step in strengthening operational field models in complex fuel structures. The purpose of this research is to imitate the flame merging of the solid fuels in different geometries in order to describe fire behavior in complex fuel structures, such as trees or shrubs. Ceramic felts soaked in n-heptane were used as a fuel source to conduct flame-merging experiments. Flame characteristics such as flame length and flame width were measured for both single and merged flames. Our data shows that by altering the separation distance between felts in both vertical and horizontal directions, flame area, height and width vary to a large extent. The region of flame merging is mapped in both the horizontal and vertical directions. These data are being used to develop flame-merging correlations as a function of flame spacing, similar to correlations that have been developed for multiple flames in the horizontal plane.
121 a57190131647 Babaei A. p27 False Journal 22 Municipal wastewater treatment by semi-continuous and membrane algal-bacterial photo-bioreactors Conventional wastewater treatment systems demand a high cost mechanical aeration. Using algal-bacterial systems helps to reach a cost-efficient treatment method by eliminating mechanical aeration, since algae produce the oxygen needed for treatment process. In this study, two groups of experiments were performed for domestic wastewater treatment processes. For the first group, semi-continuous microalgae-bacterial photo-bioreactors were cultivated. Chlorella Vulgaris and activated sludge (AS) were used as microalgae and bacterial inoculums, respectively. The effect of different algae and AS ratios on the chemical oxygen demand (COD), N-NH4 + and P-PO4 3− removal was studied. The removal efficiency of COD was above 93 % for the three tested algae and AS inoculum ratios (5:1, 1:1, and 1:5). The reactor with algae: AS inoculum ratio of 5:1 achieved the highest final N-NH4 + and P-PO4 3− removal efficiencies (88.0 ± 1.0 % and 84.0 ± 1.0 %, respectively). Furthermore, the highest biomass concentration (1.96 g L-1 from initial amount of 0.3 g L-1) was observed in the reactor with algae: AS ratio of 5:1. The ratio of 5:1 (algae: AS) was found as the optimum ratio which promoted the cooperation between microalgae and AS for nutrient removal. For the second group of experiments, the optimum ratio of 5:1 (algae: AS) was used in a membrane bioreactor, and the results showed that this reactor enhanced the final removal efficacies from 88 to 98 % and from 84 to 89 % for N-NH4 + and P-PO4 3-, respectively. © 2020 Elsevier Ltd
122 a35612908400 Mehrnia M.R. p27 False Journal 22 Municipal wastewater treatment by semi-continuous and membrane algal-bacterial photo-bioreactors Conventional wastewater treatment systems demand a high cost mechanical aeration. Using algal-bacterial systems helps to reach a cost-efficient treatment method by eliminating mechanical aeration, since algae produce the oxygen needed for treatment process. In this study, two groups of experiments were performed for domestic wastewater treatment processes. For the first group, semi-continuous microalgae-bacterial photo-bioreactors were cultivated. Chlorella Vulgaris and activated sludge (AS) were used as microalgae and bacterial inoculums, respectively. The effect of different algae and AS ratios on the chemical oxygen demand (COD), N-NH4 + and P-PO4 3− removal was studied. The removal efficiency of COD was above 93 % for the three tested algae and AS inoculum ratios (5:1, 1:1, and 1:5). The reactor with algae: AS inoculum ratio of 5:1 achieved the highest final N-NH4 + and P-PO4 3− removal efficiencies (88.0 ± 1.0 % and 84.0 ± 1.0 %, respectively). Furthermore, the highest biomass concentration (1.96 g L-1 from initial amount of 0.3 g L-1) was observed in the reactor with algae: AS ratio of 5:1. The ratio of 5:1 (algae: AS) was found as the optimum ratio which promoted the cooperation between microalgae and AS for nutrient removal. For the second group of experiments, the optimum ratio of 5:1 (algae: AS) was used in a membrane bioreactor, and the results showed that this reactor enhanced the final removal efficacies from 88 to 98 % and from 84 to 89 % for N-NH4 + and P-PO4 3-, respectively. © 2020 Elsevier Ltd
123 a8208300700 Shayegan J. p27 False Journal 22 Municipal wastewater treatment by semi-continuous and membrane algal-bacterial photo-bioreactors Conventional wastewater treatment systems demand a high cost mechanical aeration. Using algal-bacterial systems helps to reach a cost-efficient treatment method by eliminating mechanical aeration, since algae produce the oxygen needed for treatment process. In this study, two groups of experiments were performed for domestic wastewater treatment processes. For the first group, semi-continuous microalgae-bacterial photo-bioreactors were cultivated. Chlorella Vulgaris and activated sludge (AS) were used as microalgae and bacterial inoculums, respectively. The effect of different algae and AS ratios on the chemical oxygen demand (COD), N-NH4 + and P-PO4 3− removal was studied. The removal efficiency of COD was above 93 % for the three tested algae and AS inoculum ratios (5:1, 1:1, and 1:5). The reactor with algae: AS inoculum ratio of 5:1 achieved the highest final N-NH4 + and P-PO4 3− removal efficiencies (88.0 ± 1.0 % and 84.0 ± 1.0 %, respectively). Furthermore, the highest biomass concentration (1.96 g L-1 from initial amount of 0.3 g L-1) was observed in the reactor with algae: AS ratio of 5:1. The ratio of 5:1 (algae: AS) was found as the optimum ratio which promoted the cooperation between microalgae and AS for nutrient removal. For the second group of experiments, the optimum ratio of 5:1 (algae: AS) was used in a membrane bioreactor, and the results showed that this reactor enhanced the final removal efficacies from 88 to 98 % and from 84 to 89 % for N-NH4 + and P-PO4 3-, respectively. © 2020 Elsevier Ltd
124 a57192643299 Safdari M.-S. p27 False Journal 22 Municipal wastewater treatment by semi-continuous and membrane algal-bacterial photo-bioreactors Conventional wastewater treatment systems demand a high cost mechanical aeration. Using algal-bacterial systems helps to reach a cost-efficient treatment method by eliminating mechanical aeration, since algae produce the oxygen needed for treatment process. In this study, two groups of experiments were performed for domestic wastewater treatment processes. For the first group, semi-continuous microalgae-bacterial photo-bioreactors were cultivated. Chlorella Vulgaris and activated sludge (AS) were used as microalgae and bacterial inoculums, respectively. The effect of different algae and AS ratios on the chemical oxygen demand (COD), N-NH4 + and P-PO4 3− removal was studied. The removal efficiency of COD was above 93 % for the three tested algae and AS inoculum ratios (5:1, 1:1, and 1:5). The reactor with algae: AS inoculum ratio of 5:1 achieved the highest final N-NH4 + and P-PO4 3− removal efficiencies (88.0 ± 1.0 % and 84.0 ± 1.0 %, respectively). Furthermore, the highest biomass concentration (1.96 g L-1 from initial amount of 0.3 g L-1) was observed in the reactor with algae: AS ratio of 5:1. The ratio of 5:1 (algae: AS) was found as the optimum ratio which promoted the cooperation between microalgae and AS for nutrient removal. For the second group of experiments, the optimum ratio of 5:1 (algae: AS) was used in a membrane bioreactor, and the results showed that this reactor enhanced the final removal efficacies from 88 to 98 % and from 84 to 89 % for N-NH4 + and P-PO4 3-, respectively. © 2020 Elsevier Ltd
124 a57192643299 Safdari M.-S. p802 False Conference 338 Investigation of merging flames in horizontal and vertical geometries One of the main needs for accurate shrub combustion modeling is the complicated flame growth pattern due to merging of flames from multiple leaves and small branches. The interactions of neighboring flames have only been studied using regularly spaced fuel sources located on a horizontal plane. Flames in a burning shrub or tree merge to form large flames from fuel arrangements, which are not described by horizontal plane geometries. A careful study of flame interactions from fuels in three-dimensional arrangements is a necessary step in strengthening operational field models in complex fuel structures. The purpose of this research is to imitate the flame merging of the solid fuels in different geometries in order to describe fire behavior in complex fuel structures, such as trees or shrubs. Ceramic felt soaked in n-heptane were used as a fuel source to conduct flame-merging experiments. Flame characteristics such as flame length and flame width were measured for both single and merged flames. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
124 a57192643299 Safdari M.-S. p809 True Conference 344 Analysis of pyrolysis products from live shrub fuels Approximately 6 million acres per year are burned by prescribed fire shrublands in the southeastern United States. Burning the understory every 2-4 years prevents fires from spreading to the canopy. However, combustion of live shrubs is not well understood, and has been shown to differ from combustion of dead biomass fuels. The purpose of this study is to investigate pyrolysis products from live shrub fuels. The pyrolysis products constitute the fuel for the gaseous flames in a fire. Amounts of pyrolyzed species depend on heating rate, temperature, fuel type, and fuel properties. In order to provide pyrolysis conditions and oxygen-free environment, a flat-flame burner (FFB) was designed and operated in a fuel-rich mode. Hot and cold traps were used to separate low and high molecular weight (tars) pyrolysis products and then analyzed in two different GC-MS systems. The data obtained help focus modeling efforts for combustion of live shrubs. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
124 a57192643299 Safdari M.-S. p810 False Conference 345 Pyrolysis of live vegetation at slow heating rates Wildland fire is an important component of many American ecosystems. Wildland fires can have necessary ecological influences in many North American ecosystems or can dangerously affect life, property and natural resources. These hazards decrease with the proper application of controlled burning. Controlled burning destroys smaller plants and also decreases combustible materials and the potential for ignition and fire propagation in the fuel bed. Fuel bed pyrolysis and ignition determine fire ignition and propagation rates in both wildland fires and prescribed burning, but the details of solid fuel reaction under wildland fire conditions remain poorly understood. The purpose of this study is to provide fundamental information about pyrolysis of live shrub fuels at slow heating rates. A programmable heater apparatus was used to study the pyrolysis products of three different kind of live shrubs from forests of the Southeastern United States. Low and high molecular weight pyrolysis products were collected in a cold trap and then analyzed using GC-MS.
124 a57192643299 Safdari M.-S. p812 False Conference 347 Investigation of merging flames in Horizontal and vertical Geometries One of the main needs for accurate shrub combustion modeling is the complicated flame growth pattern due to merging of flames from multiple leaves and small branches. A careful study of flame interactions from fuels in three-dimensional arrangements is a necessary step in strengthening operational field models in complex fuel structures. The purpose of this research is to imitate the flame merging of the solid fuels in different geometries in order to describe fire behavior in complex fuel structures, such as trees or shrubs. Ceramic felts soaked in n-heptane were used as a fuel source to conduct flame-merging experiments. Flame characteristics such as flame length and flame width were measured for both single and merged flames. Our data shows that by altering the separation distance between felts in both vertical and horizontal directions, flame area, height and width vary to a large extent. The region of flame merging is mapped in both the horizontal and vertical directions. These data are being used to develop flame-merging correlations as a function of flame spacing, similar to correlations that have been developed for multiple flames in the horizontal plane.
125 a57215136260 Weaver B.P. p28 True Journal 23 Estimating correlations with censored data KEY POINT: Including censored observations, when estimating correlations, has a nontrivial impact on the analysis. © 2020, © 2020 Taylor & Francis Group, LLC.
126 a56442655200 Kaufeld K. p28 False Journal 23 Estimating correlations with censored data KEY POINT: Including censored observations, when estimating correlations, has a nontrivial impact on the analysis. © 2020, © 2020 Taylor & Francis Group, LLC.
127 a55827824100 Warr R. p28 False Journal 23 Estimating correlations with censored data KEY POINT: Including censored observations, when estimating correlations, has a nontrivial impact on the analysis. © 2020, © 2020 Taylor & Francis Group, LLC.
127 a55827824100 Warr R. p275 False Journal 181 Failure time distributions for complex equipment The exponential distribution is inadequate as a failure time model for most components; however, under certain conditions (in particular, that component failure rates are small and mutually independent, and failed components are immediately replaced or perfectly repaired), it is applicable to complex repairable systems with large numbers of components in series, regardless of component distributions, as shown by Drenick in 1960. This result implies that system behavior may become simpler as more components are added. We review necessary conditions for the result and present some simulation studies to assess how well it holds in systems with finite numbers of components. We also note that Drenick's result is analogous to similar results in other systems disciplines, again resulting in simpler behavior as the number of entities in the system increases. © 2018 John Wiley & Sons, Ltd.
128 a57197773578 Pack A.T. p29 True Journal 24 Social impact in product design, an exploration of current industry practices Though academic research for identifying and considering the social impact of products is emerging, additional insights can be gained from engineers who design products every day. This paper explores current practices in industries used by design engineers to consider the social impact of products. Forty-six individuals from 34 different companies were interviewed to discover what disconnects exist between academia and industry when considering a product's social impact. These interviews were also used to discover how social impact might be considered in a design setting moving forward. This is not a study to find “the state of the art,” but considers the average engineering professional's work to design products in various industries. Social impact assessments (SIA) and social life cycle assessments (SLCA) are two of the most common processes discussed in the literature to evaluate social impact, both generally and in products. Interestingly, these processes did not arise in any discussion in interviews, despite respondents affirming that they do consider social impact in the product design. Processes used to predict social impact, rather than simply evaluate, were discussed by the respondents. These tended to be developed within the company and often related to industry imposed government regulations. To build on this study, the findings herein should be further validated for executives, managers, and engineers. A study specific to these roles should be designed to understand the disconnect better. Additionally, processes should be developed to assist engineers in considering the social impact of their products. Work should also be done to help educate engineers and their leaders on the value of considering the social impact in product design. Copyright © 2019 by ASME
128 a57197773578 Pack A.T. p358 False Journal 199 Using a Product's Sustainability Space as a Design Exploration Tool Sustainable design is often practiced and assessed through the consideration of three essential areas: economic sustainability, environmental sustainability, and social sustainability. For even the simplest of products, the complexities of these three areas and their tradeoffs cause decision-making transparency to be lost in most practical situations. The existing field of multiobjective optimization offers a natural framework to define and explore a given design space. In this paper, a method for defining a product's sustainability space (defined by economic, environmental, and social sustainability objectives) is outlined and used to explore the tradeoffs within the space, thus offering both the design team and the decision makers a means of better understanding the sustainability tradeoffs. This paper concludes that sustainable product development can indeed benefit from tradeoff characterization using multiobjective optimization techniques - even when using only basic models of sustainability. Interestingly, the unique characteristics of the three essential sustainable development areas lead to an alternative view of some traditional multiobjective optimization concepts, such as weak-Pareto optimality. The sustainable redesign of a machine to drill boreholes for water wells is presented as a practical example for method demonstration and discussion. Copyright © The Author(s) 2019.
128 a57197773578 Pack A.T. p584 True Conference 229 Social impact in product design, an exploration of current industry practices Though academic research for identifying and considering the social impact of products is emerging, the actual use of these processes in industry is undeclared in the literature. The gap between academic research and the industry adoption of these theories and methodologies can have real consequences. This paper explores current practices in industry that design engineers use to consider the social impact of products during the customer use stage. 30 people from nineteen different companies were interviewed to discover what disconnects exist between academia and industry when considering a product’s social impact. Although social impact assessments (SIA) and social life cycle assessments (SLCA) are two of the most common evaluative processes discussed in the literature, not a single company interviewed used either of these processes despite affirming that they do consider social impact in product design. Predictive processes were discussed by the respondents that tended to be developed within the company and often related to government regulations. Copyright © 2018 ASME.
128 a57197773578 Pack A.T. p818 True Conference 353 An assessment of village drill sustainability, with recommendations Sustainability is commonly broken into three categories: Economic, environmental, and social. For products, there is a need for design tools that allow decision makers to handle the tradeoffs between each of these three pillars of sustainability. This paper simultaneously assesses all three pillars of sustainability for the Village Drill, a machine used to dig water wells in rural areas around the world. Using data and methods from Mattson et al. [1, 2] relationships are developed between the drill's design parameters and key sustainability issues. These relationships are used to evaluate the sustainability of the current drill design as well as any alternatives. One million random sets of drill parameters are generated and the resulting drill alternatives are evaluated. A three-dimensional design space for the sustainability of the drill is found and recommendations are given with potential for improvements in each pillar of sustainability. © 2017 ASME.
129 a57204761536 Phipps E.R. p29 False Journal 24 Social impact in product design, an exploration of current industry practices Though academic research for identifying and considering the social impact of products is emerging, additional insights can be gained from engineers who design products every day. This paper explores current practices in industries used by design engineers to consider the social impact of products. Forty-six individuals from 34 different companies were interviewed to discover what disconnects exist between academia and industry when considering a product's social impact. These interviews were also used to discover how social impact might be considered in a design setting moving forward. This is not a study to find “the state of the art,” but considers the average engineering professional's work to design products in various industries. Social impact assessments (SIA) and social life cycle assessments (SLCA) are two of the most common processes discussed in the literature to evaluate social impact, both generally and in products. Interestingly, these processes did not arise in any discussion in interviews, despite respondents affirming that they do consider social impact in the product design. Processes used to predict social impact, rather than simply evaluate, were discussed by the respondents. These tended to be developed within the company and often related to industry imposed government regulations. To build on this study, the findings herein should be further validated for executives, managers, and engineers. A study specific to these roles should be designed to understand the disconnect better. Additionally, processes should be developed to assist engineers in considering the social impact of their products. Work should also be done to help educate engineers and their leaders on the value of considering the social impact in product design. Copyright © 2019 by ASME
129 a57204761536 Phipps E.R. p584 False Conference 229 Social impact in product design, an exploration of current industry practices Though academic research for identifying and considering the social impact of products is emerging, the actual use of these processes in industry is undeclared in the literature. The gap between academic research and the industry adoption of these theories and methodologies can have real consequences. This paper explores current practices in industry that design engineers use to consider the social impact of products during the customer use stage. 30 people from nineteen different companies were interviewed to discover what disconnects exist between academia and industry when considering a product’s social impact. Although social impact assessments (SIA) and social life cycle assessments (SLCA) are two of the most common evaluative processes discussed in the literature, not a single company interviewed used either of these processes despite affirming that they do consider social impact in product design. Predictive processes were discussed by the respondents that tended to be developed within the company and often related to government regulations. Copyright © 2018 ASME.
130 a7004300863 Mattson C.A. p29 False Journal 24 Social impact in product design, an exploration of current industry practices Though academic research for identifying and considering the social impact of products is emerging, additional insights can be gained from engineers who design products every day. This paper explores current practices in industries used by design engineers to consider the social impact of products. Forty-six individuals from 34 different companies were interviewed to discover what disconnects exist between academia and industry when considering a product's social impact. These interviews were also used to discover how social impact might be considered in a design setting moving forward. This is not a study to find “the state of the art,” but considers the average engineering professional's work to design products in various industries. Social impact assessments (SIA) and social life cycle assessments (SLCA) are two of the most common processes discussed in the literature to evaluate social impact, both generally and in products. Interestingly, these processes did not arise in any discussion in interviews, despite respondents affirming that they do consider social impact in the product design. Processes used to predict social impact, rather than simply evaluate, were discussed by the respondents. These tended to be developed within the company and often related to industry imposed government regulations. To build on this study, the findings herein should be further validated for executives, managers, and engineers. A study specific to these roles should be designed to understand the disconnect better. Additionally, processes should be developed to assist engineers in considering the social impact of their products. Work should also be done to help educate engineers and their leaders on the value of considering the social impact in product design. Copyright © 2019 by ASME
130 a7004300863 Mattson C.A. p46 False Journal 24 Analysis of perceived social impacts of existing products designed for the developing world, with implications for new product development Engineered products often have more social impacts than are realized. A product review was conducted to bring this to light. In this paper, we show the extent to which different social impacts in 11 impact categories are co-present in 150 products and how this can help engineers and others during the product development process. Specifically, we show how social impact categories not previously considered can be identified. The product review resulted in 13,200 data points that were divided into two data sets, one with 8800 data points from which a social impact probability table was created. The remaining data points were then used to validate the table. All data points were then combined to create a final social impact probability table. This table provides insight for how various social impact categories correlate and can assist engineers in expanding their views to include additional social impact objectives and thus achieve a design with broader social impact or a design with minimized unwanted negative social impact. A simple method for predicting social impact is also created in order to assist engineers when developing products with social impacts in mind. © 2019 by ASME.
130 a7004300863 Mattson C.A. p59 False Journal 24 A Method for Creating Product Social Impact Models of Engineered Products All products impact the lives of their users, this is called social impact. Some social impacts are commonly recognized by the engineering community, such as impacts to a user's health and safety, while other social impacts can be more difficult to recognize, such as impacts on families and gender roles. When engineers make design decisions, without considering social impacts, they can unknowingly cause negative social impacts. Even harming the user and/or society. Despite its challenges, measuring a program's or policy's social impact is a common practice in the field of social sciences. These measurements are made using social impact indicators, which are simply the things observed to verify that true progress is being made. While there are clear benefits to predicting the social impact of an engineered product, it is unclear how engineers should select indicators and build predictive social impact models that are functions of engineering parameters and decisions. This paper introduces a method for selecting social impact indicators and creating predictive social impact models that can help engineers predict and improve the social impact of their products. As a first step in the method, an engineer identifies the product's users, objectives, and requirements. Then, the social impact categories that are related to the product are determined. From each of these categories, the engineer selects several social impact indicators. Finally, models are created for each indicator to predict how a product's parameters will change these indicators. The impact categories and indicators can be translated into product requirements and performance measures that can be used in product development processes. This method is used to predict the social impact of the proposed, expanded U.S. Mexico border wall. © 2019 Copernicus GmbH. All rights reserved.
130 a7004300863 Mattson C.A. p194 False Journal 131 Quantifying the effects of various factors on the utility of design ethnography in the developing world Ethnography, a tool traditionally used by social scientists, has been adopted by product design engineers as a tool to build empathy, understand customers and their contexts, and learn about needs for a product. This tool is particularly valuable for designers from the developed world working on products for customers in developing communities as differences in culture, language, and life experience make the designer’s intuition less reliable in these communities. This paper reports the use of design ethnography under a variety of conditions in the developing world. The data analyzed here come from field studies completed in four different developing communities on four different continents. Researchers had varying degrees of cultural familiarity, language fluency, and community partner participation in each location. Other factors were also included in the study such as the effects of gender and age of the respondents, the ethnographic activity used, and others. Some of the results are intuitive and some are surprising, but all are quantified through rigorous statistical analysis. The results of this study can help design teams of all types including NGOs, student teams, industrial teams, and any other team with an interest in product design in developing communities. These results can help teams plan their own ethnographic activities to increase the likelihood of collecting information that is useful for making product design decisions based on the conditions of their particular project. © 2019, Springer-Verlag London Ltd., part of Springer Nature.
130 a7004300863 Mattson C.A. p262 False Journal 172 Over-Design Versus Redesign as a Response to Future Requirements Though little research has been done in the field of over-design as a product development strategy, an over-design approach can help products avoid the issue of premature obsolescence. This paper compares over-design to redesign as approaches to address the emergence of future requirements. Net present value (NPV) analyses of several real world applications are examined from the perspective of manufacturers (i.e., defense contractors, automobile, pharmaceutical, and microprocessor manufactures) and customers (i.e., purchases of vehicles, televisions, cell phones, washing machines, and buildings). This analysis is used to determine the conditions under which an over-design approach provides a greater benefit than a redesign approach. Over-design is found to have a higher NPV than redesign when future requirements occur soon after the initial release, discount rates are low, initial research, and development cost or price is high, and when the incremental costs of the future requirements are low. © 2019 by ASME.
130 a7004300863 Mattson C.A. p285 True Journal 186 Product development: Principles and tools for creating desirable and transferable designs Introduction This book explores the evolution of products from the beginning idea through mass-production. Rather than prescribing a one-size-fits-all process, the authors explain the theory behind product development and challenge readers to develop their own customized development process uniquely suited for their individual situation. In addition to theory, the book provides development case studies, exercises and self-evaluation criteria at the end of each chapter, and a product development reference that introduces a wide variety of design tools and methods. Class-tested for three consecutive years by hundreds of students in four different courses, the book is an ideal text for senior design classes in mechanical engineering and related disciplines as well as a reference for practicing engineers/product designers. Focuses on excellent design outcomes, rather than rote activities; Maximizes readers’ contextual understanding with real examples of student design and case studies; Reinforces readers’ grasp of theory and best-practices with exercises at the end of each chapter and self-evaluation criteria; Includes a comprehensive product development reference ordered alphabetically and cross-referenced by stage of development, design skills, and design objective; Adopts a concise and engaging writing style and attractive layout with many informative figures. © Springer Nature Switzerland AG 2020.
130 a7004300863 Mattson C.A. p297 False Conference 79 The personification of big data Organizations all over the world, both national and international, gather demographic data so that the progress of nations and peoples can be tracked. This data is often made available to the public in the form of aggregated national level data or individual responses (microdata). Product designers likewise conduct surveys to better understand their customer and create personas. Personas are archetypes of the individuals who will use, maintain, sell or otherwise be affected by the products created by designers. Personas help designers better understand the person the product is designed for. Unfortunately, the process of collecting customer information and creating personas is often a slow and expensive process. In this paper, we introduce a new method of creating personas, leveraging publicly available databanks of both aggregated national level and information on individuals in the population. A computational persona generator is introduced that creates a population of personas that mirrors a real population in terms of size and statistics. Realistic individual personas are filtered from this population for use in product development. © 2019 Design Society. All rights reserved.
130 a7004300863 Mattson C.A. p317 False Conference 97 Factors leading to sustainable social impact on the affected communities of engineering service learning projects University engineering programs across the USA engage in service learning projects. These projects involve student teams designing and implementing products or solutions for communities in need, often in developing nations. There has been much research done relating to pedagogy and the impact of these programs on student learning. However, less research has been done on measuring the impact of these programs on the affected communities. This paper examines factors that practitioners believe are related to successfully delivering a desirable and transferable solution to affected communities. The authors identified 46 distinct factors from the literature that implicitly or explicitly are suggested to contribute to successful project outcomes. Formed as postulates in this paper, these 46 factors have been separated into 5 categories to assist understanding and implementing these factors into service learning programs. Lastly, different methods of analyzing and measuring project success and impact are discussed. Future methods for proving the viability of the 46 postulates are discussed as well. Copyright © 2019 ASME.
130 a7004300863 Mattson C.A. p320 False Conference 100 Benefits of a short-term engineering study abroad: A survey of students over the past 15 years Since 2004, Brigham Young University has offered a graduate study abroad course in mechanical engineering to help prepare students to be leaders in globally-influenced product development organizations. The course is offered as a study abroad program where faculty lead a group of students across several countries to learn about global product development. This is accomplished in a 2-3 week time period consisting of visits to companies and universities as well as participation in cultural activities. While much research has been done on the benefits of study abroad, it remains unclear how effective study abroad programs are at helping engineering students, especially short-term study abroad programs. The purpose of this paper is to present and examine the benefits of a short-term, study abroad program to engineering students. Data was collected from students who have taken the Global Product Development Course over the past 15 years in a mixed methods survey. Trends show that technical and cultural visits positively effect engineering students in their perception of global product development. It is also shown that a short, 2-3 week, engineering study abroad program can be as or more effective than traditional study abroad programs in certain areas. Copyright © 2019 ASME.
130 a7004300863 Mattson C.A. p323 False Conference 103 Machine learning for evaluating the social impact of engineered products: A framework Evaluating the social impact indicators of engineered products is crucial to better understanding how products affect individuals’ lives and discover how to design for positive social impact. Most existing methods for evaluating social impact indicators require direct human interaction with users of a product, such as one-on-one interviews. These interactions produce high-fidelity data that are rich in information but provide only a single snapshot in time of the product’s impacts and are less frequently collected due to the significant human resources and cost associated with obtaining them. A framework is proposed that describes how low-fidelity data passively obtained using remote sensors, satellites, and digital technology can be collected and correlated with high-fidelity, low-frequency data using machine learning. Using this framework provides an inexpensive way to continuously monitor the social impact indicators of products by augmenting high-fidelity, low-frequency data with low-fidelity, continuously-collected data using machine learning. We illustrate an application of this framework by demonstrating how it can be used to examine the gender-related social impact indicators of water pumps in Uganda. The provided example uses a deep learning model to correlate pump handle movement (measured via an integrated motion unit) with user type (man, woman, or child) of 1,200 hand pump users. Copyright © 2019 ASME.
130 a7004300863 Mattson C.A. p325 False Conference 105 Establishing baseline performance for off-the-shelf nitrile seals for the India Mark II hand pump system Accessing clean water is a persistent, and life threatening, challenge for millions of people in the world. Mechanical hand pumps have a long history of helping people access clean ground water for drinking and daily use. Among the most ubiquitous are the India Mark II and III pump systems, for which there are more than 4,000,000 installed across the world. These are estimated to serve between 600M and 1B people. All pumps degrade in performance over time, requiring service; many do not receive it causing pumps to become dysfunctional. The purpose of this paper is to establish a baseline for nitrile seal performance of India Mark II hand pump systems. Understanding off-the-shelf performance and using it as a baseline is an important step toward understanding degradation of performance over time, which is the focus of a much larger study to understand – mechanically and socially – how hand pumps perform, degrade, and ultimately meet human needs. In this paper, 110 off-the-shelf nitrile seals that were purchased in Uganda were tested and the following was characterized: (i) geometric variation, (ii) material variation, (iii) leak performance, and (iv) correlation between these. The seal leak performance was found to be very robust to variations in geometry and material at zero cycles. This important baseline supports our future work to understand how and to what degree seals become sensitive to geometric and material degradation during use. Copyright © 2019 ASME.
130 a7004300863 Mattson C.A. p353 False Conference 124 Do capstone students really understand the needs of the customer?: Observations on students’ blind spots left by early program curriculum Student capstone teams have varying degrees of success in meeting the expectations of their project sponsors. Keeping sponsors happy is important to these programs in order to ensure continued support from these industry representatives, so finding ways to improve project outcomes is critical. In order to find blind spots that students may have been left with after their first 6-7 weeks of instruction, we conducted structured interviews with students in capstone programs at Brigham Young University and the US Air Force Academy. These interviews were then transcribed, coded, and analyzed for themes that may have been well understood or misunderstood by students. We found that a significant number of students had not understood concepts such as a design being more than a prototype, that sponsors have expectations for the tradeoffs between product cost and performance, or that they need to be thinking about how their designs might be deployed. It was also interesting to note that most students also reported feeling confident in their understanding despite their apparent lack thereof, indicating that these could represent major blind spots for students. We propose that developing methods for teaching these principles early on will help students see more clearly what their end goals need to be, and thus help them be more successful in delivering desirable designs. Copyright © 2019 ASME.
130 a7004300863 Mattson C.A. p354 False Conference 125 The technology/tactics (TEC/TAC) plot: Explicit representation of user actions in the product design space The initial phases of the design process – including interactions with stakeholders, ideation of concept candidates, and the selection of the best candidates – have a large impact on the success of a project as a whole. They also tend to be the most unstructured portion of the project, and are often marginalized by teams who assume they already understand stakeholder needs and the best solution paths to pursue. Design researchers have developed methods shown to increase the creativity and divergent thinking of the design team during these initial phases of design. Nevertheless, these methods often rely on only a vague or amorphous representation of the design space (the set of all possible concepts the design team could feasibly select to meet the objective of the project). In this paper, we introduce a particular design-space structure that can help teams ideate and evaluate their ideation, thus improving the early phases of the design process. The design space presented here is a vector space with a basis of technology (the physical product people will use) and tactics (the procedure for using the product). Also presented are definitions, principles, and sub-theories that facilitate the creation and use of technology-tactics plots to represent the design space. Considering the design space in this structured way, the design team can gain valuable insights that improve the effectiveness of the initial stages of design, and may yield additional benefits to the design process as a whole, if further developed. Copyright © 2019 ASME.
130 a7004300863 Mattson C.A. p358 True Journal 199 Using a Product's Sustainability Space as a Design Exploration Tool Sustainable design is often practiced and assessed through the consideration of three essential areas: economic sustainability, environmental sustainability, and social sustainability. For even the simplest of products, the complexities of these three areas and their tradeoffs cause decision-making transparency to be lost in most practical situations. The existing field of multiobjective optimization offers a natural framework to define and explore a given design space. In this paper, a method for defining a product's sustainability space (defined by economic, environmental, and social sustainability objectives) is outlined and used to explore the tradeoffs within the space, thus offering both the design team and the decision makers a means of better understanding the sustainability tradeoffs. This paper concludes that sustainable product development can indeed benefit from tradeoff characterization using multiobjective optimization techniques - even when using only basic models of sustainability. Interestingly, the unique characteristics of the three essential sustainable development areas lead to an alternative view of some traditional multiobjective optimization concepts, such as weak-Pareto optimality. The sustainable redesign of a machine to drill boreholes for water wells is presented as a practical example for method demonstration and discussion. Copyright © The Author(s) 2019.
130 a7004300863 Mattson C.A. p525 False Journal 274 Toward a Universal Social Impact Metric for Engineered Products That Alleviate Poverty One of the purposes of creating products for developing countries is to improve the consumer's quality of life. Currently, there is no standard method for measuring the social impact of these types of products. As a result, engineers have used their own metrics, if at all. Some of the common metrics used include products sold and revenue, which measure the financial success of a product without recognizing the social successes or failures it might have. In this paper, we introduce a potential universal metric, the product impact metric (PIM), which quantifies the impact a product has on impoverished individuals - especially those living in developing countries. It measures social impact broadly in five dimensions: health, education, standard of living, employment quality, and security. By measuring impact multidimensionally, it captures impacts both anticipated and unanticipated, thereby providing a broader assessment of the product's total impact than with other more specific metrics. The PIM is calculated based on 18 simple field measurements of the consumer. It is inspired by the UN's Multidimensional Poverty Index (UNMPI) created by the United Nations Development Programme (UNDP). The UNMPI measures how level of poverty within a nation changes year after year, and the PIM measures how an individual's poverty level changes after being affected by an engineered product. The PIM can be used to measure social impact (using specific data from products introduced into the market) or predict social impact (using personas that represent real individuals). Copyright © 2018 by ASME.
130 a7004300863 Mattson C.A. p584 False Conference 229 Social impact in product design, an exploration of current industry practices Though academic research for identifying and considering the social impact of products is emerging, the actual use of these processes in industry is undeclared in the literature. The gap between academic research and the industry adoption of these theories and methodologies can have real consequences. This paper explores current practices in industry that design engineers use to consider the social impact of products during the customer use stage. 30 people from nineteen different companies were interviewed to discover what disconnects exist between academia and industry when considering a product’s social impact. Although social impact assessments (SIA) and social life cycle assessments (SLCA) are two of the most common evaluative processes discussed in the literature, not a single company interviewed used either of these processes despite affirming that they do consider social impact in product design. Predictive processes were discussed by the respondents that tended to be developed within the company and often related to government regulations. Copyright © 2018 ASME.
130 a7004300863 Mattson C.A. p585 False Conference 230 Over-design versus redesign as a response to future requirements Though little research has been done in the field of overdesign as a product development strategy, an over-design approach can help products avoid the issue of premature obsolescence. This paper compares over-design to redesign as approaches to address the emergence of future requirements. Net present value (NPV) analyses of several real world applications are examined from the perspective of manufacturers and customers. This analysis is used to determine the conditions under which an over-design approach provides a greater benefit than a redesign approach. Over-design is found to have a higher net present value than redesign when future requirements occur soon after the initial release, discount rates are low, initial research and development cost or price is high, and when the incremental costs of the future requirements are low. Copyright © 2018 ASME.
130 a7004300863 Mattson C.A. p689 False Journal 335 Design for excess capability to handle uncertain product requirements in a developing world setting Products designed for the developing world often go unused or underused by the intended customers. One cause of this problem is uncertainty regarding the actual requirements of customers in the developing world. This can result when designers, with experience in technologically advanced countries, apply their own value structure to the products they design. Because of the designers’ lack of experience in the culture and environment of the developing world, the actual requirements are only partially known to them. This problem can be mitigated by (i) optimizing product flexibility and adaptability to react to uncertain requirements, and (ii) reducing the most critical uncertainties. The flexibility of a product to adapt to new or changing requirements has been shown to extend the service life of large complex engineered systems (e.g., aircraft carriers, aircraft, communication systems, and space craft). These systems must remain in service for extended periods of time, even though the environments and requirements may change dramatically. Applying these proven techniques to products designed for the developing world can alleviate the problem of uncertain requirements. This paper presents and demonstrates a technique aimed at improving the success of developing world engineering projects. Flexibility and adaptability minimize the impact of uncertainties, and are enabled by numerically optimized amounts of designed-in excess. A sensitivity analysis performed on the system model helps the designer prioritize the set of uncertain requirements and parameters for refinement. The technique is demonstrated in the design of a cookstove intended for use in the developing world. © 2017, Springer-Verlag London.
130 a7004300863 Mattson C.A. p743 True Journal 358 Village Drill: A Case Study in Engineering for Global Development with Five Years of Data Post Market-Introduction This paper presents a case study in engineering for global development. It introduces the Village Drill, which is an engineered product that has - 5 years after its introduction to the market - enabled hundreds of thousands of people across 15 countries and three continents to have access to clean water. The Village Drill creates a 15 cm (6 in) borehole as deep as 76 m (250 ft) to reach groundwater suitable for drinking. The case study presents facts for the actual development and sustaining and are unaltered for the purpose of publication. This approach provides the reader with a realistic view of the development time, testing conditions, fundraising, and the work needed to sustain the drill through 5 years of sales and distribution. The purpose of the case study is to provide sufficient and frank data about a real project so as to promote discussion, critique, and other evaluations that will lead to new developments that inspire and inform successful engineering for global development. As part of the case, the paper describes six fundamental items: the product, the customer, the impact, the manufacturing, the delivery, and the revenue model of the drill. Copyright © 2017 by ASME.
130 a7004300863 Mattson C.A. p818 False Conference 353 An assessment of village drill sustainability, with recommendations Sustainability is commonly broken into three categories: Economic, environmental, and social. For products, there is a need for design tools that allow decision makers to handle the tradeoffs between each of these three pillars of sustainability. This paper simultaneously assesses all three pillars of sustainability for the Village Drill, a machine used to dig water wells in rural areas around the world. Using data and methods from Mattson et al. [1, 2] relationships are developed between the drill's design parameters and key sustainability issues. These relationships are used to evaluate the sustainability of the current drill design as well as any alternatives. One million random sets of drill parameters are generated and the resulting drill alternatives are evaluated. A three-dimensional design space for the sustainability of the drill is found and recommendations are given with potential for improvements in each pillar of sustainability. © 2017 ASME.
130 a7004300863 Mattson C.A. p819 False Conference 354 A simple starting point for designing for and/or assessing the social impact of products In this paper we present a starting point for designing for and/or assessing the social impact of engineered products. The starting point is a set of tables comprising products, their general functional characteristics, and the accompanying social impacts. We have constructed these tables by first extracting a set of social impact categories from the literature, then 65 products were qualitatively reviewed to find their social impact. The resulting product impact tables can be used at either the beginning of the product development process to decide what social impact to design for and discover product functions that lead to it, or later to qualitatively assess the social impact of a product being designed and/or to assess the impact of an existing product. © 2017 ASME.
130 a7004300863 Mattson C.A. p874 False Conference 392 Towards a universal social impact metric for engineered products that alleviate poverty More than ever before, engineers are creating products for developing countries. One of the purposes of these products is to improve the consumer's quality of life. Currently, there is no established method of measuring the social impact of these types of products. As a result, engineers have used their own metrics to assess their product's impact, if at all. Some of the common metrics used include products sold and revenue, which measure the financial success of a product without recognizing the social successes or failures it might have. In this paper we introduce a potential metric, the Product Impact Metric (PIM), which quantifies the impact a product has on impoverished individuals - especially those living in developing countries. It measures social impact broadly in five dimensions: Health, education, standard of living, employment quality, and security. The PIM is inspired by the Multidimensional Poverty Index (MPI) created by the United Nations Development Programme. The MPI measures how the depth of poverty within a nation changes year after year, and the PIM measures how an individual's quality of life changes after being affected by an engineered product. The Product Impact Metric can be used to predict social impacts (using personas that represent real individuals) or measure social impacts (using specific data from products introduced into the market). © 2017 ASME.
131 a8421746800 Dahlin E.C. p29 False Journal 24 Social impact in product design, an exploration of current industry practices Though academic research for identifying and considering the social impact of products is emerging, additional insights can be gained from engineers who design products every day. This paper explores current practices in industries used by design engineers to consider the social impact of products. Forty-six individuals from 34 different companies were interviewed to discover what disconnects exist between academia and industry when considering a product's social impact. These interviews were also used to discover how social impact might be considered in a design setting moving forward. This is not a study to find “the state of the art,” but considers the average engineering professional's work to design products in various industries. Social impact assessments (SIA) and social life cycle assessments (SLCA) are two of the most common processes discussed in the literature to evaluate social impact, both generally and in products. Interestingly, these processes did not arise in any discussion in interviews, despite respondents affirming that they do consider social impact in the product design. Processes used to predict social impact, rather than simply evaluate, were discussed by the respondents. These tended to be developed within the company and often related to industry imposed government regulations. To build on this study, the findings herein should be further validated for executives, managers, and engineers. A study specific to these roles should be designed to understand the disconnect better. Additionally, processes should be developed to assist engineers in considering the social impact of their products. Work should also be done to help educate engineers and their leaders on the value of considering the social impact in product design. Copyright © 2019 by ASME
131 a8421746800 Dahlin E.C. p46 False Journal 24 Analysis of perceived social impacts of existing products designed for the developing world, with implications for new product development Engineered products often have more social impacts than are realized. A product review was conducted to bring this to light. In this paper, we show the extent to which different social impacts in 11 impact categories are co-present in 150 products and how this can help engineers and others during the product development process. Specifically, we show how social impact categories not previously considered can be identified. The product review resulted in 13,200 data points that were divided into two data sets, one with 8800 data points from which a social impact probability table was created. The remaining data points were then used to validate the table. All data points were then combined to create a final social impact probability table. This table provides insight for how various social impact categories correlate and can assist engineers in expanding their views to include additional social impact objectives and thus achieve a design with broader social impact or a design with minimized unwanted negative social impact. A simple method for predicting social impact is also created in order to assist engineers when developing products with social impacts in mind. © 2019 by ASME.
131 a8421746800 Dahlin E.C. p59 False Journal 24 A Method for Creating Product Social Impact Models of Engineered Products All products impact the lives of their users, this is called social impact. Some social impacts are commonly recognized by the engineering community, such as impacts to a user's health and safety, while other social impacts can be more difficult to recognize, such as impacts on families and gender roles. When engineers make design decisions, without considering social impacts, they can unknowingly cause negative social impacts. Even harming the user and/or society. Despite its challenges, measuring a program's or policy's social impact is a common practice in the field of social sciences. These measurements are made using social impact indicators, which are simply the things observed to verify that true progress is being made. While there are clear benefits to predicting the social impact of an engineered product, it is unclear how engineers should select indicators and build predictive social impact models that are functions of engineering parameters and decisions. This paper introduces a method for selecting social impact indicators and creating predictive social impact models that can help engineers predict and improve the social impact of their products. As a first step in the method, an engineer identifies the product's users, objectives, and requirements. Then, the social impact categories that are related to the product are determined. From each of these categories, the engineer selects several social impact indicators. Finally, models are created for each indicator to predict how a product's parameters will change these indicators. The impact categories and indicators can be translated into product requirements and performance measures that can be used in product development processes. This method is used to predict the social impact of the proposed, expanded U.S. Mexico border wall. © 2019 Copernicus GmbH. All rights reserved.
131 a8421746800 Dahlin E.C. p323 False Conference 103 Machine learning for evaluating the social impact of engineered products: A framework Evaluating the social impact indicators of engineered products is crucial to better understanding how products affect individuals’ lives and discover how to design for positive social impact. Most existing methods for evaluating social impact indicators require direct human interaction with users of a product, such as one-on-one interviews. These interactions produce high-fidelity data that are rich in information but provide only a single snapshot in time of the product’s impacts and are less frequently collected due to the significant human resources and cost associated with obtaining them. A framework is proposed that describes how low-fidelity data passively obtained using remote sensors, satellites, and digital technology can be collected and correlated with high-fidelity, low-frequency data using machine learning. Using this framework provides an inexpensive way to continuously monitor the social impact indicators of products by augmenting high-fidelity, low-frequency data with low-fidelity, continuously-collected data using machine learning. We illustrate an application of this framework by demonstrating how it can be used to examine the gender-related social impact indicators of water pumps in Uganda. The provided example uses a deep learning model to correlate pump handle movement (measured via an integrated motion unit) with user type (man, woman, or child) of 1,200 hand pump users. Copyright © 2019 ASME.
131 a8421746800 Dahlin E.C. p584 False Conference 229 Social impact in product design, an exploration of current industry practices Though academic research for identifying and considering the social impact of products is emerging, the actual use of these processes in industry is undeclared in the literature. The gap between academic research and the industry adoption of these theories and methodologies can have real consequences. This paper explores current practices in industry that design engineers use to consider the social impact of products during the customer use stage. 30 people from nineteen different companies were interviewed to discover what disconnects exist between academia and industry when considering a product’s social impact. Although social impact assessments (SIA) and social life cycle assessments (SLCA) are two of the most common evaluative processes discussed in the literature, not a single company interviewed used either of these processes despite affirming that they do consider social impact in product design. Predictive processes were discussed by the respondents that tended to be developed within the company and often related to government regulations. Copyright © 2018 ASME.
131 a8421746800 Dahlin E.C. p819 False Conference 354 A simple starting point for designing for and/or assessing the social impact of products In this paper we present a starting point for designing for and/or assessing the social impact of engineered products. The starting point is a set of tables comprising products, their general functional characteristics, and the accompanying social impacts. We have constructed these tables by first extracting a set of social impact categories from the literature, then 65 products were qualitatively reviewed to find their social impact. The resulting product impact tables can be used at either the beginning of the product development process to decide what social impact to design for and discover product functions that lead to it, or later to qualitatively assess the social impact of a product being designed and/or to assess the impact of an existing product. © 2017 ASME.
132 a57203660684 White J.H. p30 True Journal 25 An iterative pose estimation algorithm based on epipolar geometry with application to multi-target tracking This paper introduces a new algorithm for estimating the relative pose of a moving camera using consecutive frames of a video sequence. State-of-the-art algorithms for calculating the relative pose between two images use matching features to estimate the essential matrix. The essential matrix is then decomposed into the relative rotation and normalized translation between frames. To be robust to noise and feature match outliers, these methods generate a large number of essential matrix hypotheses from randomly selected minimal subsets of feature pairs, and then score these hypotheses on all feature pairs. Alternatively, the algorithm introduced in this paper calculates relative pose hypotheses by directly optimizing the rotation and normalized translation between frames, rather than calculating the essential matrix and then performing the decomposition. The resulting algorithm improves computation time by an order of magnitude. If an inertial measurement unit (IMU) is available, it is used to seed the optimizer, and in addition, we reuse the best hypothesis at each iteration to seed the optimizer thereby reducing the number of relative pose hypotheses that must be generated and scored. These advantages greatly speed up performance and enable the algorithm to run in real-time on low cost embedded hardware. We show application of our algorithm to visual multi-target tracking (MTT) in the presence of parallax and demonstrate its real-time performance on a 640 480 video sequence captured on a UAV. © 2014 Chinese Association of Automation.
132 a57203660684 White J.H. p463 True Conference 168 Extending Motion Detection to Track Stopped Objects in Visual Multi-Target Tracking Various solutions to visual multi-target tracking have been proposed, but many of them are not capable of running in real time from a moving camera on an unmanned aerial vehicle (UAV). We present a tracker that runs in real time and tracks multiple objects while accounting for camera motion on a UAV. Our algorithm is capable of processing over 10 frames per second on a 1280x720 video sequence. We utilize Recursive-RANSAC, an efficient algorithm for tracking multiple objects in clutter. Our work combines motion detection with optical flow and feature matching to allow stationary objects to be tracked. We use a feature prioritization algorithm to reduce computational complexity and spatial redundancy. We also present a ghost track reduction method which prevents tracking non-existent objects when true objects are no longer visible. We demonstrate the performance of our tracker on a moving camera video sequence. Video results are available at https://youtu.be/6bXjKb-6qY. © 2018 AACC.
133 a57218095797 Clark R. p31 True Journal 26 Tracking joint angles during whole-arm movements using electromagnetic sensors Electromagnetic (EM) motion tracking systems are suitable for many research and clinical applications, including in vivo measurements of whole-arm movements. Unfortunately, the methodology for in vivo measurements of whole-arm movements using EM sensors is not well described in the literature, making it difficult to perform new measurements and all but impossible to make meaningful comparisons between studies. The recommendations of the International Society of Biomechanics (ISB) have provided a great service, but by necessity they do not provide clear guidance or standardization on all required steps. The goal of this paper was to provide a comprehensive methodology for using EM sensors to measure whole-arm movements in vivo. We selected methodological details from past studies that were compatible with the ISB recommendations and suitable for measuring whole-arm movements using EM sensors, filling in gaps with recommendations from our own past experiments. The presented methodology includes recommendations for defining coordinate systems (CSs) and joint angles, placing sensors, performing sensor-to-body calibration, calculating rotation matrices from sensor data, and extracting unique joint angles from rotation matrices. We present this process, including all equations, for both the right and left upper limbs, models with nine or seven degrees-of-freedom (DOF), and two different calibration methods. Providing a detailed methodology for the entire process in one location promotes replicability of studies by allowing researchers to clearly define their experimental methods. It is hoped that this paper will simplify new investigations of whole-arm movement using EM sensors and facilitate comparison between studies. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.
134 a57218102993 Dickinson T. p31 False Journal 26 Tracking joint angles during whole-arm movements using electromagnetic sensors Electromagnetic (EM) motion tracking systems are suitable for many research and clinical applications, including in vivo measurements of whole-arm movements. Unfortunately, the methodology for in vivo measurements of whole-arm movements using EM sensors is not well described in the literature, making it difficult to perform new measurements and all but impossible to make meaningful comparisons between studies. The recommendations of the International Society of Biomechanics (ISB) have provided a great service, but by necessity they do not provide clear guidance or standardization on all required steps. The goal of this paper was to provide a comprehensive methodology for using EM sensors to measure whole-arm movements in vivo. We selected methodological details from past studies that were compatible with the ISB recommendations and suitable for measuring whole-arm movements using EM sensors, filling in gaps with recommendations from our own past experiments. The presented methodology includes recommendations for defining coordinate systems (CSs) and joint angles, placing sensors, performing sensor-to-body calibration, calculating rotation matrices from sensor data, and extracting unique joint angles from rotation matrices. We present this process, including all equations, for both the right and left upper limbs, models with nine or seven degrees-of-freedom (DOF), and two different calibration methods. Providing a detailed methodology for the entire process in one location promotes replicability of studies by allowing researchers to clearly define their experimental methods. It is hoped that this paper will simplify new investigations of whole-arm movement using EM sensors and facilitate comparison between studies. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.
135 a57218105310 Loaiza J. p31 False Journal 26 Tracking joint angles during whole-arm movements using electromagnetic sensors Electromagnetic (EM) motion tracking systems are suitable for many research and clinical applications, including in vivo measurements of whole-arm movements. Unfortunately, the methodology for in vivo measurements of whole-arm movements using EM sensors is not well described in the literature, making it difficult to perform new measurements and all but impossible to make meaningful comparisons between studies. The recommendations of the International Society of Biomechanics (ISB) have provided a great service, but by necessity they do not provide clear guidance or standardization on all required steps. The goal of this paper was to provide a comprehensive methodology for using EM sensors to measure whole-arm movements in vivo. We selected methodological details from past studies that were compatible with the ISB recommendations and suitable for measuring whole-arm movements using EM sensors, filling in gaps with recommendations from our own past experiments. The presented methodology includes recommendations for defining coordinate systems (CSs) and joint angles, placing sensors, performing sensor-to-body calibration, calculating rotation matrices from sensor data, and extracting unique joint angles from rotation matrices. We present this process, including all equations, for both the right and left upper limbs, models with nine or seven degrees-of-freedom (DOF), and two different calibration methods. Providing a detailed methodology for the entire process in one location promotes replicability of studies by allowing researchers to clearly define their experimental methods. It is hoped that this paper will simplify new investigations of whole-arm movement using EM sensors and facilitate comparison between studies. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.
136 a57197795830 Geiger D.W. p31 False Journal 26 Tracking joint angles during whole-arm movements using electromagnetic sensors Electromagnetic (EM) motion tracking systems are suitable for many research and clinical applications, including in vivo measurements of whole-arm movements. Unfortunately, the methodology for in vivo measurements of whole-arm movements using EM sensors is not well described in the literature, making it difficult to perform new measurements and all but impossible to make meaningful comparisons between studies. The recommendations of the International Society of Biomechanics (ISB) have provided a great service, but by necessity they do not provide clear guidance or standardization on all required steps. The goal of this paper was to provide a comprehensive methodology for using EM sensors to measure whole-arm movements in vivo. We selected methodological details from past studies that were compatible with the ISB recommendations and suitable for measuring whole-arm movements using EM sensors, filling in gaps with recommendations from our own past experiments. The presented methodology includes recommendations for defining coordinate systems (CSs) and joint angles, placing sensors, performing sensor-to-body calibration, calculating rotation matrices from sensor data, and extracting unique joint angles from rotation matrices. We present this process, including all equations, for both the right and left upper limbs, models with nine or seven degrees-of-freedom (DOF), and two different calibration methods. Providing a detailed methodology for the entire process in one location promotes replicability of studies by allowing researchers to clearly define their experimental methods. It is hoped that this paper will simplify new investigations of whole-arm movement using EM sensors and facilitate comparison between studies. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.
136 a57197795830 Geiger D.W. p707 False Conference 299 Toward quantitative characterization of essential tremor for future tremor suppression Tremor is the most common movement deficit and manifests in a variety of disorders, including Essential Tremor, Parkinson's Disease, Dystonia, and Cerebellar Ataxia. Although medication and surgical interventions have significantly reduced patient suffering, they are only partially effective and can carry undesired side effects, leaving many patients without satisfactory treatment options. Wearable tremor-suppressing devices could provide an alternative to medication and surgery. Multiple research groups have developed orthotic prototypes to low-pass filter tremor, but these devices have not yet been optimized for in-vivo use. Optimizing non-invasive tremor suppression requires an understanding of where the tremor originates mechanically (which muscles) and how it propagates to the hand (where it matters most). Here we present on the beginnings of our multi-pronged work to determine the origin, propagation, and distribution of Essential Tremor, and we provide preliminary results. © 2017 IEEE.
137 a14033673100 Charles S.K. p31 False Journal 26 Tracking joint angles during whole-arm movements using electromagnetic sensors Electromagnetic (EM) motion tracking systems are suitable for many research and clinical applications, including in vivo measurements of whole-arm movements. Unfortunately, the methodology for in vivo measurements of whole-arm movements using EM sensors is not well described in the literature, making it difficult to perform new measurements and all but impossible to make meaningful comparisons between studies. The recommendations of the International Society of Biomechanics (ISB) have provided a great service, but by necessity they do not provide clear guidance or standardization on all required steps. The goal of this paper was to provide a comprehensive methodology for using EM sensors to measure whole-arm movements in vivo. We selected methodological details from past studies that were compatible with the ISB recommendations and suitable for measuring whole-arm movements using EM sensors, filling in gaps with recommendations from our own past experiments. The presented methodology includes recommendations for defining coordinate systems (CSs) and joint angles, placing sensors, performing sensor-to-body calibration, calculating rotation matrices from sensor data, and extracting unique joint angles from rotation matrices. We present this process, including all equations, for both the right and left upper limbs, models with nine or seven degrees-of-freedom (DOF), and two different calibration methods. Providing a detailed methodology for the entire process in one location promotes replicability of studies by allowing researchers to clearly define their experimental methods. It is hoped that this paper will simplify new investigations of whole-arm movement using EM sensors and facilitate comparison between studies. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.
137 a14033673100 Charles S.K. p183 False Journal 125 Simulated Tremor Propagation in the Upper Limb: From Muscle Activity to Joint Displacement Although tremor is the most common movement disorder, there are few noninvasive treatment options. Creating effective tremor suppression devices requires a knowledge of where tremor originates mechanically (which muscles) and how it propagates through the limb (to which degrees-of-freedom (DOF)). To simulate tremor propagation, we created a simple model of the upper limb, with tremorogenic activity in the 15 major superficial muscles as inputs and tremulous joint displacement in the seven major DOF as outputs. The model approximated the muscle excitation-contraction dynamics, musculoskeletal geometry, and mechanical impedance of the limb. From our simulations, we determined fundamental principles for tremor propagation: (1) The distribution of tremor depends strongly on musculoskeletal dynamics. (2) The spreading of tremor is due to inertial coupling (primarily) and musculoskeletal geometry (secondarily). (3) Tremorogenic activity in a given muscle causes significant tremor in only a small subset of DOF, though these affected DOF may be distant from the muscle. (4) Assuming uniform distribution of tremorogenic activity among muscles, tremor increases proximal-distally, and the contribution from muscles increases proximal-distally. (5) Although adding inertia (e.g., with weighted utensils) is often used to suppress tremor, it is possible to increase tremor by adding inertia to the wrong DOF. (6) Similarly, adding viscoelasticity to the wrong DOF can increase tremor. Based solely on the musculoskeletal system, these principles indicate that tremor treatments targeting muscles should focus first on the distal muscles, and devices targeting DOF should focus first on the distal DOF. © 2019 by ASME.
137 a14033673100 Charles S.K. p212 False Journal 144 EFFECT OF GYROSCOPE PARAMETERS ON GYROSCOPIC TREMOR SUPPRESSION IN A SINGLE DEGREE OF FREEDOM Although tremor is one of the most common movement disorders, there are few effective tremor-suppressing options available to patients. Gyrostabilization is a potential option, but we do not currently know how to optimize gyrostabilization for tremor suppression. To address this gap, we present a systematic investigation of how gyrostabilizer parameters affect tremor suppression in a single degree of freedom (DOF). A simple model with a single DOF at the wrist and a gyroscope mounted on the back of the hand was used to focus on the most basic effects. We simulated the frequency response of the system (hand + gyroscope) to a tremorogenic input torque at the wrist. Varying system parameters one at a time, we determined the effect of individual parameters on the system's frequency response. To minimize the bandwidth without adding significant inertia, the inertia and spin speed of the flywheel should be as high as design constraints allow, whereas the distance from the wrist joint axis to the gyroscope and the precession stiffness and damping should be kept as low as possible. The results demonstrate the potential of gyroscopic tremor suppression and can serve as foundation for further investigations of gyroscopic tremor suppression in the upper limb. © 2019 World Scientific Publishing Company.
137 a14033673100 Charles S.K. p307 False Journal 188 Frequency response of the leap motion controller and its suitability for measuring tremor Although tremor is one of the most common movement disorders, it is evaluated using relatively coarse clinical scales. We propose to measure tremor in clinical settings using the Leap Motion Controller (LMC), which is a markerless motion capture sensor that has a low cost, zero set-up time, and dynamic accuracy of 1.2 mm. However, the frequency response of the LMC has not been characterized, so its ability to track oscillations such as tremor is unknown. To characterize the frequency response of the LMC, we measured the position of a mannequin hand simultaneously with the LMC and a high-resolution encoder while the mannequin hand oscillated at various combinations of frequency (1–15 Hz) and amplitudes (0.01–30 mm). We calculated the magnitude ratio and phase shift of the LMC and found the bandwidth of the LMC to range from 0–3 Hz to 0–5 Hz for tremor amplitudes greater than the dynamic accuracy. This bandwidth is too small to accurately measure most tremors. However, we developed an inverse filter to estimate the actual tremor amplitude and phase despite the limited bandwidth. Over the combinations of frequency and amplitude mentioned above, the inverse filter estimated the actual tremor amplitude and phase with errors of 3% and 2%, respectively. © 2018
137 a14033673100 Charles S.K. p707 True Conference 299 Toward quantitative characterization of essential tremor for future tremor suppression Tremor is the most common movement deficit and manifests in a variety of disorders, including Essential Tremor, Parkinson's Disease, Dystonia, and Cerebellar Ataxia. Although medication and surgical interventions have significantly reduced patient suffering, they are only partially effective and can carry undesired side effects, leaving many patients without satisfactory treatment options. Wearable tremor-suppressing devices could provide an alternative to medication and surgery. Multiple research groups have developed orthotic prototypes to low-pass filter tremor, but these devices have not yet been optimized for in-vivo use. Optimizing non-invasive tremor suppression requires an understanding of where the tremor originates mechanically (which muscles) and how it propagates to the hand (where it matters most). Here we present on the beginnings of our multi-pronged work to determine the origin, propagation, and distribution of Essential Tremor, and we provide preliminary results. © 2017 IEEE.
137 a14033673100 Charles S.K. p761 False Journal 320 Fundamental Principles of Tremor Propagation in the Upper Limb Although tremor is the most common movement disorder, there exist few effective tremor-suppressing devices, in part because the characteristics of tremor throughout the upper limb are unknown. To clarify, optimally suppressing tremor requires a knowledge of the mechanical origin, propagation, and distribution of tremor throughout the upper limb. Here we present the first systematic investigation of how tremor propagates between the shoulder, elbow, forearm, and wrist. We simulated tremor propagation using a linear, time-invariant, lumped-parameter model relating joint torques and the resulting joint displacements. The model focused on the seven main degrees of freedom from the shoulder to the wrist and included coupled joint inertia, damping, and stiffness. We deliberately implemented a simple model to focus first on the most basic effects. Simulating tremorogenic joint torque as a sinusoidal input, we used the model to establish fundamental principles describing how input parameters (torque location and frequency) and joint impedance (inertia, damping, and stiffness) affect tremor propagation. We expect that the methods and principles presented here will serve as the groundwork for future refining studies to understand the origin, propagation, and distribution of tremor throughout the upper limb in order to enable the future development of optimal tremor-suppressing devices. © 2016, Biomedical Engineering Society.
138 a57205285411 Rose M.T. p32 True Journal 27 Case study: Noise reduction of a vacuum-assisted toilet Flushing a vacuum-assisted toilet generates noise levels that can be disturbing both to users and those nearby. Peak radiated noise levels correlate with the time when the valve opens and closes, while the noise levels when the valve is completely open are also relatively high. Significant noise ranges between 300 Hz and 3000 Hz. It was hypothesized that increasing the in-tube distance between the flush valve and the bowl in addition to increasing the bend radius of the tube would reduce radiated noise levels. These modifications resulted in a reduction of about 14 dB in the radiated noise during the valve opening and closing in addition to a reduction of about 5 dB while the valve is completely opened. Intermediate results of varying the tube length and bend radius are presented to show their effects on the radiated sound levels. Two tube inserts were designed to fit (1) underneath and (2) behind the toilet in a compact manner. They were tested to show that they maintain noise control performance without modifying any other part of the toilet. © 2020 Institute of Noise Control Engineering. © 2020 Institute of Noise Control Engineering. All rights reserved.
139 a57205288709 Pielstick B.D. p32 False Journal 27 Case study: Noise reduction of a vacuum-assisted toilet Flushing a vacuum-assisted toilet generates noise levels that can be disturbing both to users and those nearby. Peak radiated noise levels correlate with the time when the valve opens and closes, while the noise levels when the valve is completely open are also relatively high. Significant noise ranges between 300 Hz and 3000 Hz. It was hypothesized that increasing the in-tube distance between the flush valve and the bowl in addition to increasing the bend radius of the tube would reduce radiated noise levels. These modifications resulted in a reduction of about 14 dB in the radiated noise during the valve opening and closing in addition to a reduction of about 5 dB while the valve is completely opened. Intermediate results of varying the tube length and bend radius are presented to show their effects on the radiated sound levels. Two tube inserts were designed to fit (1) underneath and (2) behind the toilet in a compact manner. They were tested to show that they maintain noise control performance without modifying any other part of the toilet. © 2020 Institute of Noise Control Engineering. © 2020 Institute of Noise Control Engineering. All rights reserved.
140 a57205293533 Jones Z.T. p32 False Journal 27 Case study: Noise reduction of a vacuum-assisted toilet Flushing a vacuum-assisted toilet generates noise levels that can be disturbing both to users and those nearby. Peak radiated noise levels correlate with the time when the valve opens and closes, while the noise levels when the valve is completely open are also relatively high. Significant noise ranges between 300 Hz and 3000 Hz. It was hypothesized that increasing the in-tube distance between the flush valve and the bowl in addition to increasing the bend radius of the tube would reduce radiated noise levels. These modifications resulted in a reduction of about 14 dB in the radiated noise during the valve opening and closing in addition to a reduction of about 5 dB while the valve is completely opened. Intermediate results of varying the tube length and bend radius are presented to show their effects on the radiated sound levels. Two tube inserts were designed to fit (1) underneath and (2) behind the toilet in a compact manner. They were tested to show that they maintain noise control performance without modifying any other part of the toilet. © 2020 Institute of Noise Control Engineering. © 2020 Institute of Noise Control Engineering. All rights reserved.
141 a6701746882 Sommerfeldt S.D. p32 False Journal 27 Case study: Noise reduction of a vacuum-assisted toilet Flushing a vacuum-assisted toilet generates noise levels that can be disturbing both to users and those nearby. Peak radiated noise levels correlate with the time when the valve opens and closes, while the noise levels when the valve is completely open are also relatively high. Significant noise ranges between 300 Hz and 3000 Hz. It was hypothesized that increasing the in-tube distance between the flush valve and the bowl in addition to increasing the bend radius of the tube would reduce radiated noise levels. These modifications resulted in a reduction of about 14 dB in the radiated noise during the valve opening and closing in addition to a reduction of about 5 dB while the valve is completely opened. Intermediate results of varying the tube length and bend radius are presented to show their effects on the radiated sound levels. Two tube inserts were designed to fit (1) underneath and (2) behind the toilet in a compact manner. They were tested to show that they maintain noise control performance without modifying any other part of the toilet. © 2020 Institute of Noise Control Engineering. © 2020 Institute of Noise Control Engineering. All rights reserved.
141 a6701746882 Sommerfeldt S.D. p138 False Journal 97 Modeling acoustic resonators using higher-order equivalent circuits Helmholtz resonators are widely used, but classical models for the resonators, such as the lumped-element equivalent circuit, are inaccurate for most geometries. This article presents higher-order equivalent circuits for describing the resonators based on the one-dimensional wave equation. Impedance expressions are also derived. These circuits and expressions are given for various constituent resonator components, which may be combined to model resonators with curved, tapered, and straight necks. Resonance frequency predictions using this theory are demonstrated on two realistic resonators. The higher-order predictions are also applied to the theory of side branch attenuators in a duct and the theory of resonator coupling with a mode of an enclosure. © 2019 Institute of Noise Control Engineering.
141 a6701746882 Sommerfeldt S.D. p673 False Journal 325 Analysis of the external radiation from circular cylindrical shells Structurally radiated sound power is a critical design parameter. The acoustic radiation mode approach for computing sound power was developed in the early 1990s and has since been widely used. It has been shown to be a rather efficient approach for determining the radiated sound power. In previous research, radiation mode expressions have been developed for planar and spherical structures, as well as axisymmetric modes of internal and external radiation from cylinders. In this work, the radiation modes for external radiating cylinders which account for both axial and circumferential dependence are presented. The expressions are uniquely developed using cylindrical basis functions which are a more natural match to the geometry than past developments, which have been based on spherical harmonics. Higher order radiation modes than have been previously presented are shown. The “leapfrog effect”, whereby higher order modes leapfrog over lower modes in terms of their radiation efficiencies as the frequency goes above the cut-on frequency for those modes, is discussed in detail. The relationships between the mode efficiency and the coincidence effect associated with the cut-on frequencies of the vibration modes are described. © 2017 Elsevier Ltd
142 a10141271600 Gee K.L. p32 False Journal 27 Case study: Noise reduction of a vacuum-assisted toilet Flushing a vacuum-assisted toilet generates noise levels that can be disturbing both to users and those nearby. Peak radiated noise levels correlate with the time when the valve opens and closes, while the noise levels when the valve is completely open are also relatively high. Significant noise ranges between 300 Hz and 3000 Hz. It was hypothesized that increasing the in-tube distance between the flush valve and the bowl in addition to increasing the bend radius of the tube would reduce radiated noise levels. These modifications resulted in a reduction of about 14 dB in the radiated noise during the valve opening and closing in addition to a reduction of about 5 dB while the valve is completely opened. Intermediate results of varying the tube length and bend radius are presented to show their effects on the radiated sound levels. Two tube inserts were designed to fit (1) underneath and (2) behind the toilet in a compact manner. They were tested to show that they maintain noise control performance without modifying any other part of the toilet. © 2020 Institute of Noise Control Engineering. © 2020 Institute of Noise Control Engineering. All rights reserved.
142 a10141271600 Gee K.L. p117 False Journal 78 Coherence analysis of the noise from a simulated highly heated laboratory-scale jet Measurements of full-scale high-performance military aircraft reveal phenomena that are not widely seen at laboratory scales. However, recent modifications to large eddy-simulation (LES) methods allow for simulations of jets operating at a high-temperature ratio in a similar regime as military aircraft operating at afterburner. This work applies coherence analyses that have been previously used to study the jet noise field produced by military aircraft to the LES of a highly heated laboratory-scale jet. The coherence of the complex pressures along a near-field line approximately parallel to the shear layer as well as along the nozzle lip line shows evidence of distinct noise production mechanisms that transfer information differently from the flow to the field. A phenomenological comparison between the LES and measurements of an afterburning F-35 aircraft is then made. Although the LES is not run at the exact same conditions as the aircraft and does not reproduce all of the phenomena present in the aircraft’s jet noise field, differences between noise production mechanisms observed in the LES may describe some of the spatiospectral lobe phenomena observed in the measurements of the F-35. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
142 a10141271600 Gee K.L. p370 False Conference 132 Three-way spectral decompositions of high-performance military aircraft noise High-performance military aircraft noise contains large- and fine-scale turbulent mixing noise and broadband shock-associated noise. A three-way spectral decomposition quantifies the contribution from each noise type in the sound of a tied-down F-35B aircraft on a linear ground-based array spanning 35–152 deg. This large spatial aperture allows for detailed investigation into the spatial variation in broadband shock-associated noise and fine- and large-scale turbulent mixing noise. The spectral models used in the decomposition capture the main features of the measured spectra with three exceptions: 1) that the F-35B engine noise contains multiple spectral peaks in the maximum radiation region, 2) that the nonlinear propagation increases the high-frequency spectral levels, and 3) that the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The F-35B broadband shock-associated noise has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. However, the peak level and width exhibit different trends than laboratory-scale broadband shock-associated noise and those recently reported for the F/A-18E aircraft. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
142 a10141271600 Gee K.L. p373 False Conference 134 Crackle-related beamforming of military jet aircraft noise Crackle is a perceptual feature of supersonic jet noise that is related to the presence of acoustic shocks. This study investigates the apparent source locations of events related to crackle for a high-performance military jet aircraft using an event-based, time-domain beamforming method. This method utilizes the cross correlation between adjacent microphones to determine the angle of propagation of an ensemble of shock-related events within the time waveform. This angle of propagation is then traced back towards the source to find the apparent source location. Based on the angle of propagation, derivative skewness, and overall sound pressure level, the microphone pairs along the array can be sorted into six groups. With increasing engine condition, groups related to the presence of crackle tend to shift downstream and broaden, in qualitative agreement with the general aeroacoustic source locations. However, a comparison with near-field acoustical holography shows that the apparent source region of crackle-related events appears upstream of the overall energy at intermediate power but appear to converge at maximum afterburner. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
142 a10141271600 Gee K.L. p374 False Conference 135 Coherence analysis of the noise from a simulated highly-heated laboratory-scale jet Large-eddy simulations (LES) have been shown to reproduce the flow and acoustic fields of laboratory-scale jets with increasing accuracy. However, measurements of full-scale, high-performance military aircraft reveal phenomena that are not widely seen at laboratory scales. Recent modifications to LES methods allow for simulations of jets operating at a high temperature ratio, in a similar regime as military aircraft operating at afterburner. This work applies coherence analyses that have been previously used to study the jet noise field produced by military aircraft to the LES of a highly-heated, laboratory-scale jet. The coherence of the complex pressures along a near-field line approximately parallel to the shear layer shows evidence of four distinct field regions. The coherence between this line and complex pressures along the simulated jet lipline provide source regions in the jet plume corresponding to each field region. Differences in how information is transferred from the flow to the field suggests that the source regions represent different noise production mechanisms. The field regions compare favorably to some spatiospectral lobe features observed in measurements of an F-35B aircraft operating at afterburner, though do not reproduce all of the phenomena present in the aircraft’s jet noise field. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
142 a10141271600 Gee K.L. p623 False Conference 259 Spatiotemporal correlation analysis of jet noise from a round-nozzle supersonic aircraft Spatiotemporal analysis of noise from a tethered F-35B provides insight into the spatial, spectral and temporal relationships within the sound field. Six engine power conditions ranging from 25% to 150% engine thrust request were measured using a 71-microphone linear ground array located approximately 8 m from the estimated shear layer. Mixing noise trends with engine power for the round-nozzle F-35B are similar to those of a nominally rectangular-nozzle high-performance jet aircraft [Harker et al, AIAA, 2016]. Cross-correlation and coherence measures are used to corroborate and confirm identifications of fine- and large-scale turbulent mixing noise contributions from a concurrent study of the F-35B dataset [Neilsen et al., AIAA, 2018]. The relationships observed between multiple spatiospectral lobes seen in the maximum radiation regions of prior and concurrent high-performance aircraft noise studies [Leete et al., AIAA, 2018] are confirmed and expanded upon. Correlograms help identify how the multiple spatiospectral lobes have different apparent phase speeds across the array, corresponding to different directionality, some components of which also change with engine power. Increased overlap of lobes with increased engine power appears to drive global decreases in field coherence. Finally, the structure of the spatiospectral lobes appears to be more visible in nondimensionalized coherence length than in the spectrum itself. Broadband shock-associated noise (BBSAN) is found in the upstream direction at engine powers of 75% engine thrust request and above. Coherence is also used to separate BBSAN from jet mixing noise because the BBSAN is coherent within the relevant frequency range while adjacent fine-scale mixing noise is not. However, correlation and coherence analyses show that the upstream BBSAN signature is related to sound received in the peak radiation region dominated by the spatiospectral lobes. Possible links between the shock-associated noise and the spatiospectral lobes are discussed. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
142 a10141271600 Gee K.L. p624 False Conference 260 Dependence of high-performance military aircraft noise on frequency and engine power To further understand the unique characteristics of military aircraft noise, the sound field in the vicinity of a tied-down F-35B was measured for various engine powers, from 25% to 150% Engine Thrust Request (ETR). Synchronous measurements along a linear ground array approximately parallel to the shear layer were used to image the entire field through multisource statistically optimized near-field acoustical holography (M-SONAH). The field in the direction of maximum radiation consists of multiple lobes in the spatiospectral domain, which are manifest as multiple local maxima in space for a fixed frequency or multiple peaks in the spectra at a fixed location. Multiple lobes are observed at non-afterburning and afterburning engine conditions. As frequency increases for a given engine power, lobes appear towards the sideline and shift aft until they disappear beyond the measurement aperture and new lobe(s) take their place. As engine power is increased at a fixed frequency, the forwardmost lobe increases in its relative contribution to the field, which is a major contributing factor to the forward shift in overall directivity with increasing engine power. Field reconstructions and data in the forward direction outside of the region of maximum radiation show the presence of broadband shock-associated noise (BBSAN) for 75% ETR and above. Reconstructions along the nozzle lipline of the jet indicate the BBSAN originates from approximately the same region as the sources for the main radiation direction. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
142 a10141271600 Gee K.L. p625 False Conference 261 Inclusion of broadband shock-associated noise in spectral decomposition of noise from highperformance military aircraft Attempts to reduce the noise from high-performance military aircraft requires an understanding of the different jet noise generation mechanisms. The primary noise sources originate from interactions between turbulent mixing noise associated with large and finescale turbulent structures and the ambient air. A nonideally expanded jet also contains broadband shock-associated noise. A three-way decomposition of the spectral density measured near a tied-down F-35B quantifies the contribution from each type of noise. The decomposition is performed on noise from a ground-based, linear array of microphones, approximately 8 m from the estimated shear layer, which spanned an angular aperture of 35° to 152° (relative to engine inlet). This large spatial aperture allows for a detailed investigation into the spatial variation in broadband shock-associated noise and fine and large-scale turbulent mixing noise. The spectral decompositions match the measured spectral levels with three main exceptions: 1) the F-35B noise contains multiple spectral peaks in the maximum radiation region, 2) nonlinear propagation increases the high-frequency spectral levels, and 3) the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The main peak of the F-35B broadband shock-associated noise, evident from 35°-70°, has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. The F-35B broadband shockassociated noise peak level and width exhibit different trends than laboratory-scale BBSAN and those recently reported for the F/A-18E [Tam et al., Journal of Sound and Vibration, Vol. 422, 2018, pp. 92-111]. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation from high-performance military aircraft. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
142 a10141271600 Gee K.L. p626 False Conference 262 Comparison of noise from high-performance military aircraft for ground run-up and flyover operations While the majority of jet noise analysis takes place with a static jet or aircraft, airbase and community military jet noise exposure happens for the most part when the aircraft is in flight. Comparisons between flyover and ground run-up measurements for high-performance military aircraft have not been previously published. This paper presents comparisons between static ground run-up and flyover measurements for the F-35 operating at 150% Engine Thrust Request. The overall sound pressure levels and spectra are shown for the two scenarios, as well as indicators of nonlinear propagation and shock content, specifically the derivative skewness and average steepening factor. The overall sound pressure level is reduced in the peak radiation direction aft of the aircraft but increased in the forward direction. The peak frequency of the noise is relatively unaffected by flight effects, though the amplitude of each frequency may vary. The increase in level in the forward direction results in shock formation that is absent during ground run-up measurements. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
142 a10141271600 Gee K.L. p640 False Journal 312 Effect of nozzle–plate distance on acoustic phenomena from supersonic impinging jet For an adequate understanding of the broadband acoustic phenomena generated by a rocket exhaust jet impinging on a flame deflector, this study experimentally clarifies the factors that cause the difference in the broadband acoustic field of a supersonic ideally expanded jet impinging on an inclined flat plate for various nozzle–plate distances. According to previous studies, there are two possible factors: the Mach waves, which are radiated from the free-jet region and reflected by the plate, and the acoustic waves generated in the impingement region. To distinguish the effects of these factors, this study compares the following three results: the overall sound pressure level distribution, images extracted from the schlieren visualization movies using acoustic-triggered conditional sampling, and tracing lines of the acoustic intensity vectors of the Mach waves. The results reveal that the nozzle–plate distance affects the fraction of the Mach waves that are generated in the free-jet region and reflected by the plate, resulting in a higher overall sound pressure level in the upstream direction for larger nozzle–plate distances. It is concluded that the location of the plate relative to the source region of the Mach waves significantly affects the acoustic phenomena, owing to the variation in the nozzle–plate distances. Copyright © 2018 by Masahito Akamine, Koji Okamoto, Kent L. Gee, Tracianne B. Neilsen, Susumu Teramoto, Takeo Okunuki, and Seiji Tsutsumi.
142 a10141271600 Gee K.L. p861 False Conference 382 Acoustic shock formation in noise propagation during ground run-up operations of military aircraft A distinctive feature of many propagating, high-amplitude jet noise waveforms is the presence of acoustic shocks. Metrics indicative of shock presence, specifically the skewness of the time derivative of the waveform, the average steepening factor, and a new wavelet-based metric called the shock energy fraction (SEF), are used to quantify the strength and prevalence of acoustic shocks within waveforms recorded 10-305 m from a tethered military aircraft. The derivative skewness is more sensitive to the presence of the largest and steepest shocks, while the ASF and SEF tend to emphasize aggregate behavior of the entire waveform. These metrics are applied at engine conditions ranging from 50% to 150% engine thrust request, over a wide range of angles and distances, to assess the growth and decay of shock waves. The responses of these metrics point to significant shock formation occurring through nonlinear propagation out to 76 m from the microphone array reference position. Although these strongest shocks decay, the metrics point to continued nonlinear propagation in the far-field, out to 305 m. Many of these features are accurately characterized using a nonlinear propagation scheme based on the Burgers equation, but this scheme fails to account for multipath interference and significant atmospheric effects over the long propagation distances, resulting in an overestimation of nonlinearity metrics. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
142 a10141271600 Gee K.L. p862 False Conference 383 Level-educed wavepacket representation of Mach 1.8 laboratory-scale jet noise The search for an equivalent acoustic source model for high-speed jet noise has recently focused on wavepacket representations. A wavepacket is defined as a spatially extended source with an axial amplitude distribution that grows, saturates and decays, an axial phase relationship that produces directional noise, and correlation lengths longer than the integral length scales of the turbulent structures. This definition of a wavepacket has the same characteristics as the large-scale turbulent mixing noise; if the turbulent mixing noise can be isolated, the associate equivalent acoustic wavepacket—defined as a pressure fluctuation on a cylinder around the jet nozzle—can be found. An estimate of the frequencydependent, spatial variation in the large-scale turbulent mixing noise comes from a similarity spectra decomposition of the measured autospectral density, which in turn leads to data-educed wavenumber axial spectra associated with the frequency-dependent equivalent wavepackets. This wavepacket eduction technique has been applied to acoustical measurements of an unheated, Mach 1.8 jet in the near and far fields. At both locations, the resulting frequency-dependent, data-educed wavenumber spectra exhibit different types of self-similarity for low and high frequency regimes that become apparent when the axial wavenumber is scaled by the acoustic wavenumber, with a transition band between the two regimes. As expected, the data-educed wavenumber spectra can be used to predict field levels in the dominant radiation lobe. Addition of an uncorrelated source distribution, derived from the similarity spectra decomposition associated with the fine-scale turbulent mixing noise, creates a model that accounts for the sideline levels. This field-prediction ability of the wavepacket-plus-uncorrelated-distribution model is tested using the near and far field measurements. When predicting the field at the other location, the model’s average error is less than 2 dB for St = 0.04-0.25 but increases for larger St because the apparent directivity changes from near to far field, likely due to the frequency dependence of the extended source region. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
142 a10141271600 Gee K.L. p863 False Conference 384 Beamforming-based wavepacket model for noise environment predictions of tactical aircraft Jet noise consists of extended, partially correlated sources such that a single-wavepacket source representation is inadequate. A multiple-wavepacket (MWP) model provides an analytical framework for jet-noise-like radiation to simulate jet noise field levels as well as the corresponding spatial coherence properties within the field. Here, a beamforming method with regularization is applied to noise measured by a linear array near a high-performance military aircraft. Beamforming results are decomposed into a reduced-order MWP model and the predicted radiation is validated in terms of level and coherence properties using benchmark measurements. Sound levels and coherence lengths generated by the beamforming results show good agreement with benchmark measurements over a range of frequencies that contribute significantly to the overall radiation. The MWP model is shown to predict full-scale specific features such as multilobe directivity patterns, and the addition of an uncorrelated distribution (UD) model adequately predicts the sideline radiation that is otherwise difficult to reproduce from wavepacket radiation. The MWP model predicted radiation characteristics are an improvement over single-wavepacket models, which do not incorporate spatiotemporal features of the radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
142 a10141271600 Gee K.L. p864 True Conference 385 Characterization of supersonic laboratory-scale jet noise with vector acoustic intensity A new method for the calculation of vector acoustic intensity from pressure microphone measurements has been applied to the aeroacoustic source characterization of an unheated, Mach 1.8 laboratory-scale jet. Because of the ability to unwrap the phase of the transfer functions between microphone pairs in the measurement of a radiating, broadband source, physically meaningful near-field intensity vectors are calculated up to the maximum analysis frequency of 32 kHz. The new intensity method is used to obtain a detailed description of the sound energy flow near the jet. The resulting intensity vectors have been used with a ray-tracing technique to identify the dominant source region over a broad range of frequencies. Additional aeroacoustics analyses provide insight into the frequency-dependent characteristics of jet noise radiation, including the nature of the hydrodynamic field and the transition between the principal lobe and sideline radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
142 a10141271600 Gee K.L. p865 False Conference 386 Preliminary investigation of multilobe fighter jet noise sources using acoustical holography An understanding of jet noise source mechanisms can facilitate targeted noise reduction efforts. This understanding has been enhanced with acoustic imaging technologies, such as near-field acoustical holography (NAH). In this study, multisource statistically optimized NAH (M-SONAH) was used to image the sound field near a tethered F-35 aircraft at multiple frequencies. A linear microphone array, placed along the ground, spanned the length of the jet exhaust plume. A multisource model of the sound field was included in the algorithm to incorporate the effects of the ground reflection on the measurement. Narrowband reconstructions elucidated fine details of the radiation patterns, such as multilobe radiation patterns (which may supersede “dual-lobe” patterns shown in previous studies), and broadband shock-associated noise. [Work supported by F-35 JPO.] © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
143 a7202277096 Thomson S.L. p32 False Journal 27 Case study: Noise reduction of a vacuum-assisted toilet Flushing a vacuum-assisted toilet generates noise levels that can be disturbing both to users and those nearby. Peak radiated noise levels correlate with the time when the valve opens and closes, while the noise levels when the valve is completely open are also relatively high. Significant noise ranges between 300 Hz and 3000 Hz. It was hypothesized that increasing the in-tube distance between the flush valve and the bowl in addition to increasing the bend radius of the tube would reduce radiated noise levels. These modifications resulted in a reduction of about 14 dB in the radiated noise during the valve opening and closing in addition to a reduction of about 5 dB while the valve is completely opened. Intermediate results of varying the tube length and bend radius are presented to show their effects on the radiated sound levels. Two tube inserts were designed to fit (1) underneath and (2) behind the toilet in a compact manner. They were tested to show that they maintain noise control performance without modifying any other part of the toilet. © 2020 Institute of Noise Control Engineering. © 2020 Institute of Noise Control Engineering. All rights reserved.
144 a6701720294 Magleby S.P. p33 False Journal 28 Developable mechanisms on right conical surfaces An approach for designing developable mechanisms on a conical surface is presented. By aligning the joint axes of spherical mechanisms to the ruling lines, the links can be created in a way that the mechanism conforms to a conical surface. Terminology is defined for mechanisms mapped onto a right cone. Models are developed to describe the motion of the mechanism with respect to the apex of the cone, and connections are made to cylindrical developable mechanisms using projected angles. The Loop Sum Method is presented as an approach to determine the geometry of the cone to which a given spherical mechanism can be mapped. A method for position analysis is presented to determine the location of any point along the link of a mechanism with respect to the conical geometry. These methods are also applied to multiloop spherical mechanisms. © 2020 Elsevier Ltd
144 a6701720294 Magleby S.P. p94 False Journal 72 Using Cyclic Quadrilaterals to Design Cylindrical Developable Mechanisms Developable mechanisms on regular cylindrical surfaces can be described using cyclic quadrilaterals. Mechanisms can exist in either an open or crossed configuration, and these configurations correspond to convex and crossed cyclic quadrilaterals. Using equations developed for both convex and crossed cyclic quadrilaterals, the geometry of the reference surface to which a four-bar mechanism can be mapped is found. Grashof mechanisms can be mapped to two surfaces in open or crossed configurations. The only way to map a non-Grashof mechanism to a cylindrical surface is in its open configuration. Extramobile and intramobile behavior can be achieved depending on selected pairs within a cyclic quadrilateral and its position within the circumcircle. Selecting different sets of links as the ground link changes the potential behavior of the mechanism. Different cases are tabulated to represent all possibilities. A non-Grashof developable mechanism can only exhibit extramobile or intramobile behavior if all of the joints lie on one half of the circumcircle. © 2020, Springer Nature Switzerland AG.
144 a6701720294 Magleby S.P. p104 False Conference 17 Design and analysis of self-deployable, self-stiffening, and retractable arrays Self-deployable, self-stiffening, and retractable (SDSR) arrays were introduced by the authors as a novel architecture of deployable space structures which leverages array surface topology, as opposed to dedicated structures, to achieve desirable deployed structural performance. The application of the technology to solar electric propulsion is discussed. The effects of array shape are discussed, concluding that circular arrays are more structurally efficient than several smaller rectangular arrays, especially for large scales. A system architecture is proposed that considers circular origami-based flasher SDSR arrays integrated with a spacecraft: stowage restraints during launch, deployment, and repeatable retraction. This paper studies the design and analysis of such arrays for scalability, including the performance metrics of specific power, power density, stiffness, and strength. Key advantages of the architecture are the trends of performance metrics which indicate increased performance with increased array power. The limiting constraint is found to be the stowed height dimension and another candidate folding pattern is discussed that eliminates the height constraint violation. Strengths and weaknesses of the architecture are discussed. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
144 a6701720294 Magleby S.P. p106 False Journal 78 Self-deployable, self-stiffening, and retractable origami-based arrays for spacecraft Spacecraft with large arrays sometimes have deployed sizes that are much larger than the launch volumes; in this case, deployable arrays are used. Several methods exist for stowing, deploying, and stiffening large space arrays. Often these functions are performed by separate systems. This work presents a novel array system that integrates these functions into one system, without the need for external deployment or stiffening structures. The integration comes from the combination of the kinematics of origami-based folding approaches, stored strain energy of compliant hinges, and tension cables. Additionally, due to the origami-based folding approach used, tunable deployed shapes and retraction are possible using reeled cables. The result is a new array architecture that is self-deployable, self-stiffening, and retractable (SDSR) and is described in this work. To understand the behavior of such systems, this work presents the modeling and testing of an SDSR array using an origami flasher pattern and discusses the results for the performance considerations of deployment motion, deployment stiffness, and dynamics. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
144 a6701720294 Magleby S.P. p115 False Journal 83 On the modeling of a contact-aided cross-axis flexural pivot This paper reports the study of a planar Cross-Axis Flexural Pivot (CAFP) comprising an additional contact pair. The proposed device may be useful for applications requiring a revolute joint that behaves differently when deflecting clockwise/anti-clockwise. The presence of the contact pair reduces the free length of one flexures, resulting in a considerable increment of the overall joint stiffness. The pivot behaviour is investigated, for different load cases, via the Chained-Beam-Constraint Model (CBCM), namely an accurate method to be applied in large deflection problems. A framework comprising Matlab and ANSYS is developed for testing the CAFP performances in terms of rotational stiffness, parasitic shift and maximum stress, with different combinations of geometrical aspect ratios and contact extensions. Results achieved via CBCM for a pure rotation applied to the CAFP's output link are then verified through Finite Element Analysis. The resulting performance maps show good agreement between the numerical results. Furthermore, the CBCM shows an improved computational efficiency, which is a crucial aspect for preliminary design steps. At last, direct comparison between simulations and experiments, developed by means of two custom test rigs, confirms the efficacy of the proposed design method for the modeling of contacts in large deflection problems. © 2019
144 a6701720294 Magleby S.P. p136 False Journal 95 Developable mechanisms on regular cylindrical surfaces Developable mechanisms can provide high functionality and compact stowability. This paper presents engineering models to aid in the design of cylindrical developable mechanisms. These models take into account the added spatial restrictions imposed by the developable surface. Equations are provided for the kinematic analysis of cylindrical developable mechanisms. A new classification for developable mechanisms is also presented (intramobile, extramobile, and transmobile) and two graphical methods are provided for determining this classification for single-DOF planar cylindrical developable mechanisms. Characteristics specific to four-bar cylindrical developable mechanisms are also discussed. © 2019 Elsevier Ltd
144 a6701720294 Magleby S.P. p153 False Journal 108 Heat set creases in polyethylene terephthalate (PET) sheets to enable origami-based applications Polyethylene terephthalate (PET) sheets show promise for application in origami-based engineering design. Origami-based engineering provides advantages that are not readily available in traditional engineering design methods. Several processing methods were examined to identify trends and determine the effect of processing of PET sheets on the crease properties of origami mechanisms in PET. Various annealing times, temperatures, and cooling rates were evaluated and data collected for over 1000 samples. It was determined that annealing temperature plays the largest role in crease response. An increase in the crystallinity of a PET sheet while in the folded state likely increases the force response of the crease in PET sheets. An annealing time of at least 60 min at 160 C-180 C with a quick cooling results in a high force response in the crease. The effectiveness of the processing methods was demonstrated in several origami patterns of various complexities. © 2019 IOP Publishing Ltd.
144 a6701720294 Magleby S.P. p246 False Journal 161 Origami-Based Design of Conceal-and-Reveal Systems This work introduces a type of motion termed "conceal-and-reveal" which is characterized by a state that protects a payload, a state that exposes the payload, and coupled motions between these two states. As techniques for thick, rigid origami-based engineering designs are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design similar thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns can be used to initiate viable approaches to achieving conceal-and-reveal motion. © 2019 by ASME.
144 a6701720294 Magleby S.P. p283 False Journal 185 Origami fold states: Concept and design tool The ability of origami to alter its properties and behaviors with its shape makes it an elegant source of inspiration for many engineering designs challenges. Fold states specify the shape of the origami - its facets, creases, and fold angles. Origami research recognizes several acknowledged fold states: The unfolded, fully folded, and flat-folded states. However, these fold states are not comprehensive, excluding some of the most predominant fold states in origami-based devices. In this paper we propose a comprehensive list of fold states based on fold angles. We support the method of categorizing fold states by evaluating the functions and fold states of a large sample of origami-based devices. These correlations provide insight for selecting fold states for origami-based design. We discuss properties and behaviors of the fold states individually and provide a process for fold-state selection. © Author(s) 2019.
144 a6701720294 Magleby S.P. p314 False Conference 94 Characteristics of self-deployment in origami-based systems The potential of compliant mechanisms and related origami-based mechanical systems to store strain energy make them ideal candidates for applications requiring an actuation or deployment process, such as space system arrays, minimally invasive surgical devices and deployable barriers. Many origami structures can be thought of as a compliant mechanism because, like compliant mechanisms, its function is performed through the elastic deformation of its members. This stored strain energy could prove useful. There are opportunities using strain energy to develop approaches to deploy particular mechanical systems. In order to better understand the principles of self-actuation and promote the designs of such systems, a taxonomy of deployable origami mechanisms is presented. This taxonomy demonstrates that there are several different types of deployable origami mechanisms and provides an organizational method to better understand the design space. Characteristics of self deployment in concentrated, deployable origami strain energy mechanisms with internal actuation are identified and examples of strain energy based deployment are provided. Copyright © 2019 ASME.
144 a6701720294 Magleby S.P. p315 False Conference 95 Deployable euler spiral connectors (DESCs) Deployable Euler Spiral Connectors (DESCs) are introduced as a way to use compliant flexures that lay flat when under strain in a stowed position. This paper presents the design of DESCs using the Euler spiral equations. An application of a spinal device is presented as a proof-of-concept of the use of DESCs. Copyright © 2019 ASME.
144 a6701720294 Magleby S.P. p316 False Conference 96 Cylindrical developable mechanisms for minimally invasive surgical instruments Developable mechanisms conform to and emerge from developable, or specially curved, surfaces. The cylindrical developable mechanism can have applications in many industries due to the popularity of cylindrical or tube-based devices. Laparoscopic surgical devices in particular are widely composed of instruments attached at the proximal end of a cylindrical shaft. In this paper, properties of cylindrical developable mechanisms are discussed, including their behaviors, characteristics, and potential functions. One method for designing cylindrical developable mechanisms is discussed. Two example developable surgical devices that exemplify these behaviors, characteristics, and functions, along with the kinematic mechanisms comprising them, are discussed in detail. Copyright © 2019 ASME.
144 a6701720294 Magleby S.P. p318 False Conference 98 Conceptualizing stable states in origami-based devices using an energy visualization approach In many origami-based applications a device needs to be maintained in one or more fold states. The origami stability integration method (OSIM) presented in this paper provides an approach for graphically combining various techniques to achieve stability. Techniques are divided into four groups based on whether they are intrinsic or extrinsic to the origami pattern and whether they exhibit differentiable or non-differentiable energy storage behaviors. These categorizations can help designers select appropriate techniques for their application. The paper also contains design considerations and resources for several intrinsic techniques. Finally, two case studies are presented which use the OSIM and the technique guidelines to conceptualize stability in origami-based devices. Copyright © 2019 ASME.
144 a6701720294 Magleby S.P. p319 False Conference 99 Thick folding through regionally-sandwiched compliant sheets The regional-sandwiching of compliant sheets (ReCS) technique presented in this work creates flat-foldable, rigid-foldable, and self-deploying thick origami-based mechanisms. Regional-sandwiching of the compliant sheet is used to create mountain/valley assignments for each fold about a vertex, constraining motion to a single branch of folding. Strain energy in deflected flexible members is used to enable self-deployment. This work presents the methods to design origami-based mechanisms using the ReCS technique, including volume trimming at the vertex of the compliant sheet and of the panels used in the sandwich. Physical models of a simple single fold mechanism and a degree-four vertex mechanism are presented to demonstrate the ReCS technique using acrylic panels and spring steel. Consideration is given to the risk of yielding of the compliant sheet due to parasitic motion with possible mitigation of yielding by decreasing the thickness of the sheet. Copyright © 2019 ASME.
144 a6701720294 Magleby S.P. p320 False Conference 100 Benefits of a short-term engineering study abroad: A survey of students over the past 15 years Since 2004, Brigham Young University has offered a graduate study abroad course in mechanical engineering to help prepare students to be leaders in globally-influenced product development organizations. The course is offered as a study abroad program where faculty lead a group of students across several countries to learn about global product development. This is accomplished in a 2-3 week time period consisting of visits to companies and universities as well as participation in cultural activities. While much research has been done on the benefits of study abroad, it remains unclear how effective study abroad programs are at helping engineering students, especially short-term study abroad programs. The purpose of this paper is to present and examine the benefits of a short-term, study abroad program to engineering students. Data was collected from students who have taken the Global Product Development Course over the past 15 years in a mixed methods survey. Trends show that technical and cultural visits positively effect engineering students in their perception of global product development. It is also shown that a short, 2-3 week, engineering study abroad program can be as or more effective than traditional study abroad programs in certain areas. Copyright © 2019 ASME.
144 a6701720294 Magleby S.P. p321 False Conference 101 Kirigami-based deployable transcrease hard stop models usable in origami patterns Stopping origami in arbitrary fold states can present a challenge for origami-based design. In this paper two categories of kirigami-based models are presented for stopping the fold motion of individual creases using deployable hard stops. These models are transcrease (across a crease) and deploy from a flat sheet. The first category is planar and has behavior similar to a four-bar linkage. The second category is spherical and behaves like a degree-4 origami vertex. These models are based on the zero-thickness assumption of paper and can be applied to origami patterns made from thin materials, limiting the motion of the base origami pattern through self-interference within the original facets. Model parameters are based on a desired fold or dihedral angle, as well as facet dimensions. Examples show model benefits and limitations. Copyright © 2019 ASME.
144 a6701720294 Magleby S.P. p367 False Conference 129 Self-deployable, self-stiffening, and retractable origami-based arrays for spacecraft Large deployable arrays are needed for spacecraft that require small stowed volumes. Several methods exist for stowing, deploying, and stiffening large space arrays. Often these functions are performed by separate systems. This paper presents a novel array system that integrates these functions into one system, without the need for external deployment or stiffening structures. The integration comes from the combination of the kinematics of origami-based folding approaches, stored strain energy of compliant hinges, and tension cables. Additionally, due to the origami-based folding approach used, tunable deployed shapes and retraction are possible using reeled cables. The result is a new class of arrays that are self-deployable, self-stiffening, and retractable (SDSR), which are described in this work. To understand the behavior of such systems, this paper presents the modeling and testing of an SDSR array using an origami flasher pattern and discusses the results for the performance metrics of stiffness and shape. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
144 a6701720294 Magleby S.P. p381 False Conference 139 Rigidly foldable thick origami using designed-offset linkages We present new families of thick origami mechanisms that achieve rigid foldability and parallel stacking of panels in the flat-folded state using linkages for some or all of the hinges between panels. A degree-four vertex results in a multi-loop eight-bar spatial mechanism that can be analyzed as separate linkages. The individual linkages are designed so that they introduce offsets perpendicular to the panels that are mutually compatible around each vertex. This family of mechanisms offers the unique combination of a planar unfolded state, parallel-stacked panels in the flat folded state, and kinematic single-degree-of-freedom motion from the flat-unfolded to the flat-folded state. Copyright © 2019 ASME.
144 a6701720294 Magleby S.P. p383 False Journal 209 Developable mechanisms on developable surfaces The trend toward smaller mechanism footprints and volumes, while maintaining the ability to perform complex tasks, presents the opportunity for exploration of hypercompact mechanical systems integrated with curved surfaces. Developable surfaces are shapes that a flat sheet can take without tearing or stretching, and they represent a wide range of manufactured surfaces. This work introduces “developable mechanisms” as devices that emerge from or conform to developable surfaces. They are made possible by aligning hinge axes with developable surface ruling lines to enable mobility. Because rigid-link motion depends on the relative orientation of hinge axes and not link geometry, links can take the shape of the corresponding developable surface. Mechanisms are classified by their associated surface type, and these relationships are defined and demonstrated by example. Developable mechanisms show promise for meeting unfilled needs using systems not previously envisioned. © 2019 The Authors, some rights reserved.
144 a6701720294 Magleby S.P. p412 False Journal 222 A model for multi-input mechanical advantage in origami-based mechanisms Mechanical advantage is traditionally defined for single-input and single-output rigidbody mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origamibased mechanisms are capable of offering unique solutions to engineering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi-input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. © 2018 by ASME.
144 a6701720294 Magleby S.P. p454 False Conference 160 Zipper Tube Reinforcement to Mitigate Flexible Shaft Buckling The Zipper Tube Reinforcement (ZTR) is a novel support system developed to mitigate buckling in thin flexible devices used in robotic surgery. The ZTR was inspired by a construction technique called a Buckling Restrained Braced Frame (BRBF) and deployable booms for space applications. It utilizes a zipper function to allow a rolled sheet to deploy into a variable-length tube and stow in a small volume spooled on a mandrel. The tube envelops the device and allows it to support a much higher compressive load before buckling failure through the insertion stroke. The ZTR also enables the possibility of smaller, more flexible devices due to its design for continuous support and could find application in other fields. © 2018 IEEE.
144 a6701720294 Magleby S.P. p455 False Conference 161 Modified Material Properties in Curved Panels Through Lamina Emergent Torsional Joints Compliant joints have a number of advantages that make them suitable for highly constrained design problems. While much work has been done on the design of compliant joints manufactured from planar sheet materials, this work focuses on the design of cylindrically-curved joints. A method for using lamina emergent torsional (LET) joints to increase energy storage efficiency in curved sheet materials is presented. A numerical model is provided for predicting the stiffness and maximum applied moment of a curved LET joint. Predicted curved LET joint stiffnesses and maximum moments are utilized to create shape factors that produce an effective modulus of elasticity and an effective modulus of resilience. For a given case, the effective modulus of elasticity is shown to decrease by about three orders of magnitude while the effective resilience decreases by approximately one order of magnitude. Designers can use this information to tailor materials to fit design requirements or to select alternative materials that were previously unsuited for an application. © 2018 IEEE.
144 a6701720294 Magleby S.P. p456 False Conference 162 An Origami-based Thickness-Accommodating Bistable Mechanism in Monolithic Thick-sheet Materials Origami-based mechanisms can provide useful capabilities in folding large structures to stow in small volumes. However, when using monolithic thick-sheet materials for these types of mechanisms, accommodating the thickness proves challenging. One approach to solve this is to create compliant mechanisms along the fold lines that inherently store energy when actuated and causes the mechanism to tend toward its low energy state. This tendency can be used to create bistable states. We outline a method to use this stored energy to achieve bistable states and name the resulting mechanism an origami-based "Thickness-accommodating bistable interior vertex" (TABIV) in monolithic thick-sheet materials. The kinematics and energy-displacement relationships of this mechanism are derived. Prototypes are shown to exhibit the predicted bistable behavior and the mechanism is integrated and prototyped into origami-based mechanisms demonstrating advantageous multi-stable behaviors. © 2018 IEEE.
144 a6701720294 Magleby S.P. p457 False Conference 163 Implementation of Rolling Contacts for SORCE Joints The Synchronized-offset-rolling-contact element (SORCE) technique for thickness accommodation in origami-inspired mechanisms combines selected strengths of several thickness-accomadation techniques but with the tradeoff of manufacturing complexity of rolling joints. This work presents principles to facilitate the construction of rolling joints suitable for applications like the SORCE technique. These include leveraging fold-angle multipliers of origami vertices, variations of flexure assembly, sunken flexures, and form-closed rolling joints. Prototypes of origami-mechanisms using the SORCE technique are constructed demonstrating these principles. © 2018 IEEE.
144 a6701720294 Magleby S.P. p484 False Conference 176 Outreach potential of displaying research artifacts in art museums This paper explores how displaying engineering research artifacts in art museums can facilitate expanded outreach opportunities. A combination of visual art and innovative engineering offers an unusual opportunity to engage a wide spectrum of society. To evaluate the potential, faculty and students collaborated with the Brigham Young University Museum of Art to create a museum exhibition that connected the art of origami to engineering, math, science, and product design. A framework is introduced that includes the creation of a museum exhibition; and once the initial investment is made to create the central exhibition, the results are efficiently used to extend outreach efforts through first-generation products (coincident with the exhibition) and then through second-generation products (after the exhibition). The paper describes a detailed example of this framework and provides evidence to support the concept that displaying research artifacts in an art museum can expand research opportunities. Products from the exhibition that provided expanded outreach opportunities include the following: an exhibit catalog originally created for the gift shop that was expanded for publication with a national publisher; a tablet/smart phone app that includes origami instructions followed by related engineering activities, which has had broad use beyond the museum activity room; a video that was prepared for museum patrons but has since been made available to larger audiences; materials created for hands-on museum activities that were used for outreach activities after the exhibition; and leverage for industry visits that led to additional applications and research projects. This paper describes the museum exhibition, the first- and second-generation products, the impact of each product, and the benefits and pitfalls of using a museum exhibition to extend outreach impact. © American Society for Engineering Education, 2018.
144 a6701720294 Magleby S.P. p503 False Journal 274 Membrane-Enhanced Lamina Emergent Torsional Joints for Surrogate Folds Lamina emergent compliant mechanisms (including origami-adapted compliant mechanisms) are mechanical devices that can be fabricated from a planar material (a lamina) and have motion that emerges out of the fabrication plane. Lamina emergent compliant mechanisms often exhibit undesirable parasitic motions due to the planar fabrication constraint. This work introduces a type of lamina emergent torsion (LET) joint that reduces parasitic motions of lamina emergent mechanisms, and presents equations for modeling parasitic motion of LET joints. The membrane joint also makes possible one-way joints that can ensure origami-based mechanisms emerge from their flat state (a change point) into the desired configuration. Membrane-enhanced LET (M-LET) joints, including one-way surrogate folds, are described here and show promise for use in a wide range of compliant mechanisms and origami-based compliant mechanisms. They are demonstrated as individual joints and in mechanisms such as a kaleidocycle (a 6R Bricard linkage), degree-4 origami vertices (spherical mechanisms), and waterbomb base mechanisms (an 8R multi-degrees-of-freedom origami-based mechanism). © 2018 by ASME.
144 a6701720294 Magleby S.P. p581 False Conference 226 Origami-based design of conceal-and-reveal systems This work introduces a type of motion termed “conceal-and-reveal” which is characterized by a state that protects a payload, a state that exposes the payload, and continuous motion between these two states. As techniques for thick, rigid origami-based engineering design are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design other thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns represent viable approaches to achieving conceal-and-reveal motion. Copyright © 2018 ASME
144 a6701720294 Magleby S.P. p582 False Conference 227 Automating the design of thick-origami mechanisms Applying an origami pattern to thick, non-paper-like materials is a challenging task. Though many techniques have been developed to accommodate thickness in origami, creating 3D models of such thick-origami mechanisms is complex. The time and knowledge required to manually model an origami mechanism can impede the exploration of the design space and creation of robust designs. This work presents data structures based on origami that can be used in the automation of thick-origami mechanism design. These structures are described and an example computer program that implements them is investigated. The program automatically generates all the necessary 3D CAD part models and an assembly model for a user-specified origami crease pattern. Models resulting from the program for several crease patterns are demonstrated with a discussion of the advantages and limitations of the system. With further development of the data structures and program, this framework has the potential to help mitigate some of the barriers to more widespread use of origami-based design. Copyright © 2018 ASME
144 a6701720294 Magleby S.P. p583 False Conference 228 Retractable anti-buckling support systems for flexible medical devices This work presents two novel support systems used to help mitigate flexible device buckling during insertion such as the insertion of medical device into the body. These systems are collapsible to accommodate the changing length of the flexible device as it is inserted. They use tension in wires or geometry to provide systems with lateral stiffness used to support the device. Through modeling, the performance of these systems can be predicted and they can be designed to a desired performance. This was validated in the geometry-based support system. They provide systems with small operating volumes and part counts. Copyright © 2018 ASME.
144 a6701720294 Magleby S.P. p598 False Journal 306 A Review of Thickness-Accommodation Techniques in Origami-Inspired Engineering Origami has served as the inspiration for a number of engineered systems. In most cases, they require nonpaper materials where material thickness is non-negligible. Foldable mechanisms based on origami-like forms present special challenges for preserving kinematics and assuring non-self-intersection when the thickness of the panels must be accommodated. Several design approaches for constructing thick origami mechanisms by beginning with a zero-thickness origami pattern and transforming it into a rigidly foldable mechanism with thick panels are reviewed. The review includes existing approaches and introduces new hybrid approaches. The approaches are compared and contrasted and their manufacturability analyzed. © 2018 by ASME.
144 a6701720294 Magleby S.P. p599 False Journal 306 Closure to "discussion of 'a review of thickness-accommodation techniques in origami-inspired engineering'" (Lang, R. J., Tolman, K. A., Crampton, E. B., Magleby, S. P., and Howell, L. L., 2018, ASME Appl. Mech. Rev., 70(1), p. 010805) [No abstract available]
144 a6701720294 Magleby S.P. p600 False Journal 307 Cylindrical cross-axis flexural pivots The cylindrical cross-axis flexural pivot (CCAFP) is proposed as an ultra-compact flexure capable of being integrated into hollow cylindrical shafts, enabling shaft motion without inhibiting cables or other components inside the shaft. Mechanism geometry, materials, and manufacturing are proposed and the results analyzed and tested. A parametric finite element model of the CCAFP was created to analyze the force-deflection and strain-deflection relationships and the predicted behavior was verified by experiment. Analytic models of stress-limiting cam-surfaces suggest even larger motions may be possible when not limited by current practical constraints. The CCAFP is demonstrated and tested at multiple size scales and in multiple materials, ranging from 28.6 mm diameter 4130 steel (achieving 9 degrees of angular deflection) to 3 mm diameter NiTi (achieving an angular deflection of 85 degrees). The results are generalized to apply to a range of applications, and the CCAFP particularly shows promise for implementation in minimally invasive surgical instruments to decrease instrument size while maintaining instrument performance. © 2017 Elsevier Inc.
144 a6701720294 Magleby S.P. p699 False Journal 342 Inverted L-arm gripper compliant mechanism This work exploits the advantages of compliant mechanisms (devices that achieve their motion through the deflection of flexible members) to enable the creation of small instruments for minimally invasive surgery (MIS). Using flexures to achieve motion presents challenges, three of which are considered in this work. First, compliant mechanisms generally perform inadequately in compression. Second, for a 690 deg range of motion desired for each jaw, the bending stresses in the flexures are prohibitive considering materials used in current instruments. Third, for cables attached at fixed points on the mechanism, the mechanical advantage will vary considerably during actuation. Research results are presented that address these challenges using compliant mechanism principles as demonstrated in a two-degree-of-freedom (2DoF) L-Arm gripper. © 2017 by ASME.
144 a6701720294 Magleby S.P. p762 False Journal 371 Thick rigidly foldable origami mechanisms based on synchronized offset rolling contact elements We present a general technique for achieving kinematic single degree of freedom (1DOF) origami-based mechanisms with thick rigid panels using synchronized offset rolling contact elements (SORCEs). We present general design analysis for planar and 3D relative motions between panels and show physically realized examples. The technique overcomes many of the limitations of previous approaches for thick rigidly foldable mechanisms. © 2017 by ASME.
144 a6701720294 Magleby S.P. p815 False Conference 350 Realizing origami mechanisms from metal sheets Consideration of a product's manufacturability is a vital aspect of product design. When considering manufacturability of panels for origami-adapted products, there are tradeoffs between panel design approaches as well as thicknessaccommodation techniques. The use of bent sheet metal for panels shows promise as a panel design approach that mitigates several of these trade-offs. This paper describes a process that can be employed to use sheet metal in designs of origami-adapted mechanisms that utilize specific thickness-accommodation techniques. The process is demonstrated for a square-twist mechanism designed using the hinge shift technique for accommodating thickness in origami patterns. A Miura-ori mechanism is also shown in sheet metal. The characteristics of these bent panel approaches are discussed and compared to other approaches for designing panels for manufacturing. The use of bent sheet metal panels allows for mitigation of several trade-offs and shows the applicability of origami-adapted design to sheet metal. Copyright © 2017 ASME.
144 a6701720294 Magleby S.P. p816 False Conference 351 Designing for power transfer across fold-lines in mechanisms with origami-like movement using surrogate folds As mechanisms with origami-like movement increase in popularity, there is a need for conducting electrical power across folds. This need could potentially be filled by the use of surrogate folds. Surrogate folds are a localized reduction in stiffness in a given direction allowing the material to function like a fold. Current methods for conducting across folds are reviewed along with current opportunities. A framework for designing conductive surrogate folds that can be adapted to fit specific applications is presented. Equations for calculating the resistance in single surrogate folds as well as arrays are given. Prototypes of several conductive joints are presented and discussed. The framework is then followed in the designing and manufacturing of a conductive origami-inspired mechanism. Copyright © 2017 ASME.
144 a6701720294 Magleby S.P. p852 False Conference 376 Elastic energy absorption of origami-based corrugations The mechanical properties of origami tessellations may provide innovative new designs for energy absorbing applications. The elastic energy absorbing properties of a particular tesselation, the Miura-ori, is investigated. Analytical models for the kinematics and force-deflection of a unit cell based on two different modes of elastic energy absorption are derived. The force-deflection model is developed based on the application of compliant mechanism theory and virtual work analysis. The models are verified through comparison with published results for similar models, analysis using commercial kinematics software and comparison to physical testing. Physical prototypes are used to determine values stiffness terms. The analytical models are used to explore the effects of the key geometrical parameters of the tessellation. This work lays a foundation for the use of origami-based corrugations in elastic energy absorption applications. Copyright © 2017 ASME.
144 a6701720294 Magleby S.P. p853 False Conference 377 A framework for energy-based kinetostatic modeling of compliant mechanisms Although energy-based methods have advantages over the Newtonian methods for kinetostatic modeling, the geometric nonlinearities inherent in deflections of compliant mechanisms preclude most of the energy-based theorems. Castigliano's first theorem and the Crotti-Engesser theorem, which don't require the problem being solved to be linear, are selected to construct the energy-based kinetostatic modeling framework for compliant mechanisms in this work. Utilization of these two theorems requires explicitly formulating the strain energy in terms of deflections and the complementary strain energy in terms of loads, which are derived based on the beam constraint model. The kinetostatic modeling of two compliant mechanisms are provided to demonstrate the effectiveness of using Castigliano's first theorem and the Crotti-Engesser theorem with the explicit formulations in this framework. Future work will be focused on incorporating use of the principle of minimum strain energy and the principle of minimum complementary strain energy. Copyright © 2017 ASME.
144 a6701720294 Magleby S.P. p854 False Conference 378 Kinematics and discretization of curved-fold mechanisms We present several new properties of curved-fold mechanisms, those with smoothly curved surfaces joined by sharp curved folds. After describing curved folds and various relationships among their geometric properties, we show that there is an important class, uniform folds, that is particularly well suited to low-degree-of-freedom mechanisms. There is a natural discretization algorithm for uniform curved folds; we present this algorithm and show discretized example mechanisms. Copyright © 2017 ASME.
144 a6701720294 Magleby S.P. p855 False Conference 379 Split-vertex technique for thickness-accommodation in origami-based mechanisms A novel thickness-accommodation technique for origami based mechanisms is introduced. This technique modifies a zerothickness pattern by splitting each vertex along the minor folds into a system of two vertices. The modified fold pattern then has thickness applied to it and the resulting mechanism is kinematically equivalent to the modified fold pattern. Origami patterns that are rigid-foldable and only have two panels that stack between folds are utilized in the technique. The technique produces thick origami mechanisms where all panels lie in a plane in the unfolded state without any holes or protrusions and maintain a single degree of freedom. Steps for synthesizing split-vertex mechanisms are presented and examples of split-vertex mechanisms are shown. Advantages and potential applications of the technique are discussed. Copyright © 2017 ASME.
144 a6701720294 Magleby S.P. p881 False Conference 396 Highly compressible origami bellows for microgravity drilling-debris containment The design and testing of an origami-based bellows for microgravity drilling is described. The potential benefits of an origami-based solution created an opportunity for application on NASA’s Asteroid Redirect Mission (ARM) to protect sensitive parts from debris. Origami-based bellows were designed to fit spatial limitations and meet needed compression ratios. Designs have demonstrated high mass reductions, improved stroke length, greatly decreased stowed volume, improved flexibility, and reduced reaction forces in comparison with traditional metal bellows. A nylon-reinforced polyvinyl fluoride based bellows with an aramid fiber stitched seam is well suited for debris containment in space conditions. Various epoxies maintained an adequate bond with polyvinyl fluoride below expected environmental temperature for bellows mounting. Asymmetric compression of the bellows occurs at extreme low temperatures and is preventable by balancing stiffness within the structure. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
145 a57211516485 Howell L.L. p33 False Journal 28 Developable mechanisms on right conical surfaces An approach for designing developable mechanisms on a conical surface is presented. By aligning the joint axes of spherical mechanisms to the ruling lines, the links can be created in a way that the mechanism conforms to a conical surface. Terminology is defined for mechanisms mapped onto a right cone. Models are developed to describe the motion of the mechanism with respect to the apex of the cone, and connections are made to cylindrical developable mechanisms using projected angles. The Loop Sum Method is presented as an approach to determine the geometry of the cone to which a given spherical mechanism can be mapped. A method for position analysis is presented to determine the location of any point along the link of a mechanism with respect to the conical geometry. These methods are also applied to multiloop spherical mechanisms. © 2020 Elsevier Ltd
145 a57211516485 Howell L.L. p75 False Journal 55 A CPRBM-based method for large-deflection analysis of contact-aided compliant mechanisms considering beam-to-beam contacts Contact-aided compliant mechanisms (CCMs) utilize contact to achieve enhanced functionality. The contact phenomenon of CCMs increases the difficulties of their analysis and design, especially when they exhibit beam-to-beam contact. Considering the particularity of CCMs analysis, which is more about the mechanisms’ deformation, this paper presents a numerical method to analyze the large deflection and stress of the CCMs considering beam-to-beam contacts. Based on our previous work on beam-to-rigid contact, the large deformation of general beams in CCMs is modeled by using the chained pseudo-rigid-body model (CPRBM). An approximation based on the geometric information of CPRBM is proposed in this paper to rapidly determine the moving boundary curve for beam-to-beam contact constraints. The static equilibrium configuration of CCMs is solved by minimizing its potential energy function under the geometric constraints from the boundary curves of contacts. A formulation is also provided to evaluate the normal stress along the deformed beam based on the deformation of CPRBM's torsional springs. Numerical examples and finite element analysis are used to verify the feasibility and accuracy of the proposed method. © 2019 Elsevier Ltd
145 a57211516485 Howell L.L. p94 False Journal 72 Using Cyclic Quadrilaterals to Design Cylindrical Developable Mechanisms Developable mechanisms on regular cylindrical surfaces can be described using cyclic quadrilaterals. Mechanisms can exist in either an open or crossed configuration, and these configurations correspond to convex and crossed cyclic quadrilaterals. Using equations developed for both convex and crossed cyclic quadrilaterals, the geometry of the reference surface to which a four-bar mechanism can be mapped is found. Grashof mechanisms can be mapped to two surfaces in open or crossed configurations. The only way to map a non-Grashof mechanism to a cylindrical surface is in its open configuration. Extramobile and intramobile behavior can be achieved depending on selected pairs within a cyclic quadrilateral and its position within the circumcircle. Selecting different sets of links as the ground link changes the potential behavior of the mechanism. Different cases are tabulated to represent all possibilities. A non-Grashof developable mechanism can only exhibit extramobile or intramobile behavior if all of the joints lie on one half of the circumcircle. © 2020, Springer Nature Switzerland AG.
145 a57211516485 Howell L.L. p105 False Journal 72 Unpacking the Mathematics of Modeling Origami Folding Transformations with Quaternions This paper seeks to bring mathematical clarity to the modelling of rigid motion origami involving quaternions and dual quaternions. We illustrate with an analysis of a single vertex Muria-ori pattern utilizing quaternions and an analysis of a multi-vertex Muria-ori pattern utilizing dual quaternions. We construct a complete lists of formulas that determine the edge vectors, normal vectors and fold angles throughout the folding transformations. In addition we provide explicit functional representations of the resulting folding transformations. © 2020, Springer Nature Switzerland AG.
145 a57211516485 Howell L.L. p115 False Journal 83 On the modeling of a contact-aided cross-axis flexural pivot This paper reports the study of a planar Cross-Axis Flexural Pivot (CAFP) comprising an additional contact pair. The proposed device may be useful for applications requiring a revolute joint that behaves differently when deflecting clockwise/anti-clockwise. The presence of the contact pair reduces the free length of one flexures, resulting in a considerable increment of the overall joint stiffness. The pivot behaviour is investigated, for different load cases, via the Chained-Beam-Constraint Model (CBCM), namely an accurate method to be applied in large deflection problems. A framework comprising Matlab and ANSYS is developed for testing the CAFP performances in terms of rotational stiffness, parasitic shift and maximum stress, with different combinations of geometrical aspect ratios and contact extensions. Results achieved via CBCM for a pure rotation applied to the CAFP's output link are then verified through Finite Element Analysis. The resulting performance maps show good agreement between the numerical results. Furthermore, the CBCM shows an improved computational efficiency, which is a crucial aspect for preliminary design steps. At last, direct comparison between simulations and experiments, developed by means of two custom test rigs, confirms the efficacy of the proposed design method for the modeling of contacts in large deflection problems. © 2019
145 a57211516485 Howell L.L. p124 False Journal 88 Kinetostatic and dynamic modeling of flexure-based compliant mechanisms: A survey Flexure-based compliant mechanisms are becoming increasingly promising in precision engineering, robotics, and other applications due to the excellent advantages of no friction, no backlash, no wear, and minimal requirement of assembly. Because compliant mechanisms have inherent coupling of kinematic-mechanical behaviors with large deflections and/or complex serial-parallel configurations, the kinetostatic and dynamic analyses are challenging in comparison to their rigid-body counterparts. To address these challenges, a variety of techniques have been reported in a growing stream of publications. This paper surveys and compares the conceptual ideas, key advances, and applicable scopes, and open problems of the state-of-the-art kinetostatic and dynamic modeling methods for compliant mechanisms in terms of small and large deflections. Future challenges are discussed and new opportunities for extended study are highlighted as well. The presented review provides a guide on how to select suitable modeling approaches for those engaged in the field of compliant mechanisms. © 2020 Oxford University Press. All rights reserved.
145 a57211516485 Howell L.L. p136 False Journal 95 Developable mechanisms on regular cylindrical surfaces Developable mechanisms can provide high functionality and compact stowability. This paper presents engineering models to aid in the design of cylindrical developable mechanisms. These models take into account the added spatial restrictions imposed by the developable surface. Equations are provided for the kinematic analysis of cylindrical developable mechanisms. A new classification for developable mechanisms is also presented (intramobile, extramobile, and transmobile) and two graphical methods are provided for determining this classification for single-DOF planar cylindrical developable mechanisms. Characteristics specific to four-bar cylindrical developable mechanisms are also discussed. © 2019 Elsevier Ltd
145 a57211516485 Howell L.L. p153 False Journal 108 Heat set creases in polyethylene terephthalate (PET) sheets to enable origami-based applications Polyethylene terephthalate (PET) sheets show promise for application in origami-based engineering design. Origami-based engineering provides advantages that are not readily available in traditional engineering design methods. Several processing methods were examined to identify trends and determine the effect of processing of PET sheets on the crease properties of origami mechanisms in PET. Various annealing times, temperatures, and cooling rates were evaluated and data collected for over 1000 samples. It was determined that annealing temperature plays the largest role in crease response. An increase in the crystallinity of a PET sheet while in the folded state likely increases the force response of the crease in PET sheets. An annealing time of at least 60 min at 160 C-180 C with a quick cooling results in a high force response in the crease. The effectiveness of the processing methods was demonstrated in several origami patterns of various complexities. © 2019 IOP Publishing Ltd.
145 a57211516485 Howell L.L. p162 False Journal 112 Origami-inspired sacrificial joints for folding compliant mechanisms Folding is a manufacturing method which can create complex 3D geometries from flat materials and can be particularly useful in cost-sensitive or planar-limited fabrication applications. This paper introduces compliant mechanisms that employ folding techniques from origami to evolve from a flat material to deployed state. We present origami-inspired sacrificial joints, joints which have mobility during assembly of the mechanism but are rigid in their final position, to create regions of high and low stiffness and the proper alignment of compliant flexures in folded mechanisms. To demonstrate the method we fold steel sheet to create some well-known and complex compliant mechanisms. © 2019 Elsevier Ltd
145 a57211516485 Howell L.L. p201 False Journal 135 Normalized Coordinate Equations and an Energy Method for Predicting Natural Curved-Fold Configurations Of the many valid configurations that a curved fold may assume, it is of particular interest to identify natural - or lowest energy - configurations that physical models will preferentially assume. We present normalized coordinate equations - equations that relate fold surface properties to their edge of regression - to simplify curved-fold relationships. An energy method based on these normalized coordinate equations is developed to identify natural configurations of general curved folds. While it has been noted that natural configurations have nearly planar creases for curved folds, we show that nonplanar behavior near the crease ends substantially reduces the energy of a fold. © 2019 ASME.
145 a57211516485 Howell L.L. p246 False Journal 161 Origami-Based Design of Conceal-and-Reveal Systems This work introduces a type of motion termed "conceal-and-reveal" which is characterized by a state that protects a payload, a state that exposes the payload, and coupled motions between these two states. As techniques for thick, rigid origami-based engineering designs are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design similar thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns can be used to initiate viable approaches to achieving conceal-and-reveal motion. © 2019 by ASME.
145 a57211516485 Howell L.L. p283 False Journal 185 Origami fold states: Concept and design tool The ability of origami to alter its properties and behaviors with its shape makes it an elegant source of inspiration for many engineering designs challenges. Fold states specify the shape of the origami - its facets, creases, and fold angles. Origami research recognizes several acknowledged fold states: The unfolded, fully folded, and flat-folded states. However, these fold states are not comprehensive, excluding some of the most predominant fold states in origami-based devices. In this paper we propose a comprehensive list of fold states based on fold angles. We support the method of categorizing fold states by evaluating the functions and fold states of a large sample of origami-based devices. These correlations provide insight for selecting fold states for origami-based design. We discuss properties and behaviors of the fold states individually and provide a process for fold-state selection. © Author(s) 2019.
145 a57211516485 Howell L.L. p314 False Conference 94 Characteristics of self-deployment in origami-based systems The potential of compliant mechanisms and related origami-based mechanical systems to store strain energy make them ideal candidates for applications requiring an actuation or deployment process, such as space system arrays, minimally invasive surgical devices and deployable barriers. Many origami structures can be thought of as a compliant mechanism because, like compliant mechanisms, its function is performed through the elastic deformation of its members. This stored strain energy could prove useful. There are opportunities using strain energy to develop approaches to deploy particular mechanical systems. In order to better understand the principles of self-actuation and promote the designs of such systems, a taxonomy of deployable origami mechanisms is presented. This taxonomy demonstrates that there are several different types of deployable origami mechanisms and provides an organizational method to better understand the design space. Characteristics of self deployment in concentrated, deployable origami strain energy mechanisms with internal actuation are identified and examples of strain energy based deployment are provided. Copyright © 2019 ASME.
145 a57211516485 Howell L.L. p315 False Conference 95 Deployable euler spiral connectors (DESCs) Deployable Euler Spiral Connectors (DESCs) are introduced as a way to use compliant flexures that lay flat when under strain in a stowed position. This paper presents the design of DESCs using the Euler spiral equations. An application of a spinal device is presented as a proof-of-concept of the use of DESCs. Copyright © 2019 ASME.
145 a57211516485 Howell L.L. p316 False Conference 96 Cylindrical developable mechanisms for minimally invasive surgical instruments Developable mechanisms conform to and emerge from developable, or specially curved, surfaces. The cylindrical developable mechanism can have applications in many industries due to the popularity of cylindrical or tube-based devices. Laparoscopic surgical devices in particular are widely composed of instruments attached at the proximal end of a cylindrical shaft. In this paper, properties of cylindrical developable mechanisms are discussed, including their behaviors, characteristics, and potential functions. One method for designing cylindrical developable mechanisms is discussed. Two example developable surgical devices that exemplify these behaviors, characteristics, and functions, along with the kinematic mechanisms comprising them, are discussed in detail. Copyright © 2019 ASME.
145 a57211516485 Howell L.L. p318 False Conference 98 Conceptualizing stable states in origami-based devices using an energy visualization approach In many origami-based applications a device needs to be maintained in one or more fold states. The origami stability integration method (OSIM) presented in this paper provides an approach for graphically combining various techniques to achieve stability. Techniques are divided into four groups based on whether they are intrinsic or extrinsic to the origami pattern and whether they exhibit differentiable or non-differentiable energy storage behaviors. These categorizations can help designers select appropriate techniques for their application. The paper also contains design considerations and resources for several intrinsic techniques. Finally, two case studies are presented which use the OSIM and the technique guidelines to conceptualize stability in origami-based devices. Copyright © 2019 ASME.
145 a57211516485 Howell L.L. p321 False Conference 101 Kirigami-based deployable transcrease hard stop models usable in origami patterns Stopping origami in arbitrary fold states can present a challenge for origami-based design. In this paper two categories of kirigami-based models are presented for stopping the fold motion of individual creases using deployable hard stops. These models are transcrease (across a crease) and deploy from a flat sheet. The first category is planar and has behavior similar to a four-bar linkage. The second category is spherical and behaves like a degree-4 origami vertex. These models are based on the zero-thickness assumption of paper and can be applied to origami patterns made from thin materials, limiting the motion of the base origami pattern through self-interference within the original facets. Model parameters are based on a desired fold or dihedral angle, as well as facet dimensions. Examples show model benefits and limitations. Copyright © 2019 ASME.
145 a57211516485 Howell L.L. p380 False Conference 138 Regular 2D and 3D linkage-based origami tessellations Linkage origami is one effective approach for addressing stiffness and accommodating panels of finite size in origami models and tessellations. However, successfully implementing linkage origami in tessellations can be challenging. In this work, multiple theorems are presented that provide criteria for designing origami units or cells that can be assembled into arbitrarily large tessellations. The application of these theorems is demonstrated through examples of tessellations in two and three dimensions. Copyright © 2019 ASME.
145 a57211516485 Howell L.L. p381 False Conference 139 Rigidly foldable thick origami using designed-offset linkages We present new families of thick origami mechanisms that achieve rigid foldability and parallel stacking of panels in the flat-folded state using linkages for some or all of the hinges between panels. A degree-four vertex results in a multi-loop eight-bar spatial mechanism that can be analyzed as separate linkages. The individual linkages are designed so that they introduce offsets perpendicular to the panels that are mutually compatible around each vertex. This family of mechanisms offers the unique combination of a planar unfolded state, parallel-stacked panels in the flat folded state, and kinematic single-degree-of-freedom motion from the flat-unfolded to the flat-folded state. Copyright © 2019 ASME.
145 a57211516485 Howell L.L. p383 False Journal 209 Developable mechanisms on developable surfaces The trend toward smaller mechanism footprints and volumes, while maintaining the ability to perform complex tasks, presents the opportunity for exploration of hypercompact mechanical systems integrated with curved surfaces. Developable surfaces are shapes that a flat sheet can take without tearing or stretching, and they represent a wide range of manufactured surfaces. This work introduces “developable mechanisms” as devices that emerge from or conform to developable surfaces. They are made possible by aligning hinge axes with developable surface ruling lines to enable mobility. Because rigid-link motion depends on the relative orientation of hinge axes and not link geometry, links can take the shape of the corresponding developable surface. Mechanisms are classified by their associated surface type, and these relationships are defined and demonstrated by example. Developable mechanisms show promise for meeting unfilled needs using systems not previously envisioned. © 2019 The Authors, some rights reserved.
145 a57211516485 Howell L.L. p390 False Journal 213 A design approach to fully compliant multistable mechanisms employing a single bistable mechanism A fully compliant multistable mechanism is a monolithic structure that is capable of staying at multiple positions without power input, and has many applications including switches, valves, positioners. However, it is difficult to design such a mechanism because of the complexities of the multistable behavior, the practical stress limits and the buckling constraints. This paper discusses the design approach for fully compliant multistable mechanisms which employs a single bistable mechanism and several end-effectors connected in series. The force-displacement characteristics of the end-effectors are derived using the pseudo-rigid-body model. The design approach to the fully compliant multistable mechanism is provided to determine the design parameters for the flexible segments considering the critical buckling load and the bending strength. Two design examples are presented to demonstrate the feasibility of the approach. © 2019, © 2019 Taylor & Francis Group, LLC.
145 a57211516485 Howell L.L. p409 False Journal 219 Regional Stiffness Reduction Using Lamina Emergent Torsional Joints for Flexible Printed Circuit Board Design Flexible printed circuit boards (PCBs) make it possible for engineers to design devices that use space efficiently and can undergo changes in shape and configuration. However, they also suffer from tradeoffs due to nonideal material properties. Here, a method is presented that allows engineers to introduce regions of flexibility in otherwise rigid PCB substrates. This method employs geometric features to reduce local stiffness in the PCB, rather than reducing the global stiffness by material selection. Analytical and finite element models are presented to calculate the maximum stresses caused by deflection. An example device is produced and tested to verify the models. Copyright © 2018 by ASME.
145 a57211516485 Howell L.L. p412 False Journal 222 A model for multi-input mechanical advantage in origami-based mechanisms Mechanical advantage is traditionally defined for single-input and single-output rigidbody mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origamibased mechanisms are capable of offering unique solutions to engineering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi-input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. © 2018 by ASME.
145 a57211516485 Howell L.L. p413 False Journal 223 Symmetric Equations for Evaluating Maximum Torsion Stress of Rectangular Beams in Compliant Mechanisms There are several design equations available for calculating the torsional compliance and the maximum torsion stress of a rectangular cross-section beam, but most depend on the relative magnitude of the two dimensions of the cross-section (i.e., the thickness and the width). After reviewing the available equations, two thickness-to-width ratio independent equations that are symmetric with respect to the two dimensions are obtained for evaluating the maximum torsion stress of rectangular cross-section beams. Based on the resulting equations, outside lamina emergent torsional joints are analyzed and some useful design insights are obtained. These equations, together with the previous work on symmetric equations for calculating torsional compliance, provide a convenient and effective way for designing and optimizing torsional beams in compliant mechanisms. © 2018, The Author(s).
145 a57211516485 Howell L.L. p443 False Journal 222 A pseudo-static model for dynamic analysis on frequency domain of distributed compliant mechanisms This paper presents a pseudo-static modeling methodology for dynamic analysis of distributed compliant mechanisms to provide accurate and efficient solutions. First, a dynamic stiffness matrix of the flexible beam is deduced, which has the same definition and a similar form as the traditional static compliance/stiffness matrix but is frequency dependent. Second, the pseudo-static modeling procedure for the dynamic analysis is implemented in a statics-similar way based on D'alembert's principle. Then, all the kinematic, static and dynamic performances of compliant mechanisms can be analyzed based on the pseudo-static model. The superiority of the proposed method is that when it is used for the dynamic modeling of compliant mechanisms, the traditional dynamic modeling procedures, such as calculation of the elastic and kinetic energies as well as using Lagrange's equation, are avoided and the dynamic modeling is converted to a staticssimilar problem. Comparison of the proposed method with an elastic-beam-based model in previous literature and finite element analysis for an exemplary XY precision positioning stage reveals its high accuracy and easy operation. © 2018 by ASME.
145 a57211516485 Howell L.L. p446 False Journal 250 Deployable lenticular stiffeners for origami-inspired mechanisms Light-weight origami-inspired mechanisms can provide advantages in deployable space systems and other applications. However, a significant challenge in their design is ensuring that they are sufficiently stiff. Compliant, deployable stiffeners utilizing a profile that approximates the Euler Spiral are proposed as one possible solution. It is shown that a structure with this specific profile, called a lenticular stiffener, permits stiffeners to be flattened using a force applied at their edge. Formulas for calculating the increase in stiffness are developed. Relations needed to design the deployment behavior of the stiffeners are also derived. Finally, advantages of different configurations of stiffeners are evaluated. These results are verified through simulation and experiments. © 2018 Taylor & Francis.
145 a57211516485 Howell L.L. p454 False Conference 160 Zipper Tube Reinforcement to Mitigate Flexible Shaft Buckling The Zipper Tube Reinforcement (ZTR) is a novel support system developed to mitigate buckling in thin flexible devices used in robotic surgery. The ZTR was inspired by a construction technique called a Buckling Restrained Braced Frame (BRBF) and deployable booms for space applications. It utilizes a zipper function to allow a rolled sheet to deploy into a variable-length tube and stow in a small volume spooled on a mandrel. The tube envelops the device and allows it to support a much higher compressive load before buckling failure through the insertion stroke. The ZTR also enables the possibility of smaller, more flexible devices due to its design for continuous support and could find application in other fields. © 2018 IEEE.
145 a57211516485 Howell L.L. p455 False Conference 161 Modified Material Properties in Curved Panels Through Lamina Emergent Torsional Joints Compliant joints have a number of advantages that make them suitable for highly constrained design problems. While much work has been done on the design of compliant joints manufactured from planar sheet materials, this work focuses on the design of cylindrically-curved joints. A method for using lamina emergent torsional (LET) joints to increase energy storage efficiency in curved sheet materials is presented. A numerical model is provided for predicting the stiffness and maximum applied moment of a curved LET joint. Predicted curved LET joint stiffnesses and maximum moments are utilized to create shape factors that produce an effective modulus of elasticity and an effective modulus of resilience. For a given case, the effective modulus of elasticity is shown to decrease by about three orders of magnitude while the effective resilience decreases by approximately one order of magnitude. Designers can use this information to tailor materials to fit design requirements or to select alternative materials that were previously unsuited for an application. © 2018 IEEE.
145 a57211516485 Howell L.L. p456 False Conference 162 An Origami-based Thickness-Accommodating Bistable Mechanism in Monolithic Thick-sheet Materials Origami-based mechanisms can provide useful capabilities in folding large structures to stow in small volumes. However, when using monolithic thick-sheet materials for these types of mechanisms, accommodating the thickness proves challenging. One approach to solve this is to create compliant mechanisms along the fold lines that inherently store energy when actuated and causes the mechanism to tend toward its low energy state. This tendency can be used to create bistable states. We outline a method to use this stored energy to achieve bistable states and name the resulting mechanism an origami-based "Thickness-accommodating bistable interior vertex" (TABIV) in monolithic thick-sheet materials. The kinematics and energy-displacement relationships of this mechanism are derived. Prototypes are shown to exhibit the predicted bistable behavior and the mechanism is integrated and prototyped into origami-based mechanisms demonstrating advantageous multi-stable behaviors. © 2018 IEEE.
145 a57211516485 Howell L.L. p457 False Conference 163 Implementation of Rolling Contacts for SORCE Joints The Synchronized-offset-rolling-contact element (SORCE) technique for thickness accommodation in origami-inspired mechanisms combines selected strengths of several thickness-accomadation techniques but with the tradeoff of manufacturing complexity of rolling joints. This work presents principles to facilitate the construction of rolling joints suitable for applications like the SORCE technique. These include leveraging fold-angle multipliers of origami vertices, variations of flexure assembly, sunken flexures, and form-closed rolling joints. Prototypes of origami-mechanisms using the SORCE technique are constructed demonstrating these principles. © 2018 IEEE.
145 a57211516485 Howell L.L. p479 False Journal 265 Kinetostatic modeling of complex compliant mechanisms with serial-parallel substructures: A semi-analytical matrix displacement method Kinetostatic analysis of compliant mechanisms are crucial at the early stage of design, and it can be difficult and laborsome for complex configurations with distributed compliance. In this paper, a kinetostatic modeling method for flexure-hinge-based compliant mechanisms with hybrid serial-parallel substructures is presented to provide accurate and concise solutions by combining the matrix displacement method with the transfer matrix method. The transition between the elemental stiffness matrix and the transfer matrix of flexure hinges/flexible beams is straightforward, enabling the condensation of a hybrid serial-parallel substructure into one equivalent two-node element simple. A general kinetostatic model of the whole compliant mechanisms is first established based on the equilibrium equation of the nodal force. Then, a condensed two-port mechanical network representing the input/output force-displacement relations of single-degree-of-freedom (DOF) compliant mechanisms and the Jacobian matrix for multi-DOF compliant mechanisms are respectively built. Comparison of the proposed method with the compliance matrix method in previous literature, finite element analysis and experiment for three exemplary mechanisms reveals good prediction accuracy, suggesting its feasibility for fast performance evaluation and parameter optimization at the initial stage of design. © 2018 Elsevier Ltd
145 a57211516485 Howell L.L. p484 True Conference 176 Outreach potential of displaying research artifacts in art museums This paper explores how displaying engineering research artifacts in art museums can facilitate expanded outreach opportunities. A combination of visual art and innovative engineering offers an unusual opportunity to engage a wide spectrum of society. To evaluate the potential, faculty and students collaborated with the Brigham Young University Museum of Art to create a museum exhibition that connected the art of origami to engineering, math, science, and product design. A framework is introduced that includes the creation of a museum exhibition; and once the initial investment is made to create the central exhibition, the results are efficiently used to extend outreach efforts through first-generation products (coincident with the exhibition) and then through second-generation products (after the exhibition). The paper describes a detailed example of this framework and provides evidence to support the concept that displaying research artifacts in an art museum can expand research opportunities. Products from the exhibition that provided expanded outreach opportunities include the following: an exhibit catalog originally created for the gift shop that was expanded for publication with a national publisher; a tablet/smart phone app that includes origami instructions followed by related engineering activities, which has had broad use beyond the museum activity room; a video that was prepared for museum patrons but has since been made available to larger audiences; materials created for hands-on museum activities that were used for outreach activities after the exhibition; and leverage for industry visits that led to additional applications and research projects. This paper describes the museum exhibition, the first- and second-generation products, the impact of each product, and the benefits and pitfalls of using a museum exhibition to extend outreach impact. © American Society for Engineering Education, 2018.
145 a57211516485 Howell L.L. p503 False Journal 274 Membrane-Enhanced Lamina Emergent Torsional Joints for Surrogate Folds Lamina emergent compliant mechanisms (including origami-adapted compliant mechanisms) are mechanical devices that can be fabricated from a planar material (a lamina) and have motion that emerges out of the fabrication plane. Lamina emergent compliant mechanisms often exhibit undesirable parasitic motions due to the planar fabrication constraint. This work introduces a type of lamina emergent torsion (LET) joint that reduces parasitic motions of lamina emergent mechanisms, and presents equations for modeling parasitic motion of LET joints. The membrane joint also makes possible one-way joints that can ensure origami-based mechanisms emerge from their flat state (a change point) into the desired configuration. Membrane-enhanced LET (M-LET) joints, including one-way surrogate folds, are described here and show promise for use in a wide range of compliant mechanisms and origami-based compliant mechanisms. They are demonstrated as individual joints and in mechanisms such as a kaleidocycle (a 6R Bricard linkage), degree-4 origami vertices (spherical mechanisms), and waterbomb base mechanisms (an 8R multi-degrees-of-freedom origami-based mechanism). © 2018 by ASME.
145 a57211516485 Howell L.L. p524 False Journal 222 Rigidly foldable quadrilateral meshes from angle arrays We present a design technique for generating rigidly foldable quadrilateral meshes (RFQMs), taking as input four arrays of direction angles and fold angles for horizontal and vertical folds. By starting with angles, rather than vertex coordinates, and enforcing the fold-angle multiplier condition at each vertex, it is possible to achieve arbitrarily large and complex panel arrays that flex from unfolded to flatly folded with a single degree-of-freedom (DOF). Furthermore, the design technique is computationally simple, reducing for some cases to a simple linear-programming problem. The resulting mechanisms have applications in architectural facades, furniture design, and more. © 2018 by ASME.
145 a57211516485 Howell L.L. p580 False Conference 225 Three approaches for managing stiffness in origami-inspired mechanisms Ensuring that deployable mechanisms are sufficiently rigid is a major challenge due to their large size relative to their mass. This paper examines three basic types of stiffener that can be applied to light, origami-inspired structures to manage their stiffness. These stiffeners are modeled analytically to enable prediction and optimization of their behavior. The results obtained from this analysis are compared to results from a finite-element analysis and experimental data. After verifying these models, the advantages and disadvantages of each stiffener type are considered. This comparison will facilitate stiffener selection for future engineering applications. Copyright © 2018 ASME
145 a57211516485 Howell L.L. p581 False Conference 226 Origami-based design of conceal-and-reveal systems This work introduces a type of motion termed “conceal-and-reveal” which is characterized by a state that protects a payload, a state that exposes the payload, and continuous motion between these two states. As techniques for thick, rigid origami-based engineering design are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design other thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns represent viable approaches to achieving conceal-and-reveal motion. Copyright © 2018 ASME
145 a57211516485 Howell L.L. p583 False Conference 228 Retractable anti-buckling support systems for flexible medical devices This work presents two novel support systems used to help mitigate flexible device buckling during insertion such as the insertion of medical device into the body. These systems are collapsible to accommodate the changing length of the flexible device as it is inserted. They use tension in wires or geometry to provide systems with lateral stiffness used to support the device. Through modeling, the performance of these systems can be predicted and they can be designed to a desired performance. This was validated in the geometry-based support system. They provide systems with small operating volumes and part counts. Copyright © 2018 ASME.
145 a57211516485 Howell L.L. p598 False Journal 306 A Review of Thickness-Accommodation Techniques in Origami-Inspired Engineering Origami has served as the inspiration for a number of engineered systems. In most cases, they require nonpaper materials where material thickness is non-negligible. Foldable mechanisms based on origami-like forms present special challenges for preserving kinematics and assuring non-self-intersection when the thickness of the panels must be accommodated. Several design approaches for constructing thick origami mechanisms by beginning with a zero-thickness origami pattern and transforming it into a rigidly foldable mechanism with thick panels are reviewed. The review includes existing approaches and introduces new hybrid approaches. The approaches are compared and contrasted and their manufacturability analyzed. © 2018 by ASME.
145 a57211516485 Howell L.L. p599 False Journal 306 Closure to "discussion of 'a review of thickness-accommodation techniques in origami-inspired engineering'" (Lang, R. J., Tolman, K. A., Crampton, E. B., Magleby, S. P., and Howell, L. L., 2018, ASME Appl. Mech. Rev., 70(1), p. 010805) [No abstract available]
145 a57211516485 Howell L.L. p600 False Journal 307 Cylindrical cross-axis flexural pivots The cylindrical cross-axis flexural pivot (CCAFP) is proposed as an ultra-compact flexure capable of being integrated into hollow cylindrical shafts, enabling shaft motion without inhibiting cables or other components inside the shaft. Mechanism geometry, materials, and manufacturing are proposed and the results analyzed and tested. A parametric finite element model of the CCAFP was created to analyze the force-deflection and strain-deflection relationships and the predicted behavior was verified by experiment. Analytic models of stress-limiting cam-surfaces suggest even larger motions may be possible when not limited by current practical constraints. The CCAFP is demonstrated and tested at multiple size scales and in multiple materials, ranging from 28.6 mm diameter 4130 steel (achieving 9 degrees of angular deflection) to 3 mm diameter NiTi (achieving an angular deflection of 85 degrees). The results are generalized to apply to a range of applications, and the CCAFP particularly shows promise for implementation in minimally invasive surgical instruments to decrease instrument size while maintaining instrument performance. © 2017 Elsevier Inc.
145 a57211516485 Howell L.L. p699 False Journal 342 Inverted L-arm gripper compliant mechanism This work exploits the advantages of compliant mechanisms (devices that achieve their motion through the deflection of flexible members) to enable the creation of small instruments for minimally invasive surgery (MIS). Using flexures to achieve motion presents challenges, three of which are considered in this work. First, compliant mechanisms generally perform inadequately in compression. Second, for a 690 deg range of motion desired for each jaw, the bending stresses in the flexures are prohibitive considering materials used in current instruments. Third, for cables attached at fixed points on the mechanism, the mechanical advantage will vary considerably during actuation. Research results are presented that address these challenges using compliant mechanism principles as demonstrated in a two-degree-of-freedom (2DoF) L-Arm gripper. © 2017 by ASME.
145 a57211516485 Howell L.L. p762 False Journal 371 Thick rigidly foldable origami mechanisms based on synchronized offset rolling contact elements We present a general technique for achieving kinematic single degree of freedom (1DOF) origami-based mechanisms with thick rigid panels using synchronized offset rolling contact elements (SORCEs). We present general design analysis for planar and 3D relative motions between panels and show physically realized examples. The technique overcomes many of the limitations of previous approaches for thick rigidly foldable mechanisms. © 2017 by ASME.
145 a57211516485 Howell L.L. p815 False Conference 350 Realizing origami mechanisms from metal sheets Consideration of a product's manufacturability is a vital aspect of product design. When considering manufacturability of panels for origami-adapted products, there are tradeoffs between panel design approaches as well as thicknessaccommodation techniques. The use of bent sheet metal for panels shows promise as a panel design approach that mitigates several of these trade-offs. This paper describes a process that can be employed to use sheet metal in designs of origami-adapted mechanisms that utilize specific thickness-accommodation techniques. The process is demonstrated for a square-twist mechanism designed using the hinge shift technique for accommodating thickness in origami patterns. A Miura-ori mechanism is also shown in sheet metal. The characteristics of these bent panel approaches are discussed and compared to other approaches for designing panels for manufacturing. The use of bent sheet metal panels allows for mitigation of several trade-offs and shows the applicability of origami-adapted design to sheet metal. Copyright © 2017 ASME.
145 a57211516485 Howell L.L. p817 False Conference 352 Optimization of origami-based tubes for lightweight deployable structures Tubular origami may provide both the needed deployment displacement and sufficient strength to be useful as deployable structures. This paper reviews origami tube-based deployable mechanisms and a structural optimization of FEA models is performed. Symmetric and non-symmetric 4-sided tubes are evaluated. Panel geometries and thicknesses are varied to produce rigidly foldable origami-tube-based mechanisms that are both strong and lightweight. The mechanical properties of these tubes over various deployment lengths are discussed. Three different configurations of this mechanism are compared and the advantages of each are discussed. Copyright © 2017 ASME.
145 a57211516485 Howell L.L. p852 False Conference 376 Elastic energy absorption of origami-based corrugations The mechanical properties of origami tessellations may provide innovative new designs for energy absorbing applications. The elastic energy absorbing properties of a particular tesselation, the Miura-ori, is investigated. Analytical models for the kinematics and force-deflection of a unit cell based on two different modes of elastic energy absorption are derived. The force-deflection model is developed based on the application of compliant mechanism theory and virtual work analysis. The models are verified through comparison with published results for similar models, analysis using commercial kinematics software and comparison to physical testing. Physical prototypes are used to determine values stiffness terms. The analytical models are used to explore the effects of the key geometrical parameters of the tessellation. This work lays a foundation for the use of origami-based corrugations in elastic energy absorption applications. Copyright © 2017 ASME.
145 a57211516485 Howell L.L. p853 False Conference 377 A framework for energy-based kinetostatic modeling of compliant mechanisms Although energy-based methods have advantages over the Newtonian methods for kinetostatic modeling, the geometric nonlinearities inherent in deflections of compliant mechanisms preclude most of the energy-based theorems. Castigliano's first theorem and the Crotti-Engesser theorem, which don't require the problem being solved to be linear, are selected to construct the energy-based kinetostatic modeling framework for compliant mechanisms in this work. Utilization of these two theorems requires explicitly formulating the strain energy in terms of deflections and the complementary strain energy in terms of loads, which are derived based on the beam constraint model. The kinetostatic modeling of two compliant mechanisms are provided to demonstrate the effectiveness of using Castigliano's first theorem and the Crotti-Engesser theorem with the explicit formulations in this framework. Future work will be focused on incorporating use of the principle of minimum strain energy and the principle of minimum complementary strain energy. Copyright © 2017 ASME.
145 a57211516485 Howell L.L. p854 False Conference 378 Kinematics and discretization of curved-fold mechanisms We present several new properties of curved-fold mechanisms, those with smoothly curved surfaces joined by sharp curved folds. After describing curved folds and various relationships among their geometric properties, we show that there is an important class, uniform folds, that is particularly well suited to low-degree-of-freedom mechanisms. There is a natural discretization algorithm for uniform curved folds; we present this algorithm and show discretized example mechanisms. Copyright © 2017 ASME.
145 a57211516485 Howell L.L. p855 False Conference 379 Split-vertex technique for thickness-accommodation in origami-based mechanisms A novel thickness-accommodation technique for origami based mechanisms is introduced. This technique modifies a zerothickness pattern by splitting each vertex along the minor folds into a system of two vertices. The modified fold pattern then has thickness applied to it and the resulting mechanism is kinematically equivalent to the modified fold pattern. Origami patterns that are rigid-foldable and only have two panels that stack between folds are utilized in the technique. The technique produces thick origami mechanisms where all panels lie in a plane in the unfolded state without any holes or protrusions and maintain a single degree of freedom. Steps for synthesizing split-vertex mechanisms are presented and examples of split-vertex mechanisms are shown. Advantages and potential applications of the technique are discussed. Copyright © 2017 ASME.
145 a57211516485 Howell L.L. p856 False Conference 380 Rigidly foldable quadrilateral meshes from angle arrays We present a design technique for generating rigidly fold-able quadrilateral meshes, taking as input four arrays of direction angles and fold angles for horizontal and vertical folds. By starting with angles, rather than vertex coordinates, and enforcing the fold-angle-multiplier condition at each vertex, it is possible to achieve arbitrarily large and complex panel arrays that flex from unfolded to flatly folded with a single degree of freedom. Furthermore, the design technique is computationally simple, reducing for some cases to a simple linear programming problem. The resulting mechanisms have applications in architectural facades, furniture design, and more. Copyright © 2017 ASME.
145 a57211516485 Howell L.L. p881 False Conference 396 Highly compressible origami bellows for microgravity drilling-debris containment The design and testing of an origami-based bellows for microgravity drilling is described. The potential benefits of an origami-based solution created an opportunity for application on NASA’s Asteroid Redirect Mission (ARM) to protect sensitive parts from debris. Origami-based bellows were designed to fit spatial limitations and meet needed compression ratios. Designs have demonstrated high mass reductions, improved stroke length, greatly decreased stowed volume, improved flexibility, and reduced reaction forces in comparison with traditional metal bellows. A nylon-reinforced polyvinyl fluoride based bellows with an aramid fiber stitched seam is well suited for debris containment in space conditions. Various epoxies maintained an adequate bond with polyvinyl fluoride below expected environmental temperature for bellows mounting. Asymmetric compression of the bellows occurs at extreme low temperatures and is preventable by balancing stiffness within the structure. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
146 a57200077532 Willis J. p34 True Conference 5 State-Dependent LQR Control for a Tilt-Rotor UAV This paper develops a control scheme capable of controlling a tilt-rotor unmanned aerial vehicle during nominal hover and fixed-wing flight as well as through transitions between flight modes. The control scheme consists of two parts: a low-level angular rate controller and variable mixer, and a trajectory tracking state-dependent LQR controller. In developing this controller we also present an aerodynamic model of a tilt-rotor with parameters for the Convergence aircraft by E-Flite. Finally we present simulation results for a representative trajectory consisting of vertical takeoff and landing as well as fixed-wing flight. © 2020 AACC.
146 a57200077532 Willis J. p211 True Journal 143 Disaster reconnaissance using multiple small unmanned aerial vehicles" [No abstract available]
146 a57200077532 Willis J. p576 True Conference 221 Femtosats: Elegant flight telemetry payloads for model rockets An elegant telemetry payload, which transmits IMU, atmospheric, or light data during flight and deployment from a small model rocket, is presented. Data is received by a custom, mobile, hand-pointed ground station. The payload is patterned after a thumb-sized satellite, called a femtosat. Its design is optimized for ease of implementation. The femtosat system resulted from a grassroots, student peer-mentoring program developed at Brigham Young University. © held by the author; distribution rights International Foundation for Telemetering.
147 a55613237293 Johnson J. p34 False Conference 5 State-Dependent LQR Control for a Tilt-Rotor UAV This paper develops a control scheme capable of controlling a tilt-rotor unmanned aerial vehicle during nominal hover and fixed-wing flight as well as through transitions between flight modes. The control scheme consists of two parts: a low-level angular rate controller and variable mixer, and a trajectory tracking state-dependent LQR controller. In developing this controller we also present an aerodynamic model of a tilt-rotor with parameters for the Convergence aircraft by E-Flite. Finally we present simulation results for a representative trajectory consisting of vertical takeoff and landing as well as fixed-wing flight. © 2020 AACC.
148 a57208246750 Libano F. p35 True Journal 29 Understanding the Impact of Quantization, Accuracy, and Radiation on the Reliability of Convolutional Neural Networks on FPGAs Convolutional neural networks are quickly becoming viable solutions for self-driving vehicles, military, and aerospace applications. At the same time, due to their high level of design flexibility, reprogrammable capability, low power consumption, and relatively low cost, the field-programmable gate arrays (FPGAs) are very good candidates to implement the neural networks. Unfortunately, the radiation-induced errors are known to be an issue in static random-access memory (SRAM)-based FPGAs. More specifically, we have seen that particles can change the content of the FPGA's configuration memory, consequently corrupting the implemented circuit and generating the observable errors at the output. Through extensive fault injection, we determine the reliability impact of applying binary quantization to the convolutional layers of neural networks on FPGAs, by analyzing the relationships between model accuracy, resource utilization, performance, error criticality, and radiation cross section. We were able to find that a design with quantized convolutional layers can be 39% less sensitive to radiation, whereas the portion of errors that are considered critical (misclassifications) in the network is increased by 12%. Moreover, we also derive generic equations that consider both accuracy and radiation in order to model the overall failure rate of neural networks. © 1963-2012 IEEE.
148 a57208246750 Libano F. p386 True Journal 202 Selective hardening for neural networks in FPGAs Neural networks are becoming an attractive solution for automatizing vehicles in the automotive, military, and aerospace markets. Thanks to their low-cost, low-power consumption, and flexibility, field-programmable gate arrays (FPGAs) are among the promising devices to implement neural networks. Unfortunately, FPGAs are also known to be susceptible to radiation-induced errors. In this paper, we evaluate the effects of radiation-induced errors in the output correctness of two neural networks [Iris Flower artificial neural network (ANN) and Modified National Institute of Standards and Technology (MNIST) convolutional neural network (CNN)] implemented in static random-access memory-based FPGAs. In particular, we notice that radiation can induce errors that modify the output of the network with or without affecting the neural network's functionality. We call the former critical errors and the latter tolerable errors. Through exhaustive fault injection, we identify the portions of Iris Flower ANN and MNIST CNN implementation on FPGAs that are more likely, once corrupted, to generate a critical or a tolerable error. Based on this analysis, we propose a selective hardening strategy that triplicates only the most vulnerable layers of the neural network. With neutron radiation testing, our selective hardening solution was able to mask 40% of faults with a marginal 8% overhead in one of our tested neural networks. © 1963-2012 IEEE.
149 a57206834042 Wilson B. p35 False Journal 29 Understanding the Impact of Quantization, Accuracy, and Radiation on the Reliability of Convolutional Neural Networks on FPGAs Convolutional neural networks are quickly becoming viable solutions for self-driving vehicles, military, and aerospace applications. At the same time, due to their high level of design flexibility, reprogrammable capability, low power consumption, and relatively low cost, the field-programmable gate arrays (FPGAs) are very good candidates to implement the neural networks. Unfortunately, the radiation-induced errors are known to be an issue in static random-access memory (SRAM)-based FPGAs. More specifically, we have seen that particles can change the content of the FPGA's configuration memory, consequently corrupting the implemented circuit and generating the observable errors at the output. Through extensive fault injection, we determine the reliability impact of applying binary quantization to the convolutional layers of neural networks on FPGAs, by analyzing the relationships between model accuracy, resource utilization, performance, error criticality, and radiation cross section. We were able to find that a design with quantized convolutional layers can be 39% less sensitive to radiation, whereas the portion of errors that are considered critical (misclassifications) in the network is increased by 12%. Moreover, we also derive generic equations that consider both accuracy and radiation in order to model the overall failure rate of neural networks. © 1963-2012 IEEE.
149 a57206834042 Wilson B. p386 False Journal 202 Selective hardening for neural networks in FPGAs Neural networks are becoming an attractive solution for automatizing vehicles in the automotive, military, and aerospace markets. Thanks to their low-cost, low-power consumption, and flexibility, field-programmable gate arrays (FPGAs) are among the promising devices to implement neural networks. Unfortunately, FPGAs are also known to be susceptible to radiation-induced errors. In this paper, we evaluate the effects of radiation-induced errors in the output correctness of two neural networks [Iris Flower artificial neural network (ANN) and Modified National Institute of Standards and Technology (MNIST) convolutional neural network (CNN)] implemented in static random-access memory-based FPGAs. In particular, we notice that radiation can induce errors that modify the output of the network with or without affecting the neural network's functionality. We call the former critical errors and the latter tolerable errors. Through exhaustive fault injection, we identify the portions of Iris Flower ANN and MNIST CNN implementation on FPGAs that are more likely, once corrupted, to generate a critical or a tolerable error. Based on this analysis, we propose a selective hardening strategy that triplicates only the most vulnerable layers of the neural network. With neutron radiation testing, our selective hardening solution was able to mask 40% of faults with a marginal 8% overhead in one of our tested neural networks. © 1963-2012 IEEE.
150 a7003292762 Wirthlin M. p35 False Journal 29 Understanding the Impact of Quantization, Accuracy, and Radiation on the Reliability of Convolutional Neural Networks on FPGAs Convolutional neural networks are quickly becoming viable solutions for self-driving vehicles, military, and aerospace applications. At the same time, due to their high level of design flexibility, reprogrammable capability, low power consumption, and relatively low cost, the field-programmable gate arrays (FPGAs) are very good candidates to implement the neural networks. Unfortunately, the radiation-induced errors are known to be an issue in static random-access memory (SRAM)-based FPGAs. More specifically, we have seen that particles can change the content of the FPGA's configuration memory, consequently corrupting the implemented circuit and generating the observable errors at the output. Through extensive fault injection, we determine the reliability impact of applying binary quantization to the convolutional layers of neural networks on FPGAs, by analyzing the relationships between model accuracy, resource utilization, performance, error criticality, and radiation cross section. We were able to find that a design with quantized convolutional layers can be 39% less sensitive to radiation, whereas the portion of errors that are considered critical (misclassifications) in the network is increased by 12%. Moreover, we also derive generic equations that consider both accuracy and radiation in order to model the overall failure rate of neural networks. © 1963-2012 IEEE.
150 a7003292762 Wirthlin M. p61 False Conference 11 Using Partial Duplication with Compare to Detect Radiation-Induced Failure in a Commercial FPGA-Based Networking System Duplication with compare, a circuit-level fault-detection technique, is used in this study in a partial manner to detect radiation-induced failures in a commercial FPGA-based networking system. A novel approach is taken to overcome challenges presented by multiple clock domains, the use of third-party IP, and the collection of error detection signals dispersed throughout the design. Novel fault injection techniques are also used to evaluate critical regions of the target design. Accelerated neutron radiation testing was performed to evaluate the effectiveness of the applied technique. One design version was able to detect 45% of all failures with the proposed technique applied to 29% of the circuit components within the design. Another design version was able to detect 31% of all failures with the proposed technique applied to only 8% of circuit components. © 2020 IEEE.
150 a7003292762 Wirthlin M. p100 False Conference 16 Modeling common cause failures in systems with triple modular redundancy and repair Triple modular redundancy (TMR) is commonly employed to increase the reliability and mean time to failure (MTTF) of a system. This improvement can be shown by using a continuous time Markov chain. However, typical Markov chain models do not model common cause failures (CCF), which is a singular event that simultaneously causes failure in multiple redundant modules. This paper introduces a new Markov chain to model CCF in TMR with repair systems. This new model is compared to the idealized models of TMR with repair without CCF. The fundamental limitations that CCF imposes on the system are shown and discussed. In a motivating example, it is seen that CCF imposes a limitation of 51× on the reliability improvement in a system with TMR and repair compared to a simplex system, (i.e., without TMR). A case study is also presented where the likelihood of CCF is reduced by a factor of 18× using various mitigation techniques. Reducing the CCF compounds the reliability improvement of TMR with repair and leads to a overall system reliability improvement of 10,000× compared to the simplex system as supported by the proposed model. © 2020 IEEE.
150 a7003292762 Wirthlin M. p112 False Journal 29 Improving the Reliability of TMR with Nontriplicated I/O on SRAM FPGAs Triple modular redundancy (TMR) with repair is a commonly employed mitigation strategy used on SRAM field-programmable gate arrays (FPGAs) to reduce the effects of ionizing radiation and improve a circuit's sensitive cross section. This article examines TMR circuits, where the I/O ports of the circuit have not been triplicated, but the internal circuitry has. Such circuits introduce single-point failures (SPFs) into the circuit that limit the neutron cross-sectional improvement offered by TMR to only 3× for the b13 benchmark circuit used in this article. This article proposes two different mitigation techniques to address SPFs, which alter the placement and routing of the circuit. These mitigation techniques reduce the neutron cross section by 26× over the unmitigated circuit while minimally affecting the circuit's maximum clock frequency and resource utilization. © 1963-2012 IEEE.
150 a7003292762 Wirthlin M. p113 False Journal 29 Statistical method to extract radiation-induced multiple-cell upsets in SRAM-Based FPGAs Radiation-induced multiple-cell upsets (MCUs) are a concern because they can overcome the protection of error correction code and triplicated designs. Extracting MCU data from radiation tests is helpful to perform more accurate fault injection tests, where MCUs could be simulated with the injection of bits based on the MCUs shapes, sizes, and frequencies. This article presents a statistical method to extract MCU shapes and frequencies from components with no information regarding their physical layout. The proposed method can be used to extract MCU information from BRAM and CRAM alike. The results show the MCU data for three families of Xilinx field-programmable gate arrays (FPGAs). © 1963-2012 IEEE.
150 a7003292762 Wirthlin M. p123 False Journal 29 Applying Compiler-Automated Software Fault Tolerance to Multiple Processor Platforms Several recent works have explored the feasibility of using commercial off-the-shelf (COTS) processing systems in radiation-prone environments, such as spacecraft. Typically, this approach requires some form of protection to ensure that the software can tolerate radiation upsets without compromising the system. Our recent work, COmpiler Assisted Software fault Tolerance (COAST), provides automated compiler modification of software programs to insert dual-or triple-modular redundancy. In this article, we extend COAST to support several new processing platforms, including RISC-V and Xilinx, San Jose, CA, USA, SoC-based products. The automated software protection mechanisms are tested for a variety of configurations, altering the benchmark and cache configuration. Across the different configurations, the cross sections were improved by 4× to 106×. In addition, a hardware-mitigation technique is tested using dual-lock-step cores on the Texas Instruments, Dallas, TX, USA, Hercules platform, which is compared with the software-only mitigation approach. © 1963-2012 IEEE.
150 a7003292762 Wirthlin M. p195 False Conference 44 Single-Event Characterization of a Stratix® 10 FPGA Using Neutron Irradiation FPGAs are being used in data center applications in large quantities. Single-event upsets (SEUs) occur more frequently within large-scale deployments of SRAM-based FPGAs. This work estimates the neutron cross section for SEUs in the configuration memory and memory blocks of a 14-nm FinFET Stratix 10 FPGA. SEU data was collected using a custom SEU data collection system. The developed system takes advantage of SEU mitigation features available on the device. The New York City FIT rate for SEUs is estimated to be 3.2 FIT per Mbit for configuration memory and 7.1 FIT per Mbit for memory blocks. © 2019 IEEE.
150 a7003292762 Wirthlin M. p196 False Conference 45 Neutron radiation testing of fault tolerant risc-v soft processor on xilinx SRAM-based FPGAs Many space applications are considering the use of commercial SRAM-based FPGAs over radiation hardened devices. When using SRAM-based FPGAs, soft processors may be required to fulfill application requirements, but the FPGA designs must overcome radiation-induced soft errors to provide a reliable system. TMR is one solution in designing a fault tolerant soft processor to mitigate the failures caused by SEUs. This paper compares the neutron soft-error reliability of an unmitigated and TMR version of a Taiga RISC-V soft processor on a Xilinx SRAM-based FPGA. The TMR RISC-V processor showed a 33× reduction in the neutron cross section and a 27% decrease in operational frequency, resulting in a 24× improvement of the mean work to failure with a cost of around 5.6× resource utilization. © 2019 IEEE.
150 a7003292762 Wirthlin M. p267 False Conference 62 Impact of soft errors on large-scale FPGA cloud computing FPGAs are being used in large numbers within cloud computing to provide high-performance, low-power alternatives to more traditional computing structures. While FPGAs provide a number of important benefits to cloud computing environments, they are susceptible to radiation-induced soft errors, which can lead to silent data corruption or system instability. Although soft errors within a single FPGA occur infrequently, soft errors in large-scale FPGAs systems can occur at a relatively high rate. This paper investigates the failure rate of several FPGA applications running within an FPGA cloud computing node by performing fault injection experiments to determine the susceptibility of these applications to soft-errors. The results from these experiments suggest that silent data corruption will occur every few hours within a 100,000 node FPGA system and that such a system can only maintain high-levels of reliability for short periods of operation. These results suggest that soft-error detection and mitigation techniques may be needed in large-scale FPGA systems. © 2019 Association for Computing Machinery.
150 a7003292762 Wirthlin M. p362 False Journal 202 Strategies for Removing Common Mode Failures from TMR Designs Deployed on SRAM FPGAs Triple modular redundancy (TMR) with repair has proven to be an effective strategy for mitigating the effects of single-event upsets within the configuration memory of static random access memory field-programmable gate arrays. Applying TMR to the design successfully reduces the design's neutron cross section by 80×. The effectiveness of TMR, however, is limited by the presence of single bits in the configuration memory which cause more than one TMR domain to fail simultaneously. We present three strategies to mitigate against these failures and improve the effectiveness of TMR: incremental routing, incremental placement, and striping. These techniques were tested using both fault injection and a wide spectrum neutron beam with the best technique offering a 400× reduction to the design's sensitive neutron cross section. An analysis from the radiation test shows that no single bits caused failure and that multicell upsets were the main cause of failure for these mitigation strategies. © 1963-2012 IEEE.
150 a7003292762 Wirthlin M. p385 False Journal 202 Microcontroller compiler-assisted software fault tolerance Commercial off-the-shelf microcontrollers can be useful for noncritical processing on spaceborne platforms. These microprocessors can be inexpensive and consume small amounts of power. However, the software running on these processors is vulnerable to radiation upsets. In this paper, we present a fully automated, configurable, software-based tool to increase the reliability of microprocessors in high-radiation environments. This tool consists of a set of open-source LLVM compiler passes to automatically implement software-based mitigation techniques. We duplicate or triplicate computations and insert voting mechanisms into software during the compilation process, allowing for runtime error correction. While the techniques we implement are not novel, previous work has typically been closed source, processor architecture dependent, not automated, and not tested in real high-radiation environments. In contrast, the compiler passes presented in this paper are publicly available, highly customizable, and are platform independent and language independent. We have tested our modified software using both fault injection and through neutron beam radiation on a Texas Instruments MSP430 microcontroller. When tested by a neutron beam, we were able to decrease the cross section of programs by 17-29 × , increasing mean-work-to-failure by 4-7 ×. © 1963-2012 IEEE.
150 a7003292762 Wirthlin M. p386 False Journal 202 Selective hardening for neural networks in FPGAs Neural networks are becoming an attractive solution for automatizing vehicles in the automotive, military, and aerospace markets. Thanks to their low-cost, low-power consumption, and flexibility, field-programmable gate arrays (FPGAs) are among the promising devices to implement neural networks. Unfortunately, FPGAs are also known to be susceptible to radiation-induced errors. In this paper, we evaluate the effects of radiation-induced errors in the output correctness of two neural networks [Iris Flower artificial neural network (ANN) and Modified National Institute of Standards and Technology (MNIST) convolutional neural network (CNN)] implemented in static random-access memory-based FPGAs. In particular, we notice that radiation can induce errors that modify the output of the network with or without affecting the neural network's functionality. We call the former critical errors and the latter tolerable errors. Through exhaustive fault injection, we identify the portions of Iris Flower ANN and MNIST CNN implementation on FPGAs that are more likely, once corrupted, to generate a critical or a tolerable error. Based on this analysis, we propose a selective hardening strategy that triplicates only the most vulnerable layers of the neural network. With neutron radiation testing, our selective hardening solution was able to mask 40% of faults with a marginal 8% overhead in one of our tested neural networks. © 1963-2012 IEEE.
150 a7003292762 Wirthlin M. p404 False Conference 150 Neutron Radiation Beam Results for the Xilinx UltraScale+ MPSoC The paper summarizes the single-event upset (SEU) results obtained from neutron testing on the UltraScale+ MPSoC ZU9EG device. This complex device contains a large amount of programmable logic and multiple processor cores. Tests were performed on the programmable logic and the processing system simultaneously. Estimates of the single-event upset neutron cross section were obtained for the programmable logic CRAM, BRAM, OCM memory, and cache memories. During the test, no processor crashes or silent data corruptions were observed. In addition, a processor failure cross section was estimated for several software benchmark operating on the various processor cores. Several FPGA CRAM scrubbers were tested including an external JTAG, the Xilinx 'SEM' IP, and the use of the PCAP operating in baremetal. In parallel with these tests, single-event induced high current events were monitored using an external power supply and monitoring scripts. © 2018 IEEE.
150 a7003292762 Wirthlin M. p405 False Conference 151 Single-Event Characterization of 16 nm FinFET Xilinx UltraScale+ Devices with Heavy Ion and Neutron Irradiation This study examines the single-event response of Xilinx 16nm FinFET UltraScale+ FPGA and MPSoC device families. Heavy-ion single-event latch-up, single-event upsets in configuration SRAM, BlockRAM™ memories, and flip-flops, and neutron-induced single-event latch-up results are provided. © 2018 IEEE.
150 a7003292762 Wirthlin M. p588 False Journal 304 Dynamic SEU Sensitivity of Designs on Two 28-nm SRAM-Based FPGA Architectures Two field-programmable gate array (FPGA) designs are tested for dynamic single event upset (SEU) sensitivity on two different 28-nm static random access memory-based FPGAs - an Intel Stratix V and a Xilinx Kintex 7 FPGA. These designs were tested in both a conventional unmitigated version and a version to tolerate SEUs with feedback triple modular redundancy (TMR). The unmitigated design sensitivity and the low-level device sensitivity were found to be similar between the devices through neutron radiation testing. Results also show that feedback TMR and configuration scrubbing benefit both designs on both FPGAs. While TMR is helpful, the benefit of TMR depends on the design structure and the device architecture. TMR and scrubbing reduced dynamic SEU sensitivity by a factor of 4- 54×. © 1963-2012 IEEE.
150 a7003292762 Wirthlin M. p690 False Journal 336 Mitigated FPGA design of multi-gigabit transceivers for application in high radiation environments of High Energy Physics experiments SRAM-based Field Programmable Gate Array (FPGA) logic devices are very attractive in applications where high data throughput is needed, such as the latest generation of High Energy Physics (HEP) experiments. FPGAs have been rarely used in such experiments because of their sensitivity to radiation. The present paper proposes a mitigation approach applied to commercial FPGA devices to meet the reliability requirements for the front-end electronics of the Liquid Argon (LAr) electromagnetic calorimeter of the ATLAS experiment, located at CERN. Particular attention will be devoted to define a proper mitigation scheme of the multi-gigabit transceivers embedded in the FPGA, which is a critical part of the LAr data acquisition chain. A demonstrator board is being developed to validate the proposed methodology. Mitigation techniques such as Triple Modular Redundancy (TMR) and scrubbing will be used to increase the robustness of the design and to maximize the fault tolerance from Single-Event Upsets (SEUs). © 2017 Elsevier Ltd
150 a7003292762 Wirthlin M. p721 False Conference 305 Move the Laser Spot, Not the DUT: Investigating the New Micro-mirror Capability and Challenges for Localizing SEE Sites on Large Modern ICs Small spot size laser testing for single-event effects has proven to be a particularly productive path to insights on the physics of charge collection and circuit response that are difficult or impossible to obtain through broad ion beam tests. As a result, there are a number of such laser facilities; for example, four of them were compared in 2012 [1], but a relatively new facility at the facility at the University of Saskatchewan offers a unique galvo-mirror, laser-spot scanning capability in addition to the usual micrometer-based DUT motion stage [2]. Operating in a fashion similar to LASIX eye surgery, fast pin-point redirection of the laser beam makes tractable (seconds, not hours or days) comprehensive scanning of a millimeter size field-of-view. Combined with auto-stepping the field-of-view, this new spot scanning capability opens up the possibility of comprehensively covering a large die and finding all SEE sites, including the rare, but important, ones such as SEFIs. © 2017 IEEE.
150 a7003292762 Wirthlin M. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
150 a7003292762 Wirthlin M. p823 False Journal 393 A Hybrid Approach to FPGA Configuration Scrubbing This paper describes a FPGA configuration scrubbing approach for Xilinx 7-Series FPGAs that combines the high-speed internal scrubbing available within these devices with an external scrubber. The internal scrubbing unit continuously monitors the frames of the FPGA configuration memory and corrects single-bit frame errors and is used to detect multi-bit frame errors. Multi-bit upsets are repaired by means of a secondary scrubbing mechanism that is primarily external to the FPGA fabric. This Xilinx 7-Series hybrid configuration scrubbing architecture scans 25,636,224 bits of the XC7Z020 device in several microseconds and detects upsets within 8 ms and then corrects most multi-cell upsets in under an additional 6 ms. This configuration scrubber was validated with configuration fault injection and neutron radiation testing. © 2016 IEEE.
150 a7003292762 Wirthlin M. p824 False Journal 393 Benefits of Complementary SEU Mitigation for the LEON3 Soft Processor on SRAM-Based FPGAs A variety of mitigation techniques have been demonstrated to reduce the sensitivity of FPGA designs to soft errors. Without mitigation, SEUs can cause failure by altering the logic, routing, and state of a design operating on an SRAM-based FPGA. Various combinations of SEU mitigation and repair techniques are applied to the LEON3 soft-core processor to study the effects and complementary nature of each technique. This work focuses on Triple modular redundancy (TMR), configuration memory (CRAM) scrubbing, and internal block memory (BRAM) scrubbing. All mitigation methods demonstrate some improvement in both fault injection and neutron radiation testing. Results in this paper show complementary SEU mitigation techniques working together to improve fault-tolerance. The results also suggest that fault injection can be a good way to estimate the cross section of a design before going to a radiation test. TMR with CRAM scrubbing demonstrates a 27 × improvement whereas TMR with both CRAM and BRAM scrubbing demonstrates approximately a 50 × improvement. © 2016 IEEE.
151 a19638969800 Rech P. p35 False Journal 29 Understanding the Impact of Quantization, Accuracy, and Radiation on the Reliability of Convolutional Neural Networks on FPGAs Convolutional neural networks are quickly becoming viable solutions for self-driving vehicles, military, and aerospace applications. At the same time, due to their high level of design flexibility, reprogrammable capability, low power consumption, and relatively low cost, the field-programmable gate arrays (FPGAs) are very good candidates to implement the neural networks. Unfortunately, the radiation-induced errors are known to be an issue in static random-access memory (SRAM)-based FPGAs. More specifically, we have seen that particles can change the content of the FPGA's configuration memory, consequently corrupting the implemented circuit and generating the observable errors at the output. Through extensive fault injection, we determine the reliability impact of applying binary quantization to the convolutional layers of neural networks on FPGAs, by analyzing the relationships between model accuracy, resource utilization, performance, error criticality, and radiation cross section. We were able to find that a design with quantized convolutional layers can be 39% less sensitive to radiation, whereas the portion of errors that are considered critical (misclassifications) in the network is increased by 12%. Moreover, we also derive generic equations that consider both accuracy and radiation in order to model the overall failure rate of neural networks. © 1963-2012 IEEE.
151 a19638969800 Rech P. p386 False Journal 202 Selective hardening for neural networks in FPGAs Neural networks are becoming an attractive solution for automatizing vehicles in the automotive, military, and aerospace markets. Thanks to their low-cost, low-power consumption, and flexibility, field-programmable gate arrays (FPGAs) are among the promising devices to implement neural networks. Unfortunately, FPGAs are also known to be susceptible to radiation-induced errors. In this paper, we evaluate the effects of radiation-induced errors in the output correctness of two neural networks [Iris Flower artificial neural network (ANN) and Modified National Institute of Standards and Technology (MNIST) convolutional neural network (CNN)] implemented in static random-access memory-based FPGAs. In particular, we notice that radiation can induce errors that modify the output of the network with or without affecting the neural network's functionality. We call the former critical errors and the latter tolerable errors. Through exhaustive fault injection, we identify the portions of Iris Flower ANN and MNIST CNN implementation on FPGAs that are more likely, once corrupted, to generate a critical or a tolerable error. Based on this analysis, we propose a selective hardening strategy that triplicates only the most vulnerable layers of the neural network. With neutron radiation testing, our selective hardening solution was able to mask 40% of faults with a marginal 8% overhead in one of our tested neural networks. © 1963-2012 IEEE.
152 a55301279200 Brunhaver J. p35 False Journal 29 Understanding the Impact of Quantization, Accuracy, and Radiation on the Reliability of Convolutional Neural Networks on FPGAs Convolutional neural networks are quickly becoming viable solutions for self-driving vehicles, military, and aerospace applications. At the same time, due to their high level of design flexibility, reprogrammable capability, low power consumption, and relatively low cost, the field-programmable gate arrays (FPGAs) are very good candidates to implement the neural networks. Unfortunately, the radiation-induced errors are known to be an issue in static random-access memory (SRAM)-based FPGAs. More specifically, we have seen that particles can change the content of the FPGA's configuration memory, consequently corrupting the implemented circuit and generating the observable errors at the output. Through extensive fault injection, we determine the reliability impact of applying binary quantization to the convolutional layers of neural networks on FPGAs, by analyzing the relationships between model accuracy, resource utilization, performance, error criticality, and radiation cross section. We were able to find that a design with quantized convolutional layers can be 39% less sensitive to radiation, whereas the portion of errors that are considered critical (misclassifications) in the network is increased by 12%. Moreover, we also derive generic equations that consider both accuracy and radiation in order to model the overall failure rate of neural networks. © 1963-2012 IEEE.
153 a7402258065 Lawson J. p37 True Journal 31 Comparison of conditional main effects analysis to the analysis of follow-up experiments for separating confounded two-factor interaction effects in 2 IVk−p fractional factorial experiments Two-factor interactions, where the effect of one factor depends on the level of another factor, are common, and understanding them is often the key to solving quality problems or making process improvements using designed experiments. Resolution IV 2 (Formula presented.) fractional factorial designs are efficient and require fewer experiments or runs than resolution V or full factorial experiments. However, two-factor interactions are confounded with other two-factor interactions in resolution IV designs and their effects cannot be separated. Follow-up experiments have been recommended in the literature to separate the effects of significant but confounded strings of two-factor interactions in resolution IV designs. Recently, an analysis based on conditional main effects (or CMEs) has been shown to be useful in determining which interaction in a confounded string of two-factor interactions is actually causing the significance without the need for follow-up experiments. In this article, I investigate the value of this method of analysis by comparing its use with the analysis of follow-up experiments using the data from three published experiments where follow-up experiments were used to “de-alias” confounded interactions. © 2020 John Wiley & Sons, Ltd.
153 a7402258065 Lawson J. p189 True Journal 130 Phase II monitoring of variability using Cusum and EWMA charts with individual observations When monitoring a process mean in Phase II, it is well known that time-weighted control charts (such as the Cusum or EWMA) of individual observations are more sensitive for detecting small mean changes than are the traditional Shewhart control charts for individuals. Further, by collecting one observation every 12 minutes, rather than a subgroup of five every hour, the time-weighted charts of individual values result in a shorter ATS (average time to signal) than would be possible using Shewhart charts of subgrouped data. This article explores a similar strategy of monitoring process variability using time-weighted control charts and individual observations. The average time to signal a change in variability using these charts is studied when there are targets or known values for the in-control process mean and standard deviation. The results show that the ATS of both the Cusum and EWMA are substantially shorter than the ATS for the standard R charts or the more efficient S2 chart using subgroups of 5. The article also describes how the control limits for the EWMA chart to monitor process variability should be modified if the in-control process mean and standard deviations are unknown and must be estimated from a Phase I study. Computer functions that are available in R packages for creating Cusum-EWMA charts and computing their ARL (average run length) are demonstrated in this study and are included in the appendix. © 2019, © 2019 Taylor & Francis Group, LLC.
154 a36987999600 Afran M.S. p38 True Journal 20 On the effects of channel sparsity on joint estimators in aeronautical telemetry Minimum mean-squared error (MMSE) equalizers are a viable solution to mitigate the frequency selectivity of the aeronautical telemetry channel. Because the MMSE equalizer filter coefficients are a function of the carrier frequency offset (CFO), the equivalent discrete-time channel, and the noise variance, reliable estimates of those parameters are required. The CFO is due primarily to the high velocity of the airborne transmitter. Because the equivalent discrete-time channel in aeronautical telemetry is sparse, the performance of the joint estimator based on a sparse channel estimator is superior to the performance of a traditional nonsparse maximum-likelihood-inspired joint estimator. The improvement is seen in lower estimator error variances for the parameters, particularly for the CFO and channel estimate, and in the postequalizer bit-error rate. Simulation results demonstrate that the postequalizer bit-error rate using the sparse estimator is almost as good as that using ideal estimators. © 1965-2011 IEEE.
154 a36987999600 Afran M.S. p85 True Journal 20 Sparse Equalization in Aeronautical Telemetry Using Two Transmit Antennas This correspondence explores the application of sparse equalizers in generalized time-reversed space-time block codes (GTR-STBCs) for a two-transmit/one-receive antenna aeronautical telemetry link. It is shown that the jointly optimum design of the sparse equalizer coefficients and the power sharing parameter \rho in GTR-STBCs is computationally challenging because the active tap ratio of the sparse equalizers is a non-convex function of \rho. A search algorithm based on a grid search followed by an interpolation is shown to yield impressive results. Our numerical results demonstrate that depending on signal-to-noise ratio and channel conditions, the number of non-zero taps of sparse equalizers for GTR-STBCs can be reduced by 53% to 86\% at the cost of 0.25 dB relaxation in the mean-squared error. © 1965-2011 IEEE.
154 a36987999600 Afran M.S. p159 False Journal 111 On Sparse Channel Estimation in Aeronautical Telemetry This paper examines the application of sparse estimation techniques for the estimation of a discrete-time equivalent multipath channel in the aeronautical telemetry context. The sensing matrix comprises samples of shaped offset QPSK-TG (a continuous phase modulation) based on the pilot bit sequence currently defined in the aeronautical telemetry standard. Representative algorithms from the three broad classes of sparse estimators were examined side by side using computer simulations to estimate the postequalizer bit error rate (BER). Ideal and nonideal frequency offset synchronization were assumed in the simulations. The results show that the performance of the matching pursuit (MP) algorithms seemed to be better suited to this application in the sense that no additional steps were required and the postequalizer BER of the best MP algorithm was slightly better than that of the other sparse estimation techniques. In the case of both ideal and nonideal frequency offset synchronization, the postequalizer BER achieved by the generalized orthogonal MP algorithm was approximately 1.5 dB better than that obtained using the nonsparse-constrained maximum likelihood channel estimate. © 1965-2011 IEEE.
154 a36987999600 Afran M.S. p619 True Conference 256 Cfo estimation by exploiting channel sparsity in aeronautical telemetry In this paper, we explore a carrier frequency offset (CFO) estimation scheme with sparsity-constraint (SC) on the aeronautical telemetry channels. This SC CFO estimator is implemented in two steps. In the first step, channel support is recovered by combining compressed sensing techniques with the CFO estimate based on the non-sparsity constraint (NSC) on the channel. Next we use the estimated channel support to derive the SC CFO estimator. Simulations are performed to compare the performance of the SC CFO estimator against the existing NSC CFO estimators using shaped offset QPSK version TG (SOQPSK-TG) modulated iNET-formatted data over an aeronautical test channel. © held by the author; distribution rights International Foundation for Telemetering.
154 a36987999600 Afran M.S. p848 True Conference 372 Sparse MMSE equalizer for GTR-STBC in aeronautical telemetry This paper investigates the performance of sparse minimum mean squared error (MMSE) equalizer for generalized time-reversed space-time block codes (GTR-STBC) in aeronautical telemetry. GTR-STBC equipped with MMSE equalizer performs the best trade-offbetween the signal-tonoise ratio and inter-symbol interference by allocating unequal power over aeronautical telemetry channels. However, aeronautical telemetry channels are in general consists of larger delay spreads which make the MMSE equalization of aeronautical channels with GTR-STBC computationally complex. Interestingly enough, in spite of larger delays aeronautical channels are made of few sparsely distributed multipaths and therefore their MMSE equalizers are highly compressible. In this paper, compressed sensing based greedy algorithm is used for the design of sparse MMSE equalizer and a convex curve-fitting algorithm is used to find the sub-optimum power allocation parameter at the same sparsity level for GTR-STBC. Our simulation results show that 75-90% of the non-zero equalizer taps can be reduced with a slight relaxation of the mean-squared error (or equivalently slight degradation of bit-error rate performance). It is also observed that the optimum transmitter power profile for the sparse MMSE equalizer is different than that of the non-sparse equalizer.
154 a36987999600 Afran M.S. p886 False Conference 398 A summary of data-aided equalizer experiments at edwards AFB This paper summarizes the analysis of bit error rate data captured during flight tests designed to compare data-aided equalizers with SOQPSK-TG to unequalized and currently available blind, adaptive equalizers with SOQPSK-TG. The number of bit errors, on a second-by-second basis, are analyzed. The results are different for each test point. Given the uncertain behavior of the preamble detector for the data-aided equalizer and the differing channel conditions between the data-aided equalizer channel and the conventional serial streaming telemetry channel, we are unable to draw any firm comparative conclusions.
155 a7003868048 Saquib M. p38 False Journal 20 On the effects of channel sparsity on joint estimators in aeronautical telemetry Minimum mean-squared error (MMSE) equalizers are a viable solution to mitigate the frequency selectivity of the aeronautical telemetry channel. Because the MMSE equalizer filter coefficients are a function of the carrier frequency offset (CFO), the equivalent discrete-time channel, and the noise variance, reliable estimates of those parameters are required. The CFO is due primarily to the high velocity of the airborne transmitter. Because the equivalent discrete-time channel in aeronautical telemetry is sparse, the performance of the joint estimator based on a sparse channel estimator is superior to the performance of a traditional nonsparse maximum-likelihood-inspired joint estimator. The improvement is seen in lower estimator error variances for the parameters, particularly for the CFO and channel estimate, and in the postequalizer bit-error rate. Simulation results demonstrate that the postequalizer bit-error rate using the sparse estimator is almost as good as that using ideal estimators. © 1965-2011 IEEE.
155 a7003868048 Saquib M. p85 False Journal 20 Sparse Equalization in Aeronautical Telemetry Using Two Transmit Antennas This correspondence explores the application of sparse equalizers in generalized time-reversed space-time block codes (GTR-STBCs) for a two-transmit/one-receive antenna aeronautical telemetry link. It is shown that the jointly optimum design of the sparse equalizer coefficients and the power sharing parameter \rho in GTR-STBCs is computationally challenging because the active tap ratio of the sparse equalizers is a non-convex function of \rho. A search algorithm based on a grid search followed by an interpolation is shown to yield impressive results. Our numerical results demonstrate that depending on signal-to-noise ratio and channel conditions, the number of non-zero taps of sparse equalizers for GTR-STBCs can be reduced by 53% to 86\% at the cost of 0.25 dB relaxation in the mean-squared error. © 1965-2011 IEEE.
155 a7003868048 Saquib M. p159 False Journal 111 On Sparse Channel Estimation in Aeronautical Telemetry This paper examines the application of sparse estimation techniques for the estimation of a discrete-time equivalent multipath channel in the aeronautical telemetry context. The sensing matrix comprises samples of shaped offset QPSK-TG (a continuous phase modulation) based on the pilot bit sequence currently defined in the aeronautical telemetry standard. Representative algorithms from the three broad classes of sparse estimators were examined side by side using computer simulations to estimate the postequalizer bit error rate (BER). Ideal and nonideal frequency offset synchronization were assumed in the simulations. The results show that the performance of the matching pursuit (MP) algorithms seemed to be better suited to this application in the sense that no additional steps were required and the postequalizer BER of the best MP algorithm was slightly better than that of the other sparse estimation techniques. In the case of both ideal and nonideal frequency offset synchronization, the postequalizer BER achieved by the generalized orthogonal MP algorithm was approximately 1.5 dB better than that obtained using the nonsparse-constrained maximum likelihood channel estimate. © 1965-2011 IEEE.
155 a7003868048 Saquib M. p619 False Conference 256 Cfo estimation by exploiting channel sparsity in aeronautical telemetry In this paper, we explore a carrier frequency offset (CFO) estimation scheme with sparsity-constraint (SC) on the aeronautical telemetry channels. This SC CFO estimator is implemented in two steps. In the first step, channel support is recovered by combining compressed sensing techniques with the CFO estimate based on the non-sparsity constraint (NSC) on the channel. Next we use the estimated channel support to derive the SC CFO estimator. Simulations are performed to compare the performance of the SC CFO estimator against the existing NSC CFO estimators using shaped offset QPSK version TG (SOQPSK-TG) modulated iNET-formatted data over an aeronautical test channel. © held by the author; distribution rights International Foundation for Telemetering.
155 a7003868048 Saquib M. p848 False Conference 372 Sparse MMSE equalizer for GTR-STBC in aeronautical telemetry This paper investigates the performance of sparse minimum mean squared error (MMSE) equalizer for generalized time-reversed space-time block codes (GTR-STBC) in aeronautical telemetry. GTR-STBC equipped with MMSE equalizer performs the best trade-offbetween the signal-tonoise ratio and inter-symbol interference by allocating unequal power over aeronautical telemetry channels. However, aeronautical telemetry channels are in general consists of larger delay spreads which make the MMSE equalization of aeronautical channels with GTR-STBC computationally complex. Interestingly enough, in spite of larger delays aeronautical channels are made of few sparsely distributed multipaths and therefore their MMSE equalizers are highly compressible. In this paper, compressed sensing based greedy algorithm is used for the design of sparse MMSE equalizer and a convex curve-fitting algorithm is used to find the sub-optimum power allocation parameter at the same sparsity level for GTR-STBC. Our simulation results show that 75-90% of the non-zero equalizer taps can be reduced with a slight relaxation of the mean-squared error (or equivalently slight degradation of bit-error rate performance). It is also observed that the optimum transmitter power profile for the sparse MMSE equalizer is different than that of the non-sparse equalizer.
155 a7003868048 Saquib M. p886 False Conference 398 A summary of data-aided equalizer experiments at edwards AFB This paper summarizes the analysis of bit error rate data captured during flight tests designed to compare data-aided equalizers with SOQPSK-TG to unequalized and currently available blind, adaptive equalizers with SOQPSK-TG. The number of bit errors, on a second-by-second basis, are analyzed. The results are different for each test point. Given the uncertain behavior of the preamble detector for the data-aided equalizer and the differing channel conditions between the data-aided equalizer channel and the conventional serial streaming telemetry channel, we are unable to draw any firm comparative conclusions.
156 a57190402922 Ellingson G. p39 True Journal 32 Relative navigation of fixed-wing aircraft in GPS-denied environments This work enables GPS-denied flight on fixed-wing UAS by accounting for fixed-wing-specific sensing requirements and using a methodology called relative navigation as an overarching framework. The development of an odometry-like, front-end, EKF-based estimator that utilizes only a monocular camera and an inertial measurement unit (IMU) is presented. The filter uses the measurement model of the multi-state-constraint Kalman filter. The filter also regularly resets its origin in coordination with the declaration of keyframe images. The keyframe-to-keyframe odometry estimates and their covariances are sent to a global back end that represents the global state as a pose graph. The back end is better suited to represent nonlinear uncertainties and incorporate opportunistic global constraints. We also introduce a method to account for front-end velocity bias in the back-end optimization. The paper provides simulation and hardware flight-test results of the front-end estimator and performs several back-end optimizations on the front-end data. © 2020 Institute of Navigation
156 a57190402922 Ellingson G. p121 True Journal 81 Cooperative relative navigation of multiple aircraft in global positioning system-denied/degraded environments This paper introduces a method for enabling multiple small unmannedaircraft to improve navigational accuracy in Global Positioning System (GPS)-denied environments by cooperatively sharing information. The method uses a multilevel framework called relative navigation and visual-inertial odometry: Both of which have been used for singlevehicle GPS-denied navigation. This work modifies the relative navigation architecture by adding the necessary elements to enable decentralized, cooperative operations. The proposed framework also includes the ability to incorporate intervehicle measurements and uses a new concept called the coordinated reset, which is necessary for optimizing the cooperative odometry and improving localization. A simple communication protocol is presented, as well as flight-test results that show its effectiveness. The method is first demonstrated in simulation, including Monte Carlo testing, to show the expected improvement gained from cooperation. Finally, results from hardware testing are presented that show the ability of the system to reject initialization errors, to operate with temporary communications dropouts, and to greatly reduce the total amount of shared data compared to a naive approach. The proposed method is able to improve both global navigation accuracy and the accuracy of the relative aircraft positions for missions that require formation flying. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
156 a57190402922 Ellingson G. p213 False Conference 48 Deep RC: Enabling remote control through deep learning Human remote-control (RC) pilots have the ability to perceive the position and orientation of an aircraft using only third-person-perspective visual sensing. While novice pilots often struggle when learning to control RC aircraft, they can sense the orientation of the aircraft with relative ease. In this paper, we hypothesize and demonstrate that deep learning methods can be used to mimic the human ability to perceive the orientation of an aircraft from monocular imagery. This work uses a neural network to directly sense the aircraft attitude. The network is combined with more conventional image processing methods for visual tracking of the aircraft. The aircraft track and attitude measurements from the convolutional neural network (CNN) are combined in a particle filter that provides a complete state estimate of the aircraft. The network topology, training, and testing results are presented as well as filter development and results. The proposed method was tested in simulation and hardware flight demonstrations. © 2019 IEEE.
156 a57190402922 Ellingson G. p497 True Conference 187 Relative visual-inertial odometry for fixed-wing aircraft in GPS-denied environments This paper introduces an odometry-like front-end estimator for GPS-denied fixed-wing flight using a monocular camera. This development is a critical component for enabling fixed-wing aircraft to use a novel methodology called relative navigation. Relative navigation allows a single vehicle to gracefully accommodate intermittent GPS or geo-registered image updates. It can also enable communication and a computationally feasible cooperative, batch-based navigation approach for numerous vehicles. This paper presents a visual-odometry estimator that is appropriate for fixed-wing flight characteristics and sensing requirements. We propose a modification to the multi-state-constraint Kalman filter which, instead of running the filter in a single inertial/global frame, regularly resets the navigation frame to a new local origin. The vehicle operates based on the most recent keyframe and produces a marginalized change in pose (odometry) and covariance output whenever the keyframe is updated. This allows the front end to operate at the IMU rate to accommodate guidance and control inputs while sharing marginalized keyframe-to-keyframe odometry estimates with a back-end, graph optimization at a much lower rate than traditional batch navigation schemes. Results from testing the proposed method in a high-fidelity simulation of the filter is also presented. © 2018 IEEE.
156 a57190402922 Ellingson G. p662 True Conference 289 Deep visual gravity vector detection for unmanned aircraft attitude estimation This paper demonstrates a feasible method for using a deep neural network as a sensor to estimate the attitude of a flying vehicle using only flight video. A dataset of still images and associated gravity vectors was collected and used to perform supervised learning. The network builds on a previously trained network and was trained to be able to approximate the attitude of the camera with an average error of about 8 degrees. Flight test video was recorded and processed with a relatively simple visual odometry method. The aircraft attitude is then estimated with the visual odometry as the state propagation and network providing the attitude measurement in an extended Kalman filter. Results show that the proposed method of having the neural network provide a gravity vector attitude measurement from the flight imagery reduces the standard deviation of the attitude error by approximately 12 times compared to a baseline approach. © 2017 IEEE.
157 a9535406000 Sansom R.L. p40 True Journal 33 Increasing Student Use of a Learner Dashboard Use of online learning systems, such as learner dashboards, is increasing in university chemistry courses. Learning analytics can support student learning by providing feedback on concept mastery. This paper investigated how student use of a chemistry learner dashboard might be increased through class structure, instructor practice, and dashboard design changes across three iterations in a general chemistry course. Once acceptable levels of student dashboard use were achieved, further investigation of how students interacted with the dashboard, including accessing the variety of available resources, was conducted. Survey data and clickstream data from the dashboard were collected and analyzed in a convergent mixed methods design. This study found that changes in course structure, teacher practice, and dashboard design increased use of the dashboard and utilization of the variety of materials offered in it. Recommendations for instructors to effectively utilize a learner dashboard and increase student trust in the system are provided. © 2020, Springer Nature B.V.
158 a56703308500 Bodily R. p40 False Journal 33 Increasing Student Use of a Learner Dashboard Use of online learning systems, such as learner dashboards, is increasing in university chemistry courses. Learning analytics can support student learning by providing feedback on concept mastery. This paper investigated how student use of a chemistry learner dashboard might be increased through class structure, instructor practice, and dashboard design changes across three iterations in a general chemistry course. Once acceptable levels of student dashboard use were achieved, further investigation of how students interacted with the dashboard, including accessing the variety of available resources, was conducted. Survey data and clickstream data from the dashboard were collected and analyzed in a convergent mixed methods design. This study found that changes in course structure, teacher practice, and dashboard design increased use of the dashboard and utilization of the variety of materials offered in it. Recommendations for instructors to effectively utilize a learner dashboard and increase student trust in the system are provided. © 2020, Springer Nature B.V.
158 a56703308500 Bodily R. p688 True Journal 334 Review of research on student-facing learning analytics dashboards and educational recommender systems This article is a comprehensive literature review of student-facing learning analytics reporting systems that track learning analytics data and report it directly to students. This literature review builds on four previously conducted literature reviews in similar domains. Out of the 945 articles retrieved from databases and journals, 93 articles were included in the analysis. Articles were coded based on the following five categories: functionality, data sources, design analysis, student perceptions, and measured effects. Based on this review, we need research on learning analytics reporting systems that targets the design and development process of reporting systems, not only the final products. This design and development process includes needs analyses, visual design analyses, information selection justifications, and student perception surveys. In addition, experiments to determine the effect of these systems on student behavior, achievement, and skills are needed to add to the small existing body of evidence. Furthermore, experimental studies should include usability tests and methodologies to examine student use of these systems, as these factors may affect experimental findings. Finally, observational study methods, such as propensity score matching, should be used to increase student access to these systems but still rigorously measure experimental effects. © 2016 IEEE.
159 a57216531463 Bates C.O. p40 False Journal 33 Increasing Student Use of a Learner Dashboard Use of online learning systems, such as learner dashboards, is increasing in university chemistry courses. Learning analytics can support student learning by providing feedback on concept mastery. This paper investigated how student use of a chemistry learner dashboard might be increased through class structure, instructor practice, and dashboard design changes across three iterations in a general chemistry course. Once acceptable levels of student dashboard use were achieved, further investigation of how students interacted with the dashboard, including accessing the variety of available resources, was conducted. Survey data and clickstream data from the dashboard were collected and analyzed in a convergent mixed methods design. This study found that changes in course structure, teacher practice, and dashboard design increased use of the dashboard and utilization of the variety of materials offered in it. Recommendations for instructors to effectively utilize a learner dashboard and increase student trust in the system are provided. © 2020, Springer Nature B.V.
160 a23050937200 Leary H. p40 False Journal 33 Increasing Student Use of a Learner Dashboard Use of online learning systems, such as learner dashboards, is increasing in university chemistry courses. Learning analytics can support student learning by providing feedback on concept mastery. This paper investigated how student use of a chemistry learner dashboard might be increased through class structure, instructor practice, and dashboard design changes across three iterations in a general chemistry course. Once acceptable levels of student dashboard use were achieved, further investigation of how students interacted with the dashboard, including accessing the variety of available resources, was conducted. Survey data and clickstream data from the dashboard were collected and analyzed in a convergent mixed methods design. This study found that changes in course structure, teacher practice, and dashboard design increased use of the dashboard and utilization of the variety of materials offered in it. Recommendations for instructors to effectively utilize a learner dashboard and increase student trust in the system are provided. © 2020, Springer Nature B.V.
161 a57199050938 Small K.A. p41 True Journal 34 Interplay of dislocation substructure and elastic strain evolution in additively manufactured Inconel 625 The unique thermal history of direct metal laser sintering (DMLS) leads to complex microstructures and local elastic residual strains which accumulate to affect the global residual stress and mechanical properties of components. Characterization of residual stress using neutron and x-ray diffraction result in bulk and grain level residual stress measurements; however, the contribution of the microscale residual strain remains largely unaccounted for. High-resolution electron backscatter diffraction (HR-EBSD) has emerged as a promising tool for the characterization of such micron-level elastic strains. This work presents an early effort in analysis of microscale elastic strain in conjunction with subgrain dislocation structures to further the understanding of microstructural evolution during laser additive manufacturing (AM) techniques. Elastic strain in DMLS fabricated IN625 is analyzed using open source cross-correlation software OpenXY while the geometrically necessary dislocation (GND) density is calculated from EBSD data using the Nye tensor. Dislocation structures previously seen in similar materials are shown here to contain low elastic strain gradients, supporting the assertion that these structures occur as strain minimization mechanisms during solidification. © 2020 Elsevier B.V.
162 a57211158470 Clayburn Z. p41 False Journal 34 Interplay of dislocation substructure and elastic strain evolution in additively manufactured Inconel 625 The unique thermal history of direct metal laser sintering (DMLS) leads to complex microstructures and local elastic residual strains which accumulate to affect the global residual stress and mechanical properties of components. Characterization of residual stress using neutron and x-ray diffraction result in bulk and grain level residual stress measurements; however, the contribution of the microscale residual strain remains largely unaccounted for. High-resolution electron backscatter diffraction (HR-EBSD) has emerged as a promising tool for the characterization of such micron-level elastic strains. This work presents an early effort in analysis of microscale elastic strain in conjunction with subgrain dislocation structures to further the understanding of microstructural evolution during laser additive manufacturing (AM) techniques. Elastic strain in DMLS fabricated IN625 is analyzed using open source cross-correlation software OpenXY while the geometrically necessary dislocation (GND) density is calculated from EBSD data using the Nye tensor. Dislocation structures previously seen in similar materials are shown here to contain low elastic strain gradients, supporting the assertion that these structures occur as strain minimization mechanisms during solidification. © 2020 Elsevier B.V.
163 a57195286623 DeMott R. p41 False Journal 34 Interplay of dislocation substructure and elastic strain evolution in additively manufactured Inconel 625 The unique thermal history of direct metal laser sintering (DMLS) leads to complex microstructures and local elastic residual strains which accumulate to affect the global residual stress and mechanical properties of components. Characterization of residual stress using neutron and x-ray diffraction result in bulk and grain level residual stress measurements; however, the contribution of the microscale residual strain remains largely unaccounted for. High-resolution electron backscatter diffraction (HR-EBSD) has emerged as a promising tool for the characterization of such micron-level elastic strains. This work presents an early effort in analysis of microscale elastic strain in conjunction with subgrain dislocation structures to further the understanding of microstructural evolution during laser additive manufacturing (AM) techniques. Elastic strain in DMLS fabricated IN625 is analyzed using open source cross-correlation software OpenXY while the geometrically necessary dislocation (GND) density is calculated from EBSD data using the Nye tensor. Dislocation structures previously seen in similar materials are shown here to contain low elastic strain gradients, supporting the assertion that these structures occur as strain minimization mechanisms during solidification. © 2020 Elsevier B.V.
164 a35790633100 Primig S. p41 False Journal 34 Interplay of dislocation substructure and elastic strain evolution in additively manufactured Inconel 625 The unique thermal history of direct metal laser sintering (DMLS) leads to complex microstructures and local elastic residual strains which accumulate to affect the global residual stress and mechanical properties of components. Characterization of residual stress using neutron and x-ray diffraction result in bulk and grain level residual stress measurements; however, the contribution of the microscale residual strain remains largely unaccounted for. High-resolution electron backscatter diffraction (HR-EBSD) has emerged as a promising tool for the characterization of such micron-level elastic strains. This work presents an early effort in analysis of microscale elastic strain in conjunction with subgrain dislocation structures to further the understanding of microstructural evolution during laser additive manufacturing (AM) techniques. Elastic strain in DMLS fabricated IN625 is analyzed using open source cross-correlation software OpenXY while the geometrically necessary dislocation (GND) density is calculated from EBSD data using the Nye tensor. Dislocation structures previously seen in similar materials are shown here to contain low elastic strain gradients, supporting the assertion that these structures occur as strain minimization mechanisms during solidification. © 2020 Elsevier B.V.
165 a12142543700 Fullwood D. p41 False Journal 34 Interplay of dislocation substructure and elastic strain evolution in additively manufactured Inconel 625 The unique thermal history of direct metal laser sintering (DMLS) leads to complex microstructures and local elastic residual strains which accumulate to affect the global residual stress and mechanical properties of components. Characterization of residual stress using neutron and x-ray diffraction result in bulk and grain level residual stress measurements; however, the contribution of the microscale residual strain remains largely unaccounted for. High-resolution electron backscatter diffraction (HR-EBSD) has emerged as a promising tool for the characterization of such micron-level elastic strains. This work presents an early effort in analysis of microscale elastic strain in conjunction with subgrain dislocation structures to further the understanding of microstructural evolution during laser additive manufacturing (AM) techniques. Elastic strain in DMLS fabricated IN625 is analyzed using open source cross-correlation software OpenXY while the geometrically necessary dislocation (GND) density is calculated from EBSD data using the Nye tensor. Dislocation structures previously seen in similar materials are shown here to contain low elastic strain gradients, supporting the assertion that these structures occur as strain minimization mechanisms during solidification. © 2020 Elsevier B.V.
165 a12142543700 Fullwood D. p73 False Journal 53 Nanoparticle orientation distribution analysis and design for polymeric piezoresistive sensors Piezoresistive sensors, with polymer matrices and conductive nanoparticles, are a relatively new addition to the sensor class, with the potential to transform such fields as wearable sensors and the internet of things. The unusual inverse piezoresistive behavior of the sensors has been modeled using quantum tunneling and percolation theory. However, the impact of the distribution of conductive particles in the matrix, and specifically their relative orientation, has not been well studied. The initial and deformed distribution of orientations greatly influences the sensor behavior, since the quantum tunneling model is highly sensitive to the polymer gaps between nanoparticles; the evolution of these gaps under deformation is strongly dependent upon the relative orientation of neighboring particles, and determines electron transport properties, and overall sensor response. In this paper a simple analytical model for isotropic orientation distribution and subsequent Poisson-based gap evolution is compared with a more sophisticated finite element and random resistor network analysis. The new numerical model was able to explain previously unexplained physical behavior and is used to design sensors with specific desired characteristics. The appropriateness of the previously assumed percolation behavior is also examined via the model and generalized effective medium theory. © 2020
165 a12142543700 Fullwood D. p80 False Journal 60 Grain boundary structure–property model inference using polycrystals: the overdetermined case Efforts to construct predictive grain boundary (GB) structure–property models have historically relied on property measurements or calculations made on bicrystals. Experimental bicrystals can be difficult or expensive to fabricate, and computational constraints limit atomistic bicrystal simulations to high-symmetry GBs (i.e., those with small enough GB periodicity). Although the use of bicrystal property data to construct GB structure–property models is more direct, in many experimental situations the only type of data available may be measurements of the effective properties of polycrystals. In this work, we investigate the possibility of inferring GB structure–property models from measurements of the homogenized effective properties of polycrystals when the form of the structure–property model is unknown. We present an idealized case study in which GB structure–property models for diffusivity are inferred from noisy simulation results of two-dimensional microstructures, under the assumption that the number of polycrystal measurements available is larger than the number of parameters in the inferred model. We also demonstrate how uncertainty quantification for the inferred structure–property models is easily performed within this framework. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
165 a12142543700 Fullwood D. p88 False Journal 67 An investigation of geometrically necessary dislocations and back stress in large grained tantalum via EBSD and CPFEM This study explores the evolution of GNDs and their effects on back stress through experimental and computational methods. Four large-grained tantalum tensile specimens were strained in uniaxial tension, electron backscatter diffraction (EBSD) data were collected, and geometrically necessary dislocation (GND) maps of the four specimens in the unloaded state were produced. EBSD-based GND maps revealed several types of features with high GND content which caused back stress in the specimens. Correlations between five geometrically-based grain boundary (GB) transmission factors and the GB GND content were evaluated, and statistically significant correlations were found for transmission factors based on Livingston and Chalmer's N factor, Werner and Prantl's slip transfer number, and GB misorientation. The sign of individual components of the Nye tensor were used to visually and quantitatively identify clustering of GNDs of the same sign, thus giving additional evidence of increasing back stress due to deformation. Deformation of one of the specimens was simulated using multiple CPFEM based modeling approaches and predicted stress-strain responses are compared. The super dislocation model (SD model) — a crystal plasticity finite element method (CPFEM) which incorporates elastic dislocation interactions — was able to isolate impact of back stress on the overall flow stress. The SD model predicted correct stresses when compared with experimental data; however, when the elastic interactions in the SD model were turned off, stress predictions were 25% too low. Thus, demonstrating the importance of incorporating back stress into the model. © 2019 Elsevier B.V.
165 a12142543700 Fullwood D. p95 False Journal 73 Optical measurement of voids in situ during infusion of carbon reinforcements Liquid composite molding (LCM) is growing in importance as an alternative to traditional prepreg-autoclave methods for manufacture high-performance composites. The most significant roadblock to industry’s implementation of LCM is the usually higher void content compared with prepreg processing. One tool for reducing void levels in LCM involves optimization of flow velocity, which requires models to be developed to describe void formation at a given velocity. To help solve this problem, the following research illustrates the first known method for optical void measurement in situ during infusion in a carbon fiber reinforcement. Similar to previous studies on glass fiber, this work utilizes fluorescent dye and a digital camera to produce sufficient contrast and resolution for image analysis. Visible bubbles are photographed against the opaque carbon fiber background. An automated method of image analysis is outlined, which was used to analyze 230 images for three different flow orientations of a single fabric, producing the highest amount of experimental data seen so far on in situ void measurement. The resulting data identifies a minimum velocity threshold for minimal macro-void formation. The resultant void characterization framework will better enable optimization of LCM processing for high-performance composites based on carbon reinforcements. © The Author(s) 2020.
165 a12142543700 Fullwood D. p140 False Journal 98 The effects of voids in quasi-static indentation of resin-infused reinforced polymers The focus of this study is the influence of voids on the damage behaviour in quasi-static loading of resin-infused carbon fibre-reinforced polymers. Experimental results are presented for quasi-static loading in combination with high-resolution tomographic imaging and statistical analysis (homology of pores or voids and induced cracks). Three distinct mechanisms were observed to control delamination growth in the presence of sharp and blunt voids. Delamination cracks interact with the supporting yarns, especially in combination with air pockets trapped in the resin in the form of long, sharp voids. This resulted in crack growth that coalesces with delamination cracks from neighbouring yarn-voids during increased out-of-plane load–displacement, with almost no presence of intralaminar transverse cracks. This highlights the benefits and drawbacks of the supporting yarn during out-of-plane loading. © The Author(s) 2019.
165 a12142543700 Fullwood D. p199 False Journal 133 Lower-bound dislocation density mapping in microcoined tantalum using high-resolution electron backscatter diffraction High-resolution electron backscatter diffraction (HR-EBSD) is used to map the geometrically necessary dislocation (GND) density in the cross-sections of annealed, rolled, and microcoined tantalum foils that are typical targets used in modern laser-induced compression materials science studies. The microcoined samples are characteristic of microforming, where the deformation length scale is on the order of the grain size (~50 μm). In particular, inhomogeneities in dislocation density maps across 0.1–1 mm regions of interest are compared with expectations from slip line field approximations. The average HR-EBSD GND dislocation density measurements in various annealed and cold worked tantalum samples are compared with corresponding dislocation density approximations from microhardness measurements. GND densities in the range 1013 − 1015 m−2 are typical. © 2019 Elsevier Inc.
165 a12142543700 Fullwood D. p208 False Journal 141 Atomistic survey of grain boundary-dislocation interactions in FCC nickel It is well known that grain boundaries (GBs) have a strong influence on mechanical properties of polycrystalline materials. Not as well-known is how different GBs interact with dislocations to influence dislocation movement. This work presents a molecular dynamics study of 33 different FCC Ni bicrystals, each subjected to four different loading conditions to induce incident dislocation-GB interactions in 132 unique configurations. The resulting simulations produce 189 dislocation-GB interactions. Each interaction is analyzed to determine properties that affect the likelihood of transmission, reflection, or absorption of the dislocation at the GB of interest. The results confirm the ability to predict the slip system of a transmitted dislocation using common geometric criteria. Furthermore, machine learning reveals that geometric properties, such as the minimum residual Burgers vector (RBV) and the disorientation angle between the two grains, are strong indicators of whether or not a dislocation will transmit through a GB. © 2019 Elsevier B.V.
165 a12142543700 Fullwood D. p227 False Journal 149 Modeling of trans-grain twin transmission in AZ31 via a neighborhood-based viscoplastic self-consistent model The impact of twin transmission between neighboring grains as a contributor to overall twin activity is considered via a neighborhood viscoplastic self-consistent (NVPSC) model. The NVPSC model is an extension of a stochastic model for twin nucleation developed by Niezgoda et al. and a dislocation density based hardening law model developed by Knezevic et al. Beyond the baseline combined framework, the new model tracks sets of neighboring grains and allows twin transmission between them under certain conditions. The influence of grain boundary (GB) character is included in the stochastic models of twin nucleation and transmission. The starting texture from a rolled magnesium alloy AZ31B sheet was obtained using electron backscatter diffraction (EBSD) for initial input into the NVPSC. The sample was further deformed by uniaxial compression to encourage twin formation and the corresponding texture information was collected using EBSD. The accuracy of simulated twin activity was determined by comparing it with the twin activity seen in the deformed sample. The total number of predicted twins and the number of transmission twins is found to agree favorably with those observed via the EBSD scans. This validation demonstrates the significance of incorporating twin transmission as a twin formation mode in predictive models for this material. © 2018 Elsevier Ltd.
165 a12142543700 Fullwood D. p445 False Journal 249 Effect of strain path on forming limits and retained austenite transformation in Q&P 1180 steel Forming limits and retained austenite (RA) transformation in Q&P 1180 steel are quantified as a function of plastic strain levels for three different strain paths. In-plane uniaxial tension testing was performed in a standard test frame, while limiting dome height tooling was employed for out-of-plane biaxial and plane strain tension experiments. Sheet specimens were tested incrementally for each strain path, and the RA content at each level of strain was measured using electron backscatter diffraction (EBSD). The biaxial tension strain path resulted in the greatest effective strain prior to necking at 0.355, compared to 0.123 for plane strain and 0.142 for uniaxial tension. EBSD measurements for various levels of plastic strain reveal a clear dependence of RA rate of transformation on strain path for the three linear strain paths that were employed in this work. Thinning strains appear to provide a slightly better correlation to RA transformation than effective strain levels, where biaxial tension achieved the greatest level just prior to necking, followed by plane-strain tension, and then uniaxial tension. © 2018 Elsevier B.V.
165 a12142543700 Fullwood D. p455 False Conference 161 Modified Material Properties in Curved Panels Through Lamina Emergent Torsional Joints Compliant joints have a number of advantages that make them suitable for highly constrained design problems. While much work has been done on the design of compliant joints manufactured from planar sheet materials, this work focuses on the design of cylindrically-curved joints. A method for using lamina emergent torsional (LET) joints to increase energy storage efficiency in curved sheet materials is presented. A numerical model is provided for predicting the stiffness and maximum applied moment of a curved LET joint. Predicted curved LET joint stiffnesses and maximum moments are utilized to create shape factors that produce an effective modulus of elasticity and an effective modulus of resilience. For a given case, the effective modulus of elasticity is shown to decrease by about three orders of magnitude while the effective resilience decreases by approximately one order of magnitude. Designers can use this information to tailor materials to fit design requirements or to select alternative materials that were previously unsuited for an application. © 2018 IEEE.
165 a12142543700 Fullwood D. p494 False Journal 267 Preface [No abstract available]
165 a12142543700 Fullwood D. p495 False Conference 186 Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lath Martensitic Steel The study of post-transformation microstructures and their properties can be greatly enhanced by studying their dependence on the grain boundary content of parent microstructures. Recent work has extended the crystallographic reconstruction of parent austenite in steels to include the reconstruction of special boundaries, such as annealing twins. These reconstructions present unique challenges, as twinned austenite grains share a subset of possible daughter variant orientations. This gives rise to regions of ambiguity in a reconstruction. A technique for the reconstruction of twin boundaries is presented here that is capable of reconstructing 60° <1 1 1> twins, even in the case where twin regions are comprised entirely of variants that are common between the twin and the parent. This technique is demonstrated in the reconstruction of lath martensitic steels. The reconstruction method utilizes a delayed decision-making approach, where a chosen orientation relationship is used to define all possible groupings of daughter grains into possible parents before divisive decisions are made. These overlapping, inclusive groupings (called clusters) are compared to each other individually using their calculated parent austenite orientations and the topographical nature of the overlapping region. These comparisons are used to uncover possible locations of twin boundaries present in the parent austenite. This technique can be applied to future studies on the dependence of post-transformation microstructures on the special grain boundary content of parent microstructures. © 2018 Institute of Physics Publishing. All rights reserved.
165 a12142543700 Fullwood D. p505 False Journal 276 Inverse piezoresistive nanocomposite sensors for identifying human sitting posture Sitting posture is the position in which one holds his/her body upright against gravity while sitting. Poor sitting posture is regarded as an aggravating factor for various diseases. In this paper, we present an inverse piezoresistive nanocomposite sensor, and related deciphering neural network, as a new tool to identify human sitting postures accurately. As a low power consumption device, the proposed tool has simple structure, and is easy to use. The strain gauge is attached to the back of the user to acquire sitting data. A three-layer BP neural network is employed to distinguish normal sitting posture, slight hunchback and severe hunchback according to the acquired data. Experimental results show that our method is both realizable and effective, achieving 98.75% posture identification accuracy. This successful application of inverse piezoresistive nanocomposite sensors reveals that the method could potentially be used for monitoring of diverse physiological parameters in the future. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
165 a12142543700 Fullwood D. p517 False Journal 286 Effect of environmental and material factors on the response of nanocomposite foam impact sensors Nanocomposite foam (NCF) is a multifunctional material that can be used to measure impact. Interactions between the flexible polymer matrix and conductive particles dispersed throughout it produce a voltage signal under dynamic strain, which correlates to the magnitude of impact. Though promising in applications requiring both impact sensing and energy absorption, NCF's voltage response has been observed to suffer from significant signal drift. This paper investigates several causes of variance in the response of NCF sensors to consistent impacts. These effects can be classified into three general types: recoverable transient effects (such as those relating to viscoelasticity or capacitive charging), environmental drift (due to humidity and temperature), and permanent signal decay from material degradation. The motivation for the study arises from various potential repeat-impact applications where periodic recalibration of the sensor would be difficult (such as a gait-tracking insole in use for a marathon event). A cyclic drop testing machine was used to apply consistent impacts to NCF, and drift resulting from each factor (in ranges typical of an insole environment) was experimentally isolated. Models representing each factor's contribution to signal drift are presented. Of the factors investigated, humidity and temperature caused the most significant drift, with permanent material degradation accounting for only minor decay in voltage response. Transient effects were also observed, with a characteristic 'warm-up' (or 'charging') time required for the NCF to achieve steady-state; this phenomenon, and the related 'recovery' time for the material to return to its original state, were determined. The resultant data can be leveraged to implement a correction algorithm or other drift-compensating method to retain an NCF sensor's accuracy in both long and short data collection scenarios. © 2018 IOP Publishing Ltd.
165 a12142543700 Fullwood D. p546 False Journal 300 Materials selection of flexible open-cell foams in energy absorption applications Foam must be engineered to absorb a particular range of energy in various impact-related applications. Since energy absorption is dependent upon the unique stress-strain response of each foam specimen, it is difficult to quantify analytically; thus, energy absorption cannot be easily compared across materials. Current methods accomplish this using an experimental approach, individually testing foam materials, densities, and geometries to quantify how each influences energy absorption. Such methods require large amounts of time and money to characterize a narrow range of foams. This paper facilitates foam selection by deriving generalized energy absorption material indices. Assuming Euler buckling of columns in the open-cell foam structure, this paper applies equations derived by Maiti et al. to a typical impact scenario wherein the indices are extracted. Using existing Ashby charts, these indices allow polymers to be ranked by the mass and cost each would require as a foamed structure to satisfy specific energy absorption constraints. The presented method allows the energy absorption of a wide range of flexible foams to be compared and relieves the need for extensive factor-specific testing. This method is applied to football helmet foam selection; however, it can be used for many applications where energy absorption is of interest. © 2017 Elsevier Ltd
165 a12142543700 Fullwood D. p666 False Journal 320 Nano-Composite Foam Sensor System in Football Helmets American football has both the highest rate of concussion incidences as well as the highest number of concussions of all contact sports due to both the number of athletes and nature of the sport. Recent research has linked concussions with long term health complications such as chronic traumatic encephalopathy and early onset Alzheimer’s. Understanding the mechanical characteristics of concussive impacts is critical to help protect athletes from these debilitating diseases and is now possible using helmet-based sensor systems. To date, real time on-field measurement of head impacts has been almost exclusively measured by devices that rely on accelerometers or gyroscopes attached to the player’s helmet, or embedded in a mouth guard. These systems monitor motion of the head or helmet, but do not directly measure impact energy. This paper evaluates the accuracy of a novel, multifunctional foam-based sensor that replaces a portion of the helmet foam to measure impact. All modified helmets were tested using a National Operating Committee Standards for Athletic Equipment-style drop tower with a total of 24 drop tests (4 locations with 6 impact energies). The impacts were evaluated using a headform, instrumented with a tri-axial accelerometer, mounted to a Hybrid III neck assembly. The resultant accelerations were evaluated for both the peak acceleration and the severity indices. These data were then compared to the voltage response from multiple Nano Composite Foam sensors located throughout the helmet. The foam sensor system proved to be accurate in measuring both the HIC and Gadd severity index, as well as peak acceleration while also providing additional details that were previously difficult to obtain, such as impact energy. © 2017, Biomedical Engineering Society.
165 a12142543700 Fullwood D. p694 False Journal 320 Estimation of 3D Ground Reaction Force Using Nanocomposite Piezo-Responsive Foam Sensors During Walking This paper describes a method for the estimation of the 3D ground reaction force (GRF) during human walking using novel nanocomposite piezo-responsive foam (NCPF) sensors. Nine subjects (5 male, 4 female) walked on a force-instrumented treadmill at 1.34 m/s for 120 s each while wearing a shoe that was instrumented with four NCPF sensors. GRF data, measured via the treadmill, and sensor data, measured via the NCPF inserts, were used in a tenfold cross validation process to calibrate a separate model for each individual. The calibration model estimated average anterior–posterior, mediolateral and vertical GRF with mean average errors (MAE) of 6.52 N (2.14%), 4.79 N (6.34%), and 15.4 N (2.15%), respectively. Two additional models were created using the sensor data from all subjects and subject demographics. A tenfold cross validation process for this combined data set resulted in models that estimated average anterior–posterior, mediolateral and vertical GRF with less than 8.16 N (2.41%), 6.63 N (7.37%), and 19.4 N (2.31%) errors, respectively. Intra-subject estimates based on the model had a higher accuracy than inter-subject estimates, likely due to the relatively small subject cohort used in creating the model. The novel NCPF sensors demonstrate the ability to accurately estimate 3D GRF during human movement outside of the traditional biomechanics laboratory setting. © 2017, Biomedical Engineering Society.
165 a12142543700 Fullwood D. p748 False Journal 362 An RVE procedure for micromechanical prediction of mechanical behavior of dual-phase steel A “bottom-up” representative volume element (RVE) for a dual phase steel was constructed based on measured microstructural properties (“microproperties”). This differs from the common procedure of inferring hypothetical microproperties by fitting to macroscopic behavior using an assumed micro-to-macrolaw. The bottom-up approach allows the assessment of the law itself by comparing RVE-predicted mechanical behavior with independent macroscopic measurements, thus revealing the nature of the controlling micromechanisms. An RVE for DP980 steel was constructed using actual microproperties. Finite element (FE) simulations of elastic-plastic transitions were compared with independent loading-unloading-loading and compression-tension experiments. Constitutive models of three types were utilized: 1) a standard continuum model, 2) a standard Crystal Plasticity (CP) model, and 3) a SuperDislocation (SD) model similar to CP but including the elastic interactions of discrete dislocations. These comparisons led to following conclusions: 1) While a constitutive model that ignores elastic interaction of defects can be fit to macroscopic or microscopic behavior, it cannot represent both accurately, 2) Elastic interactions among dislocations are the predominant source of nonlinearity in the nominally-elastic region (i.e. at stresses below the standard yield stress), and 3) Continuum stress inhomogeneity arising from the hard martensite / soft ferrite microstructure has a minor role in the observed transitional nonlinearity in the absence of discrete dislocation interactions. © 2017 Elsevier B.V.
165 a12142543700 Fullwood D. p756 False Journal 361 Microstructure Correlation with Formability for Biaxial Stretching of Magnesium Alloy AZ31B at Mildly Elevated Temperatures Magnesium AZ31B sheets of 2 mm thickness were stretch formed with a 101.6-mm-diameter punch at temperatures from 25°C to 150°C, in 25°C increments. Surface strains were measured with a digital image correlation method. The punch height versus load curve was found to be the same for temperatures of 25°C and for 50°C, whereas at 75°C and above, the load for a given punch height started to decrease, indicating a potential change in deformation mechanism. Electron backscatter diffraction was used to quantify features of the microstructure in the tested specimens. In particular, the gradual decrease in twinning activity as a result of easier thermally activated slip with increasing temperatures is quantified across this range. Moreover, twin activity was found to predominantly involve the formation of {10 1 ¯ 1 } compression twins that rapidly transform to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
165 a12142543700 Fullwood D. p884 False Conference 397 Formability of magnesium alloy AZ31B from room temperature to 125, °C under biaxial tension Magnesium AZ31B sheets of 2, mm thickness were stretch formed using a 101.6, mm diameter punch at room temperature and subsequent increments from 25 to 125, °C. Surface strains were measured using a digital image correlation method in order to ensure that biaxial stretching was achieved. The punch height versus load curve was found to be the same for temperatures of 25 and for 50, °C, while at 75, °C the load for a given punch height was less. This difference seems to indicate a change in deformation mechanism between 50 and 75, °C. Electron Backscatter Diffraction (EBSD) was used to quantify features of the microstructure in the as-received and the strained specimens. Rather than a sudden transition from twinning to slip at low temperatures, it appears that twinning gradually decreases and slip activity increases as temperatures rise across the range from 25 to 125, °C. This confirms recent predictions found in the literature. The twin activity predominantly involves the formation of compression twins which rapidly transform further to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
166 a8715877100 Taheri M.L. p41 False Journal 34 Interplay of dislocation substructure and elastic strain evolution in additively manufactured Inconel 625 The unique thermal history of direct metal laser sintering (DMLS) leads to complex microstructures and local elastic residual strains which accumulate to affect the global residual stress and mechanical properties of components. Characterization of residual stress using neutron and x-ray diffraction result in bulk and grain level residual stress measurements; however, the contribution of the microscale residual strain remains largely unaccounted for. High-resolution electron backscatter diffraction (HR-EBSD) has emerged as a promising tool for the characterization of such micron-level elastic strains. This work presents an early effort in analysis of microscale elastic strain in conjunction with subgrain dislocation structures to further the understanding of microstructural evolution during laser additive manufacturing (AM) techniques. Elastic strain in DMLS fabricated IN625 is analyzed using open source cross-correlation software OpenXY while the geometrically necessary dislocation (GND) density is calculated from EBSD data using the Nye tensor. Dislocation structures previously seen in similar materials are shown here to contain low elastic strain gradients, supporting the assertion that these structures occur as strain minimization mechanisms during solidification. © 2020 Elsevier B.V.
167 a57209474608 McLeod A.R. p42 True Journal 35 Improving running economy through altered shoe bending stiffness across speeds Increasing the longitudinal bending stiffness of running shoes decreases energy cost until a low point is reached, suggesting an optimal shoe stiffness. Previous research found optimal stiffness varies among individuals, however, none has determined the causes of variation both between individuals and running speeds. The primary purpose of this study was to understand how optimal shoe stiffness is affected by running speed. A secondary purpose examined the anatomical and biomechanical characteristics associated with optimal stiffness variation. Six shoe stiffness conditions were manufactured with a carbon fibre plate between the midsole and outsole of a standard running shoe. Twenty-one male runners (mass = 67.1 ± 5.0 kg, height = 178.9 cm ± 4.0 cm, age = 26.4 ± 8.4 years) completed testing at 2.98 m/s and 4.47 m/s in all shoe conditions, measuring metabolic cost, and several biomechanical and anatomical variables. Data were separated by foot strike. At the fast speed, average optimal stiffness was 19.29 ± 5.62 N/mm with a metabolic benefit of 3.02 ± 2.62%. Slow speed average optimal stiffness was 17.04 ± 6.09 N/mm with a metabolic benefit of 1.93 ± 1.82%. Only rearfoot strikers demonstrated a significant increase in optimal stiffness (p =.04) across speeds. There were no correlations between any of the measured anatomical or biomechanical variables and optimal stiffness. Optimal stiffness varied between subjects but was not correlated to any of our measured characteristics. Rearfoot striking runners may benefit from a higher stiffness shoe at faster speeds to enable optimal performance. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.
167 a57209474608 McLeod A.R. p204 True Journal 137 Running shoe optimal stiffness and speed [No abstract available]
168 a12445208100 Bruening D. p42 False Journal 35 Improving running economy through altered shoe bending stiffness across speeds Increasing the longitudinal bending stiffness of running shoes decreases energy cost until a low point is reached, suggesting an optimal shoe stiffness. Previous research found optimal stiffness varies among individuals, however, none has determined the causes of variation both between individuals and running speeds. The primary purpose of this study was to understand how optimal shoe stiffness is affected by running speed. A secondary purpose examined the anatomical and biomechanical characteristics associated with optimal stiffness variation. Six shoe stiffness conditions were manufactured with a carbon fibre plate between the midsole and outsole of a standard running shoe. Twenty-one male runners (mass = 67.1 ± 5.0 kg, height = 178.9 cm ± 4.0 cm, age = 26.4 ± 8.4 years) completed testing at 2.98 m/s and 4.47 m/s in all shoe conditions, measuring metabolic cost, and several biomechanical and anatomical variables. Data were separated by foot strike. At the fast speed, average optimal stiffness was 19.29 ± 5.62 N/mm with a metabolic benefit of 3.02 ± 2.62%. Slow speed average optimal stiffness was 17.04 ± 6.09 N/mm with a metabolic benefit of 1.93 ± 1.82%. Only rearfoot strikers demonstrated a significant increase in optimal stiffness (p =.04) across speeds. There were no correlations between any of the measured anatomical or biomechanical variables and optimal stiffness. Optimal stiffness varied between subjects but was not correlated to any of our measured characteristics. Rearfoot striking runners may benefit from a higher stiffness shoe at faster speeds to enable optimal performance. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.
168 a12445208100 Bruening D. p204 False Journal 137 Running shoe optimal stiffness and speed [No abstract available]
168 a12445208100 Bruening D. p510 True Journal 279 Midtarsal locking, the windlass mechanism, and running strike pattern: A kinematic and kinetic assessment Changes in running strike pattern affect ankle and knee mechanics, but little is known about the influence of strike pattern on the joints distal to the ankle. The purpose of this study was to explore the effects of forefoot strike (FFS) and rearfoot strike (RFS) running patterns on foot kinematics and kinetics, from the perspectives of the midtarsal locking theory and the windlass mechanism. Per the midtarsal locking theory, we hypothesized that the ankle would be more inverted in early stance when using a FFS, resulting in decreased midtarsal joint excursions and increased dynamic stiffness. Associated with a more engaged windlass mechanism, we hypothesized that a FFS would elicit increased metatarsophalangeal joint excursions and negative work in late stance. Eighteen healthy female runners ran overground with both FFS and RFS patterns. Instrumented motion capture and a validated multi-segment foot model were used to analyze midtarsal and metatarsophalangeal joint kinematics and kinetics. During early stance in FFS the ankle was more inverted, with concurrently decreased midtarsal eversion (p < 0.001) and abduction excursions (p = 0.003) but increased dorsiflexion excursion (p = 0.005). Dynamic midtarsal stiffness did not differ (p = 0.761). During late stance in FFS, metatarsophalangeal extension was increased (p = 0.009), with concurrently increased negative work (p < 0.001). In addition, there was simultaneously increased midtarsal positive work (p < 0.001), suggesting enhanced power transfer in FFS. Clear evidence for the presence of midtarsal locking was not observed in either strike pattern during running. However, the windlass mechanism appeared to be engaged to a greater extent during FFS. © 2018 Elsevier Ltd
169 a35868117400 Johnson A.W. p42 False Journal 35 Improving running economy through altered shoe bending stiffness across speeds Increasing the longitudinal bending stiffness of running shoes decreases energy cost until a low point is reached, suggesting an optimal shoe stiffness. Previous research found optimal stiffness varies among individuals, however, none has determined the causes of variation both between individuals and running speeds. The primary purpose of this study was to understand how optimal shoe stiffness is affected by running speed. A secondary purpose examined the anatomical and biomechanical characteristics associated with optimal stiffness variation. Six shoe stiffness conditions were manufactured with a carbon fibre plate between the midsole and outsole of a standard running shoe. Twenty-one male runners (mass = 67.1 ± 5.0 kg, height = 178.9 cm ± 4.0 cm, age = 26.4 ± 8.4 years) completed testing at 2.98 m/s and 4.47 m/s in all shoe conditions, measuring metabolic cost, and several biomechanical and anatomical variables. Data were separated by foot strike. At the fast speed, average optimal stiffness was 19.29 ± 5.62 N/mm with a metabolic benefit of 3.02 ± 2.62%. Slow speed average optimal stiffness was 17.04 ± 6.09 N/mm with a metabolic benefit of 1.93 ± 1.82%. Only rearfoot strikers demonstrated a significant increase in optimal stiffness (p =.04) across speeds. There were no correlations between any of the measured anatomical or biomechanical variables and optimal stiffness. Optimal stiffness varied between subjects but was not correlated to any of our measured characteristics. Rearfoot striking runners may benefit from a higher stiffness shoe at faster speeds to enable optimal performance. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.
169 a35868117400 Johnson A.W. p204 False Journal 137 Running shoe optimal stiffness and speed [No abstract available]
170 a57209473859 Ward J. p42 False Journal 35 Improving running economy through altered shoe bending stiffness across speeds Increasing the longitudinal bending stiffness of running shoes decreases energy cost until a low point is reached, suggesting an optimal shoe stiffness. Previous research found optimal stiffness varies among individuals, however, none has determined the causes of variation both between individuals and running speeds. The primary purpose of this study was to understand how optimal shoe stiffness is affected by running speed. A secondary purpose examined the anatomical and biomechanical characteristics associated with optimal stiffness variation. Six shoe stiffness conditions were manufactured with a carbon fibre plate between the midsole and outsole of a standard running shoe. Twenty-one male runners (mass = 67.1 ± 5.0 kg, height = 178.9 cm ± 4.0 cm, age = 26.4 ± 8.4 years) completed testing at 2.98 m/s and 4.47 m/s in all shoe conditions, measuring metabolic cost, and several biomechanical and anatomical variables. Data were separated by foot strike. At the fast speed, average optimal stiffness was 19.29 ± 5.62 N/mm with a metabolic benefit of 3.02 ± 2.62%. Slow speed average optimal stiffness was 17.04 ± 6.09 N/mm with a metabolic benefit of 1.93 ± 1.82%. Only rearfoot strikers demonstrated a significant increase in optimal stiffness (p =.04) across speeds. There were no correlations between any of the measured anatomical or biomechanical variables and optimal stiffness. Optimal stiffness varied between subjects but was not correlated to any of our measured characteristics. Rearfoot striking runners may benefit from a higher stiffness shoe at faster speeds to enable optimal performance. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.
171 a35867849600 Hunter I. p42 False Journal 35 Improving running economy through altered shoe bending stiffness across speeds Increasing the longitudinal bending stiffness of running shoes decreases energy cost until a low point is reached, suggesting an optimal shoe stiffness. Previous research found optimal stiffness varies among individuals, however, none has determined the causes of variation both between individuals and running speeds. The primary purpose of this study was to understand how optimal shoe stiffness is affected by running speed. A secondary purpose examined the anatomical and biomechanical characteristics associated with optimal stiffness variation. Six shoe stiffness conditions were manufactured with a carbon fibre plate between the midsole and outsole of a standard running shoe. Twenty-one male runners (mass = 67.1 ± 5.0 kg, height = 178.9 cm ± 4.0 cm, age = 26.4 ± 8.4 years) completed testing at 2.98 m/s and 4.47 m/s in all shoe conditions, measuring metabolic cost, and several biomechanical and anatomical variables. Data were separated by foot strike. At the fast speed, average optimal stiffness was 19.29 ± 5.62 N/mm with a metabolic benefit of 3.02 ± 2.62%. Slow speed average optimal stiffness was 17.04 ± 6.09 N/mm with a metabolic benefit of 1.93 ± 1.82%. Only rearfoot strikers demonstrated a significant increase in optimal stiffness (p =.04) across speeds. There were no correlations between any of the measured anatomical or biomechanical variables and optimal stiffness. Optimal stiffness varied between subjects but was not correlated to any of our measured characteristics. Rearfoot striking runners may benefit from a higher stiffness shoe at faster speeds to enable optimal performance. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.
171 a35867849600 Hunter I. p204 False Journal 137 Running shoe optimal stiffness and speed [No abstract available]
172 a8929123100 Camacho R.M. p43 True Journal 36 Self-Sustaining 3D Thin Liquid Films in Ambient Environments Thin liquid films (TLF) have fundamental and technological importance ranging from the thermodynamics of cell membranes to the safety of light-water cooled nuclear reactors. The creation of stable water TLFs, however, is very difficult. In this paper, the realization of thin liquid films of water with custom 3D geometries that persist indefinitely in ambient environments is reported. The wetting films are generated using microscale “mounts” fed by microfluidic channels with small feature sizes and large aspect ratios. These devices are fabricated with a custom 3D printer and resin, which are developed to print high resolution microfluidic geometries. By modifying the 3D-printed polymer to be hydrophilic and taking advantage of well-known wetting principles and capillary effects, self-sustaining microscale “water fountains” are constructed that continuously replenish water lost to evaporation while relying on surface tension to stabilize their shape. To the authors' knowledge, this is the first demonstration of stable sub-micron thin liquid films (TLFs) of pure water on curved 3D geometries. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
172 a8929123100 Camacho R.M. p205 False Journal 138 Accelerating silicon photonic parameter extraction using artificial neural networks We present a novel silicon photonic parameter extraction tool that uses artificial neural networks. While other parameter extraction methods are restricted to relatively simple devices whose responses are easily modeled by analytic transfer functions, this method is capable of extracting parameters for any device with a discrete number of design parameters. To validate the method, we design and fabricate integrated chirped Bragg gratings. We then estimate the actual device parameters by iteratively fitting the simultaneously measured group delay and reflection profiles to the artificial neural network output. The method is fast, accurate, and capable of modeling the complicated chirping and index contrast. © 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.
172 a8929123100 Camacho R.M. p424 False Journal 234 Error correction in structured optical receivers Quantum green machines using integrated optics may enable better communication in photon-starved environments, but fabrication inconsistencies induce unpredictable internal phase errors, making them difficult to construct. We describe and experimentally demonstrate a new method to compensate for arbitrary phase errors by deriving a convex error space and implementing an algorithm to learn a unique codebook of codewords corresponding to each matrix. © 1995-2012 IEEE.
172 a8929123100 Camacho R.M. p561 False Conference 210 Open source computational photonics toolbox We present an open source and collaborative integrated photonics simulation environment capable of accurately modeling individual components using traditional vectorial methods and large circuits using linear system theory and deep learning. © 2018 The Author(s).
173 a57215607275 Fish D. p43 False Journal 36 Self-Sustaining 3D Thin Liquid Films in Ambient Environments Thin liquid films (TLF) have fundamental and technological importance ranging from the thermodynamics of cell membranes to the safety of light-water cooled nuclear reactors. The creation of stable water TLFs, however, is very difficult. In this paper, the realization of thin liquid films of water with custom 3D geometries that persist indefinitely in ambient environments is reported. The wetting films are generated using microscale “mounts” fed by microfluidic channels with small feature sizes and large aspect ratios. These devices are fabricated with a custom 3D printer and resin, which are developed to print high resolution microfluidic geometries. By modifying the 3D-printed polymer to be hydrophilic and taking advantage of well-known wetting principles and capillary effects, self-sustaining microscale “water fountains” are constructed that continuously replenish water lost to evaporation while relying on surface tension to stabilize their shape. To the authors' knowledge, this is the first demonstration of stable sub-micron thin liquid films (TLFs) of pure water on curved 3D geometries. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
174 a57215609504 Simmons M. p43 False Journal 36 Self-Sustaining 3D Thin Liquid Films in Ambient Environments Thin liquid films (TLF) have fundamental and technological importance ranging from the thermodynamics of cell membranes to the safety of light-water cooled nuclear reactors. The creation of stable water TLFs, however, is very difficult. In this paper, the realization of thin liquid films of water with custom 3D geometries that persist indefinitely in ambient environments is reported. The wetting films are generated using microscale “mounts” fed by microfluidic channels with small feature sizes and large aspect ratios. These devices are fabricated with a custom 3D printer and resin, which are developed to print high resolution microfluidic geometries. By modifying the 3D-printed polymer to be hydrophilic and taking advantage of well-known wetting principles and capillary effects, self-sustaining microscale “water fountains” are constructed that continuously replenish water lost to evaporation while relying on surface tension to stabilize their shape. To the authors' knowledge, this is the first demonstration of stable sub-micron thin liquid films (TLFs) of pure water on curved 3D geometries. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
175 a57200118993 Awerkamp P. p43 False Journal 36 Self-Sustaining 3D Thin Liquid Films in Ambient Environments Thin liquid films (TLF) have fundamental and technological importance ranging from the thermodynamics of cell membranes to the safety of light-water cooled nuclear reactors. The creation of stable water TLFs, however, is very difficult. In this paper, the realization of thin liquid films of water with custom 3D geometries that persist indefinitely in ambient environments is reported. The wetting films are generated using microscale “mounts” fed by microfluidic channels with small feature sizes and large aspect ratios. These devices are fabricated with a custom 3D printer and resin, which are developed to print high resolution microfluidic geometries. By modifying the 3D-printed polymer to be hydrophilic and taking advantage of well-known wetting principles and capillary effects, self-sustaining microscale “water fountains” are constructed that continuously replenish water lost to evaporation while relying on surface tension to stabilize their shape. To the authors' knowledge, this is the first demonstration of stable sub-micron thin liquid films (TLFs) of pure water on curved 3D geometries. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
175 a57200118993 Awerkamp P. p437 False Journal 242 Erratum: Hardware and software improvements to a low-cost horizontal parallax holographic video monitor (Applied Optics (2018) 57 (A122-A133) DOI: 10.1364/AO.57.00A122) In [1], the trademarked term "HoloMonitor," which belongs to Phase Holographic Imaging PHI AB, was removed. The article was corrected online on 10 September 2018. © 2018 Optical Society of America.
175 a57200118993 Awerkamp P. p571 False Journal 242 Hardware and software improvements to a low-cost horizontal parallax holographic video monitor Displays capable of true holographic video have been prohibitively expensive and difficult to build. With this paper, we present a suite of modularized hardware components and software tools needed to build a HoloMonitor with basic “hacker-space” equipment, highlighting improvements that have enabled the total materials cost to fall to $820, well below that of other holographic displays. It is our hope that the current level of simplicity, development, design flexibility, and documentation will enable the lay engineer, programmer, and scientist to relatively easily replicate, modify, and build upon our designs, bringing true holographic video to the masses. © 2017 Optical Society of America.
176 a57215613881 Anderson R. p43 False Journal 36 Self-Sustaining 3D Thin Liquid Films in Ambient Environments Thin liquid films (TLF) have fundamental and technological importance ranging from the thermodynamics of cell membranes to the safety of light-water cooled nuclear reactors. The creation of stable water TLFs, however, is very difficult. In this paper, the realization of thin liquid films of water with custom 3D geometries that persist indefinitely in ambient environments is reported. The wetting films are generated using microscale “mounts” fed by microfluidic channels with small feature sizes and large aspect ratios. These devices are fabricated with a custom 3D printer and resin, which are developed to print high resolution microfluidic geometries. By modifying the 3D-printed polymer to be hydrophilic and taking advantage of well-known wetting principles and capillary effects, self-sustaining microscale “water fountains” are constructed that continuously replenish water lost to evaporation while relying on surface tension to stabilize their shape. To the authors' knowledge, this is the first demonstration of stable sub-micron thin liquid films (TLFs) of pure water on curved 3D geometries. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
177 a57215598228 Carlson S. p43 False Journal 36 Self-Sustaining 3D Thin Liquid Films in Ambient Environments Thin liquid films (TLF) have fundamental and technological importance ranging from the thermodynamics of cell membranes to the safety of light-water cooled nuclear reactors. The creation of stable water TLFs, however, is very difficult. In this paper, the realization of thin liquid films of water with custom 3D geometries that persist indefinitely in ambient environments is reported. The wetting films are generated using microscale “mounts” fed by microfluidic channels with small feature sizes and large aspect ratios. These devices are fabricated with a custom 3D printer and resin, which are developed to print high resolution microfluidic geometries. By modifying the 3D-printed polymer to be hydrophilic and taking advantage of well-known wetting principles and capillary effects, self-sustaining microscale “water fountains” are constructed that continuously replenish water lost to evaporation while relying on surface tension to stabilize their shape. To the authors' knowledge, this is the first demonstration of stable sub-micron thin liquid films (TLFs) of pure water on curved 3D geometries. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
178 a57211987837 Laney J. p43 False Journal 36 Self-Sustaining 3D Thin Liquid Films in Ambient Environments Thin liquid films (TLF) have fundamental and technological importance ranging from the thermodynamics of cell membranes to the safety of light-water cooled nuclear reactors. The creation of stable water TLFs, however, is very difficult. In this paper, the realization of thin liquid films of water with custom 3D geometries that persist indefinitely in ambient environments is reported. The wetting films are generated using microscale “mounts” fed by microfluidic channels with small feature sizes and large aspect ratios. These devices are fabricated with a custom 3D printer and resin, which are developed to print high resolution microfluidic geometries. By modifying the 3D-printed polymer to be hydrophilic and taking advantage of well-known wetting principles and capillary effects, self-sustaining microscale “water fountains” are constructed that continuously replenish water lost to evaporation while relying on surface tension to stabilize their shape. To the authors' knowledge, this is the first demonstration of stable sub-micron thin liquid films (TLFs) of pure water on curved 3D geometries. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
178 a57211987837 Laney J. p301 False Journal 121 Improving photophoretic trap volumetric displays [Invited] Since the introduction of optical trap displays in 2018, there has been significant interest in further developing this technology. In an effort to channel interest in the most productive directions, this work seeks to illuminate those areas that, in the authors’ opinion, are most critical to the ultimate success of optical trap displays as a platform for aerial 3D imaging. These areas include trapping, scanning, scaling, robustness, safety, and occlusion. © 2019 Optical Society of America
179 a57209538650 Viglione M. p43 False Journal 36 Self-Sustaining 3D Thin Liquid Films in Ambient Environments Thin liquid films (TLF) have fundamental and technological importance ranging from the thermodynamics of cell membranes to the safety of light-water cooled nuclear reactors. The creation of stable water TLFs, however, is very difficult. In this paper, the realization of thin liquid films of water with custom 3D geometries that persist indefinitely in ambient environments is reported. The wetting films are generated using microscale “mounts” fed by microfluidic channels with small feature sizes and large aspect ratios. These devices are fabricated with a custom 3D printer and resin, which are developed to print high resolution microfluidic geometries. By modifying the 3D-printed polymer to be hydrophilic and taking advantage of well-known wetting principles and capillary effects, self-sustaining microscale “water fountains” are constructed that continuously replenish water lost to evaporation while relying on surface tension to stabilize their shape. To the authors' knowledge, this is the first demonstration of stable sub-micron thin liquid films (TLFs) of pure water on curved 3D geometries. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
179 a57209538650 Viglione M. p332 False Conference 108 3D printing for lab-on-a-chip devices with 20 μm channels While there is great interest in 3D printing for microfluidic device fabrication, the challenge has been to achieve feature sizes that are in the truly microfluidic regime (<100 μm). The fundamental problem is that commercial tools and materials, which excel in many other application areas, have not been developed to address the unique needs of microfluidic device fabrication. Consequently, we have created our own stereolithographic 3D printer and materials that are specifically tailored to meet these needs. We review our recent work and show that flow channels as small as 18 μm x 20 μm can be reliably fabricated, as well as compact active elements such as valves and pumps. With these capabilities, we demonstrate highly integrated 3D printed microfluidic devices that measure only a few millimeters on a side, and that integrate separate chip-to-world interfaces through high density interconnects (up to 88 interconnects per square mm) that are directly 3D printed as part of a device chip. These advances open the door to 3D printing as a replacement for expensive cleanroom fabrication processes, with the additional advantage of fast (30 minute), parallel fabrication of many devices in a single print run due to their small size. © 2019 SPIE.
180 a7005636820 Nordin G.P. p43 False Journal 36 Self-Sustaining 3D Thin Liquid Films in Ambient Environments Thin liquid films (TLF) have fundamental and technological importance ranging from the thermodynamics of cell membranes to the safety of light-water cooled nuclear reactors. The creation of stable water TLFs, however, is very difficult. In this paper, the realization of thin liquid films of water with custom 3D geometries that persist indefinitely in ambient environments is reported. The wetting films are generated using microscale “mounts” fed by microfluidic channels with small feature sizes and large aspect ratios. These devices are fabricated with a custom 3D printer and resin, which are developed to print high resolution microfluidic geometries. By modifying the 3D-printed polymer to be hydrophilic and taking advantage of well-known wetting principles and capillary effects, self-sustaining microscale “water fountains” are constructed that continuously replenish water lost to evaporation while relying on surface tension to stabilize their shape. To the authors' knowledge, this is the first demonstration of stable sub-micron thin liquid films (TLFs) of pure water on curved 3D geometries. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
180 a7005636820 Nordin G.P. p57 False Journal 44 Biocompatible PEGDA Resin for 3D Printing We report a noncytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The noncytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively noncytotoxic with a postprint 12 h ethanol wash, and that A-PEGDA, as-printed, is effectively noncytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultralow adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures. Copyright © 2020 American Chemical Society.
180 a7005636820 Nordin G.P. p289 False Conference 72 Microfluidic temperature behavior in a multi-material 3D printed chip As analysis systems shrink in size to microfluidic scales and devices, there is a need to improve temperature control in the microscale for temperature-sensitive processes. Technology that combines accurate temperature measurement and 3D spatial control of the temperature distribution is limited by common 2D layer-based microfluidic fabrication techniques but can be realized with 3D printed microfluidic chips. This work presents an iterative process to create a microfluidic chip using multimaterial 3D printing to improve temperature sensing and create an even temperature around a target volume. Through an iterative process, verification is presented of fluorophore viability (specifically CdTe quantum dots) after being secured in place by cured PR48 3D printing resin, thus confirming the possibility of fluorescent thermometry as an accurate non-contact temperature sensing method. Numerical analyses of various geometries of chip design iterations are also presented verifying spatially even heating due to the placement of heating sources in the microfluidic chip. Combining the fluorescent thermometry and improved heating will lead to improved temperature control in microfluidic devices. Copyright © 2019 ASME.
180 a7005636820 Nordin G.P. p330 False Journal 192 3D printed selectable dilution mixer pumps In this paper, we demonstrate the ability to 3D print tightly integrated structures with active valves, pumps, and mixers, and we use our compact chip-to-chip interconnects [Gong et al., Lab Chip 18, 639-647 (2018)] to move bulky world-to-chip connections to separate interface chips for both post-print flushing and post-cure device operation. As example devices, we first examine 3D printed pumps, followed by two types of selectable ratio mixer pumps, a linear dilution mixer pump (LDMP) and a parallelized dilution mixer pump (PDMP), which occupy volumes of only 1.5 mm 3 and 2.6 mm 3, respectively. The LDMP generates a selectable dilution ratio from a linear set of possibilities, while the PDMP generates a denser set of possible dilutions with a maximum dilution ratio of 1/16. The PDMP also incorporates a new 4-to-1 valve to simultaneously control 4 inlet channels. To characterize LDMP and PDMP operation and performance, we present a new, low-cost video method to directly measure the relative concentration of an absorptive dye on a pixel-by-pixel basis for each video frame. Using this method, we find that 6 periods of the active mixer that forms the core of the LDMP and PDMP are sufficient to fully mix the fluid, and that the generated concentrations track the designed dilution ratios as expected. The LDMP mixes 20 nl per 4.6 s mixer pump period, while the PDMP uses parallelized input pumps to process the same fluid volume with greater choice of dilution ratios in a 3.6 s period. © 2019 Author(s).
180 a7005636820 Nordin G.P. p332 True Conference 108 3D printing for lab-on-a-chip devices with 20 μm channels While there is great interest in 3D printing for microfluidic device fabrication, the challenge has been to achieve feature sizes that are in the truly microfluidic regime (<100 μm). The fundamental problem is that commercial tools and materials, which excel in many other application areas, have not been developed to address the unique needs of microfluidic device fabrication. Consequently, we have created our own stereolithographic 3D printer and materials that are specifically tailored to meet these needs. We review our recent work and show that flow channels as small as 18 μm x 20 μm can be reliably fabricated, as well as compact active elements such as valves and pumps. With these capabilities, we demonstrate highly integrated 3D printed microfluidic devices that measure only a few millimeters on a side, and that integrate separate chip-to-world interfaces through high density interconnects (up to 88 interconnects per square mm) that are directly 3D printed as part of a device chip. These advances open the door to 3D printing as a replacement for expensive cleanroom fabrication processes, with the additional advantage of fast (30 minute), parallel fabrication of many devices in a single print run due to their small size. © 2019 SPIE.
180 a7005636820 Nordin G.P. p475 False Journal 262 Design and characterization of a package-less hybrid PDMS-CMOS-FR4 contact-imaging system for microfluidic integration We demonstrate a hybrid "package-less" polydimethylsiloxane (PDMS)-complementary metal-oxide-semiconductor (CMOS)-FR4 system for contact imaging. The system embeds the CMOS image sensor directly in a PDMS layer instead of the standard chip package to support microfluidic structures much larger and more complex than those in prior art. The CMOS/PDMS layer is self-aligned to form a continuous, flat surface to provide structural support for upper microfluidic layers. The system consists of five layers of PDMS implementing fluid channels, valves, chambers, and inlets/outlets. A custom CMOS image sensor with integrated signal conditioning circuits directly captures light from sample fluid for high optical collection efficiency. Owing to the flexibility afforded by the integration process, the system demonstrates, for the first time, integrated valves in contact imaging. Moreover, we present the first direct comparison of the optical performance of a CMOS image sensor and a photomultiplier tube (PMT) in identical contact-imaging conditions. Measurements show that our CMOS sensor achieves 17 dB better signal-to-noise ratio (SNR) compared with a commercial PMT across a broad range of integration times, with a maximum SNR of 47 dB. Chemiluminescent testing successfully shows signal detection for different analyte concentrations and integration times. The contact-imaging system demonstrates a detection limit of 25 μM of a 9,10-diphenylanthracene-based solution. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
180 a7005636820 Nordin G.P. p481 False Journal 237 3D printed microfluidic features using dose control in X, Y, and Z dimensions Interest has grown in recent years to leverage the possibilities offered by three-dimensional (3D) printing, such as rapid iterative changes; the ability to more fully use 3D device volume; and ease of fabrication, especially as it relates to the creation of complex microfluidic devices. A major shortcoming of most commercially available 3D printers is that their resolution is not sufficient to produce features that are truly microfluidic (&lt; 100 × 100 μm2). Here, we test a custom 3D printer for making ~30 μm scale positive and negative surface features, as well as positive and negative features within internal voids (i.e., microfluidic channels). We found that optical dosage control is essential for creating the smallest microfluidic features (~30 μm wide for ridges, ~20 μm wide for trenches), and that this resolution was achieved for a number of different exposure approaches. Additionally, we printed various microfluidic particle traps, showed capture of 25 μm diameter polymer beads, and iteratively improved the trap design. The rapid feedback allowed by 3D printing, as well as the ability to carefully control optical exposure conditions, should lead to new innovations in the types and sizes of devices that can be created for microfluidics. © 2018 by the authors.
180 a7005636820 Nordin G.P. p536 False Journal 217 3D printed high density, reversible, chip-to-chip microfluidic interconnects Our latest developments in miniaturizing 3D printed microfluidics [Gong et al., Lab Chip, 2016, 16, 2450; Gong et al., Lab Chip, 2017, 17, 2899] offer the opportunity to fabricate highly integrated chips that measure only a few mm on a side. For such small chips, an interconnection method is needed to provide the necessary world-to-chip reagent and pneumatic connections. In this paper, we introduce simple integrated microgaskets (SIMs) and controlled-compression integrated microgaskets (CCIMs) to connect a small device chip to a larger interface chip that implements world-to-chip connections. SIMs or CCIMs are directly 3D printed as part of the device chip, and therefore no additional materials or components are required to make the connection to the larger 3D printed interface chip. We demonstrate 121 chip-to-chip interconnections in an 11 × 11 array for both SIMs and CCIMs with an areal density of 53 interconnections per mm2 and show that they withstand fluid pressures of 50 psi. We further demonstrate their reusability by testing the devices 100 times without seal failure. Scaling experiments show that 20 × 20 interconnection arrays are feasible and that the CCIM areal density can be increased to 88 interconnections per mm2. We then show the utility of spatially distributed discrete CCIMs by using an interconnection chip with 28 chip-to-world interconnects to test 45 3D printed valves in a 9 × 5 array. Each valve is only 300 μm in diameter (the smallest yet reported for 3D printed valves). Every row of 5 valves is tested to at least 10000 actuations, with one row tested to 1-000000 actuations. In all cases, there is no sign of valve failure, and the CCIM interconnections prove an effective means of using a single interface chip to test a series of valve array chips. © 2018 The Royal Society of Chemistry.
180 a7005636820 Nordin G.P. p558 True Conference 207 3D printed microfluidic selectable ratio mixer pump in 2 mm3 We report the use of 3D printing to fabricate a selectable ratio mixer pump in a volume of only 2 mm2. Our custom 3D printer and material is used to make very compact individual elements such as fluid channels, valves, and pumps that are laid out in 3D to achieve small overall device volume. The device includes two pumps, each connected to its own fluid source, and a two-chamber mixing unit that both mixes the fluid pumped into it from each fluid source, and acts itself as a pump to expel the mixed fluid. © 2016 TRF
180 a7005636820 Nordin G.P. p693 False Journal 337 Custom 3D printer and resin for 18 μm × 20 μm microfluidic flow channels While there is great interest in 3D printing for microfluidic device fabrication, to-date the achieved feature sizes have not been in the truly microfluidic regime (&lt;100 μm). In this paper we demonstrate that a custom digital light processor stereolithographic (DLP-SLA) 3D printer and a specifically-designed, low cost, custom resin can readily achieve flow channel cross sections as small as 18 μm × 20 μm. Our 3D printer has a projected image plane resolution of 7.6 μm and uses a 385 nm LED, which dramatically increases the available selection of UV absorbers for resin formulation compared to 3D printers with 405 nm LEDs. Beginning with 20 candidate absorbers, we demonstrate the evaluation criteria and process flow required to develop a high-resolution resin. In doing so, we introduce a new mathematical model for characterizing the resin optical penetration depth based only on measurement of the absorber's molar absorptivity. Our final resin formulation uses 2-nitrophenyl phenyl sulfide (NPS) as the UV absorber. We also develop a novel channel narrowing technique that, together with the new resin and 3D printer resolution, enables small flow channel fabrication. We demonstrate the efficacy of our approach by fabricating 3D serpentine flow channels 41 mm long in a volume of only 0.12 mm3, and by printing high aspect ratio flow channels &lt;25 μm wide and 3 mm tall. These results indicate that 3D printing is finally positioned to challenge the pre-eminence of methods such as soft lithography for microfluidic device prototyping and fabrication. © 2017 The Royal Society of Chemistry.
181 a57202910818 Knighton B.E. p44 True Conference 6 Picking Out Nonlinear Collective Couplings with Two-Dimensional Terahertz Spectroscopy 2D terahertz spectroscopy can disentangle coupling between different degrees of freedom. We discuss the complex 2D terahertz spectra of ß-barium borate and model different vibrational couplings to assign spectral features that arise from such coupling. © 2020 OSA.
181 a57202910818 Knighton B.E. p167 True Conference 33 Examining Nonlinear Terahertz Photonic and Phononic Excitation with Two-Dimensional Spectroscopy We use high-field, broadband terahertz (THz) pulses to nonlinearly excite a set of Raman active modes in centrosymmetric crystals. Using two-dimensional (2D) THz spectroscopy we can investigate photonic and phononic excitation and isolate the dominant and secondary nonlinear excitation pathways. We present a general framework for 2D THz vibrational spectroscopy in solid systems that provides important clarification for the growing new field of nonlinear phononics. © 2019 IEEE.
181 a57202910818 Knighton B.E. p168 True Conference 34 Direct Comparison between Multi-Dimensional Terahertz Vibrational Spectroscopies Multidimensional terahertz (THz) spectroscopy is a powerful tool for understanding nonlinear excitation, coherent energy flow, and coupling between collective degrees of freedom on ultrafast time scales. With extreme vibrational excitation using high-field THz light, 2D THz spectroscopy can reveal how anharmonic mode coupling results in coherent energy transfer and ascertain the excitation pathways behind nonlinear sample responses. We directly compare 2D THz-THz transmission measurements to 2D THz-THz-Raman measurements and explore evidence of anharmonic coupling between phonon modes in β-barium borate. © 2019 IEEE.
182 a55213245300 Nielson M. p44 False Conference 6 Picking Out Nonlinear Collective Couplings with Two-Dimensional Terahertz Spectroscopy 2D terahertz spectroscopy can disentangle coupling between different degrees of freedom. We discuss the complex 2D terahertz spectra of ß-barium borate and model different vibrational couplings to assign spectral features that arise from such coupling. © 2020 OSA.
182 a55213245300 Nielson M. p167 False Conference 33 Examining Nonlinear Terahertz Photonic and Phononic Excitation with Two-Dimensional Spectroscopy We use high-field, broadband terahertz (THz) pulses to nonlinearly excite a set of Raman active modes in centrosymmetric crystals. Using two-dimensional (2D) THz spectroscopy we can investigate photonic and phononic excitation and isolate the dominant and secondary nonlinear excitation pathways. We present a general framework for 2D THz vibrational spectroscopy in solid systems that provides important clarification for the growing new field of nonlinear phononics. © 2019 IEEE.
182 a55213245300 Nielson M. p168 False Conference 34 Direct Comparison between Multi-Dimensional Terahertz Vibrational Spectroscopies Multidimensional terahertz (THz) spectroscopy is a powerful tool for understanding nonlinear excitation, coherent energy flow, and coupling between collective degrees of freedom on ultrafast time scales. With extreme vibrational excitation using high-field THz light, 2D THz spectroscopy can reveal how anharmonic mode coupling results in coherent energy transfer and ascertain the excitation pathways behind nonlinear sample responses. We directly compare 2D THz-THz transmission measurements to 2D THz-THz-Raman measurements and explore evidence of anharmonic coupling between phonon modes in β-barium borate. © 2019 IEEE.
183 a57211642778 Hardy R.T. p44 False Conference 6 Picking Out Nonlinear Collective Couplings with Two-Dimensional Terahertz Spectroscopy 2D terahertz spectroscopy can disentangle coupling between different degrees of freedom. We discuss the complex 2D terahertz spectra of ß-barium borate and model different vibrational couplings to assign spectral features that arise from such coupling. © 2020 OSA.
183 a57211642778 Hardy R.T. p167 False Conference 33 Examining Nonlinear Terahertz Photonic and Phononic Excitation with Two-Dimensional Spectroscopy We use high-field, broadband terahertz (THz) pulses to nonlinearly excite a set of Raman active modes in centrosymmetric crystals. Using two-dimensional (2D) THz spectroscopy we can investigate photonic and phononic excitation and isolate the dominant and secondary nonlinear excitation pathways. We present a general framework for 2D THz vibrational spectroscopy in solid systems that provides important clarification for the growing new field of nonlinear phononics. © 2019 IEEE.
183 a57211642778 Hardy R.T. p168 False Conference 34 Direct Comparison between Multi-Dimensional Terahertz Vibrational Spectroscopies Multidimensional terahertz (THz) spectroscopy is a powerful tool for understanding nonlinear excitation, coherent energy flow, and coupling between collective degrees of freedom on ultrafast time scales. With extreme vibrational excitation using high-field THz light, 2D THz spectroscopy can reveal how anharmonic mode coupling results in coherent energy transfer and ascertain the excitation pathways behind nonlinear sample responses. We directly compare 2D THz-THz transmission measurements to 2D THz-THz-Raman measurements and explore evidence of anharmonic coupling between phonon modes in β-barium borate. © 2019 IEEE.
184 a57196372172 Alejandro A. p44 False Conference 6 Picking Out Nonlinear Collective Couplings with Two-Dimensional Terahertz Spectroscopy 2D terahertz spectroscopy can disentangle coupling between different degrees of freedom. We discuss the complex 2D terahertz spectra of ß-barium borate and model different vibrational couplings to assign spectral features that arise from such coupling. © 2020 OSA.
184 a57196372172 Alejandro A. p167 False Conference 33 Examining Nonlinear Terahertz Photonic and Phononic Excitation with Two-Dimensional Spectroscopy We use high-field, broadband terahertz (THz) pulses to nonlinearly excite a set of Raman active modes in centrosymmetric crystals. Using two-dimensional (2D) THz spectroscopy we can investigate photonic and phononic excitation and isolate the dominant and secondary nonlinear excitation pathways. We present a general framework for 2D THz vibrational spectroscopy in solid systems that provides important clarification for the growing new field of nonlinear phononics. © 2019 IEEE.
184 a57196372172 Alejandro A. p168 False Conference 34 Direct Comparison between Multi-Dimensional Terahertz Vibrational Spectroscopies Multidimensional terahertz (THz) spectroscopy is a powerful tool for understanding nonlinear excitation, coherent energy flow, and coupling between collective degrees of freedom on ultrafast time scales. With extreme vibrational excitation using high-field THz light, 2D THz spectroscopy can reveal how anharmonic mode coupling results in coherent energy transfer and ascertain the excitation pathways behind nonlinear sample responses. We directly compare 2D THz-THz transmission measurements to 2D THz-THz-Raman measurements and explore evidence of anharmonic coupling between phonon modes in β-barium borate. © 2019 IEEE.
185 a57208225620 Rawlings L. p44 False Conference 6 Picking Out Nonlinear Collective Couplings with Two-Dimensional Terahertz Spectroscopy 2D terahertz spectroscopy can disentangle coupling between different degrees of freedom. We discuss the complex 2D terahertz spectra of ß-barium borate and model different vibrational couplings to assign spectral features that arise from such coupling. © 2020 OSA.
185 a57208225620 Rawlings L. p167 False Conference 33 Examining Nonlinear Terahertz Photonic and Phononic Excitation with Two-Dimensional Spectroscopy We use high-field, broadband terahertz (THz) pulses to nonlinearly excite a set of Raman active modes in centrosymmetric crystals. Using two-dimensional (2D) THz spectroscopy we can investigate photonic and phononic excitation and isolate the dominant and secondary nonlinear excitation pathways. We present a general framework for 2D THz vibrational spectroscopy in solid systems that provides important clarification for the growing new field of nonlinear phononics. © 2019 IEEE.
185 a57208225620 Rawlings L. p168 False Conference 34 Direct Comparison between Multi-Dimensional Terahertz Vibrational Spectroscopies Multidimensional terahertz (THz) spectroscopy is a powerful tool for understanding nonlinear excitation, coherent energy flow, and coupling between collective degrees of freedom on ultrafast time scales. With extreme vibrational excitation using high-field THz light, 2D THz spectroscopy can reveal how anharmonic mode coupling results in coherent energy transfer and ascertain the excitation pathways behind nonlinear sample responses. We directly compare 2D THz-THz transmission measurements to 2D THz-THz-Raman measurements and explore evidence of anharmonic coupling between phonon modes in β-barium borate. © 2019 IEEE.
186 a57209824884 Johnson J.A. p44 False Conference 6 Picking Out Nonlinear Collective Couplings with Two-Dimensional Terahertz Spectroscopy 2D terahertz spectroscopy can disentangle coupling between different degrees of freedom. We discuss the complex 2D terahertz spectra of ß-barium borate and model different vibrational couplings to assign spectral features that arise from such coupling. © 2020 OSA.
186 a57209824884 Johnson J.A. p167 False Conference 33 Examining Nonlinear Terahertz Photonic and Phononic Excitation with Two-Dimensional Spectroscopy We use high-field, broadband terahertz (THz) pulses to nonlinearly excite a set of Raman active modes in centrosymmetric crystals. Using two-dimensional (2D) THz spectroscopy we can investigate photonic and phononic excitation and isolate the dominant and secondary nonlinear excitation pathways. We present a general framework for 2D THz vibrational spectroscopy in solid systems that provides important clarification for the growing new field of nonlinear phononics. © 2019 IEEE.
186 a57209824884 Johnson J.A. p168 False Conference 34 Direct Comparison between Multi-Dimensional Terahertz Vibrational Spectroscopies Multidimensional terahertz (THz) spectroscopy is a powerful tool for understanding nonlinear excitation, coherent energy flow, and coupling between collective degrees of freedom on ultrafast time scales. With extreme vibrational excitation using high-field THz light, 2D THz spectroscopy can reveal how anharmonic mode coupling results in coherent energy transfer and ascertain the excitation pathways behind nonlinear sample responses. We directly compare 2D THz-THz transmission measurements to 2D THz-THz-Raman measurements and explore evidence of anharmonic coupling between phonon modes in β-barium borate. © 2019 IEEE.
186 a57209824884 Johnson J.A. p365 False Conference 128 Multi-timescale pump-probe spectroscopy using time-encoding and time-stretching methods To investigate changes of ultrafast dynamics during irreversible phase change in phase change materials Ge2Sb2Te5, we performed high-repetition-rate singleshot pump-probe spectroscopy using a combination of time-encoding and timestretching methods. By measuring the pump-probe traces while ramping the pump intensity, we observed a clear change in the ultrafast pump-probe dynamics after the phase change. Correlation between the ultrafast dynamics in the femtosecond timescale and the amount of phase change observed in millisecond timescale indicates that accumulation of the excited states in the sample plays an important role in the acceleration of the phase change. The result clearly demonstrates the usefulness of our method, which could be applied to the investigation of multi-timescale dynamics in various irreversible phenomena. Improved signal-to-noise ratio and the variable time-window of the single-shot pumpprobe measurements were also demonstrated using a grating pair and a chirped fiber Bragg grating. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
186 a57209824884 Johnson J.A. p388 False Conference 140 High-acquisition-rate single-shot pump-probe measurement using chirped-fiber Bragg gratings Multi-timescale dynamics, from femtoseconds to milliseconds, for irreversible phenomena have been of fundamental importance in understanding mechanisms of chaotic phenomena, electronic bunch evaluation of an accelerator, photoinduced phase transitions, laser ablation, etc. Recently, several groups reported high acquisition rate single-shot methods using chirped-pulse single-shot detections and photonic time-stretching [1-3]. In these works, however, the long fiber with the length of several km was used to temporally stretch the time-encoded spectrum by the group velocity dispersion, but his long distance degrades the signal-to-noise ratio due to propagation losses of the probe pulses through the fiber, thus limiting the observable phenomena. © 2019 IEEE
187 a6701646284 Peatross J. p45 True Conference 7 Measured Polarization Components of Nonlinear Thomson Scattering We measure fundamental, second, and third harmonics of nonlinear Thomson scattering emitted by free electrons out the side of a laser focus with 1018 W/cm2. The redshifted photons show distinct spatial patterns when resolved by polarization. © 2020 OSA.
187 a6701646284 Peatross J. p296 False Conference 78 Polarization-resolved single-photon measurements of nonlinear Thomson scattering We report measurements of polarization-resolved nonlinear Thomson scattering made using single-photon detection techniques in a regime of low density electrons. This low density allows the study of electron dynamics in a high-intensity focus. © 2019 The Author (s).
187 a6701646284 Peatross J. p301 False Journal 121 Improving photophoretic trap volumetric displays [Invited] Since the introduction of optical trap displays in 2018, there has been significant interest in further developing this technology. In an effort to channel interest in the most productive directions, this work seeks to illuminate those areas that, in the authors’ opinion, are most critical to the ultimate success of optical trap displays as a platform for aerial 3D imaging. These areas include trapping, scanning, scaling, robustness, safety, and occlusion. © 2019 Optical Society of America
187 a6701646284 Peatross J. p591 True Conference 234 Volumetric display by movement of particles trapped in a laser via photophoresis Photophoresis can stably hold opaque microscopic particles in a laser focus surrounded by room air with strength sufficient to enable centimeter-scale patterns to be drawn by sweeping the laser beam. The resulting images rely on visual persistence as laser light scatters from the particle, which is rapidly swept through the 3-D pattern. Control can be maintained while moving the particle with air speeds up to 2 m/s. A desire to greatly increase the sweep speed motivates a re-examination of the fundamentals of photophoresis-based laser-particle traps. Most explanations offered are qualitative, with differing opinions as to whether, for example, asymmetric heating or asymmetric thermal accommodation is primarily at work. Which particles become trapped in the beam is typically based on self-selection, as a variety of particles with possible differing shapes and sizes are offered to the laser focus for capture. Characteristics that make some particles preferred over others are especially relevant. There is broad consensus that structure in the laser focus greatly aids in stable trapping. Nevertheless, it is still possible for even a relatively smooth TEM00 beam to capture and hold particles. Moreover, even in a structured focus (i.e. with aberrations and local intensity minima and maxima), questions remain as to exactly how a particle becomes stably trapped in certain beam locations. A zoomed-in look at trapped particles reveals oscillations or orbits with excursions over tens of microns and accelerations up to 10 gs. We trapped particles in zero-gravity as well as 2-g environments with no noticeable difference in stability. © 2018 SPIE.
188 a57216751001 Atkinson N. p45 False Conference 7 Measured Polarization Components of Nonlinear Thomson Scattering We measure fundamental, second, and third harmonics of nonlinear Thomson scattering emitted by free electrons out the side of a laser focus with 1018 W/cm2. The redshifted photons show distinct spatial patterns when resolved by polarization. © 2020 OSA.
188 a57216751001 Atkinson N. p296 False Conference 78 Polarization-resolved single-photon measurements of nonlinear Thomson scattering We report measurements of polarization-resolved nonlinear Thomson scattering made using single-photon detection techniques in a regime of low density electrons. This low density allows the study of electron dynamics in a high-intensity focus. © 2019 The Author (s).
189 a57216748895 Hodge D. p45 False Conference 7 Measured Polarization Components of Nonlinear Thomson Scattering We measure fundamental, second, and third harmonics of nonlinear Thomson scattering emitted by free electrons out the side of a laser focus with 1018 W/cm2. The redshifted photons show distinct spatial patterns when resolved by polarization. © 2020 OSA.
189 a57216748895 Hodge D. p296 False Conference 78 Polarization-resolved single-photon measurements of nonlinear Thomson scattering We report measurements of polarization-resolved nonlinear Thomson scattering made using single-photon detection techniques in a regime of low density electrons. This low density allows the study of electron dynamics in a high-intensity focus. © 2019 The Author (s).
190 a36913263000 Pratt B. p45 False Conference 7 Measured Polarization Components of Nonlinear Thomson Scattering We measure fundamental, second, and third harmonics of nonlinear Thomson scattering emitted by free electrons out the side of a laser focus with 1018 W/cm2. The redshifted photons show distinct spatial patterns when resolved by polarization. © 2020 OSA.
190 a36913263000 Pratt B. p296 False Conference 78 Polarization-resolved single-photon measurements of nonlinear Thomson scattering We report measurements of polarization-resolved nonlinear Thomson scattering made using single-photon detection techniques in a regime of low density electrons. This low density allows the study of electron dynamics in a high-intensity focus. © 2019 The Author (s).
191 a57217283178 Romero M. p45 False Conference 7 Measured Polarization Components of Nonlinear Thomson Scattering We measure fundamental, second, and third harmonics of nonlinear Thomson scattering emitted by free electrons out the side of a laser focus with 1018 W/cm2. The redshifted photons show distinct spatial patterns when resolved by polarization. © 2020 OSA.
191 a57217283178 Romero M. p296 False Conference 78 Polarization-resolved single-photon measurements of nonlinear Thomson scattering We report measurements of polarization-resolved nonlinear Thomson scattering made using single-photon detection techniques in a regime of low density electrons. This low density allows the study of electron dynamics in a high-intensity focus. © 2019 The Author (s).
192 a57216749286 Schulzke C. p45 False Conference 7 Measured Polarization Components of Nonlinear Thomson Scattering We measure fundamental, second, and third harmonics of nonlinear Thomson scattering emitted by free electrons out the side of a laser focus with 1018 W/cm2. The redshifted photons show distinct spatial patterns when resolved by polarization. © 2020 OSA.
192 a57216749286 Schulzke C. p296 False Conference 78 Polarization-resolved single-photon measurements of nonlinear Thomson scattering We report measurements of polarization-resolved nonlinear Thomson scattering made using single-photon detection techniques in a regime of low density electrons. This low density allows the study of electron dynamics in a high-intensity focus. © 2019 The Author (s).
193 a7005357023 Ware M. p45 False Conference 7 Measured Polarization Components of Nonlinear Thomson Scattering We measure fundamental, second, and third harmonics of nonlinear Thomson scattering emitted by free electrons out the side of a laser focus with 1018 W/cm2. The redshifted photons show distinct spatial patterns when resolved by polarization. © 2020 OSA.
193 a7005357023 Ware M. p296 True Conference 78 Polarization-resolved single-photon measurements of nonlinear Thomson scattering We report measurements of polarization-resolved nonlinear Thomson scattering made using single-photon detection techniques in a regime of low density electrons. This low density allows the study of electron dynamics in a high-intensity focus. © 2019 The Author (s).
194 a57192943554 Ottosson H.J. p46 True Journal 24 Analysis of perceived social impacts of existing products designed for the developing world, with implications for new product development Engineered products often have more social impacts than are realized. A product review was conducted to bring this to light. In this paper, we show the extent to which different social impacts in 11 impact categories are co-present in 150 products and how this can help engineers and others during the product development process. Specifically, we show how social impact categories not previously considered can be identified. The product review resulted in 13,200 data points that were divided into two data sets, one with 8800 data points from which a social impact probability table was created. The remaining data points were then used to validate the table. All data points were then combined to create a final social impact probability table. This table provides insight for how various social impact categories correlate and can assist engineers in expanding their views to include additional social impact objectives and thus achieve a design with broader social impact or a design with minimized unwanted negative social impact. A simple method for predicting social impact is also created in order to assist engineers when developing products with social impacts in mind. © 2019 by ASME.
194 a57192943554 Ottosson H.J. p325 True Conference 105 Establishing baseline performance for off-the-shelf nitrile seals for the India Mark II hand pump system Accessing clean water is a persistent, and life threatening, challenge for millions of people in the world. Mechanical hand pumps have a long history of helping people access clean ground water for drinking and daily use. Among the most ubiquitous are the India Mark II and III pump systems, for which there are more than 4,000,000 installed across the world. These are estimated to serve between 600M and 1B people. All pumps degrade in performance over time, requiring service; many do not receive it causing pumps to become dysfunctional. The purpose of this paper is to establish a baseline for nitrile seal performance of India Mark II hand pump systems. Understanding off-the-shelf performance and using it as a baseline is an important step toward understanding degradation of performance over time, which is the focus of a much larger study to understand – mechanically and socially – how hand pumps perform, degrade, and ultimately meet human needs. In this paper, 110 off-the-shelf nitrile seals that were purchased in Uganda were tested and the following was characterized: (i) geometric variation, (ii) material variation, (iii) leak performance, and (iv) correlation between these. The seal leak performance was found to be very robust to variations in geometry and material at zero cycles. This important baseline supports our future work to understand how and to what degree seals become sensitive to geometric and material degradation during use. Copyright © 2019 ASME.
194 a57192943554 Ottosson H.J. p819 True Conference 354 A simple starting point for designing for and/or assessing the social impact of products In this paper we present a starting point for designing for and/or assessing the social impact of engineered products. The starting point is a set of tables comprising products, their general functional characteristics, and the accompanying social impacts. We have constructed these tables by first extracting a set of social impact categories from the literature, then 65 products were qualitatively reviewed to find their social impact. The resulting product impact tables can be used at either the beginning of the product development process to decide what social impact to design for and discover product functions that lead to it, or later to qualitatively assess the social impact of a product being designed and/or to assess the impact of an existing product. © 2017 ASME.
195 a56709287700 Hamilton E.S. p47 True Journal 37 Direct macro-to-micro interface method for microfluidics The macro-to-micro interface method presented here meets many of the requirements for an ideal interconnect by sealing a short length of plastic tubing directly to a microfluidic chip. The adaptability and low-temperature processing make it compatible with a wide range of device materials. The method was validated on silicon, acrylic (polymethyl methacrylate), printed circuit board and glass substrates with high-pressure integrity to over 300 psi (2 MPa). Fluid interfaces created with this method were used for pressure tests on microfluidic channels constructed on silicon. © 2020 IOP Publishing Ltd.
195 a56709287700 Hamilton E.S. p62 True Journal 45 3D hydrodynamic focusing in microscale optofluidic channels formed with a single sacrificial layer Optofluidic devices are capable of detecting single molecules, but greater sensitivity and specificity is desired through hydrodynamic focusing (HDF). Three-dimensional (3D) hydrodynamic focusing was implemented in 10-μm scale microchannel cross-sections made with a single sacrificial layer. HDF is achieved using buffer fluid to sheath the sample fluid, requiring four fluid ports to operate by pressure driven flow. A low-pressure chamber, or pit, formed by etching into a substrate, enables volumetric flow ratio-induced focusing at a low flow velocity. The single layer design simplifies surface micromachining and improves device yield by 1.56 times over previous work. The focusing design was integrated with optical waveguides and used in order to analyze fluorescent signals from beads in fluid flow. The implementation of the focusing scheme was found to narrow the distribution of bead velocity and fluorescent signal, giving rise to 33% more consistent signal. Reservoir effects were observed at low operational vacuum pressures and a balance between optofluidic signal variance and intensity was achieved. The implementation of the design in optofluidic sensors will enable higher detection sensitivity and sample specificity. © 2020 by the authors.
195 a56709287700 Hamilton E.S. p173 True Conference 37 Three-Dimensional Hydrodynamic Focusing Designs for Integrated Optofluidic Detection Enhancement Three-dimensional hydrodynamic focusing promises to enhance detection capabilities of optofluidic sensors, enabling low concentration interrogation with higher confidence, critical for disease diagnosis. Novel 3DHDF designs with optofluidic channel diameters in the range of ten microns are evaluated, predicting detection enhancement of up to 3.54 times. © 2019 IEEE.
195 a56709287700 Hamilton E.S. p350 False Journal 196 Enhanced Detection of Single Viruses On-Chip via Hydrodynamic Focusing Planar optofluidics provide a powerful tool for facilitating chip-scale light-matter interactions. Silicon-based liquid core waveguides have been shown to offer single molecule sensitivity for efficient detection of bioparticles. Recently, a PDMS based planar optofluidic platform was introduced that opens the way to rapid development and prototyping of unique structures, taking advantage of the positive attributes of silicon dioxide-based optofluidics and PDMS based microfluidics. Here, hydrodynamic focusing is integrated into a PDMS based optofluidic chip to enhance the detection of single H1N1 viruses on-chip. Chip-plane focusing is provided by a system of microfluidic channels to force the particles towards a region of high optical collection efficiency. Focusing is demonstrated and enhanced detection is quantified using fluorescent polystyrene beads where the coefficient of variation is found to decrease by a factor of 4 with the addition of hydrodynamic focusing. The mean signal amplitude of fluorescently tagged single H1N1 viruses is found to increase with the addition of focusing by a factor of 1.64. © 1995-2012 IEEE.
195 a56709287700 Hamilton E.S. p522 False Journal 262 Antireflective light-blocking layers using a liquid top matte coating Methods exist for the creation of antireflective thin film layers; however, many of these methods depend on the use of high temperatures, harsh chemical etches, or are made with difficult pattern materials, rendering them unusable for many applications. In addition, most methods of light blocking are specifically designed to increase light coupling and absorption in the substrate, making them incompatible with some applications that also require blocking transmission of light. A method of forming a simple, patternable light-blocking layer that drastically reduces both transmission and reflection of light without dependence on processes that could damage underlying structures using a light scattering matte coating over a partially antireflective thin film light-blocking layer is presented. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
195 a56709287700 Hamilton E.S. p608 True Conference 246 3D hydrodynamic focusing for optofluidics using a stacked channel design We present a 3D hydrodynamic focusing design suitable for optofluidic devices allowing planar fabrication and velocity independent particle focusing. Simulations are presented and fabrication outlined with evidence that stacked SU8 layers are suitable building blocks. © OSA 2018.
195 a56709287700 Hamilton E.S. p749 False Journal 363 Mitigating Water Absorption in Waveguides Made from Unannealed PECVD SiO2 Water absorption was studied in two types of waveguides made from unannealed plasma enhanced chemical vapor deposition (PECVD) SiO2. Standard rib anti-resonant reflecting optical waveguides (ARROWs) were fabricated with thin films of different intrinsic stress and indices of refraction. Buried ARROWs (bARROWs) with low and high refractive index differences between the core and cladding regions were also fabricated from the same types of PECVD films. All waveguides were subjected to a heated, high humidity environment and their optical throughput was tested over time. Due to water absorption in the SiO2 films, the optical throughput of all of the ARROWs decreased with time spent in the wet environment. The ARROWs with the lowest stress SiO2 had the slowest rate of throughput change. High index difference bARROWs showed no decrease in optical throughput after 40 days in the wet environment and are presented as a solution for environmentally stable waveguides made from unannealed PECVD SiO2. © 2017 IEEE.
195 a56709287700 Hamilton E.S. p839 False Conference 366 Preserving optical confinement in unannealed PECVD SiO2 waveguides Rib and buried channel waveguides (BCWs) made of unannealed PECVD SiO2 were studied after exposure to high humidity. Low stressed rib waveguides had lower optical throughput change, while high index difference BCWs were practically unaffected. © 2017 OSA.
196 a7003772744 Crane N.B. p48 True Journal 38 Impact of part thickness and drying conditions on saturation limits in binder jet additive manufacturing Binder jetting (BJ) is a high build-rate additive manufacturing process with growing commercial interest. Growth in BJ applications is driven by the use of finer powders and improved post-processing methods that can produce dense, homogenous final parts. However, understanding of the basic droplet/powder interaction is relatively limited. This paper considers the impact of in-process drying, part geometry, and droplet size on a key printing parameter: binder saturation. Parts of varying thicknesses are printed with a range of saturation levels under various heating conditions. The ratio of the printed part mass to the theoretical part mass is used to detect bleeding. In unheated powder beds, part mass increases linearly with printing saturation levels across the range tested (30 %–130 %). However, when the powder is heated between layers, there is a wide range of print saturation levels (30–80 %) over which increasing binder saturation or droplet volume does not increase the part mass. This stable part mass corresponds to accurate part geometries without bleeding and is likely due to enhanced evaporation of the binder solvent between layers. Smaller droplet volume (42 pl) was also shown to decrease saturation levels in unheated powder bed and in single layer parts. The differences in part mass with print saturation and droplet volume are most pronounced in thin parts. These observations lead to a simple method for determining an appropriate print saturation parameter for a powder/binder combination in thick parts. © 2020 Elsevier B.V.
196 a7003772744 Crane N.B. p74 False Journal 54 Optimization of laser sintering for demineralized bone/polycaprolactone composite powder for bone tissue scaffold Demineralized bone matrix (DBM) is an excellent bone scaffold material, but is available in only limited sizes. An additive manufacturing (AM) method that retains these properties while enabling customized geometry fabrication would provide bone scaffolds for a larger range of geometries while maintaining the benefits of DBM. This work examines laser sintering (LS) of a blend of demineralized bone matrix (DBM) and polycaprolactone (PCL) using a CO2 laser beam. A comprehensive experimental study was carried out to find the conditions that form defect-free layers while still retaining the favorable biological features of DBM. The results identify a process setting window over which LS can be utilized to constructing complex patient-specific scaffolds. With the identified setting, first, the DBM/PCL blend was fused in the LS machine. Parts were then were further strengthened through a post-processing heat treatment. The shrinkage level, skeletal density, mechanical testing, and porosimetry of the resultant samples were compared to traditional machined DBM blocks. The maximum tensile strength of the samples and post-processing shrinkage depends on heat treatment duration. The tensile strength measurements demonstrate that the post-processing conditions can be tuned to achieve the tensile strength of the demineralized bone strips. Evaluation of the dimensional change suggests that the shrinkage along the laser paths is ~0.3% while thickness shrinks the most (up to ~20%). The porosimetry and density studies showed that the final part achieved over 40% porosity with a density comparable to blocks of DBM. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
196 a7003772744 Crane N.B. p111 False Journal 82 Volume and frequency-independent spreading of droplets driven by ultrasonic surface vibration Many industrial processes depend on the wetting of liquids on various surfaces. Understanding the wetting effects due to ultrasonic vibration could provide a means for changing the behavior of liquids on any surface. In previous studies, low-frequency surface vibrations have been used to alter wetting states of droplets by exciting droplet volume modes. While high-frequency (>20 kHz) surface vibration can also cause droplets to wet or spread on a surface, this effect is relatively uncharacterized. In this study, droplets of various liquids with volumes ranging from 2 to 70 μL were vibrated on hydrophobic-coated (FluoroSyl) glass substrates fixed to a piezoelectric transducer at varying amplitudes and at a range of frequencies between 21 and 42 kHz. The conditions for contact line motion were evaluated, and the change in droplet diameter under vibration was measured. Droplets of all tested liquids initially begin to spread out at a similar surface acceleration level. The results show that the increase in diameter is proportional to the maximum acceleration of the surface. Finally, liquid properties and surface roughness may also produce some secondary effects, but droplet volume and excitation frequency do not significantly change the droplet spreading behavior within the parameter range studied. © 2020 by the authors.
196 a7003772744 Crane N.B. p165 False Journal 115 Mechanical and temperature resilience of multi-material systems for printed electronics packaging In this work, two AM technologies were utilized to compare the effectiveness of fabricating a simple electronic device with a conductive trace and hollow cylinder representative of 'printed packaging' that would survive harsh environmental conditions. The printed packaging cylinder delineates printed potting for electronics packaging. An nScrypt direct write (DW) system was the primary manufacturing system but a developing technology - coined large area projection sintering (LAPS) - manufactured a subset of samples for comparison. The tests follow Military Standard (MIL STD) 883 K and include resiliency evaluation for die shear strength, temperature cycling, thermal shock, and high G loading by mechanical shock. Results indicate DW Master Bond epoxy devices show resilience to extreme temperatures, thermal shock, and mechanical shocks while also surpassing the die shear strength failure criteria specified by the MIL STD. LAPS sintered Nylon devices also show mechanical resilience to thermal shock and surpass the die shear strength failure criteria. However, there were some open circuits, increases in resistance, and delamination when LAPS Nylon devices were subjected to extreme temperatures and 20 000 G shock loading normal to the substrate. The thermal effects are likely due to the thermal expansion mismatch between Nylon and the conductive paste while the mechanical shock effects may be attributed to the geometry differences of the LAPS Nylon printed packaging. Further studies are required to understand these failure modes in some of the LAPS Nylon samples and refine the process to address them. © 2019 IOP Publishing Ltd.
196 a7003772744 Crane N.B. p182 False Journal 124 Binder jetting: A review of process, materials, and methods Binder Jet printing is an additive manufacturing technique that dispenses liquid binding agent on powder to form a two-dimensional pattern on a layer. The layers are stacked to build a physical article. Binder Jetting (BJ) can be adapted to almost any powder with high production rates and the BJ process utilizes a broad range of technologies including printing tehniques, powder deposition, dynamic binder/powder interaction, and post-processing methods. A wide variety of materials including polymers, metals, and ceramics have been processed successfully with Binder Jet. However, developing printing and post-processing methods that maximize part performance is a remaining challenge. This article presents a broad review of technologies and approaches that have been applied in Binder Jet printing and points towards opportunities for future advancement. © 2019 Elsevier B.V.
196 a7003772744 Crane N.B. p226 False Journal 148 Fabrication of demineralized bone matrix/polycaprolactone composites using large area projection sintering (LAPS) Cadaveric decellularized bone tissue is utilized as an allograft in many musculoskeletal surgical procedures. Typically, the allograft acts as a scaffold to guide tissue regeneration with superior biocompatibility relative to synthetic scaffolds. Traditionally these scaffolds are machined into the required dimensions and shapes. However, the geometrical simplicity and, in some cases, limited dimensions of the donated tissue restrict the use of allograft scaffolds. This could be overcome by additive manufacturing using granulated bone that is both decellularized and demineralized. In this study, the large area projection sintering (LAPS) method is evaluated as a fabrication method to build porous structures composed of granulated cortical bone bound by polycaprolactone (PCL). This additive manufacturing method utilizes visible light to selectively cure the deposited material layer-by-layer to create 3D geometry. First, the spreading behavior of the composite mixtures is evaluated and the conditions to attain improved powder bed density to fabricate the test specimens are determined. The tensile strength of the LAPS fabricated samples in both dry and hydrated states are determined and compared to the demineralized cancellous bone allograft and the heat treated demineralized-bone/PCL mixture in mold. The results indicated that the projection sintered composites of 45–55 wt %. Demineralized bone matrix (DBM) particulates produced strength comparable to processed and demineralized cancellous bone. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
196 a7003772744 Crane N.B. p229 False Journal 151 Thermal and Vapor Smoothing of Thermoplastic for Reduced Surface Roughness of Additive Manufactured RF Electronics Additive manufacturing (AM) of electronics provides a route for creating customized systems with novel geometries that are not feasible with traditional methods. Standard AM processes such as extrusion can produce substrates on which electrical traces can be deposited. However, the surface roughness of plastic extrusion reduces the effective electrical conductivity and can introduce anisotropy, especially in radio frequency (RF) devices. The roughness can be reduced using vapor smoothing (VS), but solvent absorption changes the surface composition slightly, can be environmentally hazardous, and is not feasible with all thermoplastics. A new method introduced here - coined thermal smoothing (TS) - utilizes a heat source to locally reflow the material, thus minimizing the roughness of the undulating surfaces without the drawbacks of VS. This research work compares the surface roughness impacts of both smoothing processes with profilometry and scanning electron microscope (SEM) images. Both smoothing processes significantly reduce the surface roughness of extruded components by 80% and 90% for TS and VS, respectively. This paper also examines the influence of surface smoothing on high-frequency conductivity of microdispensed conductors (CB028 paste) deposited on the substrates. The measured loss on coplanar waveguides shows an improvement of up to 40% at 7 GHz. © 2011-2012 IEEE.
196 a7003772744 Crane N.B. p251 False Journal 164 Impact of pulse length on the accuracy of defect depth measurements in pulse thermography Pulse thermography (PT) is a nondestructive testing method in which an energy pulse is applied to a surface while the surface temperature evolution is measured to detect sub surface defects and estimate their depth. This nondestructive test method was developed on the assumption of instantaneous surface heating, but recent work has shown that relatively long pulses can be used to accurately determine defect depth in polymers. This paper examines the impact of varying input pulse length on the accuracy of defect depth quantification as a function of the material properties. Simulations using both thermoplastics and metals show that measurement error is dependent on a nondimensionalized pulse length. The simulation results agree with experimental results for three-dimensional (3D) printed acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) components. Analysis and experiments show that defects can be accurately detected with minor modification to the standard methods as long as the pulse ends before the characteristic defect signal is detected. © 2019 by ASME.
196 a7003772744 Crane N.B. p336 False Conference 112 Effects of laser ablation parameters to pattern high purity magnesium surfaces Magnesium and magnesium-based alloys have relatively low weight and desirable mechanical properties for many applications in multiple industries including aerospace and automotive. In the past decade, due to its biocompatible nature, the medical field has expressed significant interest in magnesium for biodegradable implant applications. However, utilization of magnesium-based alloys in surgical implant applications is strictly limited by magnesium’s high vulnerability to corrosion causing premature disintegration inside the human body. Hydrophobic (non-wetting) behavior of metal surfaces has been proven to be beneficial for corrosion protection in academic literature. One way of achieving hydrophobic and superhydrophobic surfaces on metal surfaces without using non-biocompatible coatings is creating uniform microstructures that would alter the wetting characteristics of the surface. This work focuses on creating uniform pillar shaped micro-patterns on smooth pure magnesium surfaces by utilizing a picosecond laser (λ = 355 nm). The study reports the effects of average laser power, partial laser beam overlap and number of laser scans on the height, steepness, roughness of the resultant micro-pillars. Information gathered from this study could be useful in creating more complex or finer micro-structures on magnesium and its alloys to alter their wetting or corrosion characteristics using laser ablation which is a fast, repeatable and an un-convoluted process. Copyright © 2019 ASME.
196 a7003772744 Crane N.B. p387 False Journal 211 Adhesion testing of printed inks while varying the surface treatment of polymer substrates Additive manufacturing with conductive materials enables new approaches to printed electronics that are unachievable by standard electronics manufacturing processes. In particular, electronics can be embedded directly into structural components in nearly arbitrary 3D space. While these methods incorporate many of the same materials, the new processing methods require standard test methods to compare materials, processing conditions, and determine design limits. This work demonstrates a test method to quantitatively measure the adhesion failure of printed inks deposited on a substrate without changing the ink printing conditions. The proposed method is an adaption of single lap shear testing in which the lap joint is created by bonding the second substrate to the ink after curing. It was found that the interfacial shear strengths are independent of the adhesives used to attach cured conductive ink to the second substrate. In addition, chemical surface treatments of flame and plasma and mechanical sand-blasting increase the interfacial shear strengths by ~25% and 80%, respectively, while altering the adhesive failure mode to cohesive failure for most cases. This work also shows extruded substrates with undulated features increase adhesion strength; therefore, in addition to surface treatments, the geometric freedom of additive manufacturing (AM) could be leveraged to design surface features for enhanced adhesion. © 2019, © 2019 Taylor & Francis Group, LLC.
196 a7003772744 Crane N.B. p428 False Journal 237 Controlling normal stiffness in droplet-based linear bearings While capillary forces are negligible relative to gravity at the macroscale, they provide adequate force to effectively manipulate millimeter to micro meter objects. The fluidic actuation can be accomplished using droplets that also act as bearings. While rotary droplet bearings have been previously demonstrated, this paper addresses the positioning accuracy of a droplet-based bearing consisting of a droplet between a moving plate and a stationary substrate with constrained wetting region under a normal load. Key wetting cases are analyzed using both closed form analytical approximations and numerical simulations. The vertical force and stiffness characteristics are analyzed in relation to the wetting boundaries of the supporting surface. Case studies of different wetting boundaries are presented and summarized. Design strategies are presented for maximizing load carrying capability and stiffness. These results show that controlled wetting and opposing droplet configurations can create much higher stiffness fluidic bearings than simple droplets. © 2018 by the authors.
197 a57195970826 Aryal B.R. p49 True Journal 39 DNA origami mediated electrically connected metal—semiconductor junctions DNA-based nanofabrication of inorganic nanostructures has potential application in electronics, catalysis, and plasmonics. Previous DNA metallization has generated conductive DNA-assembled nanostructures; however, the use of semiconductors and the development of well-connected nanoscale metal—semiconductor junctions on DNA nanostructures are still at an early stage. Herein, we report the first fabrication of multiple electrically connected metal—semiconductor junctions on individual DNA origami by location-specific binding of gold and tellurium nanorods. Nanorod attachment to DNA origami was via DNA hybridization for Au and by electrostatic interaction for Te. Electroless gold plating was used to create nanoscale metal—semiconductor interfaces by filling the gaps between Au and Te nanorods. Two-point electrical characterization indicated that the Au—Te—Au junctions were electrically connected, with current—voltage properties consistent with a Schottky junction. DNA-based nanofabrication of metal—semiconductor junctions opens up potential opportunities in nanoelectronics, demonstrating the power of this bottom-up approach. [Figure not available: see fulltext.]. © 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.
198 a57203943386 Ranasinghe D.R. p49 False Journal 39 DNA origami mediated electrically connected metal—semiconductor junctions DNA-based nanofabrication of inorganic nanostructures has potential application in electronics, catalysis, and plasmonics. Previous DNA metallization has generated conductive DNA-assembled nanostructures; however, the use of semiconductors and the development of well-connected nanoscale metal—semiconductor junctions on DNA nanostructures are still at an early stage. Herein, we report the first fabrication of multiple electrically connected metal—semiconductor junctions on individual DNA origami by location-specific binding of gold and tellurium nanorods. Nanorod attachment to DNA origami was via DNA hybridization for Au and by electrostatic interaction for Te. Electroless gold plating was used to create nanoscale metal—semiconductor interfaces by filling the gaps between Au and Te nanorods. Two-point electrical characterization indicated that the Au—Te—Au junctions were electrically connected, with current—voltage properties consistent with a Schottky junction. DNA-based nanofabrication of metal—semiconductor junctions opens up potential opportunities in nanoelectronics, demonstrating the power of this bottom-up approach. [Figure not available: see fulltext.]. © 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.
199 a57193834529 Westover T.R. p49 False Journal 39 DNA origami mediated electrically connected metal—semiconductor junctions DNA-based nanofabrication of inorganic nanostructures has potential application in electronics, catalysis, and plasmonics. Previous DNA metallization has generated conductive DNA-assembled nanostructures; however, the use of semiconductors and the development of well-connected nanoscale metal—semiconductor junctions on DNA nanostructures are still at an early stage. Herein, we report the first fabrication of multiple electrically connected metal—semiconductor junctions on individual DNA origami by location-specific binding of gold and tellurium nanorods. Nanorod attachment to DNA origami was via DNA hybridization for Au and by electrostatic interaction for Te. Electroless gold plating was used to create nanoscale metal—semiconductor interfaces by filling the gaps between Au and Te nanorods. Two-point electrical characterization indicated that the Au—Te—Au junctions were electrically connected, with current—voltage properties consistent with a Schottky junction. DNA-based nanofabrication of metal—semiconductor junctions opens up potential opportunities in nanoelectronics, demonstrating the power of this bottom-up approach. [Figure not available: see fulltext.]. © 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.
200 a57203942414 Calvopiña D.G. p49 False Journal 39 DNA origami mediated electrically connected metal—semiconductor junctions DNA-based nanofabrication of inorganic nanostructures has potential application in electronics, catalysis, and plasmonics. Previous DNA metallization has generated conductive DNA-assembled nanostructures; however, the use of semiconductors and the development of well-connected nanoscale metal—semiconductor junctions on DNA nanostructures are still at an early stage. Herein, we report the first fabrication of multiple electrically connected metal—semiconductor junctions on individual DNA origami by location-specific binding of gold and tellurium nanorods. Nanorod attachment to DNA origami was via DNA hybridization for Au and by electrostatic interaction for Te. Electroless gold plating was used to create nanoscale metal—semiconductor interfaces by filling the gaps between Au and Te nanorods. Two-point electrical characterization indicated that the Au—Te—Au junctions were electrically connected, with current—voltage properties consistent with a Schottky junction. DNA-based nanofabrication of metal—semiconductor junctions opens up potential opportunities in nanoelectronics, demonstrating the power of this bottom-up approach. [Figure not available: see fulltext.]. © 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.
201 a7410190129 Davis R.C. p49 False Journal 39 DNA origami mediated electrically connected metal—semiconductor junctions DNA-based nanofabrication of inorganic nanostructures has potential application in electronics, catalysis, and plasmonics. Previous DNA metallization has generated conductive DNA-assembled nanostructures; however, the use of semiconductors and the development of well-connected nanoscale metal—semiconductor junctions on DNA nanostructures are still at an early stage. Herein, we report the first fabrication of multiple electrically connected metal—semiconductor junctions on individual DNA origami by location-specific binding of gold and tellurium nanorods. Nanorod attachment to DNA origami was via DNA hybridization for Au and by electrostatic interaction for Te. Electroless gold plating was used to create nanoscale metal—semiconductor interfaces by filling the gaps between Au and Te nanorods. Two-point electrical characterization indicated that the Au—Te—Au junctions were electrically connected, with current—voltage properties consistent with a Schottky junction. DNA-based nanofabrication of metal—semiconductor junctions opens up potential opportunities in nanoelectronics, demonstrating the power of this bottom-up approach. [Figure not available: see fulltext.]. © 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.
201 a7410190129 Davis R.C. p79 False Journal 59 Closed-Loop, Axial Temperature Control of Etched Silicon Microcolumn for Tunable Thermal Gradient Gas Chromatography Combining the resolution of conventional gas chromatography systems with the size factor of microGC systems is important for improving the affordability and portability of high performance gas analysis. Recent work has demonstrated the feasibility of high resolution separation of gases in a benchtopscale short column system by controlling thermal gradients through the column. This work reports a microfabricated thermally controllable gas chromatographic column with a small footprint (approximately 6.25 cm2). The design of the 20 cm column utilizes 21 individually controllable thin film heaters and conduction cooling to produce a desired temperature profile. The reported device is capable of heating and cooling rates exceeding 8000 °C/min and can reach temperatures of 350 °C. The control methods allow for excellent disturbance rejection and precision to within +/- 1 °C. Each length of the column between heaters was demonstrated to be individually controllable and displayed quadratic temperature profiles. This paper focuses on the fabrication process and implementation of the thermal control strategy. [2019-0113] © 1992-2012 IEEE.
201 a7410190129 Davis R.C. p363 False Journal 203 High surface-area carbon microcantilevers Microscale porous carbon mechanical resonators were formed using carbon nanotube templated microfabrication. These cantilever resonators exhibited nanoscale porosity resulting in a high surface area to volume ratio which could enable sensitive analyte detection in air. These resonators were shown to be mechanically robust and the porosity could be controllably varied resulting in densities from 102 to 103 kg m-3, with pore diameters on the order of hundreds of nanometers. Cantilevers with lengths ranging from 500 μm to 5 mm were clamped in a fixture for mechanical resonance testing where quality factors from 102 to 103 were observed at atmospheric pressure in air. © 2019 The Royal Society of Chemistry.
201 a7410190129 Davis R.C. p512 False Journal 281 Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 μm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes. © 2018 American Chemical Society.
201 a7410190129 Davis R.C. p725 False Journal 354 Carbon monolith scaffolding for high volumetric capacity silicon Li-ion battery anodes A nanoporous carbon monolith structure has been developed for use as a scaffold for silicon anodes for lithium batteries. This scaffold was fabricated by coating vertically aligned carbon nanotubes in a highly conformal coating of nanocrystalline carbon, applied via atmospheric pressure chemical vapor deposition. The coating increases the mechanical stability of the nanotube structure, which provides electrically conductive pathways through the anode. Silicon anodes were fabricated with the monoliths by low pressure chemical vapor infiltration of silicon. This platform allows the carbon and silicon volume fractions to be independently varied in the anode. Anodes with a low silicon content (less than 5% by volume) showed high stability in cycling against lithium with a capacity retention of 89.7% between cycles 2 and 185. Anodes with a high silicon content (∼25% by volume) showed poor capacity retention when the carbon content was low (<40% by volume), and transmission electron microscopy analysis indicated that the anodes failed due to the destruction of the nanocrystalline carbon coating during cycling. However, by increasing the carbon content to ∼60% volume percent in the monolith, capacity retention was substantially stabilized even for anodes with very high silicon loadings. These stabilized electrodes exhibited volumetric capacities as high as ∼1000 mA h/ml and retained over 725 mA h/ml by cycle 100. © 2017 American Vacuum Society.
202 a7007046711 Harb J.N. p49 False Journal 39 DNA origami mediated electrically connected metal—semiconductor junctions DNA-based nanofabrication of inorganic nanostructures has potential application in electronics, catalysis, and plasmonics. Previous DNA metallization has generated conductive DNA-assembled nanostructures; however, the use of semiconductors and the development of well-connected nanoscale metal—semiconductor junctions on DNA nanostructures are still at an early stage. Herein, we report the first fabrication of multiple electrically connected metal—semiconductor junctions on individual DNA origami by location-specific binding of gold and tellurium nanorods. Nanorod attachment to DNA origami was via DNA hybridization for Au and by electrostatic interaction for Te. Electroless gold plating was used to create nanoscale metal—semiconductor interfaces by filling the gaps between Au and Te nanorods. Two-point electrical characterization indicated that the Au—Te—Au junctions were electrically connected, with current—voltage properties consistent with a Schottky junction. DNA-based nanofabrication of metal—semiconductor junctions opens up potential opportunities in nanoelectronics, demonstrating the power of this bottom-up approach. [Figure not available: see fulltext.]. © 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.
202 a7007046711 Harb J.N. p68 False Journal 51 Oxidation efficiency of glucose using viologen mediators for glucose fuel cell applications with non-precious anodes Glucose is a potential source of energy for fuel cell applications. However, its complete oxidation has been a challenge. Dimethyl viologen, as an electron mediator, has been shown to promote high levels of glucose oxidation under aerobic conditions. Nevertheless, the efficiency of viologen-mediated glucose oxidation has been low in electrochemical experiments. In this study, viologen-mediated oxidation of glucose was investigated under anaerobic electrochemical conditions to understand the factors that impact the oxidation efficiency. Of particular interest was the improvement of electrochemical oxidation for glucose fuel cell applications. An experimental cell was developed to electrochemically reoxidize the mediator as it was homogeneously reduced by glucose under anaerobic conditions. In contrast, the mediator was reoxidized by direct reaction with oxygen under aerobic conditions. The aerobic oxidation efficiency was 75%, three times larger than the maximum efficiency in the electrochemical cell. 13C-NMR results show that the main product formed under aerobic conditions was formic acid, whereas glycolic acid was the principal product formed in the electrochemical cell. Carbonate was only formed under aerobic conditions. Therefore, the use of oxygen to reoxidize the mediator also directly influenced the glucose oxidation pathway. In the electrochemical cell, the oxidation efficiency depended on the electrochemical reaction rate of the mediator and was higher at faster rates. The efficiency also depended on the initial molar ratio of the mediator to glucose. The maximum oxidation efficiency of glucose in the electrochemical cell was approximately 22%, which is about three times larger than the maximum efficiency for precious-metal-based anodes. © 2019
202 a7007046711 Harb J.N. p512 False Journal 281 Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 μm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes. © 2018 American Chemical Society.
202 a7007046711 Harb J.N. p725 False Journal 354 Carbon monolith scaffolding for high volumetric capacity silicon Li-ion battery anodes A nanoporous carbon monolith structure has been developed for use as a scaffold for silicon anodes for lithium batteries. This scaffold was fabricated by coating vertically aligned carbon nanotubes in a highly conformal coating of nanocrystalline carbon, applied via atmospheric pressure chemical vapor deposition. The coating increases the mechanical stability of the nanotube structure, which provides electrically conductive pathways through the anode. Silicon anodes were fabricated with the monoliths by low pressure chemical vapor infiltration of silicon. This platform allows the carbon and silicon volume fractions to be independently varied in the anode. Anodes with a low silicon content (less than 5% by volume) showed high stability in cycling against lithium with a capacity retention of 89.7% between cycles 2 and 185. Anodes with a high silicon content (∼25% by volume) showed poor capacity retention when the carbon content was low (<40% by volume), and transmission electron microscopy analysis indicated that the anodes failed due to the destruction of the nanocrystalline carbon coating during cycling. However, by increasing the carbon content to ∼60% volume percent in the monolith, capacity retention was substantially stabilized even for anodes with very high silicon loadings. These stabilized electrodes exhibited volumetric capacities as high as ∼1000 mA h/ml and retained over 725 mA h/ml by cycle 100. © 2017 American Vacuum Society.
203 a7006111578 Woolley A.T. p49 False Journal 39 DNA origami mediated electrically connected metal—semiconductor junctions DNA-based nanofabrication of inorganic nanostructures has potential application in electronics, catalysis, and plasmonics. Previous DNA metallization has generated conductive DNA-assembled nanostructures; however, the use of semiconductors and the development of well-connected nanoscale metal—semiconductor junctions on DNA nanostructures are still at an early stage. Herein, we report the first fabrication of multiple electrically connected metal—semiconductor junctions on individual DNA origami by location-specific binding of gold and tellurium nanorods. Nanorod attachment to DNA origami was via DNA hybridization for Au and by electrostatic interaction for Te. Electroless gold plating was used to create nanoscale metal—semiconductor interfaces by filling the gaps between Au and Te nanorods. Two-point electrical characterization indicated that the Au—Te—Au junctions were electrically connected, with current—voltage properties consistent with a Schottky junction. DNA-based nanofabrication of metal—semiconductor junctions opens up potential opportunities in nanoelectronics, demonstrating the power of this bottom-up approach. [Figure not available: see fulltext.]. © 2020, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.
203 a7006111578 Woolley A.T. p172 False Conference 36 Multiplexed Detection of Single Antibiotic Drug-Resistant Plasmids using Multimode Interference Waveguide Based Optofluidic Chip A single multimode interference waveguide is used to create distinct spectral spot patterns on two liquid-core waveguides on an optofluidic chip. This device is used for multiplexed detection of antibiotic-resistant plasmids with single nucleic acid sensitivity. © 2019 IEEE.
203 a7006111578 Woolley A.T. p266 False Journal 175 Roadmap on biological pathways for electronic nanofabrication and materials Conventional microchip fabrication is energy and resource intensive. Thus, the discovery of new manufacturing approaches that reduce these expenditures would be highly beneficial to the semiconductor industry. In comparison, living systems construct complex nanometer-scale structures with high yields and low energy utilization. Combining the capabilities of living systems with synthetic DNA-/protein-based self-assembly may offer intriguing potential for revolutionizing the synthesis of complex sub-10 nm information processing architectures. The successful discovery of new biologically based paradigms would not only help extend the current semiconductor technology roadmap, but also offer additional potential growth areas in biology, medicine, agriculture and sustainability for the semiconductor industry. This article summarizes discussions surrounding key emerging technologies explored at the Workshop on Biological Pathways for Electronic Nanofabrication and Materials that was held on 16–17 November 2016 at the IBM Almaden Research Center in San Jose, CA. © 2019 IOP Publishing Ltd.
203 a7006111578 Woolley A.T. p330 False Journal 192 3D printed selectable dilution mixer pumps In this paper, we demonstrate the ability to 3D print tightly integrated structures with active valves, pumps, and mixers, and we use our compact chip-to-chip interconnects [Gong et al., Lab Chip 18, 639-647 (2018)] to move bulky world-to-chip connections to separate interface chips for both post-print flushing and post-cure device operation. As example devices, we first examine 3D printed pumps, followed by two types of selectable ratio mixer pumps, a linear dilution mixer pump (LDMP) and a parallelized dilution mixer pump (PDMP), which occupy volumes of only 1.5 mm 3 and 2.6 mm 3, respectively. The LDMP generates a selectable dilution ratio from a linear set of possibilities, while the PDMP generates a denser set of possible dilutions with a maximum dilution ratio of 1/16. The PDMP also incorporates a new 4-to-1 valve to simultaneously control 4 inlet channels. To characterize LDMP and PDMP operation and performance, we present a new, low-cost video method to directly measure the relative concentration of an absorptive dye on a pixel-by-pixel basis for each video frame. Using this method, we find that 6 periods of the active mixer that forms the core of the LDMP and PDMP are sufficient to fully mix the fluid, and that the generated concentrations track the designed dilution ratios as expected. The LDMP mixes 20 nl per 4.6 s mixer pump period, while the PDMP uses parallelized input pumps to process the same fluid volume with greater choice of dilution ratios in a 3.6 s period. © 2019 Author(s).
203 a7006111578 Woolley A.T. p332 False Conference 108 3D printing for lab-on-a-chip devices with 20 μm channels While there is great interest in 3D printing for microfluidic device fabrication, the challenge has been to achieve feature sizes that are in the truly microfluidic regime (<100 μm). The fundamental problem is that commercial tools and materials, which excel in many other application areas, have not been developed to address the unique needs of microfluidic device fabrication. Consequently, we have created our own stereolithographic 3D printer and materials that are specifically tailored to meet these needs. We review our recent work and show that flow channels as small as 18 μm x 20 μm can be reliably fabricated, as well as compact active elements such as valves and pumps. With these capabilities, we demonstrate highly integrated 3D printed microfluidic devices that measure only a few millimeters on a side, and that integrate separate chip-to-world interfaces through high density interconnects (up to 88 interconnects per square mm) that are directly 3D printed as part of a device chip. These advances open the door to 3D printing as a replacement for expensive cleanroom fabrication processes, with the additional advantage of fast (30 minute), parallel fabrication of many devices in a single print run due to their small size. © 2019 SPIE.
203 a7006111578 Woolley A.T. p481 False Journal 237 3D printed microfluidic features using dose control in X, Y, and Z dimensions Interest has grown in recent years to leverage the possibilities offered by three-dimensional (3D) printing, such as rapid iterative changes; the ability to more fully use 3D device volume; and ease of fabrication, especially as it relates to the creation of complex microfluidic devices. A major shortcoming of most commercially available 3D printers is that their resolution is not sufficient to produce features that are truly microfluidic (&lt; 100 × 100 μm2). Here, we test a custom 3D printer for making ~30 μm scale positive and negative surface features, as well as positive and negative features within internal voids (i.e., microfluidic channels). We found that optical dosage control is essential for creating the smallest microfluidic features (~30 μm wide for ridges, ~20 μm wide for trenches), and that this resolution was achieved for a number of different exposure approaches. Additionally, we printed various microfluidic particle traps, showed capture of 25 μm diameter polymer beads, and iteratively improved the trap design. The rapid feedback allowed by 3D printing, as well as the ability to carefully control optical exposure conditions, should lead to new innovations in the types and sizes of devices that can be created for microfluidics. © 2018 by the authors.
203 a7006111578 Woolley A.T. p536 False Journal 217 3D printed high density, reversible, chip-to-chip microfluidic interconnects Our latest developments in miniaturizing 3D printed microfluidics [Gong et al., Lab Chip, 2016, 16, 2450; Gong et al., Lab Chip, 2017, 17, 2899] offer the opportunity to fabricate highly integrated chips that measure only a few mm on a side. For such small chips, an interconnection method is needed to provide the necessary world-to-chip reagent and pneumatic connections. In this paper, we introduce simple integrated microgaskets (SIMs) and controlled-compression integrated microgaskets (CCIMs) to connect a small device chip to a larger interface chip that implements world-to-chip connections. SIMs or CCIMs are directly 3D printed as part of the device chip, and therefore no additional materials or components are required to make the connection to the larger 3D printed interface chip. We demonstrate 121 chip-to-chip interconnections in an 11 × 11 array for both SIMs and CCIMs with an areal density of 53 interconnections per mm2 and show that they withstand fluid pressures of 50 psi. We further demonstrate their reusability by testing the devices 100 times without seal failure. Scaling experiments show that 20 × 20 interconnection arrays are feasible and that the CCIM areal density can be increased to 88 interconnections per mm2. We then show the utility of spatially distributed discrete CCIMs by using an interconnection chip with 28 chip-to-world interconnects to test 45 3D printed valves in a 9 × 5 array. Each valve is only 300 μm in diameter (the smallest yet reported for 3D printed valves). Every row of 5 valves is tested to at least 10000 actuations, with one row tested to 1-000000 actuations. In all cases, there is no sign of valve failure, and the CCIM interconnections prove an effective means of using a single interface chip to test a series of valve array chips. © 2018 The Royal Society of Chemistry.
203 a7006111578 Woolley A.T. p558 False Conference 207 3D printed microfluidic selectable ratio mixer pump in 2 mm3 We report the use of 3D printing to fabricate a selectable ratio mixer pump in a volume of only 2 mm2. Our custom 3D printer and material is used to make very compact individual elements such as fluid channels, valves, and pumps that are laid out in 3D to achieve small overall device volume. The device includes two pumps, each connected to its own fluid source, and a two-chamber mixing unit that both mixes the fluid pumped into it from each fluid source, and acts itself as a pump to expel the mixed fluid. © 2016 TRF
203 a7006111578 Woolley A.T. p693 False Journal 337 Custom 3D printer and resin for 18 μm × 20 μm microfluidic flow channels While there is great interest in 3D printing for microfluidic device fabrication, to-date the achieved feature sizes have not been in the truly microfluidic regime (&lt;100 μm). In this paper we demonstrate that a custom digital light processor stereolithographic (DLP-SLA) 3D printer and a specifically-designed, low cost, custom resin can readily achieve flow channel cross sections as small as 18 μm × 20 μm. Our 3D printer has a projected image plane resolution of 7.6 μm and uses a 385 nm LED, which dramatically increases the available selection of UV absorbers for resin formulation compared to 3D printers with 405 nm LEDs. Beginning with 20 candidate absorbers, we demonstrate the evaluation criteria and process flow required to develop a high-resolution resin. In doing so, we introduce a new mathematical model for characterizing the resin optical penetration depth based only on measurement of the absorber's molar absorptivity. Our final resin formulation uses 2-nitrophenyl phenyl sulfide (NPS) as the UV absorber. We also develop a novel channel narrowing technique that, together with the new resin and 3D printer resolution, enables small flow channel fabrication. We demonstrate the efficacy of our approach by fabricating 3D serpentine flow channels 41 mm long in a volume of only 0.12 mm3, and by printing high aspect ratio flow channels &lt;25 μm wide and 3 mm tall. These results indicate that 3D printing is finally positioned to challenge the pre-eminence of methods such as soft lithography for microfluidic device prototyping and fabrication. © 2017 The Royal Society of Chemistry.
204 a56371366400 Fujimoto M.S. p50 True Conference 8 Kcollections: A fast and efficient library for K-mers K-mers form the backbone of many bioinformatic algorithms. They are, however, difficult to store and use efficiently because the number of k-mers increases exponentially as k increases. Many algorithms exist for compressed storage of kmers but suffer from slow insert times or are probabilistic resulting in false-positive k-mers. Furthermore, k-mer libraries usually specialize in associating specific values with k-mers such as a color in colored de Bruijn Graphs or k-mer count. We present kcollections1, a compressed and parallel data structure designed for k-mers generated from whole, assembled genomes. Kcollections is available for C++ and provides set-and maplike structures as well as a k-mer counting data structure all of which utilize parallel operations designed using a MapReduce paradigm. Additionally, we provide basic Python bindings for rapid prototyping. Kcollections makes developing bioinformatic algorithms simpler by abstracting away the tedious task of storing k-mers.1https://www.github.com/masakistan/kcollections © 2020 IEEE.
204 a56371366400 Fujimoto M.S. p458 False Conference 164 The PepSeq Pipeline: Software for Antimicrobial Motif Discovery in Randomly-Generated Peptide Libraries Bacteria with resistance genes are becoming ever more common, and new methods of discovering antibiotics are being developed. One of these new methods involves researchers creating random peptides and testing their antimicrobial activity. Developing antibiotics from these peptides requires understanding which sequence motifs will be toxic to bacteria. To determine if the toxic peptides of a randomly-generated peptide library can be uniquely classified based solely on sequence motifs, we created the PepSeq Pipeline: a new software that utilizes a Random Forest algorithm to extract motifs from a peptide library. We found that this pipeline can accurately classify 56% of the toxic peptides in the peptide library using motifs extracted from the model. Testing on simulated data with less noise, we could classify up to 94% of the toxic peptides. The pipeline extracted significant toxic motifs in every library that was tested, but its ability to classify all toxic peptides depended on the number of motifs in the library. Once extracted, these motifs can be used both to understand the biology behind why certain peptides are toxic and to create novel antibiotics. The code and data used in this analysis can be found at https://github.com/tjense25/pep-seq-pipeline. © 2018 ACM.
204 a56371366400 Fujimoto M.S. p724 True Conference 307 Modeling global and local codon bias with deep language models Codon bias, the usage patterns of synonymous codons for encoding a protein sequence as nucleotides, is a biological phenomenon that is not fully understood. Several methods exist to represent the codon bias of an organism: codon adaptation index (CAI) [1], individual codon usage (ICU), hidden stop codons (HSC) [2] and codon context (CC) [3]. These methods are often employed in the optimization of heterologous gene expression to increase the accuracy and rate of translation. They, however, have many shortcomings as they dont take into account the local and global context of a gene. We present a method for modeling global and local codon bias through deep language models that is more robust than current methods by providing more contextual information and long-range dependencies. © 2017 IEEE.
204 a56371366400 Fujimoto M.S. p727 False Conference 308 Whole genome phylogenetic tree reconstruction using colored de bruijn graphs We present kleuren, a novel assembly-free method to reconstruct phylogenetic trees using the Colored de Bruijn Graph. kleuren works by constructing the Colored de Bruijn Graph and then traversing it, finding bubble structures in the graph that provide phylogenetic signal. The bubbles are then aligned and concatenated to form a supermatrix, from which a phylogenetic tree is inferred. We introduce the algorithms that kleuren uses to accomplish this task, and show its performance on reconstructing the phylogenetic tree of 12 Drosophila species. kleuren reconstructed the established phylogenetic tree accurately, and is a viable tool for phylogenetic tree reconstruction using whole genome sequences. Software package available at: https://github.com/Colelyman/kleuren. © 2017 IEEE.
204 a56371366400 Fujimoto M.S. p728 True Conference 309 Genome polymorphism detection through relaxed de bruijn graph construction Comparing genomes to identify polymorphisms is a difficult task, especially beyond single nucleotide poly-morphisms. Polymorphism detection is important in disease association studies as well as in phylogenetic tree reconstruc-tion. We present a method for identifying polymorphisms in genomes by using a modified version de Bruijn graphs, data structures widely used in genome assembly from Next-Generation Sequencing. Using our method, we are able to identify polymorphisms that exist within a genome as well as well as see graph structures that form in the de Bruijn graph for particular types of polymorphisms (translocations, etc.) © 2017 IEEE.
205 a57202818911 Lyman C.A. p50 False Conference 8 Kcollections: A fast and efficient library for K-mers K-mers form the backbone of many bioinformatic algorithms. They are, however, difficult to store and use efficiently because the number of k-mers increases exponentially as k increases. Many algorithms exist for compressed storage of kmers but suffer from slow insert times or are probabilistic resulting in false-positive k-mers. Furthermore, k-mer libraries usually specialize in associating specific values with k-mers such as a color in colored de Bruijn Graphs or k-mer count. We present kcollections1, a compressed and parallel data structure designed for k-mers generated from whole, assembled genomes. Kcollections is available for C++ and provides set-and maplike structures as well as a k-mer counting data structure all of which utilize parallel operations designed using a MapReduce paradigm. Additionally, we provide basic Python bindings for rapid prototyping. Kcollections makes developing bioinformatic algorithms simpler by abstracting away the tedious task of storing k-mers.1https://www.github.com/masakistan/kcollections © 2020 IEEE.
205 a57202818911 Lyman C.A. p166 True Conference 32 Feedback regulation of immune response to maximum exercise in Gulf war illness Gulf War Illness is a disease that affects about a third of the veterans that served in the 1990-91 Persian Gulf War. The symptoms are varied, the cause is unknown, and there is no known treatment. In this paper we compare the dynamic characteristics of cytokines feedback response to exercise in n=12 veterans diagnosed with Gulf War Illness (GWI) and n=12 healthy veterans deployed to the same theatre of operations. A third-order transfer function is used to model the process dynamics of 18 cytokines projected onto principal components with a Proportional Integral Derivative (PID) controller enforcing the homeostatic regulation of these co-expression patterns. Transfer functions were fit to each subject for each principal component and the dynamic response parameters compared between the veteran control and GWI subject groups. Results of this analysis indicate that while much of the regulatory response dynamics are shared by both groups, there is a significant difference in the damping of the Th1:Th2 cytokine response to exercise in Gulf War Illness. © 2019 Association of Computing Machinery.
205 a57202818911 Lyman C.A. p256 False Conference 61 The polygraph: A data structure for genome alignment and variation detection Comparing whole genomes and finding variation is an important and difficult bioinfor-matic task. We present the Polygraph, a data structure for reference-free, multiple whole genome alignment that can be used to identify genomic structural variation. This data structure is built from assembled genomes and preserves the genomic structure from the assembly. It avoids the “hairball” graph structure that can occur in other graph methods such as de Bruijn graphs. The Polygraph can easily be visualized and be used for identification of structural variants. We apply the Polygraph to Escherichia coli and Saccharomyces cerevisiae for finding Structural Variants. Copyright © 2012-2020 easychair.org. All rights reserved.
205 a57202818911 Lyman C.A. p458 False Conference 164 The PepSeq Pipeline: Software for Antimicrobial Motif Discovery in Randomly-Generated Peptide Libraries Bacteria with resistance genes are becoming ever more common, and new methods of discovering antibiotics are being developed. One of these new methods involves researchers creating random peptides and testing their antimicrobial activity. Developing antibiotics from these peptides requires understanding which sequence motifs will be toxic to bacteria. To determine if the toxic peptides of a randomly-generated peptide library can be uniquely classified based solely on sequence motifs, we created the PepSeq Pipeline: a new software that utilizes a Random Forest algorithm to extract motifs from a peptide library. We found that this pipeline can accurately classify 56% of the toxic peptides in the peptide library using motifs extracted from the model. Testing on simulated data with less noise, we could classify up to 94% of the toxic peptides. The pipeline extracted significant toxic motifs in every library that was tested, but its ability to classify all toxic peptides depended on the number of motifs in the library. Once extracted, these motifs can be used both to understand the biology behind why certain peptides are toxic and to create novel antibiotics. The code and data used in this analysis can be found at https://github.com/tjense25/pep-seq-pipeline. © 2018 ACM.
205 a57202818911 Lyman C.A. p724 False Conference 307 Modeling global and local codon bias with deep language models Codon bias, the usage patterns of synonymous codons for encoding a protein sequence as nucleotides, is a biological phenomenon that is not fully understood. Several methods exist to represent the codon bias of an organism: codon adaptation index (CAI) [1], individual codon usage (ICU), hidden stop codons (HSC) [2] and codon context (CC) [3]. These methods are often employed in the optimization of heterologous gene expression to increase the accuracy and rate of translation. They, however, have many shortcomings as they dont take into account the local and global context of a gene. We present a method for modeling global and local codon bias through deep language models that is more robust than current methods by providing more contextual information and long-range dependencies. © 2017 IEEE.
205 a57202818911 Lyman C.A. p727 True Conference 308 Whole genome phylogenetic tree reconstruction using colored de bruijn graphs We present kleuren, a novel assembly-free method to reconstruct phylogenetic trees using the Colored de Bruijn Graph. kleuren works by constructing the Colored de Bruijn Graph and then traversing it, finding bubble structures in the graph that provide phylogenetic signal. The bubbles are then aligned and concatenated to form a supermatrix, from which a phylogenetic tree is inferred. We introduce the algorithms that kleuren uses to accomplish this task, and show its performance on reconstructing the phylogenetic tree of 12 Drosophila species. kleuren reconstructed the established phylogenetic tree accurately, and is a viable tool for phylogenetic tree reconstruction using whole genome sequences. Software package available at: https://github.com/Colelyman/kleuren. © 2017 IEEE.
205 a57202818911 Lyman C.A. p728 False Conference 309 Genome polymorphism detection through relaxed de bruijn graph construction Comparing genomes to identify polymorphisms is a difficult task, especially beyond single nucleotide poly-morphisms. Polymorphism detection is important in disease association studies as well as in phylogenetic tree reconstruc-tion. We present a method for identifying polymorphisms in genomes by using a modified version de Bruijn graphs, data structures widely used in genome assembly from Next-Generation Sequencing. Using our method, we are able to identify polymorphisms that exist within a genome as well as well as see graph structures that form in the de Bruijn graph for particular types of polymorphisms (translocations, etc.) © 2017 IEEE.
206 a7102523474 Clement M.J. p50 False Conference 8 Kcollections: A fast and efficient library for K-mers K-mers form the backbone of many bioinformatic algorithms. They are, however, difficult to store and use efficiently because the number of k-mers increases exponentially as k increases. Many algorithms exist for compressed storage of kmers but suffer from slow insert times or are probabilistic resulting in false-positive k-mers. Furthermore, k-mer libraries usually specialize in associating specific values with k-mers such as a color in colored de Bruijn Graphs or k-mer count. We present kcollections1, a compressed and parallel data structure designed for k-mers generated from whole, assembled genomes. Kcollections is available for C++ and provides set-and maplike structures as well as a k-mer counting data structure all of which utilize parallel operations designed using a MapReduce paradigm. Additionally, we provide basic Python bindings for rapid prototyping. Kcollections makes developing bioinformatic algorithms simpler by abstracting away the tedious task of storing k-mers.1https://www.github.com/masakistan/kcollections © 2020 IEEE.
206 a7102523474 Clement M.J. p166 False Conference 32 Feedback regulation of immune response to maximum exercise in Gulf war illness Gulf War Illness is a disease that affects about a third of the veterans that served in the 1990-91 Persian Gulf War. The symptoms are varied, the cause is unknown, and there is no known treatment. In this paper we compare the dynamic characteristics of cytokines feedback response to exercise in n=12 veterans diagnosed with Gulf War Illness (GWI) and n=12 healthy veterans deployed to the same theatre of operations. A third-order transfer function is used to model the process dynamics of 18 cytokines projected onto principal components with a Proportional Integral Derivative (PID) controller enforcing the homeostatic regulation of these co-expression patterns. Transfer functions were fit to each subject for each principal component and the dynamic response parameters compared between the veteran control and GWI subject groups. Results of this analysis indicate that while much of the regulatory response dynamics are shared by both groups, there is a significant difference in the damping of the Th1:Th2 cytokine response to exercise in Gulf War Illness. © 2019 Association of Computing Machinery.
206 a7102523474 Clement M.J. p256 False Conference 61 The polygraph: A data structure for genome alignment and variation detection Comparing whole genomes and finding variation is an important and difficult bioinfor-matic task. We present the Polygraph, a data structure for reference-free, multiple whole genome alignment that can be used to identify genomic structural variation. This data structure is built from assembled genomes and preserves the genomic structure from the assembly. It avoids the “hairball” graph structure that can occur in other graph methods such as de Bruijn graphs. The Polygraph can easily be visualized and be used for identification of structural variants. We apply the Polygraph to Escherichia coli and Saccharomyces cerevisiae for finding Structural Variants. Copyright © 2012-2020 easychair.org. All rights reserved.
206 a7102523474 Clement M.J. p458 False Conference 164 The PepSeq Pipeline: Software for Antimicrobial Motif Discovery in Randomly-Generated Peptide Libraries Bacteria with resistance genes are becoming ever more common, and new methods of discovering antibiotics are being developed. One of these new methods involves researchers creating random peptides and testing their antimicrobial activity. Developing antibiotics from these peptides requires understanding which sequence motifs will be toxic to bacteria. To determine if the toxic peptides of a randomly-generated peptide library can be uniquely classified based solely on sequence motifs, we created the PepSeq Pipeline: a new software that utilizes a Random Forest algorithm to extract motifs from a peptide library. We found that this pipeline can accurately classify 56% of the toxic peptides in the peptide library using motifs extracted from the model. Testing on simulated data with less noise, we could classify up to 94% of the toxic peptides. The pipeline extracted significant toxic motifs in every library that was tested, but its ability to classify all toxic peptides depended on the number of motifs in the library. Once extracted, these motifs can be used both to understand the biology behind why certain peptides are toxic and to create novel antibiotics. The code and data used in this analysis can be found at https://github.com/tjense25/pep-seq-pipeline. © 2018 ACM.
206 a7102523474 Clement M.J. p724 False Conference 307 Modeling global and local codon bias with deep language models Codon bias, the usage patterns of synonymous codons for encoding a protein sequence as nucleotides, is a biological phenomenon that is not fully understood. Several methods exist to represent the codon bias of an organism: codon adaptation index (CAI) [1], individual codon usage (ICU), hidden stop codons (HSC) [2] and codon context (CC) [3]. These methods are often employed in the optimization of heterologous gene expression to increase the accuracy and rate of translation. They, however, have many shortcomings as they dont take into account the local and global context of a gene. We present a method for modeling global and local codon bias through deep language models that is more robust than current methods by providing more contextual information and long-range dependencies. © 2017 IEEE.
206 a7102523474 Clement M.J. p727 False Conference 308 Whole genome phylogenetic tree reconstruction using colored de bruijn graphs We present kleuren, a novel assembly-free method to reconstruct phylogenetic trees using the Colored de Bruijn Graph. kleuren works by constructing the Colored de Bruijn Graph and then traversing it, finding bubble structures in the graph that provide phylogenetic signal. The bubbles are then aligned and concatenated to form a supermatrix, from which a phylogenetic tree is inferred. We introduce the algorithms that kleuren uses to accomplish this task, and show its performance on reconstructing the phylogenetic tree of 12 Drosophila species. kleuren reconstructed the established phylogenetic tree accurately, and is a viable tool for phylogenetic tree reconstruction using whole genome sequences. Software package available at: https://github.com/Colelyman/kleuren. © 2017 IEEE.
206 a7102523474 Clement M.J. p728 False Conference 309 Genome polymorphism detection through relaxed de bruijn graph construction Comparing genomes to identify polymorphisms is a difficult task, especially beyond single nucleotide poly-morphisms. Polymorphism detection is important in disease association studies as well as in phylogenetic tree reconstruc-tion. We present a method for identifying polymorphisms in genomes by using a modified version de Bruijn graphs, data structures widely used in genome assembly from Next-Generation Sequencing. Using our method, we are able to identify polymorphisms that exist within a genome as well as well as see graph structures that form in the de Bruijn graph for particular types of polymorphisms (translocations, etc.) © 2017 IEEE.
207 a7003927879 Bunimovich L. p51 True Journal 40 Spectral and Dynamic Consequences of Network Specialization One of the hallmarks of real networks is the ability to perform increasingly complex tasks as their topology evolves. To explain this, it has been observed that as a network grows certain subsets of the network begin to specialize the function(s) they perform. A recent model of network growth based on this notion of specialization has been able to reproduce some of the most well-known topological features found in real-world networks including right-skewed degree distributions, the small world property, modular as well as hierarchical topology, etc. Here we describe how specialization under this model also effects the spectral properties of a network. This allows us to give the conditions under which a network is able to maintain its dynamics as its topology evolves. Specifically, we show that if a network is intrinsically stable, which is a stronger version of the standard notion of global stability, then the network maintains this type of dynamics as the network evolves. This is one of the first steps toward unifying the rigorous study of the two types of dynamics exhibited by networks. These are the dynamics of a network, which is the topological evolution of the network's structure, modeled here by the process of network specialization, and the dynamics on a network, which is the changing state of the network elements, where the type of dynamics we consider is global stability. The main examples we apply our results to are recurrent neural networks, which are the basis of certain types of machine learning algorithms. © 2020 World Scientific Publishing Company.
208 a57217245563 Passey D.J. p51 False Journal 40 Spectral and Dynamic Consequences of Network Specialization One of the hallmarks of real networks is the ability to perform increasingly complex tasks as their topology evolves. To explain this, it has been observed that as a network grows certain subsets of the network begin to specialize the function(s) they perform. A recent model of network growth based on this notion of specialization has been able to reproduce some of the most well-known topological features found in real-world networks including right-skewed degree distributions, the small world property, modular as well as hierarchical topology, etc. Here we describe how specialization under this model also effects the spectral properties of a network. This allows us to give the conditions under which a network is able to maintain its dynamics as its topology evolves. Specifically, we show that if a network is intrinsically stable, which is a stronger version of the standard notion of global stability, then the network maintains this type of dynamics as the network evolves. This is one of the first steps toward unifying the rigorous study of the two types of dynamics exhibited by networks. These are the dynamics of a network, which is the topological evolution of the network's structure, modeled here by the process of network specialization, and the dynamics on a network, which is the changing state of the network elements, where the type of dynamics we consider is global stability. The main examples we apply our results to are recurrent neural networks, which are the basis of certain types of machine learning algorithms. © 2020 World Scientific Publishing Company.
209 a57198519795 Smith D. p51 False Journal 40 Spectral and Dynamic Consequences of Network Specialization One of the hallmarks of real networks is the ability to perform increasingly complex tasks as their topology evolves. To explain this, it has been observed that as a network grows certain subsets of the network begin to specialize the function(s) they perform. A recent model of network growth based on this notion of specialization has been able to reproduce some of the most well-known topological features found in real-world networks including right-skewed degree distributions, the small world property, modular as well as hierarchical topology, etc. Here we describe how specialization under this model also effects the spectral properties of a network. This allows us to give the conditions under which a network is able to maintain its dynamics as its topology evolves. Specifically, we show that if a network is intrinsically stable, which is a stronger version of the standard notion of global stability, then the network maintains this type of dynamics as the network evolves. This is one of the first steps toward unifying the rigorous study of the two types of dynamics exhibited by networks. These are the dynamics of a network, which is the topological evolution of the network's structure, modeled here by the process of network specialization, and the dynamics on a network, which is the changing state of the network elements, where the type of dynamics we consider is global stability. The main examples we apply our results to are recurrent neural networks, which are the basis of certain types of machine learning algorithms. © 2020 World Scientific Publishing Company.
210 a55100119300 Webb B. p51 False Journal 40 Spectral and Dynamic Consequences of Network Specialization One of the hallmarks of real networks is the ability to perform increasingly complex tasks as their topology evolves. To explain this, it has been observed that as a network grows certain subsets of the network begin to specialize the function(s) they perform. A recent model of network growth based on this notion of specialization has been able to reproduce some of the most well-known topological features found in real-world networks including right-skewed degree distributions, the small world property, modular as well as hierarchical topology, etc. Here we describe how specialization under this model also effects the spectral properties of a network. This allows us to give the conditions under which a network is able to maintain its dynamics as its topology evolves. Specifically, we show that if a network is intrinsically stable, which is a stronger version of the standard notion of global stability, then the network maintains this type of dynamics as the network evolves. This is one of the first steps toward unifying the rigorous study of the two types of dynamics exhibited by networks. These are the dynamics of a network, which is the topological evolution of the network's structure, modeled here by the process of network specialization, and the dynamics on a network, which is the changing state of the network elements, where the type of dynamics we consider is global stability. The main examples we apply our results to are recurrent neural networks, which are the basis of certain types of machine learning algorithms. © 2020 World Scientific Publishing Company.
211 a39861044100 Borden M.J. p52 False Journal 41 Isogeometric Bézier dual mortaring: The enriched Bézier dual basis with application to second- and fourth-order problems In this paper, we present an algorithm to construct enriched Bézier dual basis functions that can reproduce higher-order polynomials. Our construction is unique in that it is based on Bézier extraction and projection, allowing it to be used for tensor product and unstructured polynomial spline spaces, is well-conditioned, and is quadrature-free. When used as a basis for dual mortar methods, optimal approximations are achieved for both second- and fourth-order problems. In the context of fourth-order problems, both C0 and C1 continuity constraints must be applied at each intersection. We develop a novel geometry-independent C1 continuity constraint that also preserves the sparsity of the coupled problem. The performance of the proposed formulation is verified through several challenging second- and fourth-order problems. © 2020 Elsevier B.V.
211 a39861044100 Borden M.J. p496 False Journal 268 Bézier B̄ projection In this paper we demonstrate the use of Bézier projection to alleviate locking phenomena in structural mechanics applications of isogeometric analysis. Interpreting the well-known B̄ projection in two different ways we develop two formulations for locking problems in beams and nearly incompressible elastic solids. One formulation leads to a sparse symmetric system and the other leads to a sparse non-symmetric system. To demonstrate the utility of Bézier projection for both geometry and material locking phenomena we focus on transverse shear locking in Timoshenko beams and volumetric locking in nearly compressible linear elasticity although the approach can be applied generally to other types of locking phenomena as well. Bézier projection is a local projection technique with optimal approximation properties, which in many cases produces solutions that are comparable to global L2 projection. In the context of B̄ methods, the use of Bézier projection produces sparse stiffness matrices with only a slight increase in bandwidth when compared to standard displacement-based methods. Of particular importance is that the approach is applicable to any spline representation that can be written in Bézier form like NURBS, T-splines, LR-splines, etc. We discuss in detail how to integrate this approach into an existing finite element framework with minimal disruption through the use of Bézier extraction operators and a newly introduced dual basis for the Bézier projection operator. We then demonstrate the behavior of the two proposed formulations through several challenging benchmark problems. © 2018
211 a39861044100 Borden M.J. p515 False Journal 284 Isogeometric Bézier dual mortaring: Refineable higher-order spline dual bases and weakly continuous geometry In this paper we develop the isogeometric Bézier dual mortar method. It is based on Bézier extraction and projection and is applicable to any spline space which can be represented in Bézier form (i.e., NURBS, T-splines, LR-splines, etc.). The approach weakly enforces the continuity of the solution at patch interfaces and the error can be adaptively controlled by leveraging the refineability of the underlying slave dual spline basis without introducing any additional degrees of freedom. As a consequence, optimal higher-order convergence rates can be achieved without the need for an expensive shared master/slave segmentation step. We also develop weakly continuous geometry as a particular application of isogeometric Bézier dual mortaring. Weakly continuous geometry is a geometry description where the weak continuity constraints are built into properly modified Bézier extraction operators. As a result, multi-patch models can be processed in a solver directly without having to employ a mortaring solution strategy. We demonstrate the utility of the approach on several challenging benchmark problems. © 2018 Elsevier B.V.
212 a36708895400 Thomas D.C. p52 False Journal 41 Isogeometric Bézier dual mortaring: The enriched Bézier dual basis with application to second- and fourth-order problems In this paper, we present an algorithm to construct enriched Bézier dual basis functions that can reproduce higher-order polynomials. Our construction is unique in that it is based on Bézier extraction and projection, allowing it to be used for tensor product and unstructured polynomial spline spaces, is well-conditioned, and is quadrature-free. When used as a basis for dual mortar methods, optimal approximations are achieved for both second- and fourth-order problems. In the context of fourth-order problems, both C0 and C1 continuity constraints must be applied at each intersection. We develop a novel geometry-independent C1 continuity constraint that also preserves the sparsity of the coupled problem. The performance of the proposed formulation is verified through several challenging second- and fourth-order problems. © 2020 Elsevier B.V.
212 a36708895400 Thomas D.C. p496 False Journal 268 Bézier B̄ projection In this paper we demonstrate the use of Bézier projection to alleviate locking phenomena in structural mechanics applications of isogeometric analysis. Interpreting the well-known B̄ projection in two different ways we develop two formulations for locking problems in beams and nearly incompressible elastic solids. One formulation leads to a sparse symmetric system and the other leads to a sparse non-symmetric system. To demonstrate the utility of Bézier projection for both geometry and material locking phenomena we focus on transverse shear locking in Timoshenko beams and volumetric locking in nearly compressible linear elasticity although the approach can be applied generally to other types of locking phenomena as well. Bézier projection is a local projection technique with optimal approximation properties, which in many cases produces solutions that are comparable to global L2 projection. In the context of B̄ methods, the use of Bézier projection produces sparse stiffness matrices with only a slight increase in bandwidth when compared to standard displacement-based methods. Of particular importance is that the approach is applicable to any spline representation that can be written in Bézier form like NURBS, T-splines, LR-splines, etc. We discuss in detail how to integrate this approach into an existing finite element framework with minimal disruption through the use of Bézier extraction operators and a newly introduced dual basis for the Bézier projection operator. We then demonstrate the behavior of the two proposed formulations through several challenging benchmark problems. © 2018
212 a36708895400 Thomas D.C. p515 False Journal 284 Isogeometric Bézier dual mortaring: Refineable higher-order spline dual bases and weakly continuous geometry In this paper we develop the isogeometric Bézier dual mortar method. It is based on Bézier extraction and projection and is applicable to any spline space which can be represented in Bézier form (i.e., NURBS, T-splines, LR-splines, etc.). The approach weakly enforces the continuity of the solution at patch interfaces and the error can be adaptively controlled by leveraging the refineability of the underlying slave dual spline basis without introducing any additional degrees of freedom. As a consequence, optimal higher-order convergence rates can be achieved without the need for an expensive shared master/slave segmentation step. We also develop weakly continuous geometry as a particular application of isogeometric Bézier dual mortaring. Weakly continuous geometry is a geometry description where the weak continuity constraints are built into properly modified Bézier extraction operators. As a result, multi-patch models can be processed in a solver directly without having to employ a mortaring solution strategy. We demonstrate the utility of the approach on several challenging benchmark problems. © 2018 Elsevier B.V.
213 a57210419894 Yu M. p53 True Journal 42 SR-SYBA: A scale and rotation invariant synthetic basis feature descriptor with low memory usage Feature description has an important role in image matching and is widely used for a variety of computer vision applications. As an efficient synthetic basis feature descriptor, SYnthetic BAsis (SYBA) requires low computational complexity and provides accurate matching results. However, the number of matched feature points generated by SYBA suffers from large image scaling and rotation variations. In this paper, we improve SYBA’s scale and rotation invariance by adding an efficient pre-processing operation. The proposed algorithm, SR-SYBA, represents the scale of the feature region with the location of maximum gradient response along the radial direction in Log-polar coordinate system. Based on this scale representation, it normalizes all feature regions to the same reference scale to provide scale invariance. The orientation of the feature region is represented as the orientation of the vector from the center of the feature region to its intensity centroid. Based on this orientation representation, all feature regions are rotated to the same reference orientation to provide rotation invariance. The original SYBA descriptor is then applied to the scale and orientation normalized feature regions for description and matching. Experiment results show that SR-SYBA greatly improves SYBA for image matching applications with scaling and rotation variations. SR-SYBA obtains comparable or better performance in terms of matching rate compared to the mainstream algorithms while still maintains its advantages of using much less storage and simpler computations. SR-SYBA is applied to a vision-based measurement application to demonstrate its performance for image matching. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
213 a57210419894 Yu M. p184 False Journal 104 Hardware friendly robust synthetic basis feature descriptor Finding corresponding image features between two images is often the first step for many computer vision algorithms. This paper introduces an improved synthetic basis feature descriptor algorithm that describes and compares image features in an efficient and discrete manner with rotation and scale invariance. It works by performing a number of similarity tests between the feature region surrounding the feature point and a predetermined number of synthetic basis images to generate a feature descriptor that uniquely describes the feature region. Features in two images are matched by comparing their descriptors. By only storing the similarity of the feature region to each synthetic basis image, the overall storage size is greatly reduced. In short, this new binary feature descriptor is designed to provide high feature matching accuracy with computational simplicity, relatively low resource usage, and a hardware friendly design for real-time vision applications. Experimental results show that our algorithm produces higher precision rates and larger number of correct matches than the original version and other mainstream algorithms and is a good alternative for common computer vision applications. Two applications that often have to cope with scaling and rotation variations are included in this work to demonstrate its performance. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
214 a14059209700 Zhang D. p53 False Journal 42 SR-SYBA: A scale and rotation invariant synthetic basis feature descriptor with low memory usage Feature description has an important role in image matching and is widely used for a variety of computer vision applications. As an efficient synthetic basis feature descriptor, SYnthetic BAsis (SYBA) requires low computational complexity and provides accurate matching results. However, the number of matched feature points generated by SYBA suffers from large image scaling and rotation variations. In this paper, we improve SYBA’s scale and rotation invariance by adding an efficient pre-processing operation. The proposed algorithm, SR-SYBA, represents the scale of the feature region with the location of maximum gradient response along the radial direction in Log-polar coordinate system. Based on this scale representation, it normalizes all feature regions to the same reference scale to provide scale invariance. The orientation of the feature region is represented as the orientation of the vector from the center of the feature region to its intensity centroid. Based on this orientation representation, all feature regions are rotated to the same reference orientation to provide rotation invariance. The original SYBA descriptor is then applied to the scale and orientation normalized feature regions for description and matching. Experiment results show that SR-SYBA greatly improves SYBA for image matching applications with scaling and rotation variations. SR-SYBA obtains comparable or better performance in terms of matching rate compared to the mainstream algorithms while still maintains its advantages of using much less storage and simpler computations. SR-SYBA is applied to a vision-based measurement application to demonstrate its performance for image matching. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
214 a14059209700 Zhang D. p184 True Journal 104 Hardware friendly robust synthetic basis feature descriptor Finding corresponding image features between two images is often the first step for many computer vision algorithms. This paper introduces an improved synthetic basis feature descriptor algorithm that describes and compares image features in an efficient and discrete manner with rotation and scale invariance. It works by performing a number of similarity tests between the feature region surrounding the feature point and a predetermined number of synthetic basis images to generate a feature descriptor that uniquely describes the feature region. Features in two images are matched by comparing their descriptors. By only storing the similarity of the feature region to each synthetic basis image, the overall storage size is greatly reduced. In short, this new binary feature descriptor is designed to provide high feature matching accuracy with computational simplicity, relatively low resource usage, and a hardware friendly design for real-time vision applications. Experimental results show that our algorithm produces higher precision rates and larger number of correct matches than the original version and other mainstream algorithms and is a good alternative for common computer vision applications. Two applications that often have to cope with scaling and rotation variations are included in this work to demonstrate its performance. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
214 a14059209700 Zhang D. p237 False Journal 156 Recognition of Chinese food using convolutional neural network Food recognition is the first step for dietary assessment. Computer vision technology is being viewed as an effective tool for automatic food recognition for monitoring nutrition intake. Of the many food recognition algorithms in the literature, Bag-of-Features model is a proven approach that has shown impressive recognition accuracy. In this paper, we propose a small and efficient convolutional neural network architecture for Chinese food recognition, which is more applicable for resources limited platforms. Our network architecture is designed to model and perform a pipeline of processing similar to the Bag-of-Features approach. The main advantage of the proposed architecture, like other convolutional neural networks, is its ability to unifiedly optimize the entire network through back propagation, which is critical to recognition accuracy. We further compare and correlate our architecture with the traditional Bag-of-Features model in an attempt to investigate the similarities between them and identify factors that influence the recognition accuracy. The proposed architecture with a 5-layer deep convolutional neural network achieves the top-1 accuracy of 97.12% and the top-5 accuracy of 99.86% on a newly created Chinese food image dataset that is composed of 8734 images of 25 food categories. Our experimental result demonstrates the feasibility of applying the proposed compact CNN architecture to a challenging problem and achieve real-time performance. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
214 a14059209700 Zhang D. p505 False Journal 276 Inverse piezoresistive nanocomposite sensors for identifying human sitting posture Sitting posture is the position in which one holds his/her body upright against gravity while sitting. Poor sitting posture is regarded as an aggravating factor for various diseases. In this paper, we present an inverse piezoresistive nanocomposite sensor, and related deciphering neural network, as a new tool to identify human sitting postures accurately. As a low power consumption device, the proposed tool has simple structure, and is easy to use. The strain gauge is attached to the back of the user to acquire sitting data. A three-layer BP neural network is employed to distinguish normal sitting posture, slight hunchback and severe hunchback according to the acquired data. Experimental results show that our method is both realizable and effective, achieving 98.75% posture identification accuracy. This successful application of inverse piezoresistive nanocomposite sensors reveals that the method could potentially be used for monitoring of diverse physiological parameters in the future. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
215 a7406665619 Lee D.-J. p53 False Journal 42 SR-SYBA: A scale and rotation invariant synthetic basis feature descriptor with low memory usage Feature description has an important role in image matching and is widely used for a variety of computer vision applications. As an efficient synthetic basis feature descriptor, SYnthetic BAsis (SYBA) requires low computational complexity and provides accurate matching results. However, the number of matched feature points generated by SYBA suffers from large image scaling and rotation variations. In this paper, we improve SYBA’s scale and rotation invariance by adding an efficient pre-processing operation. The proposed algorithm, SR-SYBA, represents the scale of the feature region with the location of maximum gradient response along the radial direction in Log-polar coordinate system. Based on this scale representation, it normalizes all feature regions to the same reference scale to provide scale invariance. The orientation of the feature region is represented as the orientation of the vector from the center of the feature region to its intensity centroid. Based on this orientation representation, all feature regions are rotated to the same reference orientation to provide rotation invariance. The original SYBA descriptor is then applied to the scale and orientation normalized feature regions for description and matching. Experiment results show that SR-SYBA greatly improves SYBA for image matching applications with scaling and rotation variations. SR-SYBA obtains comparable or better performance in terms of matching rate compared to the mainstream algorithms while still maintains its advantages of using much less storage and simpler computations. SR-SYBA is applied to a vision-based measurement application to demonstrate its performance for image matching. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
215 a7406665619 Lee D.-J. p71 False Journal 42 Smart camera for quality inspection and grading of food products Due to the increasing consumption of food products and demand for food quality and safety, most food processing facilities in the United States utilize machines to automate their processes, such as cleaning, inspection and grading, packing, storing, and shipping. Machine vision technology has been a proven solution for inspection and grading of food products since the late 1980s. The remaining challenges, especially for small to midsize facilities, include the system and operating costs, demand for high-skilled workers for complicated configuration and operation and, in some cases, unsatisfactory results. This paper focuses on the development of an embedded solution with learning capability to alleviate these challenges. Three simple application cases are included to demonstrate the operation of this unique solution. Two datasets of more challenging cases were created to analyze and demonstrate the performance of our visual inspection algorithm. One dataset includes infrared images of Medjool dates of four levels of skin delamination for surface quality grading. The other one consists of grayscale images of oysters with varying shape for shape quality evaluation. Our algorithm achieved a grading accuracy of 95.0% on the date dataset and 98.6% on the oyster dataset, both easily surpassed manual grading, which constantly faces the challenges of human fatigue or other distractions. Details of the design and functions of our smart camera and our simple visual inspection algorithm are discussed in this paper. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
215 a7406665619 Lee D.-J. p72 True Journal 42 Optimization and implementation of synthetic basis feature descriptor on FPGA Feature detection, description, and matching are crucial steps for many computer vision algorithms. These steps rely on feature descriptors to match image features across sets of images. Previous work has shown that our SYnthetic BAsis (SYBA) feature descriptor can offer superior performance to other binary descriptors. This paper focused on various optimizations and hardware implementation of the newer and optimized version. The hardware implementation on a field-programmable gate array (FPGA) is a high-throughput low-latency solution which is critical for applications such as high-speed object detection and tracking, stereo vision, visual odometry, structure from motion, and optical flow. We compared our solution to other hardware designs of binary descriptors. We demonstrated that our implementation of SYBA as a feature descriptor in hardware offered superior image feature matching performance and used fewer resources than most binary feature descriptor implementations. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
215 a7406665619 Lee D.-J. p149 False Journal 104 Efficient evolutionary learning algorithm for real-time embedded vision applications This paper reports the development of an efficient evolutionary learning algorithm designed specifically for real-time embedded visual inspection applications. The proposed evolutionary learning algorithm constructs image features as a series of image transforms for image classification and is suitable for resource-limited systems. This algorithm requires only a small number of images and time for training. It does not depend on handcrafted features or manual tuning of parameters and is generalized to be versatile for visual inspection applications. This allows the system to be configured on the fly for different applications and by an operator without extensive experience. An embedded vision system, equipped with an ARM processor running Linux, is capable of performing at roughly one hundred 640 × 480 frames per second which is more than adequate for real-time visual inspection applications. As example applications, three image datasets were created to test the performance of this algorithm. The first dataset was used to demonstrate the suitability of the algorithm for visual inspection automation applications. This experiment combined two applications to make it a more challenging test. One application was for separating fertilized and unfertilized eggs. The other one was for detecting two common defects on the eggshell. Two other datasets were created for road condition classification and pavement quality evaluation. The proposed algorithm was 100% for fertilized egg detection and 98.6% for eggshell quality inspection for a combined 99.1% accuracy. It had an accuracy of 92% for the road condition classification and 100% for pavement quality evaluation. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
215 a7406665619 Lee D.-J. p170 False Journal 117 Just-noticeable difference binary pattern for reduced reference image quality assessment Just-noticeable difference (JND) is defined as the smallest intensity change in an image that can be noticed by the human vision system (HVS). Any perceptible distortion level must be greater than the JND. Based on this observation, a local binary pattern (LBP) is developed for image quality assessment. First, the JND map of the image is computed. The spatial and relative intensity relationships among pixels in a local neighborhood are employed to generate the proposed LBP based on the JND map. Then, image contrast is used as a weighting factor for the LBP histogram generation to characterize the structural and contrast information of the image. Finally, the contrast and structure changes due to image distortion are measured by calculating the similarity between contrast-weighted histograms of the reference and distorted images. Support vector regression is employed to pool the similarity to predict the quality. Experimental results on benchmark databases demonstrate that the proposed LBP can effectively and accurately measure image quality, which is consistent with the HVS. The proposed method achieves high consistency with subjective perception using 18 reference values and performs better than other state-of-The-Art reduced reference image quality assessment methods. © 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).
215 a7406665619 Lee D.-J. p178 False Journal 120 Design of a Clinical Decision Support System for Predicting Erectile Dysfunction in Men Using NHIRD Dataset Erectile dysfunction (ED) affects millions of men worldwide. Men with ED generally complain failure to attain or maintain an adequate erection during sexual activity. The prevalence of ED is strongly correlated with age, affecting about 40% of men at age 40 and nearly 70% at age 70. A variety of chronic diseases, including diabetes, ischemic heart disease, congestive heart failure, hypertension, depression, chronic renal failure, obstructive sleep apnea, prostate disease, gout, and sleep disorder, were reported to be associated with ED. In this study, data retrieved from a subset of the National Health Insurance Research Database of Taiwan were used for designing the clinical decision support system (CDSS) for predicting ED incidences in men. The positive cases were male patients aged 20-65 who were diagnosed with ED between January 2000 and December 2010 confirmed by at least three outpatient visits or at least one inpatient visit, while the negative cases were randomly selected from the database without a history of ED and were frequency (1:1), age, and index year matched with the ED patients. Data of a total of 2832 ED patients and 2832 non-ED patients, each consisting of 41 features including index age, 10 comorbidities, and 30 other comorbidity-related variables, were retrieved for designing the predictive models. Integrated genetic algorithm and support vector machine was adopted to design the CDSSs with two experiments of independent training and testing (ITT) conducted to verify their effectiveness. In the 1st ITT experiment, data extracted from January 2000 till December 2005 (61.51%, 1742 positive cases and 1742 negative cases) were used for training and validating and the data retrieved from January 2006 till December 2010 were used for testing (38.49%), whereas in the 2nd ITT experiment, data in the training set (77.78%) were extracted from January 2000 till Deceber 2007 and those in the testing set (22.22%) were retrieved afterward. Tenfold cross validation and three different objective functions were adopted for obtaining the optimal models with best predictive performance in the training phase. The testing results show that the CDSSs achieved a predictive performance with accuracy, sensitivity, specificity, g-mean, and area under ROC curve of 74.72%-76.65%, 72.33%-83.76%, 69.54%-77.10%, 0.7468-0.7632, and 0.766-0.817, respectively. In conclusion, the CDSSs designed based on cost-sensitive objective functions as well as salient comorbidity-related features achieve satisfactory predictive performance for predicting ED incidences. © 2013 IEEE.
215 a7406665619 Lee D.-J. p184 False Journal 104 Hardware friendly robust synthetic basis feature descriptor Finding corresponding image features between two images is often the first step for many computer vision algorithms. This paper introduces an improved synthetic basis feature descriptor algorithm that describes and compares image features in an efficient and discrete manner with rotation and scale invariance. It works by performing a number of similarity tests between the feature region surrounding the feature point and a predetermined number of synthetic basis images to generate a feature descriptor that uniquely describes the feature region. Features in two images are matched by comparing their descriptors. By only storing the similarity of the feature region to each synthetic basis image, the overall storage size is greatly reduced. In short, this new binary feature descriptor is designed to provide high feature matching accuracy with computational simplicity, relatively low resource usage, and a hardware friendly design for real-time vision applications. Experimental results show that our algorithm produces higher precision rates and larger number of correct matches than the original version and other mainstream algorithms and is a good alternative for common computer vision applications. Two applications that often have to cope with scaling and rotation variations are included in this work to demonstrate its performance. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
215 a7406665619 Lee D.-J. p217 False Journal 104 A review of binarized neural networks In this work, we review Binarized Neural Networks (BNNs). BNNs are deep neural networks that use binary values for activations and weights, instead of full precision values. With binary values, BNNs can execute computations using bitwise operations, which reduces execution time. Model sizes of BNNs are much smaller than their full precision counterparts. While the accuracy of a BNN model is generally less than full precision models, BNNs have been closing accuracy gap and are becoming more accurate on larger datasets like ImageNet. BNNs are also good candidates for deep learning implementations on FPGAs and ASICs due to their bitwise efficiency. We give a tutorial of the general BNN methodology and review various contributions, implementations and applications of BNNs. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
215 a7406665619 Lee D.-J. p233 False Journal 104 Jet features: Hardware-friendly, learned convolutional kernels for high-speed image classification This paper explores a set of learned convolutional kernels which we call Jet Features. Jet Features are efficient to compute in software, easy to implement in hardware and perform well on visual inspection tasks. Because Jet Features can be learned, they can be used in machine learning algorithms. Using Jet Features, we make significant improvements on our previous work, the Evolution Constructed Features (ECO Features) algorithm. Not only do we gain a 3.7× speedup in software without loosing any accuracy on the CIFAR-10 and MNIST datasets, but Jet Features also allow us to implement the algorithm in an FPGA using only a fraction of its resources. We hope to apply the benefits of Jet Features to Convolutional Neural Networks in the future. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
215 a7406665619 Lee D.-J. p237 False Journal 156 Recognition of Chinese food using convolutional neural network Food recognition is the first step for dietary assessment. Computer vision technology is being viewed as an effective tool for automatic food recognition for monitoring nutrition intake. Of the many food recognition algorithms in the literature, Bag-of-Features model is a proven approach that has shown impressive recognition accuracy. In this paper, we propose a small and efficient convolutional neural network architecture for Chinese food recognition, which is more applicable for resources limited platforms. Our network architecture is designed to model and perform a pipeline of processing similar to the Bag-of-Features approach. The main advantage of the proposed architecture, like other convolutional neural networks, is its ability to unifiedly optimize the entire network through back propagation, which is critical to recognition accuracy. We further compare and correlate our architecture with the traditional Bag-of-Features model in an attempt to investigate the similarities between them and identify factors that influence the recognition accuracy. The proposed architecture with a 5-layer deep convolutional neural network achieves the top-1 accuracy of 97.12% and the top-5 accuracy of 99.86% on a newly created Chinese food image dataset that is composed of 8734 images of 25 food categories. Our experimental result demonstrates the feasibility of applying the proposed compact CNN architecture to a challenging problem and achieve real-time performance. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
215 a7406665619 Lee D.-J. p657 False Journal 316 Design of a clinical decision support system for fracture prediction using imbalanced dataset More than 1 billion people suffer from chronic respiratory diseases worldwide, accounting for more than 4 million deaths annually. Inhaled corticosteroid is a popular medication for treating chronic respiratory diseases. Its side effects include decreased bone mineral density and osteoporosis. The aims of this study are to investigate the association of inhaled corticosteroids and fracture and to design a clinical support system for fracture prediction. The data of patients aged 20 years and older, who had visited healthcare centers and been prescribed with inhaled corticosteroids within 2002-2010, were retrieved from the National Health Insurance Research Database (NHIRD). After excluding patients diagnosed with hip fracture or vertebrate fractures before using inhaled corticosteroid, a total of 11645 patients receiving inhaled corticosteroid therapy were included for this study. Among them, 1134 (9.7%) were diagnosed with hip fracture or vertebrate fracture. The statistical results showed that demographic information, chronic respiratory diseases and comorbidities, and corticosteroid-related variables (cumulative dose, mean exposed daily dose, follow-up duration, and exposed duration) were significantly different between fracture and nonfracture patients. The clinical decision support systems (CDSSs) were designed with integrated genetic algorithm (GA) and support vector machine (SVM) by training and validating the models with balanced training sets obtained by random and cluster-based undersampling methods and testing with the imbalanced NHIRD dataset. Two different objective functions were adopted for obtaining optimal models with best predictive performance. The predictive performance of the CDSSs exhibits a sensitivity of 69.84-77.00% and an AUC of 0.7495-0.7590. It was concluded that long-term use of inhaled corticosteroids may induce osteoporosis and exhibit higher incidence of hip or vertebrate fractures. The accumulated dose of ICS and OCS therapies should be continuously monitored, especially for patients with older age and women after menopause, to prevent from exceeding the maximum dosage. © 2018 Yung-Fu Chen et al.
215 a7406665619 Lee D.-J. p842 False Journal 397 Efficient feature descriptor for unmanned aerial vehicle ground moving object tracking A synthetic basis (SYBA) feature descriptor was used to perform frame-to-frame feature matching for frame differencing. The SYBAfeature descriptor is a robust algorithm that performs well with different degrees of image variation including: illumination, blurring, rotation, and perspective variations. The first step in detecting moving objects is to find the absolute difference between two image frames. To find the difference, the homography that describes the geometric relationship between the two frames is calculated using matched image feature points. The homography is then used to transform and align the images accurately. The transformed images are then used to calculate the absolute difference of the two images. It is then visually apparent where objects have moved or changed between the two images. Frame-to-frame object movement can be approximated to a linear process making the Kalman filter algorithm the best option. Once an object is lost, its corresponding track is deleted along with its corresponding motion model. During tracking, an object may be occluded by other objects in the scene. The MOT metric is designed to evaluate the performance of an object tracker by considering the tracking continuity, distance error for each path, and the reliability of detection. Thus, only the position of the object is considered in generating the MOT metric. The results demonstrate the effectiveness and robustness of the method and prove that the SYBA descriptor works well with various image deformations.
216 a7201793184 Desai A. p53 False Journal 42 SR-SYBA: A scale and rotation invariant synthetic basis feature descriptor with low memory usage Feature description has an important role in image matching and is widely used for a variety of computer vision applications. As an efficient synthetic basis feature descriptor, SYnthetic BAsis (SYBA) requires low computational complexity and provides accurate matching results. However, the number of matched feature points generated by SYBA suffers from large image scaling and rotation variations. In this paper, we improve SYBA’s scale and rotation invariance by adding an efficient pre-processing operation. The proposed algorithm, SR-SYBA, represents the scale of the feature region with the location of maximum gradient response along the radial direction in Log-polar coordinate system. Based on this scale representation, it normalizes all feature regions to the same reference scale to provide scale invariance. The orientation of the feature region is represented as the orientation of the vector from the center of the feature region to its intensity centroid. Based on this orientation representation, all feature regions are rotated to the same reference orientation to provide rotation invariance. The original SYBA descriptor is then applied to the scale and orientation normalized feature regions for description and matching. Experiment results show that SR-SYBA greatly improves SYBA for image matching applications with scaling and rotation variations. SR-SYBA obtains comparable or better performance in terms of matching rate compared to the mainstream algorithms while still maintains its advantages of using much less storage and simpler computations. SR-SYBA is applied to a vision-based measurement application to demonstrate its performance for image matching. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
216 a7201793184 Desai A. p184 False Journal 104 Hardware friendly robust synthetic basis feature descriptor Finding corresponding image features between two images is often the first step for many computer vision algorithms. This paper introduces an improved synthetic basis feature descriptor algorithm that describes and compares image features in an efficient and discrete manner with rotation and scale invariance. It works by performing a number of similarity tests between the feature region surrounding the feature point and a predetermined number of synthetic basis images to generate a feature descriptor that uniquely describes the feature region. Features in two images are matched by comparing their descriptors. By only storing the similarity of the feature region to each synthetic basis image, the overall storage size is greatly reduced. In short, this new binary feature descriptor is designed to provide high feature matching accuracy with computational simplicity, relatively low resource usage, and a hardware friendly design for real-time vision applications. Experimental results show that our algorithm produces higher precision rates and larger number of correct matches than the original version and other mainstream algorithms and is a good alternative for common computer vision applications. Two applications that often have to cope with scaling and rotation variations are included in this work to demonstrate its performance. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
216 a7201793184 Desai A. p842 True Journal 397 Efficient feature descriptor for unmanned aerial vehicle ground moving object tracking A synthetic basis (SYBA) feature descriptor was used to perform frame-to-frame feature matching for frame differencing. The SYBAfeature descriptor is a robust algorithm that performs well with different degrees of image variation including: illumination, blurring, rotation, and perspective variations. The first step in detecting moving objects is to find the absolute difference between two image frames. To find the difference, the homography that describes the geometric relationship between the two frames is calculated using matched image feature points. The homography is then used to transform and align the images accurately. The transformed images are then used to calculate the absolute difference of the two images. It is then visually apparent where objects have moved or changed between the two images. Frame-to-frame object movement can be approximated to a linear process making the Kalman filter algorithm the best option. Once an object is lost, its corresponding track is deleted along with its corresponding motion model. During tracking, an object may be occluded by other objects in the scene. The MOT metric is designed to evaluate the performance of an object tracker by considering the tracking continuity, distance error for each path, and the reliability of detection. Thus, only the position of the object is considered in generating the MOT metric. The results demonstrate the effectiveness and robustness of the method and prove that the SYBA descriptor works well with various image deformations.
217 a56692412900 Gunnarsson A. p54 True Journal 43 Discrete-ordinates modelling of the radiative heat transfer in a pilot-scale rotary kiln This paper presents work focused on the development, evaluation and use of a 3D model for investigation of the radiative heat transfer in rotary kilns. The model applies a discrete-ordinates method to solve the radiative transfer equation considering emission, absorption and scattering of radiation by gas species and particles for cylindrical and semi-cylindrical enclosures. Modelling input data on temperature, particle distribution and gas composition in the radial, axial and angular directions are experimentally gathered in a down-scaled version of a rotary kiln. The model is tested in its capability to predict the radiative intensity and heat flux to the inner wall of the furnace and good agreement was found when compared to measurements. Including the conductive heat transfer through the furnace wall, the model also satisfactorily predicts the intermediate wall temperature. The work also includes a first study on the effect of the incident radiative heat flux to the different surfaces while adding a cold bed material. With further development of the model, it can be used to study the heat transfer in full-scale rotary kilns. © 2020 by the authors.
217 a56692412900 Gunnarsson A. p86 True Journal 65 Full-scale 3D-modelling of the radiative heat transfer in rotary kilns with a present bed material This work discusses the development and use of a detailed 3D radiative heat transfer model of a rotary kiln with a present bed material, used for iron ore pelletizing. A discrete ordinates method is used to solve the radiative heat transfer equation with radiative properties calculated using a weighted-sum-of-grey-gases (WSGG) model for gases and Mie and Rayleigh theory for particles including fuel, ash and soot. Measurement data gathered from a pilot-scale test furnace, comprising temperature, gas composition and particle concentration, is used in combination with temperature data and operation parameters gathered from a conventional rotary kiln to model a full-scale rotary kiln with a present bed material. The modelled cases have a thermal input of about 37 MWth and in addition to radiative heat transfer, conductive heat transfer within, as well as between, the bed and wall material are included in the model along with convective heat transfer from the gas and heat release from exothermic reactions in the bed. The model also considers the rotational wall and includes a simplified mixing model of the bed material as well as heat losses from the outside wall of the rotary kiln due to radiation and convection. For two different flames, one coal and one oil flame, surface temperatures are calculated on the inside and outside of the rotary kiln and compared to measurements. The model appears to predict the inner wall and bed surface temperatures well with errors less than 11%. The total heat transfer to the present bed material was also studied revealing that more than 80% originated from the radiative heat transfer within the furnace. © 2019 Elsevier Ltd
218 a57211105311 Andersson K. p54 False Journal 43 Discrete-ordinates modelling of the radiative heat transfer in a pilot-scale rotary kiln This paper presents work focused on the development, evaluation and use of a 3D model for investigation of the radiative heat transfer in rotary kilns. The model applies a discrete-ordinates method to solve the radiative transfer equation considering emission, absorption and scattering of radiation by gas species and particles for cylindrical and semi-cylindrical enclosures. Modelling input data on temperature, particle distribution and gas composition in the radial, axial and angular directions are experimentally gathered in a down-scaled version of a rotary kiln. The model is tested in its capability to predict the radiative intensity and heat flux to the inner wall of the furnace and good agreement was found when compared to measurements. Including the conductive heat transfer through the furnace wall, the model also satisfactorily predicts the intermediate wall temperature. The work also includes a first study on the effect of the incident radiative heat flux to the different surfaces while adding a cold bed material. With further development of the model, it can be used to study the heat transfer in full-scale rotary kilns. © 2020 by the authors.
218 a57211105311 Andersson K. p86 False Journal 65 Full-scale 3D-modelling of the radiative heat transfer in rotary kilns with a present bed material This work discusses the development and use of a detailed 3D radiative heat transfer model of a rotary kiln with a present bed material, used for iron ore pelletizing. A discrete ordinates method is used to solve the radiative heat transfer equation with radiative properties calculated using a weighted-sum-of-grey-gases (WSGG) model for gases and Mie and Rayleigh theory for particles including fuel, ash and soot. Measurement data gathered from a pilot-scale test furnace, comprising temperature, gas composition and particle concentration, is used in combination with temperature data and operation parameters gathered from a conventional rotary kiln to model a full-scale rotary kiln with a present bed material. The modelled cases have a thermal input of about 37 MWth and in addition to radiative heat transfer, conductive heat transfer within, as well as between, the bed and wall material are included in the model along with convective heat transfer from the gas and heat release from exothermic reactions in the bed. The model also considers the rotational wall and includes a simplified mixing model of the bed material as well as heat losses from the outside wall of the rotary kiln due to radiation and convection. For two different flames, one coal and one oil flame, surface temperatures are calculated on the inside and outside of the rotary kiln and compared to measurements. The model appears to predict the inner wall and bed surface temperatures well with errors less than 11%. The total heat transfer to the present bed material was also studied revealing that more than 80% originated from the radiative heat transfer within the furnace. © 2019 Elsevier Ltd
219 a7202518970 Adams B.R. p54 False Journal 43 Discrete-ordinates modelling of the radiative heat transfer in a pilot-scale rotary kiln This paper presents work focused on the development, evaluation and use of a 3D model for investigation of the radiative heat transfer in rotary kilns. The model applies a discrete-ordinates method to solve the radiative transfer equation considering emission, absorption and scattering of radiation by gas species and particles for cylindrical and semi-cylindrical enclosures. Modelling input data on temperature, particle distribution and gas composition in the radial, axial and angular directions are experimentally gathered in a down-scaled version of a rotary kiln. The model is tested in its capability to predict the radiative intensity and heat flux to the inner wall of the furnace and good agreement was found when compared to measurements. Including the conductive heat transfer through the furnace wall, the model also satisfactorily predicts the intermediate wall temperature. The work also includes a first study on the effect of the incident radiative heat flux to the different surfaces while adding a cold bed material. With further development of the model, it can be used to study the heat transfer in full-scale rotary kilns. © 2020 by the authors.
219 a7202518970 Adams B.R. p86 False Journal 65 Full-scale 3D-modelling of the radiative heat transfer in rotary kilns with a present bed material This work discusses the development and use of a detailed 3D radiative heat transfer model of a rotary kiln with a present bed material, used for iron ore pelletizing. A discrete ordinates method is used to solve the radiative heat transfer equation with radiative properties calculated using a weighted-sum-of-grey-gases (WSGG) model for gases and Mie and Rayleigh theory for particles including fuel, ash and soot. Measurement data gathered from a pilot-scale test furnace, comprising temperature, gas composition and particle concentration, is used in combination with temperature data and operation parameters gathered from a conventional rotary kiln to model a full-scale rotary kiln with a present bed material. The modelled cases have a thermal input of about 37 MWth and in addition to radiative heat transfer, conductive heat transfer within, as well as between, the bed and wall material are included in the model along with convective heat transfer from the gas and heat release from exothermic reactions in the bed. The model also considers the rotational wall and includes a simplified mixing model of the bed material as well as heat losses from the outside wall of the rotary kiln due to radiation and convection. For two different flames, one coal and one oil flame, surface temperatures are calculated on the inside and outside of the rotary kiln and compared to measurements. The model appears to predict the inner wall and bed surface temperatures well with errors less than 11%. The total heat transfer to the present bed material was also studied revealing that more than 80% originated from the radiative heat transfer within the furnace. © 2019 Elsevier Ltd
219 a7202518970 Adams B.R. p299 True Conference 81 Modeling pressurized dense phase coal fluidization and transport A transient gas-solid model based on CPFD Software’s Barracuda Virtual Reactor was developed for a feed system to a pilot-scale pressurized oxy-coal (POC) reactor. A simplified geometry with a vertical coal hopper feeding into a 0.635-cm diameter horizontal pipe was used to represent key elements of the feed system. Coal particles were transported with 20-atm CO2 gas. The feed system was required to maintain a steady flow of gas and solids at a coal flow rate of approximately 3.8 g/s and a CO2 to coal mass ratio in the range 1-2. Sensitivity of model results to mesh size and particle interaction sub-model settings was assessed. Two design concepts were evaluated. A gravity-fed concept was found to be infeasible due to inadequate coal flow rates even at very high CO2 to coal flow ratios. This was due to gravitational forces being insufficient to move the pressurized coal from the hopper into the CO2 stream at the desired rate. A fluidized bed concept was found to provide the desired coal flow rate and CO2 to coal flow ratio. CO2 injected at the hopper base first fluidized the vertical coal bed before transporting it through a horizontal exit pipe. A second CO2 inlet downstream of the hopper exit pipe was used to dilute the fluidized coal and increase pipe velocities to minimize coal drop out. The amount of coal transported from the hopper was dependent on the net CO2 hopper flow but independent of the CO2 dilution flow. This meant that the coal flow rate and CO2 to coal flow ratio could be controlled independently. Pipe exit coal flow rates were found to fluctuate at levels acceptable for steady burner operation. Copyright © 2019 ASME.
219 a7202518970 Adams B.R. p329 False Journal 191 Measurement of radiative gas and particle emissions in biomass flames Radiation is the dominant mode of heat transfer near the burner of coal and biomass-fired boilers. Predicting and measuring heat transfer is critical to the design and operation of new boiler concepts. The individual contributions of gas and particle phases are dependent on gas and particle concentration, particle size, and gas and particle temperature which vary with location relative to the flame. A method for measuring the contributions of both gas and particle radiation capable of being applied in harsh high temperature and pressure environments has been demonstrated using emission from particles and water vapor using an optical fiber probe transmitting a signal to a Fourier Transform Infrared (FTIR) spectrometer. The method was demonstrated in four environments of varying gas and particle loading using natural gas and pulverized wood flames in a down-fired 130 kWth cylindrical reactor. The method generates a gas and particle temperature, gas concentrations (H2O and CO2), total gas and particle intensities, and gas and particle total effective emissivity from line-of-sight emission measurements. For the conditions measured, downstream of the luminous flame zone, water vapor and CO2 radiation were the dominant modes of heat transfer (effective emissivity 0.13-0.19) with particles making a minor contribution (effective emissivity 0.01-0.02). Within a lean natural gas flame, soot emission was low (effective emissivity 0.02) compared to gas (0.14) but within a luminous flame of burning wood particles (500 μm mean diameter) the particles (soot and burning wood) produced a higher effective emissivity (0.17) than the gas (0.12). The measurement technique was therefore found to be effective for several types of combustion environments. © 2018 The Combustion Institute.
219 a7202518970 Adams B.R. p421 False Journal 231 An optical method for the measurement of combustion gas temperature in particle laden flows Temperature measurements in combustion systems are challenging due to the physical limitations of measurement devices and the complexity of combustion flows. The objective of this work is to investigate the Integrated Spectral Band Ratio (ISBR) method for measuring the temperature of combustion product gases surrounded by radiating walls or within a mixture of gas and particles. Five conditions in a multi-fuel reactor were investigated using an optical probe. A Fourier Transform Infrared spectrometer provided detailed spectral measurements of hot gas and particle emissions at wavelengths of 1.69–2.15 μm, focusing on a spectral region where H2O is the dominant participating gas. These measurements were used to infer the gas temperature of the flows. It was found that the measurement path length needed to be at least 0.25 m in order to obtain a signal large enough to infer temperature accurately. For four of the five operating conditions tested, optically measured gas temperatures were found to be in good agreement with the average temperature along the measured path as taken with a suction pyrometer (aspirated thermocouple). For these four operating conditions the particle media were optically thin. Temperatures for the in-flame fine wood particle condition did not exhibit as good of agreement due to high particle loading causing optically thick zones along the line of sight. Modeling experiments showed that when particles and gasses are optically thin, the optical gas temperature measured with this technique will be near the arithmetic mean of the line of sight temperature. © 2018 Elsevier Inc.
219 a7202518970 Adams B.R. p811 False Conference 346 Impact of particle properties on radiative heat flux in an oxy-coal reactor A sensitivity study testing the significance of particle size, scattering phase functions, and distribution in oxy-coal combustion was conducted. Literature review suggests that particle size and number density play a more critical role in determination of radiative properties than the complex index of refraction. Radiative data was produced from numerical experiments using one of two particle distribution profiles (narrow or wide). A comparison of highly forward scattering cases for two particle sizes (25μm vs. 75μm) revealed a significant difference in incident heat flux maximum (25%). This difference was observed in both profiles examined. It was also generally observed that as particle size increases the difference between incident heat flux for forward and backward scattering decreases. No significant difference was observed between the large diffuse sphere and no scattering cases, suggesting that accurate modelling of larger particle size distributions can be achieved while neglecting scattering and phase functions. This result agrees with current practice in industry for air - coal mixtures. However, data suggests that phase function/scattering coefficient influence becomes more and more important with increasingly fine particle size.
219 a7202518970 Adams B.R. p813 False Conference 348 Modeling a pressurized coal feed system A gas-solid model was developed for a feed system to a pressurized oxy-coal (POC) reactor utilizing the multiphase particle-in-cell (MP-PIC) method. The model was created using CPFD Software's Barracuda Virtual Reactor 17.2.0. The geometry of the feed system was simple and contained a vertical standpipe of five inches feeding into a horizontal pipe of twelve inches. The coal particles from the standpipe were transported into the reactor with gas. To ensure appropriate combustion in the reactor, the feed system needed to maintain both a steady flow rate of gas and solids in the pipe and uniform distribution of solids through the cross-section of the channel. Steadiness was determined by the mass flow rate of the coal leaving the feed system. Uniformity was assessed by plotting gas and particle velocities at the end of the channel. The uniformity and steadiness of the flow was assessed for different grid sizes, starting pressure and boundary conditions, and other parameters within Barracuda.
219 a7202518970 Adams B.R. p814 False Conference 349 A fast-running simulation tool for axisymmetric oxy-coal combustors FENICS (Flame Equilibrium Numeric Iterative Calculation Software) is a code developed to be a fast running tool for use in designing axisymmetric, oxy-coal furnaces. The code calculates gas temperature and composition, wall heat flux, and wall and refractory temperatures using 1D, equilibrium chemistry and a 3D discrete ordinates radiation solver. Chemistry and temperature calculations are made for a discrete number of axial zones wherein the temperature and species composition are assumed to be uniform. Radiation calculations are performed on a finer grid and assume gray gases. The code was validated by comparing to experimental data obtained from the L1500 Multifuel Furnace. The experimental data were taken from a single oxy-coal combustion experiment with flue gas recirculation run at a firing rate of 880kW and an air-fuel ratio of 3.6. FENICS was able to qualitatively match the wall flux and temperature profiles quite well. The major exception to this being that peak flux cannot accurately be predicted due the assumptions utilized 'smearing' the flame. Quantitatively, FENICS showed good agreement with the data. Wall temperatures were accurate to within 150K (13%) while total wall radiative heat loss was within 4%. FENICS was also used to evaluate temperatue and flux profiles for a new pilot-scale oxy-coal reactor.
219 a7202518970 Adams B.R. p820 False Conference 355 Impact of computational mesh on CFD combustion predictions This study has examined the impact of cell type and mesh refinement on predicted combustion results. Mesh refinement in regions of high velocity gradients was shown to be the most critical factor in achieving realistic simulation results. In Case 5 where mesh refinement was focused near the geometric shapes of the cooling tubes and burner tile, insufficient mesh refinement existed in the fuel-air mixing zones around and above the burner to accurately predict fuel jet penetration and fuel-air mixing, resulting in inaccurate predictions for flame shape and heat flux profiles at the cooling tubes. Differences in predicted incident flux, total heat transfer and flame shape between the highest levels of mesh refinement (~2 million cells) between the structured trimmed-cell mesh and the unstructured polyhedral mesh were minimal. At lower mesh levels of 1 million cells, there were slightly greater discrepancies between the structured trimmed-cell mesh and the unstructured polyhedral mesh, particularly with respect to the flame shape and upper furnace flux profile predicted in Case 3. Interestingly, the differences in thermal efficiency and total heat transfer were greater between Case 2 and Case 1 (2 million versus 1 million cells) than between Case 2 and Case 5 (2 million versus 1 million cells with poor refinement). This trend was also observed with Case 4 and Case 3. This suggests both cell count and local mesh refinement are important to achieving accurate combustion predictions, but that there is minimal difference between the results with differing mesh types as long as the cell count and refinement are sufficient to represent the expected jet mixing behavior. These results also suggest that while the flame shape does impact the boundary flux profile as expected, the impact on thermal efficiency may be less well correlated. Thus, total heat transfer results should not be used to assess flame shape behavior; boundary flux profiles provided better correlation to flame shape.
220 a12445742400 Fredriksson C. p54 False Journal 43 Discrete-ordinates modelling of the radiative heat transfer in a pilot-scale rotary kiln This paper presents work focused on the development, evaluation and use of a 3D model for investigation of the radiative heat transfer in rotary kilns. The model applies a discrete-ordinates method to solve the radiative transfer equation considering emission, absorption and scattering of radiation by gas species and particles for cylindrical and semi-cylindrical enclosures. Modelling input data on temperature, particle distribution and gas composition in the radial, axial and angular directions are experimentally gathered in a down-scaled version of a rotary kiln. The model is tested in its capability to predict the radiative intensity and heat flux to the inner wall of the furnace and good agreement was found when compared to measurements. Including the conductive heat transfer through the furnace wall, the model also satisfactorily predicts the intermediate wall temperature. The work also includes a first study on the effect of the incident radiative heat flux to the different surfaces while adding a cold bed material. With further development of the model, it can be used to study the heat transfer in full-scale rotary kilns. © 2020 by the authors.
220 a12445742400 Fredriksson C. p86 False Journal 65 Full-scale 3D-modelling of the radiative heat transfer in rotary kilns with a present bed material This work discusses the development and use of a detailed 3D radiative heat transfer model of a rotary kiln with a present bed material, used for iron ore pelletizing. A discrete ordinates method is used to solve the radiative heat transfer equation with radiative properties calculated using a weighted-sum-of-grey-gases (WSGG) model for gases and Mie and Rayleigh theory for particles including fuel, ash and soot. Measurement data gathered from a pilot-scale test furnace, comprising temperature, gas composition and particle concentration, is used in combination with temperature data and operation parameters gathered from a conventional rotary kiln to model a full-scale rotary kiln with a present bed material. The modelled cases have a thermal input of about 37 MWth and in addition to radiative heat transfer, conductive heat transfer within, as well as between, the bed and wall material are included in the model along with convective heat transfer from the gas and heat release from exothermic reactions in the bed. The model also considers the rotational wall and includes a simplified mixing model of the bed material as well as heat losses from the outside wall of the rotary kiln due to radiation and convection. For two different flames, one coal and one oil flame, surface temperatures are calculated on the inside and outside of the rotary kiln and compared to measurements. The model appears to predict the inner wall and bed surface temperatures well with errors less than 11%. The total heat transfer to the present bed material was also studied revealing that more than 80% originated from the radiative heat transfer within the furnace. © 2019 Elsevier Ltd
221 a57218836048 Peters W. p55 True Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
222 a57194504247 Jones T. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
223 a7202040335 Efimov A. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
224 a14631026900 Pedersoli E. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
225 a55159798000 Foglia L. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
226 a54941111500 Mincigrucci R. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
227 a55258876800 Nikolov I. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
228 a7006038251 Trebino R. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
229 a20735824800 Sandberg R. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
229 a20735824800 Sandberg R. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
230 a55846910700 Danailov M. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
231 a6602657620 Capotondi F. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
232 a14033765300 Bencivenga F. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
233 a13005462200 Bowlan P. p55 False Conference 9 Single-Shot Measurement of Extreme Ultraviolet Free Electron Laser Pulses We demonstrate an all-optical approach for measuring spectrograms of individual FEL pulses by measuring a spectrally-resolved EUV-EUV-optical four-wave-mixing signal. We experimentally demonstrate that this is phase-sensitive can be applied to structured and unstable pulse trains. © 2020 OSA.
234 a55770396700 Frazer D. p56 True Journal 17 Cryogenic Stress-Driven Grain Growth Observed via Microcompression with in situ Electron Backscatter Diffraction The deformation of materials at cryogenic temperature is of interest for space, arctic, and fundamental science applications. In this work, a custom-built cooling system attached to a commercial picoindenter was used for in situ cryogenic microcompression testing of equal-channel angular-pressed copper with real-time electron backscatter diffraction. Stress-driven grain growth at cryogenic temperatures was observed during a series of elastic and plastic deformations. These results provide direct evidence for the previously predicted phenomenon, whereas previous ex situ examinations demonstrated coarsening after cryogenic loading when samples were not maintained at cryogenic temperatures between deformation and characterization. © 2020, The Minerals, Metals & Materials Society.
235 a23099630500 Hosemann P. p56 False Journal 17 Cryogenic Stress-Driven Grain Growth Observed via Microcompression with in situ Electron Backscatter Diffraction The deformation of materials at cryogenic temperature is of interest for space, arctic, and fundamental science applications. In this work, a custom-built cooling system attached to a commercial picoindenter was used for in situ cryogenic microcompression testing of equal-channel angular-pressed copper with real-time electron backscatter diffraction. Stress-driven grain growth at cryogenic temperatures was observed during a series of elastic and plastic deformations. These results provide direct evidence for the previously predicted phenomenon, whereas previous ex situ examinations demonstrated coarsening after cryogenic loading when samples were not maintained at cryogenic temperatures between deformation and characterization. © 2020, The Minerals, Metals & Materials Society.
236 a57215680724 Warr C. p57 True Journal 44 Biocompatible PEGDA Resin for 3D Printing We report a noncytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The noncytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively noncytotoxic with a postprint 12 h ethanol wash, and that A-PEGDA, as-printed, is effectively noncytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultralow adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures. Copyright © 2020 American Chemical Society.
237 a57205652801 Valdoz J.C. p57 False Journal 44 Biocompatible PEGDA Resin for 3D Printing We report a noncytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The noncytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively noncytotoxic with a postprint 12 h ethanol wash, and that A-PEGDA, as-printed, is effectively noncytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultralow adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures. Copyright © 2020 American Chemical Society.
238 a57195427378 Bickham B.P. p57 False Journal 44 Biocompatible PEGDA Resin for 3D Printing We report a noncytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The noncytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively noncytotoxic with a postprint 12 h ethanol wash, and that A-PEGDA, as-printed, is effectively noncytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultralow adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures. Copyright © 2020 American Chemical Society.
238 a57195427378 Bickham B.P. p693 False Journal 337 Custom 3D printer and resin for 18 μm × 20 μm microfluidic flow channels While there is great interest in 3D printing for microfluidic device fabrication, to-date the achieved feature sizes have not been in the truly microfluidic regime (&lt;100 μm). In this paper we demonstrate that a custom digital light processor stereolithographic (DLP-SLA) 3D printer and a specifically-designed, low cost, custom resin can readily achieve flow channel cross sections as small as 18 μm × 20 μm. Our 3D printer has a projected image plane resolution of 7.6 μm and uses a 385 nm LED, which dramatically increases the available selection of UV absorbers for resin formulation compared to 3D printers with 405 nm LEDs. Beginning with 20 candidate absorbers, we demonstrate the evaluation criteria and process flow required to develop a high-resolution resin. In doing so, we introduce a new mathematical model for characterizing the resin optical penetration depth based only on measurement of the absorber's molar absorptivity. Our final resin formulation uses 2-nitrophenyl phenyl sulfide (NPS) as the UV absorber. We also develop a novel channel narrowing technique that, together with the new resin and 3D printer resolution, enables small flow channel fabrication. We demonstrate the efficacy of our approach by fabricating 3D serpentine flow channels 41 mm long in a volume of only 0.12 mm3, and by printing high aspect ratio flow channels &lt;25 μm wide and 3 mm tall. These results indicate that 3D printing is finally positioned to challenge the pre-eminence of methods such as soft lithography for microfluidic device prototyping and fabrication. © 2017 The Royal Society of Chemistry.
239 a57215684781 Knight C.J. p57 False Journal 44 Biocompatible PEGDA Resin for 3D Printing We report a noncytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The noncytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively noncytotoxic with a postprint 12 h ethanol wash, and that A-PEGDA, as-printed, is effectively noncytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultralow adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures. Copyright © 2020 American Chemical Society.
240 a57215687139 Franks N.A. p57 False Journal 44 Biocompatible PEGDA Resin for 3D Printing We report a noncytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The noncytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively noncytotoxic with a postprint 12 h ethanol wash, and that A-PEGDA, as-printed, is effectively noncytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultralow adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures. Copyright © 2020 American Chemical Society.
241 a57215697686 Chartrand N. p57 False Journal 44 Biocompatible PEGDA Resin for 3D Printing We report a noncytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The noncytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively noncytotoxic with a postprint 12 h ethanol wash, and that A-PEGDA, as-printed, is effectively noncytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultralow adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures. Copyright © 2020 American Chemical Society.
242 a56251876800 Van Ry P.M. p57 False Journal 44 Biocompatible PEGDA Resin for 3D Printing We report a noncytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The noncytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively noncytotoxic with a postprint 12 h ethanol wash, and that A-PEGDA, as-printed, is effectively noncytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultralow adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures. Copyright © 2020 American Chemical Society.
243 a7202687601 Christensen K.A. p57 False Journal 44 Biocompatible PEGDA Resin for 3D Printing We report a noncytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The noncytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively noncytotoxic with a postprint 12 h ethanol wash, and that A-PEGDA, as-printed, is effectively noncytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultralow adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures. Copyright © 2020 American Chemical Society.
244 a56514586700 Cook A.D. p57 False Journal 44 Biocompatible PEGDA Resin for 3D Printing We report a noncytotoxic resin compatible with and designed for use in custom high-resolution 3D printers that follow the design approach described in Gong et al., Lab Chip 17, 2899 (2017). The noncytotoxic resin is based on a poly(ethylene glycol) diacrylate (PEGDA) monomer with avobenzone as the UV absorber instead of 2-nitrophenyl phenyl sulfide (NPS). Both NPS-PEGDA and avobenzone-PEGDA (A-PEGDA) resins were evaluated for cytotoxicity and cell adhesion. We show that NPS-PEGDA can be made effectively noncytotoxic with a postprint 12 h ethanol wash, and that A-PEGDA, as-printed, is effectively noncytotoxic. 3D prints made with either resin do not support strong cell adhesion in their as-printed state; however, cell adhesion increases dramatically with a short plasma treatment. Using A-PEGDA, we demonstrate spheroid formation in ultralow adhesion 3D printed wells, and cell migration from spheroids on plasma-treated adherent surfaces. Given that A-PEGDA can be 3D printed with high resolution, it has significant promise for a wide variety of cell-based applications using 3D printed microfluidic structures. Copyright © 2020 American Chemical Society.
244 a56514586700 Cook A.D. p411 False Journal 221 Feasibility of induced pluripotent stem cell therapies for treatment of type 1 diabetes Despite their potential for treating type 1 diabetes (T1D), induced pluripotent stem cells (iPSCs) have not yet been used successfully in the clinic. In this article, advances in iPSC therapies are reviewed and compared with current methods of treating T1D. Encapsulation of iPSCs is being pursued to address such safety concerns as the possibility of immune rejection or teratoma formation, and provide for retrievability. Issues of material selection, cell differentiation, size of islet aggregates, sites of implantation, animal models, and vascularization are also being addressed. Clinical trials are being conducted to test a variety of new devices with the hope of providing additional therapies for T1D. This review of iPSCs to treat T1D provides a current assessment of the challenges and potential for this proposed new therapy. © Copyright 2018, Mary Ann Liebert, Inc., publishers 2018.
244 a56514586700 Cook A.D. p444 False Journal 248 Corrigendum: Efficient decellularization of whole porcine kidneys improves reseeded cell behavior (Biomedical Materials (Bristol) (2016) 11 (025003) DOI: 10.1088/1748-6041/11/2/025003) The above manuscript describes our efforts to improve the process for recellularization of porcine kidneys. We obtained what we believed to be an immortalized cell line of human renal cortical tubular epithelium (RCTE) cells from the Feinberg School of Medicine, Northwestern University to conduct our reseeding experiments. The RCTE cells that were provided to us were later discovered to actually be Madin-Darby Canine Kidney (MDCK) epithelial cells. Despite being of canine origin, MDCK cells are a distal tubule epithelial cell line that behave similarly to human RCTE cells. The conclusions regarding reseeding as reported in our paper are still sound, as described in the following. © 2018 IOP Publishing Ltd.
244 a56514586700 Cook A.D. p805 False Journal 391 Re-epithelialization of whole porcine kidneys with renal epithelial cells Decellularized porcine kidneys were recellularized with renal epithelial cells by three methods: perfusion through the vasculature under high pressure, perfusion through the ureter under high pressure, or perfusion through the ureter under moderate vacuum. Histology, scanning electron microscopy, confocal microscopy, and magnetic resonance imaging were used to assess vasculature preservation and the distribution of cells throughout the kidneys. Cells were detected in the magnetic resonance imaging by labeling them with iron oxide. Perfusion of cells through the ureter under moderate vacuum (40 mmHg) produced the most uniform distribution of cells throughout the kidneys. © 2017, © The Author(s) 2017.
245 a57197765353 Stevenson P.D. p59 True Journal 24 A Method for Creating Product Social Impact Models of Engineered Products All products impact the lives of their users, this is called social impact. Some social impacts are commonly recognized by the engineering community, such as impacts to a user's health and safety, while other social impacts can be more difficult to recognize, such as impacts on families and gender roles. When engineers make design decisions, without considering social impacts, they can unknowingly cause negative social impacts. Even harming the user and/or society. Despite its challenges, measuring a program's or policy's social impact is a common practice in the field of social sciences. These measurements are made using social impact indicators, which are simply the things observed to verify that true progress is being made. While there are clear benefits to predicting the social impact of an engineered product, it is unclear how engineers should select indicators and build predictive social impact models that are functions of engineering parameters and decisions. This paper introduces a method for selecting social impact indicators and creating predictive social impact models that can help engineers predict and improve the social impact of their products. As a first step in the method, an engineer identifies the product's users, objectives, and requirements. Then, the social impact categories that are related to the product are determined. From each of these categories, the engineer selects several social impact indicators. Finally, models are created for each indicator to predict how a product's parameters will change these indicators. The impact categories and indicators can be translated into product requirements and performance measures that can be used in product development processes. This method is used to predict the social impact of the proposed, expanded U.S. Mexico border wall. © 2019 Copernicus GmbH. All rights reserved.
245 a57197765353 Stevenson P.D. p262 False Journal 172 Over-Design Versus Redesign as a Response to Future Requirements Though little research has been done in the field of over-design as a product development strategy, an over-design approach can help products avoid the issue of premature obsolescence. This paper compares over-design to redesign as approaches to address the emergence of future requirements. Net present value (NPV) analyses of several real world applications are examined from the perspective of manufacturers (i.e., defense contractors, automobile, pharmaceutical, and microprocessor manufactures) and customers (i.e., purchases of vehicles, televisions, cell phones, washing machines, and buildings). This analysis is used to determine the conditions under which an over-design approach provides a greater benefit than a redesign approach. Over-design is found to have a higher NPV than redesign when future requirements occur soon after the initial release, discount rates are low, initial research, and development cost or price is high, and when the incremental costs of the future requirements are low. © 2019 by ASME.
245 a57197765353 Stevenson P.D. p297 True Conference 79 The personification of big data Organizations all over the world, both national and international, gather demographic data so that the progress of nations and peoples can be tracked. This data is often made available to the public in the form of aggregated national level data or individual responses (microdata). Product designers likewise conduct surveys to better understand their customer and create personas. Personas are archetypes of the individuals who will use, maintain, sell or otherwise be affected by the products created by designers. Personas help designers better understand the person the product is designed for. Unfortunately, the process of collecting customer information and creating personas is often a slow and expensive process. In this paper, we introduce a new method of creating personas, leveraging publicly available databanks of both aggregated national level and information on individuals in the population. A computational persona generator is introduced that creates a population of personas that mirrors a real population in terms of size and statistics. Realistic individual personas are filtered from this population for use in product development. © 2019 Design Society. All rights reserved.
245 a57197765353 Stevenson P.D. p525 True Journal 274 Toward a Universal Social Impact Metric for Engineered Products That Alleviate Poverty One of the purposes of creating products for developing countries is to improve the consumer's quality of life. Currently, there is no standard method for measuring the social impact of these types of products. As a result, engineers have used their own metrics, if at all. Some of the common metrics used include products sold and revenue, which measure the financial success of a product without recognizing the social successes or failures it might have. In this paper, we introduce a potential universal metric, the product impact metric (PIM), which quantifies the impact a product has on impoverished individuals - especially those living in developing countries. It measures social impact broadly in five dimensions: health, education, standard of living, employment quality, and security. By measuring impact multidimensionally, it captures impacts both anticipated and unanticipated, thereby providing a broader assessment of the product's total impact than with other more specific metrics. The PIM is calculated based on 18 simple field measurements of the consumer. It is inspired by the UN's Multidimensional Poverty Index (UNMPI) created by the United Nations Development Programme (UNDP). The UNMPI measures how level of poverty within a nation changes year after year, and the PIM measures how an individual's poverty level changes after being affected by an engineered product. The PIM can be used to measure social impact (using specific data from products introduced into the market) or predict social impact (using personas that represent real individuals). Copyright © 2018 by ASME.
245 a57197765353 Stevenson P.D. p585 False Conference 230 Over-design versus redesign as a response to future requirements Though little research has been done in the field of overdesign as a product development strategy, an over-design approach can help products avoid the issue of premature obsolescence. This paper compares over-design to redesign as approaches to address the emergence of future requirements. Net present value (NPV) analyses of several real world applications are examined from the perspective of manufacturers and customers. This analysis is used to determine the conditions under which an over-design approach provides a greater benefit than a redesign approach. Over-design is found to have a higher net present value than redesign when future requirements occur soon after the initial release, discount rates are low, initial research and development cost or price is high, and when the incremental costs of the future requirements are low. Copyright © 2018 ASME.
245 a57197765353 Stevenson P.D. p874 True Conference 392 Towards a universal social impact metric for engineered products that alleviate poverty More than ever before, engineers are creating products for developing countries. One of the purposes of these products is to improve the consumer's quality of life. Currently, there is no established method of measuring the social impact of these types of products. As a result, engineers have used their own metrics to assess their product's impact, if at all. Some of the common metrics used include products sold and revenue, which measure the financial success of a product without recognizing the social successes or failures it might have. In this paper we introduce a potential metric, the Product Impact Metric (PIM), which quantifies the impact a product has on impoverished individuals - especially those living in developing countries. It measures social impact broadly in five dimensions: Health, education, standard of living, employment quality, and security. The PIM is inspired by the Multidimensional Poverty Index (MPI) created by the United Nations Development Programme. The MPI measures how the depth of poverty within a nation changes year after year, and the PIM measures how an individual's quality of life changes after being affected by an engineered product. The Product Impact Metric can be used to predict social impacts (using personas that represent real individuals) or measure social impacts (using specific data from products introduced into the market). © 2017 ASME.
246 a57188681207 Hyatt P. p60 True Journal 10 Real-Time Nonlinear Model Predictive Control of Robots Using a Graphics Processing Unit In past robotics applications, Model Predictive Control (MPC) has often been limited to linear models and relatively short time horizons. In recent years however, research in optimization, optimal control, and simulation has enabled some forms of nonlinear model predictive control which find locally optimal solutions. The limiting factor for applying nonlinear MPC for robotics remains the computation necessary to solve the optimization, especially for complex systems and for long time horizons. This letter presents a new solution method which addresses computational concerns related to nonlinear MPC called nonlinear Evolutionary MPC (NEMPC), and then we compare it to several existing methods. These comparisons include simulations on torque-limited robots performing a swing-up task and demonstrate that NEMPC is able to discover complex behaviors to accomplish the task. Comparisons with state-of-the-art nonlinear MPC algorithms show that NEMPC finds high quality control solutions very quickly using a global, instead of local, optimization method. Finally, an application in hardware (a 24 state pneumatically actuated continuum soft robot) demonstrates that this method is tractable for real-time control of high degree of freedom systems. © 2016 IEEE.
246 a57188681207 Hyatt P. p270 True Journal 177 Configuration estimation for accurate position control of large-scale soft robots There is a significant trend in robotics of exploring passively compliant and low inertia systems that can safely make contact with the environment. This paper defines many of the problems associated with developing effective control of soft, pneumatically actuated, inflatable robots, and proposes an approach to solving a subset of these problems. We show that we can obtain a global measurement of orientation for a given soft-robot link using two different types of sensors (not including motion capture). Given the orientation measurement, it is possible to estimate relative configurations of the soft actuators and joints. In order to validate the ability to control position and orientation at the end effector, we show a new method for calibrating the coordinate frames of two unrelated measurement systems. Then, using one of our configuration estimation methods, we demonstrate its viability by performing simple behaviors with a large-scale (approximately 1.5 m long) soft-robot platform attached to the K-Rex rover at NASA Ames in an outdoor environment. Our results also show the importance of soft-robot kinematic calibration and the sensitivity of a soft robot to simple perturbations in the structure like deflation and reinflation. Finally, we show that end effector error can be significantly reduced by doing a form of servoing. In summary, our approach and demonstrations show effective soft-robot configuration estimation and control for large-scale soft robots capable of performing manipulation tasks. © 1996-2012 IEEE.
247 a36349287300 Killpack M.D. p60 False Journal 10 Real-Time Nonlinear Model Predictive Control of Robots Using a Graphics Processing Unit In past robotics applications, Model Predictive Control (MPC) has often been limited to linear models and relatively short time horizons. In recent years however, research in optimization, optimal control, and simulation has enabled some forms of nonlinear model predictive control which find locally optimal solutions. The limiting factor for applying nonlinear MPC for robotics remains the computation necessary to solve the optimization, especially for complex systems and for long time horizons. This letter presents a new solution method which addresses computational concerns related to nonlinear MPC called nonlinear Evolutionary MPC (NEMPC), and then we compare it to several existing methods. These comparisons include simulations on torque-limited robots performing a swing-up task and demonstrate that NEMPC is able to discover complex behaviors to accomplish the task. Comparisons with state-of-the-art nonlinear MPC algorithms show that NEMPC finds high quality control solutions very quickly using a global, instead of local, optimization method. Finally, an application in hardware (a 24 state pneumatically actuated continuum soft robot) demonstrates that this method is tractable for real-time control of high degree of freedom systems. © 2016 IEEE.
247 a36349287300 Killpack M.D. p101 False Journal 75 Comparing model-based control methods for simultaneous stiffness and position control of inflatable soft robots Inflatable robots are naturally lightweight and compliant, which may make them well suited for operating in unstructured environments or in close proximity to people. The inflatable joints used in this article consist of a strong fabric exterior that constrains two opposing compliant air bladders that generate torque (unlike McKibben actuators where pressure changes cause translation). This antagonistic structure allows the simultaneous control of position and stiffness. However, dynamic models of soft robots that allow variable stiffness control have not been well developed. In this work, a model that includes stiffness as a state variable is developed and validated. Using the stiffness model, a sliding mode controller and model predictive controller are developed to control stiffness and position simultaneously. For sliding mode control (SMC), the joint stiffness was controlled to within 0.07 Nm/rad of a 45 Nm/rad command. For model predictive control (MPC) the joint stiffness was controlled to within 0.045 Nm/rad of the same stiffness command. Both SMC and MPC were able to control to within 0.5° of a desired position at steady state. Stiffness control was extended to a multiple-degree-of-freedom soft robot using MPC. Controlling stiffness of a 4-DOF arm reduced the end-effector deflection by approximately 50% (from 17.9 to 12.2cm) with a 4 lb (1.8 kg) step input applied at the end effector when higher joint stiffness (40 Nm/rad) was used compared with low stiffness (30 Nm/rad). This work shows that the derived stiffness model can enable effective position and stiffness control. © The Author(s) 2020.
247 a36349287300 Killpack M.D. p270 False Journal 177 Configuration estimation for accurate position control of large-scale soft robots There is a significant trend in robotics of exploring passively compliant and low inertia systems that can safely make contact with the environment. This paper defines many of the problems associated with developing effective control of soft, pneumatically actuated, inflatable robots, and proposes an approach to solving a subset of these problems. We show that we can obtain a global measurement of orientation for a given soft-robot link using two different types of sensors (not including motion capture). Given the orientation measurement, it is possible to estimate relative configurations of the soft actuators and joints. In order to validate the ability to control position and orientation at the end effector, we show a new method for calibrating the coordinate frames of two unrelated measurement systems. Then, using one of our configuration estimation methods, we demonstrate its viability by performing simple behaviors with a large-scale (approximately 1.5 m long) soft-robot platform attached to the K-Rex rover at NASA Ames in an outdoor environment. Our results also show the importance of soft-robot kinematic calibration and the sensitivity of a soft robot to simple perturbations in the structure like deflation and reinflation. Finally, we show that end effector error can be significantly reduced by doing a form of servoing. In summary, our approach and demonstrations show effective soft-robot configuration estimation and control for large-scale soft robots capable of performing manipulation tasks. © 1996-2012 IEEE.
247 a36349287300 Killpack M.D. p369 False Conference 131 Adaptive control of large-scale soft robot manipulators with unknown payloads The compliance and other nonlinear dynamics of large-scale soft robots makes effective control difficult. This is especially true when working with unknown payloads or when the system dynamics change over time which is likely to happen for soft robots. In this paper, we present a novel method of coupling model reference adaptive control (MRAC) with model predictive control (MPC) for platforms with antagonistic pneumatic actuators. We demonstrate its utility on a fully inflatable, six degreeof-freedom pneumatically actuated soft robot manipulator that is over two meters long. Specifically, we compare control performance with no integral controller, with an integral controller, and with MRAC when running a nominal model predictive controller with significant weight attached to the end effector. © 2019 ASME.
247 a36349287300 Killpack M.D. p520 False Journal 289 Scalable fabric tactile sensor arrays for soft bodies Soft robots have the potential to transform the way robots interact with their environment. This is due to their low inertia and inherent ability to more safely interact with the world without damaging themselves or the people around them. However, existing sensing for soft robots has at least partially limited their ability to control interactions with their environment. Tactile sensors could enable soft robots to sense interaction, but most tactile sensors are made from rigid substrates and are not well suited to applications for soft robots which can deform. In addition, the benefit of being able to cheaply manufacture soft robots may be lost if the tactile sensors that cover them are expensive and their resolution does not scale well for manufacturability. This paper discusses the development of a method to make affordable, high-resolution, tactile sensor arrays (manufactured in rows and columns) that can be used for sensorizing soft robots and other soft bodies. However, the construction results in a sensor array that exhibits significant amounts of cross-talk when two taxels in the same row are compressed. Using the same fabric-based tactile sensor array construction design, two different methods for cross-talk compensation are presented. The first uses a mathematical model to calculate a change in resistance of each taxel directly. The second method introduces additional simple circuit components that enable us to isolate each taxel electrically and relate voltage to force directly. Fabric sensor arrays are demonstrated for two different soft-bodied applications: an inflatable single link robot and a human wrist. © 2018 IOP Publishing Ltd.
247 a36349287300 Killpack M.D. p717 False Conference 301 Variable stiffness adaptation to mitigate system failure in inflatable robots Although inflatable soft robots are not yet a common robot platform, air leaking from the internal structure is a common and undesirable mode of failure for these platforms. In this paper we demonstrate a method to detect leaks in the structural chamber of an inflatable, pneumatically actuated robot. We then show that our method can adaptively lower commanded joint stiffness which slows the mass flow rate of the leak. This extends the operational life of the robot by decreasing long term error during operation by as much as 50% of the steady state error at the end effector when compared to the same leak if our adaptation method is not used. In future applications where we expect soft, inflatable robots to be useful, our methods can enable failure mitigation in resource-limited situations such as space exploration or disaster response. © 2017 IEEE.
247 a36349287300 Killpack M.D. p718 False Conference 302 Multi-objective design optimization of a soft, pneumatic robot We present a method for the design optimization of a soft, inflatable robot. The method described utilizes a multi-objective fitness function together with custom, platform-specific metrics related to the dexterity and load-bearing capacity of inflatable manipulators. Candidate designs are scored by computing these metrics at many randomly generated configurations and then by appropriately combining these scores within the multi-objective optimization framework. High performing designs are propagated through a genetic algorithm. The final result is a set of diverse, optimal designs lying along a Pareto front spanning the design space. By examining variations and trade-offs within this set, a designer can more appropriately choose design parameters for a target application. This is especially relevant for robots with many design parameters that can quickly be manufactured as is the case with emerging, soft robot technologies. © 2017 IEEE.
247 a36349287300 Killpack M.D. p719 False Conference 303 Motion planning for mobile robots using inverse kinematics branching A novel algorithm for planning robotic manipulation tasks is presented in which the base position and joint motions of a robot are simultaneously optimized to follow a smooth desired end-effector trajectory. During the optimization routine, the manipulator's base position and joint motions are planned simultaneously by strategically moving a set of virtual robot arms (each representing a single configuration in a sequence) branching from a common base to a number of assigned target poses associated with a task. Additional goals (e.g. collision avoidance) and hard constraints, including joint limits are also incorporated. The optimization problem at the core of this method is a quadratic program, allowing constrained high-dimensional problems to be solved in very little time. This method has successfully planned motions allowing an 8-DOF manipulator to paint walls, and has proven to be highly efficient and scalable in practice. © 2017 IEEE.
248 a57189235340 Keller A. p61 True Conference 11 Using Partial Duplication with Compare to Detect Radiation-Induced Failure in a Commercial FPGA-Based Networking System Duplication with compare, a circuit-level fault-detection technique, is used in this study in a partial manner to detect radiation-induced failures in a commercial FPGA-based networking system. A novel approach is taken to overcome challenges presented by multiple clock domains, the use of third-party IP, and the collection of error detection signals dispersed throughout the design. Novel fault injection techniques are also used to evaluate critical regions of the target design. Accelerated neutron radiation testing was performed to evaluate the effectiveness of the applied technique. One design version was able to detect 45% of all failures with the proposed technique applied to 29% of the circuit components within the design. Another design version was able to detect 31% of all failures with the proposed technique applied to only 8% of circuit components. © 2020 IEEE.
248 a57189235340 Keller A. p100 False Conference 16 Modeling common cause failures in systems with triple modular redundancy and repair Triple modular redundancy (TMR) is commonly employed to increase the reliability and mean time to failure (MTTF) of a system. This improvement can be shown by using a continuous time Markov chain. However, typical Markov chain models do not model common cause failures (CCF), which is a singular event that simultaneously causes failure in multiple redundant modules. This paper introduces a new Markov chain to model CCF in TMR with repair systems. This new model is compared to the idealized models of TMR with repair without CCF. The fundamental limitations that CCF imposes on the system are shown and discussed. In a motivating example, it is seen that CCF imposes a limitation of 51× on the reliability improvement in a system with TMR and repair compared to a simplex system, (i.e., without TMR). A case study is also presented where the likelihood of CCF is reduced by a factor of 18× using various mitigation techniques. Reducing the CCF compounds the reliability improvement of TMR with repair and leads to a overall system reliability improvement of 10,000× compared to the simplex system as supported by the proposed model. © 2020 IEEE.
248 a57189235340 Keller A. p112 False Journal 29 Improving the Reliability of TMR with Nontriplicated I/O on SRAM FPGAs Triple modular redundancy (TMR) with repair is a commonly employed mitigation strategy used on SRAM field-programmable gate arrays (FPGAs) to reduce the effects of ionizing radiation and improve a circuit's sensitive cross section. This article examines TMR circuits, where the I/O ports of the circuit have not been triplicated, but the internal circuitry has. Such circuits introduce single-point failures (SPFs) into the circuit that limit the neutron cross-sectional improvement offered by TMR to only 3× for the b13 benchmark circuit used in this article. This article proposes two different mitigation techniques to address SPFs, which alter the placement and routing of the circuit. These mitigation techniques reduce the neutron cross section by 26× over the unmitigated circuit while minimally affecting the circuit's maximum clock frequency and resource utilization. © 1963-2012 IEEE.
248 a57189235340 Keller A. p195 True Conference 44 Single-Event Characterization of a Stratix® 10 FPGA Using Neutron Irradiation FPGAs are being used in data center applications in large quantities. Single-event upsets (SEUs) occur more frequently within large-scale deployments of SRAM-based FPGAs. This work estimates the neutron cross section for SEUs in the configuration memory and memory blocks of a 14-nm FinFET Stratix 10 FPGA. SEU data was collected using a custom SEU data collection system. The developed system takes advantage of SEU mitigation features available on the device. The New York City FIT rate for SEUs is estimated to be 3.2 FIT per Mbit for configuration memory and 7.1 FIT per Mbit for memory blocks. © 2019 IEEE.
248 a57189235340 Keller A. p267 True Conference 62 Impact of soft errors on large-scale FPGA cloud computing FPGAs are being used in large numbers within cloud computing to provide high-performance, low-power alternatives to more traditional computing structures. While FPGAs provide a number of important benefits to cloud computing environments, they are susceptible to radiation-induced soft errors, which can lead to silent data corruption or system instability. Although soft errors within a single FPGA occur infrequently, soft errors in large-scale FPGAs systems can occur at a relatively high rate. This paper investigates the failure rate of several FPGA applications running within an FPGA cloud computing node by performing fault injection experiments to determine the susceptibility of these applications to soft-errors. The results from these experiments suggest that silent data corruption will occur every few hours within a 100,000 node FPGA system and that such a system can only maintain high-levels of reliability for short periods of operation. These results suggest that soft-error detection and mitigation techniques may be needed in large-scale FPGA systems. © 2019 Association for Computing Machinery.
248 a57189235340 Keller A. p362 False Journal 202 Strategies for Removing Common Mode Failures from TMR Designs Deployed on SRAM FPGAs Triple modular redundancy (TMR) with repair has proven to be an effective strategy for mitigating the effects of single-event upsets within the configuration memory of static random access memory field-programmable gate arrays. Applying TMR to the design successfully reduces the design's neutron cross section by 80×. The effectiveness of TMR, however, is limited by the presence of single bits in the configuration memory which cause more than one TMR domain to fail simultaneously. We present three strategies to mitigate against these failures and improve the effectiveness of TMR: incremental routing, incremental placement, and striping. These techniques were tested using both fault injection and a wide spectrum neutron beam with the best technique offering a 400× reduction to the design's sensitive neutron cross section. An analysis from the radiation test shows that no single bits caused failure and that multicell upsets were the main cause of failure for these mitigation strategies. © 1963-2012 IEEE.
248 a57189235340 Keller A. p588 True Journal 304 Dynamic SEU Sensitivity of Designs on Two 28-nm SRAM-Based FPGA Architectures Two field-programmable gate array (FPGA) designs are tested for dynamic single event upset (SEU) sensitivity on two different 28-nm static random access memory-based FPGAs - an Intel Stratix V and a Xilinx Kintex 7 FPGA. These designs were tested in both a conventional unmitigated version and a version to tolerate SEUs with feedback triple modular redundancy (TMR). The unmitigated design sensitivity and the low-level device sensitivity were found to be similar between the devices through neutron radiation testing. Results also show that feedback TMR and configuration scrubbing benefit both designs on both FPGAs. While TMR is helpful, the benefit of TMR depends on the design structure and the device architecture. TMR and scrubbing reduced dynamic SEU sensitivity by a factor of 4- 54×. © 1963-2012 IEEE.
248 a57189235340 Keller A. p824 True Journal 393 Benefits of Complementary SEU Mitigation for the LEON3 Soft Processor on SRAM-Based FPGAs A variety of mitigation techniques have been demonstrated to reduce the sensitivity of FPGA designs to soft errors. Without mitigation, SEUs can cause failure by altering the logic, routing, and state of a design operating on an SRAM-based FPGA. Various combinations of SEU mitigation and repair techniques are applied to the LEON3 soft-core processor to study the effects and complementary nature of each technique. This work focuses on Triple modular redundancy (TMR), configuration memory (CRAM) scrubbing, and internal block memory (BRAM) scrubbing. All mitigation methods demonstrate some improvement in both fault injection and neutron radiation testing. Results in this paper show complementary SEU mitigation techniques working together to improve fault-tolerance. The results also suggest that fault injection can be a good way to estimate the cross section of a design before going to a radiation test. TMR with CRAM scrubbing demonstrates a 27 × improvement whereas TMR with both CRAM and BRAM scrubbing demonstrates approximately a 50 × improvement. © 2016 IEEE.
249 a55547123342 Anderson J. p61 False Conference 11 Using Partial Duplication with Compare to Detect Radiation-Induced Failure in a Commercial FPGA-Based Networking System Duplication with compare, a circuit-level fault-detection technique, is used in this study in a partial manner to detect radiation-induced failures in a commercial FPGA-based networking system. A novel approach is taken to overcome challenges presented by multiple clock domains, the use of third-party IP, and the collection of error detection signals dispersed throughout the design. Novel fault injection techniques are also used to evaluate critical regions of the target design. Accelerated neutron radiation testing was performed to evaluate the effectiveness of the applied technique. One design version was able to detect 45% of all failures with the proposed technique applied to 29% of the circuit components within the design. Another design version was able to detect 31% of all failures with the proposed technique applied to only 8% of circuit components. © 2020 IEEE.
250 a25639041400 Wen S.-J. p61 False Conference 11 Using Partial Duplication with Compare to Detect Radiation-Induced Failure in a Commercial FPGA-Based Networking System Duplication with compare, a circuit-level fault-detection technique, is used in this study in a partial manner to detect radiation-induced failures in a commercial FPGA-based networking system. A novel approach is taken to overcome challenges presented by multiple clock domains, the use of third-party IP, and the collection of error detection signals dispersed throughout the design. Novel fault injection techniques are also used to evaluate critical regions of the target design. Accelerated neutron radiation testing was performed to evaluate the effectiveness of the applied technique. One design version was able to detect 45% of all failures with the proposed technique applied to 29% of the circuit components within the design. Another design version was able to detect 31% of all failures with the proposed technique applied to only 8% of circuit components. © 2020 IEEE.
250 a25639041400 Wen S.-J. p721 False Conference 305 Move the Laser Spot, Not the DUT: Investigating the New Micro-mirror Capability and Challenges for Localizing SEE Sites on Large Modern ICs Small spot size laser testing for single-event effects has proven to be a particularly productive path to insights on the physics of charge collection and circuit response that are difficult or impossible to obtain through broad ion beam tests. As a result, there are a number of such laser facilities; for example, four of them were compared in 2012 [1], but a relatively new facility at the facility at the University of Saskatchewan offers a unique galvo-mirror, laser-spot scanning capability in addition to the usual micrometer-based DUT motion stage [2]. Operating in a fashion similar to LASIX eye surgery, fast pin-point redirection of the laser beam makes tractable (seconds, not hours or days) comprehensive scanning of a millimeter size field-of-view. Combined with auto-stepping the field-of-view, this new spot scanning capability opens up the possibility of comprehensively covering a large die and finding all SEE sites, including the rare, but important, ones such as SEFIs. © 2017 IEEE.
251 a55967471000 Fung R. p61 False Conference 11 Using Partial Duplication with Compare to Detect Radiation-Induced Failure in a Commercial FPGA-Based Networking System Duplication with compare, a circuit-level fault-detection technique, is used in this study in a partial manner to detect radiation-induced failures in a commercial FPGA-based networking system. A novel approach is taken to overcome challenges presented by multiple clock domains, the use of third-party IP, and the collection of error detection signals dispersed throughout the design. Novel fault injection techniques are also used to evaluate critical regions of the target design. Accelerated neutron radiation testing was performed to evaluate the effectiveness of the applied technique. One design version was able to detect 45% of all failures with the proposed technique applied to 29% of the circuit components within the design. Another design version was able to detect 31% of all failures with the proposed technique applied to only 8% of circuit components. © 2020 IEEE.
252 a57218221803 Chambers C. p61 False Conference 11 Using Partial Duplication with Compare to Detect Radiation-Induced Failure in a Commercial FPGA-Based Networking System Duplication with compare, a circuit-level fault-detection technique, is used in this study in a partial manner to detect radiation-induced failures in a commercial FPGA-based networking system. A novel approach is taken to overcome challenges presented by multiple clock domains, the use of third-party IP, and the collection of error detection signals dispersed throughout the design. Novel fault injection techniques are also used to evaluate critical regions of the target design. Accelerated neutron radiation testing was performed to evaluate the effectiveness of the applied technique. One design version was able to detect 45% of all failures with the proposed technique applied to 29% of the circuit components within the design. Another design version was able to detect 31% of all failures with the proposed technique applied to only 8% of circuit components. © 2020 IEEE.
253 a56387524600 Ganjalizadeh V. p62 False Journal 45 3D hydrodynamic focusing in microscale optofluidic channels formed with a single sacrificial layer Optofluidic devices are capable of detecting single molecules, but greater sensitivity and specificity is desired through hydrodynamic focusing (HDF). Three-dimensional (3D) hydrodynamic focusing was implemented in 10-μm scale microchannel cross-sections made with a single sacrificial layer. HDF is achieved using buffer fluid to sheath the sample fluid, requiring four fluid ports to operate by pressure driven flow. A low-pressure chamber, or pit, formed by etching into a substrate, enables volumetric flow ratio-induced focusing at a low flow velocity. The single layer design simplifies surface micromachining and improves device yield by 1.56 times over previous work. The focusing design was integrated with optical waveguides and used in order to analyze fluorescent signals from beads in fluid flow. The implementation of the focusing scheme was found to narrow the distribution of bead velocity and fluorescent signal, giving rise to 33% more consistent signal. Reservoir effects were observed at low operational vacuum pressures and a balance between optofluidic signal variance and intensity was achieved. The implementation of the design in optofluidic sensors will enable higher detection sensitivity and sample specificity. © 2020 by the authors.
253 a56387524600 Ganjalizadeh V. p173 False Conference 37 Three-Dimensional Hydrodynamic Focusing Designs for Integrated Optofluidic Detection Enhancement Three-dimensional hydrodynamic focusing promises to enhance detection capabilities of optofluidic sensors, enabling low concentration interrogation with higher confidence, critical for disease diagnosis. Novel 3DHDF designs with optofluidic channel diameters in the range of ten microns are evaluated, predicting detection enhancement of up to 3.54 times. © 2019 IEEE.
253 a56387524600 Ganjalizadeh V. p235 True Conference 56 Single Particle Detection Enhancement with Wavelet-based Signal Processing Technique Chip-based single molecule detection requires ultra-sensitive devices and robust signal processing methods. A new wavelet-based signal processing method is introduced that improves detection and error rates on an optofluidic platform by 2x and 3x, respectively. © 2019 The Author(s) 2019 OSA.
253 a56387524600 Ganjalizadeh V. p347 True Conference 119 Single particle detection enhancement with wavelet-based signal processing technique Chip-based single molecule detection requires ultra-sensitive devices and robust signal processing methods. A new wavelet-based signal processing method is introduced that improves detection and error rates on an optofluidic platform by 2x and 3x, respectively. © 2019 The Author(s)
253 a56387524600 Ganjalizadeh V. p459 False Journal 256 Buried Rib SiO2 Multimode Interference Waveguides for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used to create wavelength-dependent spot patterns which enables simultaneous analyte detection on a single optofluidic chip, useful for disease diagnostics. The fidelity of such multi-spot patterns is important for high sensitivity and accurate target identification. Buried rib structures have been incorporated into these SiO2-based waveguides to improve environmental stability. Through experiments and simulation, this letter explores design parameters for a buried MMI rib waveguide based on anti-resonant reflecting optical waveguides in order to produce high-fidelity spot patterns. Optimal rib heights and widths are reported in the context of available microfabrication etch technology and performance for an optimized biosensor is shown. © 1989-2012 IEEE.
253 a56387524600 Ganjalizadeh V. p502 False Journal 273 Optimized ARROW-Based MMI Waveguides for High Fidelity Excitation Patterns for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used for multiplexing and de-multiplexing optical signals. High fidelity, wavelength dependent multi-spot patterns from MMI waveguides are useful for sensitive and simultaneous identification of multiple targets in multiplexed fluorescence optofluidic biosensors. Through experiments and simulation, this paper explores design parameters for an MMI rib anti-resonant reflecting optical waveguide in order to produce high fidelity spot patterns at the liquid core biomarker excitation region. Width and etch depth of the single excitation rib waveguide used to excite the MMI waveguide are especially critical because they determine the size of the input optical mode which is imaged at the MMI waveguide's output. To increase optical throughput into the MMI waveguide when light is coupled in from an optical fiber, tapers in the waveguide width can be used for better mode matching. © 2012 IEEE.
253 a56387524600 Ganjalizadeh V. p607 False Conference 245 High fidelity MMI excitation patterns for optofluidic multiplexing High fidelity interference patterns from multimode interference waveguides are needed for multiplexed optofluidic biosensors. Spot pattern fidelity can be optimized by careful design of the single-mode waveguides used to excite the multimode waveguides. © OSA 2018.
253 a56387524600 Ganjalizadeh V. p706 False Journal 347 Optofluidic lab-on-a-chip fluorescence sensor using integrated buried ARROW (bARROW) waveguides Optofluidic, lab-on-a-chip fluorescence sensors were fabricated using buried anti-resonant reflecting optical waveguides (bARROWs). The bARROWs are impervious to the negative water absorption effects that typically occur in waveguides made using hygroscopic, plasma-enhanced chemical vapor deposition (PECVD) oxides. These sensors were used to detect fluorescent microbeads and had an average signal-to-noise ratio (SNR) that was 81.3% higher than that of single-oxide ARROW fluorescence sensors. While the single-oxide ARROW sensors were annealed at 300 ◦ C to drive moisture out of the waveguides, the bARROW sensors required no annealing process to obtain a high SNR. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.
254 a57202735625 Wright J.G. p62 False Journal 45 3D hydrodynamic focusing in microscale optofluidic channels formed with a single sacrificial layer Optofluidic devices are capable of detecting single molecules, but greater sensitivity and specificity is desired through hydrodynamic focusing (HDF). Three-dimensional (3D) hydrodynamic focusing was implemented in 10-μm scale microchannel cross-sections made with a single sacrificial layer. HDF is achieved using buffer fluid to sheath the sample fluid, requiring four fluid ports to operate by pressure driven flow. A low-pressure chamber, or pit, formed by etching into a substrate, enables volumetric flow ratio-induced focusing at a low flow velocity. The single layer design simplifies surface micromachining and improves device yield by 1.56 times over previous work. The focusing design was integrated with optical waveguides and used in order to analyze fluorescent signals from beads in fluid flow. The implementation of the focusing scheme was found to narrow the distribution of bead velocity and fluorescent signal, giving rise to 33% more consistent signal. Reservoir effects were observed at low operational vacuum pressures and a balance between optofluidic signal variance and intensity was achieved. The implementation of the design in optofluidic sensors will enable higher detection sensitivity and sample specificity. © 2020 by the authors.
254 a57202735625 Wright J.G. p173 False Conference 37 Three-Dimensional Hydrodynamic Focusing Designs for Integrated Optofluidic Detection Enhancement Three-dimensional hydrodynamic focusing promises to enhance detection capabilities of optofluidic sensors, enabling low concentration interrogation with higher confidence, critical for disease diagnosis. Novel 3DHDF designs with optofluidic channel diameters in the range of ten microns are evaluated, predicting detection enhancement of up to 3.54 times. © 2019 IEEE.
254 a57202735625 Wright J.G. p608 False Conference 246 3D hydrodynamic focusing for optofluidics using a stacked channel design We present a 3D hydrodynamic focusing design suitable for optofluidic devices allowing planar fabrication and velocity independent particle focusing. Simulations are presented and fabrication outlined with evidence that stacked SU8 layers are suitable building blocks. © OSA 2018.
255 a7003381644 Warnick K.F. p63 True Journal 46 Teaching and Learning Electromagnetics in 2020: Issues, trends, opportunities, and ideas for developing courses Electromagnetics (EM) and its applications have been a vital part of scientific and engineering instruction for well over a century. As approaches, applications, and curricular models evolve, educators in the field face many challenges and pressures. Here, we consider issues that face those who teach EM theory, identify some of the trends and opportunities that lie ahead, and make recommendations for the next decade of training and course development in the field of EM. © 1990-2011 IEEE.
255 a7003381644 Warnick K.F. p78 False Journal 58 Compact structure with high TX-RX isolation for frequency domain duplexing on printed circuit boards When developing compact and lightweight antenna systems for unmanned aerial systems, achieving high isolation between transmit and receive signal paths is challenging. To address this issue, we demonstrate a prototype isolation design on a printed circuit board for a frequency division duplexed X band antenna system. Key components include a microstrip defected ground plane notch filter and a copper grating barrier that provides 20 dB higher isolation than free space separation between the transmit and receive antennas. The hardware provides at least 105 dB of transmit isolation into the receiver low noise amplifier in the transmit band. The proposed design is lighter and more compact than traditional machined metal waveguide isolation techniques used for ground-based systems yet achieves similar isolation performance. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.
255 a7003381644 Warnick K.F. p90 False Journal 69 Optimising the design of phased array feeds for survey speed The scientific capability of an astronomical phased array feed receiver can be quantified by combining the bandwidth, sensitivity, and field of view into the overall survey speed of the instrument. The authors investigate the relationships between survey speed and reflector geometry, array layout, element spacing and element configuration using numerical simulations, to determine the values of these parameters that lead to optimal system performance. They characterise the array element spacing that leads to maximum survey speed as a function of the reflector f/D. To further improve survey speed in relation to the overall number of array elements, the authors explore the possibility of using elements with modest levels of superdirectivity to sample more of the focal plane Airy pattern and increase optimal spacing for survey speed figure of merit. The results explain how optimal survey speed is controlled primarily by the influence of element type and array layout on the peak achievable aperture efficiency. © The Institution of Engineering and Technology 2020
255 a7003381644 Warnick K.F. p119 False Journal 85 Array Antenna Gain Enhancement with the Poynting Streamline Method Streamlines of the Poynting vector field connect antenna figures of merit with the energy flow characteristics near a receiving antenna. Poynting streamlines properties and absorption aperture of antenna under different load conditions have been studied in this letter. Based on its Poynting streamline characteristics, the short-circuit dipole can be used as a parasitic element to direct the flow of energy, increase the absorption aperture, and enhance the gain of the array. Numerical examples show that this strategy can not only enhance the gain of dipole array, but also improve the gain of circularly polarized antenna array without deteriorating the axial ratio. Poynting streamline-based methods augment commonly used radiation-mode antenna analysis techniques by providing an intuitive and visual way to guide the design of antenna arrays. © 2002-2011 IEEE.
255 a7003381644 Warnick K.F. p276 False Journal 101 An intuitive way to understand mutual coupling effects in antenna arrays using the poynting streamline method The flow of energy around array antenna in receiving mode can be modeled by generating streamlines of the Poynting vector field. From the streamlines that terminate on the array element loads, a geometrical shape can be assigned to the effective area of the array. These concepts provide an intuitive tool for understanding mutual coupling effects in antenna arrays. The decrease in directivity associated with mutual coupling effects, the so-called element-gain paradox, can be explained by the overlap of the element effective area shapes. The critical element spacing for the element-gain paradox effect can be predicted from the effective area shape for a single isolated array element. Antenna design for minimizing mutual coupling, which is of interest in multiple input multiple output communications systems, magnetic resonance imaging arrays, astronomical arrays, and other applications, can be guided by analysing the effective area shape for a single isolated array element. © 1963-2012 IEEE.
255 a7003381644 Warnick K.F. p556 False Journal 263 Practical Superdirectivity with Resonant Screened Apertures Motivated by a Poynting Streamlines Analysis Fundamental limits on the degree of practical achievable superdirectivity for antennas include narrow bandwidth, large antenna loss, and sensitivity to excitation and fabrication errors. Superdirective antennas are commonly considered as transmitters, but thinking of the antenna as a receiver may help to understand and overcome some of these limits on practical superdirectivity. We directly model a superdirective antenna in receive mode by calculating streamlines of Poynting vector field near the receiving antennas. Superdirectivity is achieved by expanding the shape of the effective area beyond the antenna physical aperture area. The degree of superdirectivity is parameterized by an effective area expansion distance. The theory predicts that superdirectivity is practical for electrically small and middle size antennas and electrically large antennas with a large aspect ratio. With this motivation, a 1.5 λ × 2 λ superdirective horn antenna with resonant screen structure in front of the antenna aperture is designed and fabricated. The superdirective horn achieves a measured antenna efficiency of 115% over a reasonable bandwidth and with moderate sensitivity to fabrication errors. © 1963-2012 IEEE.
255 a7003381644 Warnick K.F. p639 True Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
255 a7003381644 Warnick K.F. p651 False Journal 314 Ground-based sense-and-avoid system for small unmanned aircraft In this Paper, we present a complete, proof-of-concept sense-and-avoid solution for small unmanned aircraft systems, including a small low-cost ground-based radar system, multitarget tracking and estimation, collision detection, and an avoidance planner. We describe the development of a small frequency-modulated continuous-wave phased-array radar system that provides a three-dimensional surveillance volume. The radar measurements are processed using the recursive random sample consensus algorithm, producing tracks for the intruders and the ownship. We propose a collision-detection algorithm based on the geometric relationship between encountering aircraft. If a collision threat is detected, a collision-free new path is generated for the ownship using a two-step path-planning algorithm. In the first step, an initial suboptimal path is generated using an A search. In the second step, the path is refined using a variant of the potential fields technique, adapted to the sense-and-avoid scenario. The performance of the complete system is demonstrated with flight-test experiments. © 2018 American Institute of Aeronautics and Astronautics Inc.. All rights reserved.
255 a7003381644 Warnick K.F. p665 False Journal 319 Sidelobe Level and Aperture Efficiency Optimization for Tiled Aperiodic Array Antennas Array antennas with aperiodic element placement provide a way to mitigate grating lobe level when the array element spacing is larger than one half wavelength. Design techniques for aperiodic arrays include thinning, numerical optimization, and other methods, but even with modern tools, designing electrically large aperiodic arrays remain computationally challenging. To reduce the complexity of the large aperiodic array design problem, we study the use of discrete rotated tiles with element positions and tile orientations optimized to minimize peak sidelobe level (PSLL). The directivity, frequency sensitivity of PSLL, and optimization complexity for uniform arrays, aperiodic arrays, and tiled arrays are compared. Based on many numerical examples, an approximate relationship between PSLL and array element number and density for aperiodic and tiled arrays is proposed as a convergence estimator for the design optimization process. © 2017 IEEE.
255 a7003381644 Warnick K.F. p674 False Journal 319 Antenna Loss and Receiving Efficiency for Mutually Coupled Arrays For phased arrays used in satellite communications and radio astronomy, high sensitivity is required, and minimizing antenna losses is critical. Losses for single antennas can be minimized using high conductivity materials. It is less well understood that loss for array antennas is also influenced by mutual coupling between array elements and the beamformer weights applied to the signal from each element. In this paper, we study the antenna loss and receiving efficiency for phased array antennas and focal plane phased array feeds. To better elucidate the physics of array antenna loss related to mutual coupling and beamformer weights, losses for a coupled array can be lumped into an array effective resistance similar to the loss resistance of an equivalent single antenna. Numerical results show that although the antenna loss for a single isolated array element is low, the array antenna loss can be significantly increased by mutual coupling, particularly for beams with a large scan angle. © 2017 IEEE.
255 a7003381644 Warnick K.F. p710 False Journal 319 Improved Antenna Efficiency Measurement Uncertainty in a Reverberation Chamber at Millimeter-Wave Frequencies We provide results of antenna radiation and total radiation efficiency at millimeter-wave frequencies gathered with a new open-ended waveguide-plate method that is compared to a well-known two-antenna method. The new method yields improved uncertainty in antenna efficiency measurements. Both methods are based on use of a reverberation chamber. Measurement results are compared to numerical simulations and good agreement (3% maximum difference) is achieved. Before performing the efficiency measurements, the chamber configuration was assessed with respect to the Rician $K$ -factor, number of uncorrelated paddle orientations, and coherence bandwidth. We calculated the uncertainty using the NIST microwave uncertainty framework capable of performing parallel sensitivity and Monte Carlo analyses. The framework enables us to capture and propagate the uncertainties in the S-parameter measurements to the final efficiency result. The expanded uncertainty that we achieved for these antenna efficiency measurements is 2.60%. © 1963-2012 IEEE.
255 a7003381644 Warnick K.F. p740 False Journal 346 Optical electric field sensor sensitivity direction rerouting and enhancement using a passive integrated dipole antenna This work introduces a passive dipole antenna integrated into the packaging of a slab-coupled optical sensor to enhance the directional sensitivity of electro-optic electric field measurements parallel to the fiber axis. Using the passive integrated dipole antenna described in this work, a sensor that can typically only sense fields transverse to the fiber direction is able to sense a 1.25 kV/m field along the fiber direction with a gain of 17.5. This is verified through simulation and experiment. © 2017 Optical Society of America.
255 a7003381644 Warnick K.F. p779 False Journal 319 Poynting Streamlines, Effective Area Shape, and the Design of Superdirective Antennas A receiving antenna alters an incident field in such a way that the field is concentrated at the terminals of the antenna. The Poynting power flux density vector associated with the field carries to the antenna the power dissipated in the antenna structure and the load. Streamlines of the Poynting vector field can be used to understand electromagnetic energy flow near linear and aperture antennas. Poynting streamlines provide a way to understand and guide the design of superdirective antennas. Directivity-enhancing screens that attract Poynting streamlines and increase the aperture efficiency of a horn antenna to almost 200% are studied. Superdirective antennas generally have limited practical value due to poor radiation efficiency, narrow bandwidth, and extreme sensitivity to fabrication errors. We show that these limitations can be mitigated by using metal-only structures that are optimized for broadband operation. The tradeoff between peak achievable aperture efficiency and bandwidth is explored. © 1963-2012 IEEE.
255 a7003381644 Warnick K.F. p784 False Journal 388 Active Integrated Antenna Supporting Linear and Circular Polarizations A patch antenna and class B power amplifier are integrated for size reduction and high power added efficiency (PAE) through harmonic suppression. Harmonic suppressing slits are etched on the patch such that both linear and circular polarizations are supported. The mechanism of the slits is explained, and both components are characterized and examined for performance validation. Measured results show that the harmonic suppression leads to up to 5% improvement in PAE and that the antenna's radiation pattern is not disturbed by the added harmonic suppressing slits for all supported polarizations. © 2016 IEEE.
255 a7003381644 Warnick K.F. p828 False Conference 357 Small aircraft flight encounters database for UAS sense and avoid Hardware and software technologies that enable unmanned aircraft systems (UAS) to reliably sense and avoid (SAA) other aircraft are critical to the safe operation of UAS beyond an operator's line of sight. For small UAS, the need is especially critical because of the clutter and the air-traffic density at low altitudes where they operate. For the community of researchers who are developing SAA technology for small UAS, there is a critical need for a rich, openly-accessible compendium of encounter data with which to develop, test, and evaluate SAA algorithms. In this paper we introduce a publicly available database of small UAS encounter data, the small aircraft flight encounter (SAFE) database, with an initial deposit of 11 flight encounters. In these encounters two target aircraft, a fixed-wing and a multi-rotor are imaged by a separate fixed-wing aircraft carrying two high-definition video cameras and a unique radar unit. The data contain ground-truth navigation estimates for both the target and imaging aircraft. The target aircraft are observed in the video footage but not in the radar imagery; continuing efforts include tuning and refinement of the radar parameters and expansion of the SAFE database to support small UAS SAA technology development. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
256 a6701834327 Selvan K.T. p63 False Journal 46 Teaching and Learning Electromagnetics in 2020: Issues, trends, opportunities, and ideas for developing courses Electromagnetics (EM) and its applications have been a vital part of scientific and engineering instruction for well over a century. As approaches, applications, and curricular models evolve, educators in the field face many challenges and pressures. Here, we consider issues that face those who teach EM theory, identify some of the trends and opportunities that lie ahead, and make recommendations for the next decade of training and course development in the field of EM. © 1990-2011 IEEE.
257 a57202445593 Fistler M. p64 True Journal 47 Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence using one-dimensional turbulence Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence is investigated using one-dimensional turbulence (ODT), a low-dimensional stochastic flow simulation model. For this purpose, ODT is extended in two ways. First, a forcing scheme that maintains statistical stationarity is introduced. Unlike direct numerical simulation (DNS) of forced turbulence, the ODT framework accommodates forcing that is not directly coupled to the momentum equation. For given forcing the ODT energy dissipation rate is therefore the same in particle-laden cases as in the corresponding single-phase reference case. Second, previously implemented one-way-coupled particle phenomenology is extended to two-way coupling using the general ODT methodology for flow modulation through interaction with any specified energy and momentum sources and sinks. As in a DNS comparison case for Reλ=70, turbulence modulation is diagnosed primarily on the basis of the fluid-phase kinetic-energy spectrum. Because ODT involves subprocesses with straightforward physical interpretations, the ODT mechanisms of particle-induced turbulence modulation are clearly identified and they are plausibly relevant to particle-laden Navier-Stokes turbulence. ODT results for the ratio of particle-phase and fluid-phase kinetic energies as a function of particle Stokes number and mass loading are reported for the purpose of testing these predictions in the future when these quantities are evaluated experimentally or using DNS. © 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/" Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by "https://www.kb.se/samverkan-och-utveckling/oppen-tillgang-och-bibsamkonsortiet/bibsamkonsortiet.html" Bibsam.
257 a57202445593 Fistler M. p467 False Journal 228 One-dimensional turbulence modeling for cylindrical and spherical flows: model formulation and application The one-dimensional turbulence (ODT) model resolves a full range of time and length scales and is computationally efficient. ODT has been applied to a wide range of complex multi-scale flows, such as turbulent combustion. Previous ODT comparisons to experimental data have focused mainly on planar flows. Applications to cylindrical flows, such as round jets, have been based on rough analogies, e.g., by exploiting the fortuitous consistency of the similarity scalings of temporally developing planar jets and spatially developing round jets. To obtain a more systematic treatment, a new formulation of the ODT model in cylindrical and spherical coordinates is presented here. The model is written in terms of a geometric factor so that planar, cylindrical, and spherical configurations are represented in the same way. Temporal and spatial versions of the model are presented. A Lagrangian finite-volume implementation is used with a dynamically adaptive mesh. The adaptive mesh facilitates the implementation of cylindrical and spherical versions of the triplet map, which is used to model turbulent advection (eddy events) in the one-dimensional flow coordinate. In cylindrical and spherical coordinates, geometric stretching of the three triplet map images occurs due to the radial dependence of volume, with the stretching being strongest near the centerline. Two triplet map variants, TMA and TMB, are presented. In TMA, the three map images have the same volume, but different radial segment lengths. In TMB, the three map images have the same radial segment lengths, but different segment volumes. Cylindrical results are presented for temporal pipe flow, a spatial nonreacting jet, and a spatial nonreacting jet flame. These results compare very well to direct numerical simulation for the pipe flow, and to experimental data for the jets. The nonreacting jet treatment overpredicts velocity fluctuations near the centerline, due to the geometric stretching of the triplet maps and its effect on the eddy event rate distribution. TMB performs better than TMA. A hybrid planar-TMB (PTMB) approach is also presented, which further improves the results. TMA, TMB, and PTMB are nearly identical in the pipe flow where the key dynamics occur near the wall away from the centerline. The jet flame illustrates effects of variable density and viscosity, including dilatational effects. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
258 a7004609408 Kerstein A. p64 False Journal 47 Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence using one-dimensional turbulence Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence is investigated using one-dimensional turbulence (ODT), a low-dimensional stochastic flow simulation model. For this purpose, ODT is extended in two ways. First, a forcing scheme that maintains statistical stationarity is introduced. Unlike direct numerical simulation (DNS) of forced turbulence, the ODT framework accommodates forcing that is not directly coupled to the momentum equation. For given forcing the ODT energy dissipation rate is therefore the same in particle-laden cases as in the corresponding single-phase reference case. Second, previously implemented one-way-coupled particle phenomenology is extended to two-way coupling using the general ODT methodology for flow modulation through interaction with any specified energy and momentum sources and sinks. As in a DNS comparison case for Reλ=70, turbulence modulation is diagnosed primarily on the basis of the fluid-phase kinetic-energy spectrum. Because ODT involves subprocesses with straightforward physical interpretations, the ODT mechanisms of particle-induced turbulence modulation are clearly identified and they are plausibly relevant to particle-laden Navier-Stokes turbulence. ODT results for the ratio of particle-phase and fluid-phase kinetic energies as a function of particle Stokes number and mass loading are reported for the purpose of testing these predictions in the future when these quantities are evaluated experimentally or using DNS. © 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/" Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by "https://www.kb.se/samverkan-och-utveckling/oppen-tillgang-och-bibsamkonsortiet/bibsamkonsortiet.html" Bibsam.
258 a7004609408 Kerstein A. p467 False Journal 228 One-dimensional turbulence modeling for cylindrical and spherical flows: model formulation and application The one-dimensional turbulence (ODT) model resolves a full range of time and length scales and is computationally efficient. ODT has been applied to a wide range of complex multi-scale flows, such as turbulent combustion. Previous ODT comparisons to experimental data have focused mainly on planar flows. Applications to cylindrical flows, such as round jets, have been based on rough analogies, e.g., by exploiting the fortuitous consistency of the similarity scalings of temporally developing planar jets and spatially developing round jets. To obtain a more systematic treatment, a new formulation of the ODT model in cylindrical and spherical coordinates is presented here. The model is written in terms of a geometric factor so that planar, cylindrical, and spherical configurations are represented in the same way. Temporal and spatial versions of the model are presented. A Lagrangian finite-volume implementation is used with a dynamically adaptive mesh. The adaptive mesh facilitates the implementation of cylindrical and spherical versions of the triplet map, which is used to model turbulent advection (eddy events) in the one-dimensional flow coordinate. In cylindrical and spherical coordinates, geometric stretching of the three triplet map images occurs due to the radial dependence of volume, with the stretching being strongest near the centerline. Two triplet map variants, TMA and TMB, are presented. In TMA, the three map images have the same volume, but different radial segment lengths. In TMB, the three map images have the same radial segment lengths, but different segment volumes. Cylindrical results are presented for temporal pipe flow, a spatial nonreacting jet, and a spatial nonreacting jet flame. These results compare very well to direct numerical simulation for the pipe flow, and to experimental data for the jets. The nonreacting jet treatment overpredicts velocity fluctuations near the centerline, due to the geometric stretching of the triplet maps and its effect on the eddy event rate distribution. TMB performs better than TMA. A hybrid planar-TMB (PTMB) approach is also presented, which further improves the results. TMA, TMB, and PTMB are nearly identical in the pipe flow where the key dynamics occur near the wall away from the centerline. The jet flame illustrates effects of variable density and viscosity, including dilatational effects. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
259 a8660143800 Lignell D.O. p64 False Journal 47 Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence using one-dimensional turbulence Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence is investigated using one-dimensional turbulence (ODT), a low-dimensional stochastic flow simulation model. For this purpose, ODT is extended in two ways. First, a forcing scheme that maintains statistical stationarity is introduced. Unlike direct numerical simulation (DNS) of forced turbulence, the ODT framework accommodates forcing that is not directly coupled to the momentum equation. For given forcing the ODT energy dissipation rate is therefore the same in particle-laden cases as in the corresponding single-phase reference case. Second, previously implemented one-way-coupled particle phenomenology is extended to two-way coupling using the general ODT methodology for flow modulation through interaction with any specified energy and momentum sources and sinks. As in a DNS comparison case for Reλ=70, turbulence modulation is diagnosed primarily on the basis of the fluid-phase kinetic-energy spectrum. Because ODT involves subprocesses with straightforward physical interpretations, the ODT mechanisms of particle-induced turbulence modulation are clearly identified and they are plausibly relevant to particle-laden Navier-Stokes turbulence. ODT results for the ratio of particle-phase and fluid-phase kinetic energies as a function of particle Stokes number and mass loading are reported for the purpose of testing these predictions in the future when these quantities are evaluated experimentally or using DNS. © 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/" Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by "https://www.kb.se/samverkan-och-utveckling/oppen-tillgang-och-bibsamkonsortiet/bibsamkonsortiet.html" Bibsam.
259 a8660143800 Lignell D.O. p342 False Conference 115 One-dimensional turbulence modelling of a lifted methane/air jet flame in a vitiated coflow The present preliminary numerical study investigates a lifted methane/air jet flame in a vitiated coflow by means of the map-based, stochastic One-Dimensional Turbulence (ODT) model. In the considered configuration, a jet flame issues from a central nozzle into a vitiated coflow of hot combustion products from an array of lean H2/air flames. Centreline profiles for mixture fraction, temperature and mass fraction of O2 and OH obtained from ODT simulations with a planar and cylindrical formulation are shown and compared to measurements from Cabra et al. (2005). Additionally, two-dimensional renderings of the jet flame and scatter plots of temperature versus mixture fraction and OH mass fraction versus mixture fraction are provided. Although the application of ODT for reactive flows in jet configurations is not novel, the chosen lifted jet flame in a vitiated coflow represents a challenge for the model. The accurate representation of the subtle interactions of the hot coflow products with the cold unburnt jet flow are crucial for the reaction and autoignition of the jet (Cabra et al., 2005). Considering the reduced order of the model and the taken assumptions, the achieved results reasonably match with the measurement data. © 2019 International Symposium on Turbulence and Shear Flow Phenomena, TSFP. All rights reserved.
259 a8660143800 Lignell D.O. p467 True Journal 228 One-dimensional turbulence modeling for cylindrical and spherical flows: model formulation and application The one-dimensional turbulence (ODT) model resolves a full range of time and length scales and is computationally efficient. ODT has been applied to a wide range of complex multi-scale flows, such as turbulent combustion. Previous ODT comparisons to experimental data have focused mainly on planar flows. Applications to cylindrical flows, such as round jets, have been based on rough analogies, e.g., by exploiting the fortuitous consistency of the similarity scalings of temporally developing planar jets and spatially developing round jets. To obtain a more systematic treatment, a new formulation of the ODT model in cylindrical and spherical coordinates is presented here. The model is written in terms of a geometric factor so that planar, cylindrical, and spherical configurations are represented in the same way. Temporal and spatial versions of the model are presented. A Lagrangian finite-volume implementation is used with a dynamically adaptive mesh. The adaptive mesh facilitates the implementation of cylindrical and spherical versions of the triplet map, which is used to model turbulent advection (eddy events) in the one-dimensional flow coordinate. In cylindrical and spherical coordinates, geometric stretching of the three triplet map images occurs due to the radial dependence of volume, with the stretching being strongest near the centerline. Two triplet map variants, TMA and TMB, are presented. In TMA, the three map images have the same volume, but different radial segment lengths. In TMB, the three map images have the same radial segment lengths, but different segment volumes. Cylindrical results are presented for temporal pipe flow, a spatial nonreacting jet, and a spatial nonreacting jet flame. These results compare very well to direct numerical simulation for the pipe flow, and to experimental data for the jets. The nonreacting jet treatment overpredicts velocity fluctuations near the centerline, due to the geometric stretching of the triplet maps and its effect on the eddy event rate distribution. TMB performs better than TMA. A hybrid planar-TMB (PTMB) approach is also presented, which further improves the results. TMA, TMB, and PTMB are nearly identical in the pipe flow where the key dynamics occur near the wall away from the centerline. The jet flame illustrates effects of variable density and viscosity, including dilatational effects. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
259 a8660143800 Lignell D.O. p621 False Conference 257 Simplified modeling for soot formation from solid fuels Modeling soot formed from solid complex fuels such as coal or biomass is difficult and rare in the combustion community. Previously a detailed model was developed for soot formation depicting the soot particle size distribution using the method of moments with interpolative closure. This model is both accurate and complex. Computational expense of this model may be beyond many large-scale simulations. As a result, a simplified version of this detailed model has been developed. This simplified model makes two easy assumptions to drastically reduce the complexity of modeling soot formation. First assumption is that soot particles and soot precursors within a computational domain are assumed to be mono-dispersed, meaning all particles are the same size. This reduces the number of resolved terms to model both soot precursors and soot particles to three resolved terms rather than the 10+ terms required by the previously developed model. Second assumption is that all particles are spherical. While the simplified model is computationally less expensive, these two assumptions come with a cost in accuracy. Presented is both the development of this simplified model along with comparative simulations where the complex and simple models are ran. From these simulations, researchers and developers can justify which model may be used in their respective systems. © 2018 Western States Section/Combustion Institute. All rights reserved.
259 a8660143800 Lignell D.O. p771 False Journal 378 Evaluation of stochastic particle dispersion modeling in turbulent round jets ODT (one-dimensional turbulence) simulations of particle-carrier gas interactions are performed in the jet flow configuration. Particles with different diameters are injected onto the centerline of a turbulent air jet. The particles are passive and do not impact the fluid phase. Their radial dispersion and axial velocities are obtained as functions of axial position. The time and length scales of the jet are varied through control of the jet exit velocity and nozzle diameter. Dispersion data at long times of flight for the nozzle diameter (7 mm), particle diameters (60 and 90 µm), and Reynolds numbers (10, 000–30, 000) are analyzed to obtain the Lagrangian particle dispersivity. Flow statistics of the ODT particle model are compared to experimental measurements. It is shown that the particle tracking method is capable of yielding Lagrangian prediction of the dispersive transport of particles in a round jet. In this paper, three particle-eddy interaction models (Type-I, -C, and -IC) are presented to examine the details of particle dispersion and particle-eddy interaction in jet flow. © 2016 Elsevier Ltd
259 a8660143800 Lignell D.O. p804 False Conference 340 Modeling soot in coal systems The formation of soot in power-boiler systems can have a significant impact on boiler performance due to direct effects on local flame temperatures and wall heat flux. In this work, a soot model was developed for coal systems that accommodates differences between solid fuel systems and gaseous systems, for which most traditional soot models are developed. The developed soot model contains terms for: particle nucleation based on tar evolution in a coal system, a nucle-ation mechanism based on the formation of PAH from gaseous species, gaseous interactions with particles (including: surface growth through HACA, particle oxidation/gasification), coagulation, and aggregation of existing particles. A monodispersed-particle size distribution form of this model can be used for cost-effective simulations, or for simulations with higher fidelity, the method of moments is used to transport higher moments of the particle size distribution. Validation work is presented, comparing numerically-derived soot values from the proposed model against measured soot concentrations in a flat-flame burner. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
259 a8660143800 Lignell D.O. p849 False Conference 373 Modeling soot formation from solid complex fuels While the phenomena of soot formation in gaseous flames is well studied and understood, extension of the fundamental mechanisms to systems containing complex solid fuels can introduce large uncertainties and inaccuracies. In this study, we have developed a detailed physicsbased model for predicting the evolution of soot particles formed in systems containing complexsolid fuels such as wood or coal. This detailed physics-based model includes two particle-size distributions: that for soot particles and for soot precursor molecules. Sub-models for precursor creation, growth, and thermal cracking are included along with soot particle nucleation, coagulation, surface growth, aggregation, oxidation, and gasification. Validation work is presented comparing experimental results for a coal flame and biomass gasifier against model predicted values for soot concentrations and size distributions. The full detailed model can be computationally expensive when incorporated into CFD simulations; therefore, model simplifications are explored and presented in this work along with some preliminary work of applying particle formation physics to wildfire simulations.
259 a8660143800 Lignell D.O. p866 False Conference 387 Effect of the turbulence modeling in large-eddy simulations of nonpremixed flames undergoing extinction and reignition Simulating practical combustion systems requires the approximation of the interaction between turbulence, molecular transport and chemical reactions. Turbulent combustion models are used for this purpose, but their behavior is difficult to anticipate based on their mathematical formulations, making the use of numerical experimentation necessary. Therefore, the present work explores the effect of three turbulent-combustion models, two eddy-viscosity models, and their parameters on a combustion problem which is notoriously difficult to model: flame extinction and reignition. For this purpose, two types of temporal jets are considered, and direct-numerical-simulation results are compared qualitatively with those from large-eddy simulations. © 2017 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
260 a6506736843 Oevermann M. p64 False Journal 47 Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence using one-dimensional turbulence Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence is investigated using one-dimensional turbulence (ODT), a low-dimensional stochastic flow simulation model. For this purpose, ODT is extended in two ways. First, a forcing scheme that maintains statistical stationarity is introduced. Unlike direct numerical simulation (DNS) of forced turbulence, the ODT framework accommodates forcing that is not directly coupled to the momentum equation. For given forcing the ODT energy dissipation rate is therefore the same in particle-laden cases as in the corresponding single-phase reference case. Second, previously implemented one-way-coupled particle phenomenology is extended to two-way coupling using the general ODT methodology for flow modulation through interaction with any specified energy and momentum sources and sinks. As in a DNS comparison case for Reλ=70, turbulence modulation is diagnosed primarily on the basis of the fluid-phase kinetic-energy spectrum. Because ODT involves subprocesses with straightforward physical interpretations, the ODT mechanisms of particle-induced turbulence modulation are clearly identified and they are plausibly relevant to particle-laden Navier-Stokes turbulence. ODT results for the ratio of particle-phase and fluid-phase kinetic energies as a function of particle Stokes number and mass loading are reported for the purpose of testing these predictions in the future when these quantities are evaluated experimentally or using DNS. © 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/" Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by "https://www.kb.se/samverkan-och-utveckling/oppen-tillgang-och-bibsamkonsortiet/bibsamkonsortiet.html" Bibsam.
260 a6506736843 Oevermann M. p467 False Journal 228 One-dimensional turbulence modeling for cylindrical and spherical flows: model formulation and application The one-dimensional turbulence (ODT) model resolves a full range of time and length scales and is computationally efficient. ODT has been applied to a wide range of complex multi-scale flows, such as turbulent combustion. Previous ODT comparisons to experimental data have focused mainly on planar flows. Applications to cylindrical flows, such as round jets, have been based on rough analogies, e.g., by exploiting the fortuitous consistency of the similarity scalings of temporally developing planar jets and spatially developing round jets. To obtain a more systematic treatment, a new formulation of the ODT model in cylindrical and spherical coordinates is presented here. The model is written in terms of a geometric factor so that planar, cylindrical, and spherical configurations are represented in the same way. Temporal and spatial versions of the model are presented. A Lagrangian finite-volume implementation is used with a dynamically adaptive mesh. The adaptive mesh facilitates the implementation of cylindrical and spherical versions of the triplet map, which is used to model turbulent advection (eddy events) in the one-dimensional flow coordinate. In cylindrical and spherical coordinates, geometric stretching of the three triplet map images occurs due to the radial dependence of volume, with the stretching being strongest near the centerline. Two triplet map variants, TMA and TMB, are presented. In TMA, the three map images have the same volume, but different radial segment lengths. In TMB, the three map images have the same radial segment lengths, but different segment volumes. Cylindrical results are presented for temporal pipe flow, a spatial nonreacting jet, and a spatial nonreacting jet flame. These results compare very well to direct numerical simulation for the pipe flow, and to experimental data for the jets. The nonreacting jet treatment overpredicts velocity fluctuations near the centerline, due to the geometric stretching of the triplet maps and its effect on the eddy event rate distribution. TMB performs better than TMA. A hybrid planar-TMB (PTMB) approach is also presented, which further improves the results. TMA, TMB, and PTMB are nearly identical in the pipe flow where the key dynamics occur near the wall away from the centerline. The jet flame illustrates effects of variable density and viscosity, including dilatational effects. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
260 a6506736843 Oevermann M. p866 False Conference 387 Effect of the turbulence modeling in large-eddy simulations of nonpremixed flames undergoing extinction and reignition Simulating practical combustion systems requires the approximation of the interaction between turbulence, molecular transport and chemical reactions. Turbulent combustion models are used for this purpose, but their behavior is difficult to anticipate based on their mathematical formulations, making the use of numerical experimentation necessary. Therefore, the present work explores the effect of three turbulent-combustion models, two eddy-viscosity models, and their parameters on a combustion problem which is notoriously difficult to model: flame extinction and reignition. For this purpose, two types of temporal jets are considered, and direct-numerical-simulation results are compared qualitatively with those from large-eddy simulations. © 2017 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
261 a6507359986 Shamsabadi A. p65 True Journal 48 Validated Lateral Seismic Force-Displacement Backbone Curves for High-Speed Rail Bridge Abutments California's high-speed rail (HSR) system is slated to traverse nearly the entire length of the state, and thus it will be exposed to seismic risks from almost every known major tectonic fault there. The present study deals with the seismic responses of bridge-abutment transition backfills (BATBs), which are essential components of HSR bridges. BATBs provide a gradual variation of vertical stiffness between the bridge deck and nominal engineered backfill, enabling smooth operations for trains traveling at high speeds. All prior investigations focused on this vertical stiffness in order to better characterize the localized vertical differential movements around BATBs under periodic high axial loads from train sets. Lateral behavior of BATBs, which would be important under seismic loads, has not previously been investigated. The present study offers a parametric nonlinear lateral force-displacement backbone curve for BATBs that is verified against three-dimensional finite-element models and validated against data from large-scale tests conducted at Brigham Young University. The parametric curve takes backwall height as well as abutment skew angle into account. © 2020 American Society of Civil Engineers.
262 a57214365851 Schwicht D.E.W. p65 False Journal 48 Validated Lateral Seismic Force-Displacement Backbone Curves for High-Speed Rail Bridge Abutments California's high-speed rail (HSR) system is slated to traverse nearly the entire length of the state, and thus it will be exposed to seismic risks from almost every known major tectonic fault there. The present study deals with the seismic responses of bridge-abutment transition backfills (BATBs), which are essential components of HSR bridges. BATBs provide a gradual variation of vertical stiffness between the bridge deck and nominal engineered backfill, enabling smooth operations for trains traveling at high speeds. All prior investigations focused on this vertical stiffness in order to better characterize the localized vertical differential movements around BATBs under periodic high axial loads from train sets. Lateral behavior of BATBs, which would be important under seismic loads, has not previously been investigated. The present study offers a parametric nonlinear lateral force-displacement backbone curve for BATBs that is verified against three-dimensional finite-element models and validated against data from large-scale tests conducted at Brigham Young University. The parametric curve takes backwall height as well as abutment skew angle into account. © 2020 American Society of Civil Engineers.
263 a57212088299 Dasmeh A. p65 False Journal 48 Validated Lateral Seismic Force-Displacement Backbone Curves for High-Speed Rail Bridge Abutments California's high-speed rail (HSR) system is slated to traverse nearly the entire length of the state, and thus it will be exposed to seismic risks from almost every known major tectonic fault there. The present study deals with the seismic responses of bridge-abutment transition backfills (BATBs), which are essential components of HSR bridges. BATBs provide a gradual variation of vertical stiffness between the bridge deck and nominal engineered backfill, enabling smooth operations for trains traveling at high speeds. All prior investigations focused on this vertical stiffness in order to better characterize the localized vertical differential movements around BATBs under periodic high axial loads from train sets. Lateral behavior of BATBs, which would be important under seismic loads, has not previously been investigated. The present study offers a parametric nonlinear lateral force-displacement backbone curve for BATBs that is verified against three-dimensional finite-element models and validated against data from large-scale tests conducted at Brigham Young University. The parametric curve takes backwall height as well as abutment skew angle into account. © 2020 American Society of Civil Engineers.
264 a7003663333 Rollins K.M. p65 False Journal 48 Validated Lateral Seismic Force-Displacement Backbone Curves for High-Speed Rail Bridge Abutments California's high-speed rail (HSR) system is slated to traverse nearly the entire length of the state, and thus it will be exposed to seismic risks from almost every known major tectonic fault there. The present study deals with the seismic responses of bridge-abutment transition backfills (BATBs), which are essential components of HSR bridges. BATBs provide a gradual variation of vertical stiffness between the bridge deck and nominal engineered backfill, enabling smooth operations for trains traveling at high speeds. All prior investigations focused on this vertical stiffness in order to better characterize the localized vertical differential movements around BATBs under periodic high axial loads from train sets. Lateral behavior of BATBs, which would be important under seismic loads, has not previously been investigated. The present study offers a parametric nonlinear lateral force-displacement backbone curve for BATBs that is verified against three-dimensional finite-element models and validated against data from large-scale tests conducted at Brigham Young University. The parametric curve takes backwall height as well as abutment skew angle into account. © 2020 American Society of Civil Engineers.
264 a7003663333 Rollins K.M. p349 True Conference 121 Passive Force-Deflection Curves for Controlled Low-Strength Material (CLSM) and Lightweight Cellular Concrete (LCC) Contractors are increasingly requesting to use flowable fill (CLSM) or lightweight cellular concrete (LCC) to replace compacted granular backfill at bridge abutments because they can be placed more rapidly. In addition, LCC reduces the settlement of the underlying soils which is attractive to engineers. To evaluate the passive force-deflection curves for these materials, large-scale lab tests were performed with LCC and CLSM backfills in addition to a granular backfill for comparison. The response of the LCC was similar to that of the granular backfill with somewhat higher peak force developing at about 2.5% of the wall height. Although the stiffness was about twice as high as the granular backfill, the post-peak reduction was less than that for the granular fill. In contrast, the CLSM had a stiffness about 10 times higher than the granular fill and reached the peak value at a deflection equal to 1% of the wall height. The CLSM experienced a rapid decease in strength of about 60% after the peak strength was reached. The ductility of the LCC makes it a more suitable material for seismic loading with higher displacement demands. © 2019 American Society of Civil Engineers.
264 a7003663333 Rollins K.M. p594 True Conference 237 Evaluation and optimization of dynamic cone penetration test (DPT) for assessment of liquefaction in gravelly soils The dynamic cone penetration test (DPT) developed in China has been correlated with liquefaction resistance in gravelly soils based on field performance data from the Mw7.9 Wenchuan, China earthquake. The DPT consists of a 74 mm diameter cone tip driven by a 120 kg hammer with a free fall height of 1 m. To expand the data base, DPT soundings were performed at the Pence Ranch and Larter Ranch sites where gravelly soil liquefied during the 1983 Mw6.9 Borah Peak earthquake. DPT testing was performed using an automatic hammer with the energy specified in the Chinese standard and with an SPT hammer. In general, comparisons suggest that standard energy corrections developed for the SPT can be used for the DPT. The DPT correctly predicted liquefaction and non-liquefaction at these two test sites. Liquefaction resistance from the DPT (30% probability) also correlated reasonably well with that from Becker penetration testing (BPT). Copyright © 2018 Association of State Dam Safety Officials, Inc. All Rights Reserved.
264 a7003663333 Rollins K.M. p609 False Conference 247 Lateral resistance of piles within corrugated metal sleeves Pile foundations supporting bridge abutments are often driven inside corrugated metal pipe sleeves (CMS) which extend through the approach fill to reduce downdrag or for construction expediency. The annular space between the pile and the sleeve is typically filled with uncompacted pea gravel. Designers often assume that the lateral resistance of the pile within the sleeve will be minimal; however, no test results are available to confirm this assumption. To investigate the lateral resistance of piles driven within CMS, a full-scale lateral load test was performed. The test pile configuration included a 32.4 cm (12.75 in.) pipe pile within a 60 cm (24 in.) CMS with uncompacted pea gravel filling the annular space. Results indicate that after small pile displacements, the lateral pile resistance was similar to that provided by an individual pipe pile and was even greater at larger displacements. As the pile displaced laterally, the gravel within the annular space became engaged and displaced the CMS into the compacted fill. Back-analyses indicate that the ultimate lateral pile resistance for this case can be approximated by treating the pipe-gravel-CMS as a composite pile having an EI equal to the pipe pile but with a diameter equal to the CMS. © ASCE.
264 a7003663333 Rollins K.M. p610 False Conference 248 Analysis of post-liquefaction axial capacities of driven pile and drilled shaft foundations The results presented in this paper were obtained from a large testing program that was conducted to evaluate the post-liquefaction axial load capacities of three drilled shaft and three driven pile foundations constructed at the Turrell Arkansas testing site (TATS), located within the New Madrid Seismic Zone. An increase of side and toe resistances, significant ground and driven piles and drilled shafts top settlements were observed following blasting. This increase and settlements were attributed to the increase of effective stress as the excess porewater pressure dissipated. The liquefaction-induced dragloads that developed, at the neutral plane ranged from 200 to 650 kN. The load and settlement distribution curves for each installed foundation during the application of load to the top of each foundation and after blasting are also discussed. The induced dragloads represented more than 5 and 10% of the total resistance of the drilled shaft and driven pile foundations, respectively. © ASCE.
264 a7003663333 Rollins K.M. p611 False Conference 249 Gravelly Soil Liquefaction after the 2016 Ecuador Earthquake The Mw 7.8 Muisne-Pedernales, Ecuador, earthquake on April 16, 2016, produced significant damage through the northwest coast of Ecuador. Important state infrastructure was seriously affected, including one of the major seaports in the country, the Port of Manta, located in the city that bears its name. This paper focuses on the geotechnical exploration, site characterization, and analyses performed for the marginal wharf's embankment of the port, where clear evidence of liquefaction was observed. Laboratory results showed that the embankment was composed of gravelly sand and sandy gravels, which limited the applicability of common exploration techniques, such as SPT and CPTu tests. Subsequently, liquefaction triggering evaluations were performed based on Vs and the Chinese dynamic penetration test (DPT), which can account for the large gravel content in the soils. The results of this evaluation are presented and compared with field observations showing that these methods correctly identified the potential for liquefaction in the embankment. © 2018 American Society of Civil Engineers.
264 a7003663333 Rollins K.M. p612 True Conference 250 Evaluation of Dynamic Cone Penetration Test for Liquefaction Assessment of Gravels from Case Histories in Idaho The dynamic cone penetration test (DPT) developed in China has been correlated with liquefaction resistance in gravelly soils based on field performance data from the Mw7.9 Wenchuan earthquake. The DPT consists of a 74 mm diameter cone tip driven by a 120 kg hammer with a free fall height of 100 cm. To expand the data base, DPT soundings were performed at the Pence Ranch and Larter Ranch sites where gravelly soil liquefied during the 1983 Mw6.9 Borah Peak earthquake. DPT testing was performed using an automatic hammer with the energy specified in the Chinese standard and with an SPT hammer. Comparisons suggest that standard energy corrections developed for the SPT can be used for the DPT. In general, the DPT correctly predicted liquefaction and non-liquefaction at these two test sites. Liquefaction resistance from the DPT also correlated reasonably well with that from Becker penetration testing (BPT). © 2018 American Society of Civil Engineers.
264 a7003663333 Rollins K.M. p632 False Conference 267 Blast-Induced Liquefaction Results at the Silty-Sand Site of Mirabello, Emilia Romagna Region, Italy Recent experiences (e.g. New Zealand and United States) show that blast tests can cause liquefaction, inducing undrained cyclic loading, generating excess pore water pressure, and consequently producing real deformations. This paper introduces the results obtained from a research project on blast induced liquefaction, performed at a trial site located in Mirabello (near Ferrara, Italy), a little village strongly affected by liquefaction during the 2012 Emilia-Romagna earthquake. The liquefiable soils in this area contained significantly more fines than in previous blast tests. In particular, the objectives of the experiment were: (i) to evaluate liquefaction induced settlement of Apennine silts and sands, and Po River sands; (ii) to determine downdrag forces on pile foundations; (iii) to measure change in shear wave velocity/shear modulus with excess pore pressure; and (iv) to measure change in soil properties with time after liquefaction. This paper illustrates the results acquired before, during, and after the blast test using in-situ tests, pore pressure transducers, profilometers, topographical surveys, and a test micropile instrumented with strain gauges. © 2018 American Society of Civil Engineers.
264 a7003663333 Rollins K.M. p633 False Conference 268 Simplified Evaluation of the Seismic Failure of an Old Wharf during the 2014 Mw 8.2 Pisagua, Chile, Earthquake The seismic failure of an old quay wall, built in 1932, located in the Port of Iquique during the Mw 8.2 April 1, 2014, Pisagua, Chile, earthquake is studied. A geotechnical exploration, including boreholes, CPT soundings, and surface-based geophysical techniques, was performed to characterize the materials forming the wharf. The data and field observations are then analyzed and used to develop a geotechnical model of two cross-sections modeled in Plaxis2D, to conclude which is the most likely failure mechanism under a dynamic analysis. The results are compared against the deformations measured in a number cross sections of the wharf, suggesting that the failure can be explained by a combined effect of the dynamic increase in lateral earth pressures and the base rotation of the confining walls due to the lack of proper compaction of the rockfill prism below the confining walls. © 2018 American Society of Civil Engineers.
264 a7003663333 Rollins K.M. p654 True Conference 284 Lateral Resistance of Abutment Piles Near Mechanically Stabilized Earth Walls Pile foundations for bridges must often resist lateral loads produced by earthquakes and thermal variation. Because of the lack of large scale tests, there is almost no guidance for engineers in assessing the lateral resistance of piles located close to these MSE walls. The objective of this study was to assess lateral pile resistance as a function of distance from the wall face and predict force induced in the reinforcements. Full-scale lateral load tests were conducted on 24 piles located at 2, 3, 4, and 5 pile diameters behind 4.6 and 6-m high MSE walls. P-multipliers were developed to account for the decrease in lateral soil resistance. Little reduction occurred for piles located more than about 4 pile diameters from the wall. Measured tensile forces in the MSE reinforcements increased as the load on the pile increased and decreased rapidly with transverse distance from the direction of loading. Multiple linear regression equations were developed to predict maximum tensile force induced in reinforcing elements by lateral loading. © 2018 American Society of Civil Engineers (ASCE).All Rights Reserved.
264 a7003663333 Rollins K.M. p739 False Journal 356 Analytical fragility curves for non-skewed highway bridges in Chile Recent earthquakes in Chile and worldwide have caused significant economic losses due to the damage on the road bridge network. To conduct seismic risk assessment studies and to improve resilience of bridges, seismic vulnerability studies are required. The main objective of this study is to construct fragility curves of typical non-skewed highway bridges in Chile. The fragility curves are obtained from an incremental dynamic analysis of a two-dimensional model of the bent cap of a two-span simply supported underpass. As most bridges are constructed with seismic tie-down bars, their constitutive behavior was obtained experimentally. A total of five seismic bar specimens were tested to characterize their cyclic behavior in bridges with and without transverse diaphragms. The incremental dynamic analysis was performed with the two horizontal components of seven seismic records obtained from the Mw 8.8, 2010 Chile earthquake. Additionally, a parametric study is conducted to assess the seismic behavior of bridges with different configurations of seismic bars, with lateral stoppers, and with varying length of the transverse seat width. Results from this study reveal that seismic bars have a limited contribution to the seismic performance of the studied bridge, especially when lateral stoppers are incorporated. Additionally, the transverse seat width is found to be critical to reduce the collapse probability of the superstructure. The provided fragility curves may be used for seismic risk assessment and to evaluate possible improvements in seismic bridge design codes. © 2017 Elsevier Ltd
264 a7003663333 Rollins K.M. p843 False Conference 369 Passive force-deflection behavior of geosynthetic-reinforced soil backfill based on large-scale tests A correct understanding of passive force-deflection response is important for lateral load evaluations of bridges during extreme events such as earthquakes and during in-service conditions resulting from thermal expansion and contraction of the superstructure. The goal of this study was to better understand this behavior for abutments backfilled with both gravel and geosynthetic reinforced soil (GRS). Large-scale testing was performed with non-skewed and 30° skewed abutment configurations. Two tests were performed at each skew angle, one with gravel backfill and one with GRS backfill. The test abutment backwall was 3.35 m wide, non-skewed, and 1.68 m high and loaded laterally into the backfill. Both backfills exhibited greater passive resistance than sand backfills owing to increased internal friction angle and unit weight. Skew angle reduced the passive force in both cases by about 40%. The GRS backfills had reduced initial stiffness and only reached 79% to 87% of the passive force developed by the unreinforced gravel backfill. This reduction was considered to be a result of reduced interface friction at the geotextile-backwall interface due to wrapping. Reduced stiffness may be favorable for abutment configurations because it allows thermal movement without developing excessive induced stresses in the bridge superstructure. © ASCE.
264 a7003663333 Rollins K.M. p869 True Conference 390 Geofoam inclusions for reducing passive force on bridge abutments based on large-scale tests To decrease lateral earth pressures on structures, a zone of compressible material or an "inclusion" can be used as a barrier to decrease lateral earth pressures on structures. The compressible material is typically expanded polystyrene or geofoam. Little guidance is available on the development of passive force with an inclusion. To explore this issue, large-scale passive force tests were conducted with and without a geofoam inclusion acting as a barrier between the backfill soil and a simulated bridge abutment. The presence of the geofoam inclusion reduced the passive force by 70% relative to the sand backfill alone. Although the measured force and failure geometry appeared to conform to a log-spiral mechanism when only sand backfill was used, the geofoam inclusion transforms the failure geometry to a Rankine failure mechanism. This suggests that the geofoam acted to reduce the interface friction between the wall and the backfill sand thereby reducing the passive resistance. © ASCE.
265 a6602889035 Taciroglu E. p65 False Journal 48 Validated Lateral Seismic Force-Displacement Backbone Curves for High-Speed Rail Bridge Abutments California's high-speed rail (HSR) system is slated to traverse nearly the entire length of the state, and thus it will be exposed to seismic risks from almost every known major tectonic fault there. The present study deals with the seismic responses of bridge-abutment transition backfills (BATBs), which are essential components of HSR bridges. BATBs provide a gradual variation of vertical stiffness between the bridge deck and nominal engineered backfill, enabling smooth operations for trains traveling at high speeds. All prior investigations focused on this vertical stiffness in order to better characterize the localized vertical differential movements around BATBs under periodic high axial loads from train sets. Lateral behavior of BATBs, which would be important under seismic loads, has not previously been investigated. The present study offers a parametric nonlinear lateral force-displacement backbone curve for BATBs that is verified against three-dimensional finite-element models and validated against data from large-scale tests conducted at Brigham Young University. The parametric curve takes backwall height as well as abutment skew angle into account. © 2020 American Society of Civil Engineers.
266 a57216181629 Manandhar K. p66 True Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
267 a36245410800 Ren Y. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
268 a57191110417 Stasak D. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
269 a56622088300 Hou H. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
270 a57195921912 Kirsch D. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
271 a57215904613 Sarker S. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
272 a7402756644 Mehta A. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
273 a57217317667 Sardar S. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
274 a57195591421 Xiao M. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
275 a57217789464 Weaver J.L. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
276 a57216183270 León C. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
277 a57207901363 Hart G. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
277 a57207901363 Hart G. p77 False Journal 57 Generalized regular k-point grid generation on the fly In the DFT community, it is common practice to use regular k-point grids (Monkhorst-Pack, MP) for Brillioun zone integration. Recently Wisesa et al. (2016) and Morgan et al. (2018) demonstrated that generalized regular (GR) grids offer an advantage over traditional MP grids. The difference is simple but effective. At the same k-point density, GR grids have greater symmetry and 60% fewer irreducible k-points. GR grids have not been widely adopted because one must search through a large number of candidate grids; in many cases, a brute force search could take hours. This work describes an algorithm that can quickly search over GR grids for those that have the most uniform distribution of points and the best symmetry reduction. The grids are ∼60% more efficient, on average, than MP grids and can now be generated on the fly in seconds. © 2019 Elsevier B.V.
277 a57207901363 Hart G. p143 False Journal 100 Machine-learned multi-system surrogate models for materials prediction Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys (AgCu, AlFe, AlMg, AlNi, AlTi, CoNi, CuFe, CuNi, FeV, and NbNi) with 10 different species and all possible fcc, bcc, and hcp structures up to eight atoms in the unit cell, 15,950 structures in total. We find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys is <1 meV/atom. Several state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of <2.5% for all systems. © 2019, The Author(s).
277 a57207901363 Hart G. p244 False Journal 159 The AFLOW Library of Crystallographic Prototypes: Part 2 Materials discovery via high-throughput methods relies on the availability of structural prototypes, which are generally decorated with varying combinations of elements to produce potential new materials. To facilitate the automatic generation of these materials, we developed The AFLOW Library of Crystallographic Prototypes — a collection of crystal prototypes that can be rapidly decorated using the AFLOW software. Part 2 of this work introduces an additional 302 crystal structure prototypes, including at least one from each of the 138 space groups not included in Part 1. Combined with Part 1, the entire library consists of 590 unique crystallographic prototypes covering all 230 space groups. We also present discussions of enantiomorphic space groups, Wigner-Seitz cells, the two-dimensional plane groups, and the various different space group notations used throughout crystallography. All structures — from both Part 1 and Part 2 — are listed in the web version of the library available at http://www.aflow.org/CrystalDatabase. © 2018 Elsevier B.V.
277 a57207901363 Hart G. p366 False Journal 204 Accelerating high-throughput searches for new alloys with active learning of interatomic potentials We propose an approach to materials prediction that uses a machine-learning interatomic potential to approximate quantum-mechanical energies and an active learning algorithm for the automatic selection of an optimal training dataset. Our approach significantly reduces the amount of density functional theory (DFT) calculations needed, resorting to DFT only to produce the training data, while structural optimization is performed using the interatomic potentials. Our approach is not limited to one (or a small number of) lattice types (as is the case for cluster expansion, for example) and can predict structures with lattice types not present in the training dataset. We demonstrate the effectiveness of our algorithm by predicting the convex hull for the following three systems: Cu-Pd, Co-Nb-V, and Al-Ni-Ti. Our method is three to four orders of magnitude faster than conventional high-throughput DFT calculations and explores a wider range of materials space. In all three systems, we found unreported stable structures compared to the AFLOW database. Because our method is much cheaper and explores much more of materials space than high-throughput methods or cluster expansion, and because our interatomic potentials have a systematically improvable accuracy compared to empirical potentials such as embedded atom model, it will have a significant impact in the discovery of new alloy phases, particularly those with three or more components. © 2018
277 a57207901363 Hart G. p440 False Journal 245 Efficiency of Generalized Regular k-point grids Most DFT practitioners use regular grids (Monkhorst-Pack, MP) for integrations in the Brillouin zone. Although regular grids are the natural choice and easy to generate, more general grids whose generating vectors are not merely integer divisions of the reciprocal lattice vectors, are usually more efficient (Wisesa et al., 2016). We demonstrate the efficiency of generalized regular (GR) grids compared to Monkhorst-Pack (MP) and simultaneously commensurate (SC) grids. In the case of metals, for total energy accuracies of one meV/atom, GR grids are 60% faster on average than MP grids and 20% faster than SC grids. GR grids also have greater freedom in choosing the k-point density, enabling the practitioner to achieve a target accuracy with the minimum computational cost. © 2018 Elsevier B.V.
277 a57207901363 Hart G. p668 False Journal 322 Discovering the building blocks of atomic systems using machine learning: Application to grain boundaries Machine learning has proven to be a valuable tool to approximate functions in high-dimensional spaces. Unfortunately, analysis of these models to extract the relevant physics is never as easy as applying machine learning to a large data set in the first place. Here we present a description of atomic systems that generates machine learning representations with a direct path to physical interpretation. As an example, we demonstrate its usefulness as a universal descriptor of grain boundary systems. Grain boundaries in crystalline materials are a quintessential example of a complex, high-dimensional system with broad impact on many physical properties including strength, ductility, corrosion resistance, crack resistance, and conductivity. In addition to modeling such properties, the method also provides insight into the physical "building blocks" that influence them. This opens the way to discover the underlying physics behind behaviors by understanding which building blocks map to particular properties. Once the structures are understood, they can then be optimized for desirable behaviors. © 2017 The Author(s).
277 a57207901363 Hart G. p709 False Journal 349 Generating derivative superstructures for systems with high configurational freedom Modeling alloys requires the exploration of all possible configurations of atoms. Additionally, modeling the thermal properties of materials requires knowledge of the possible ways of displacing the atoms. One solution to finding all symmetrically unique configurations and displacements is to generate the complete list of possible configurations and remove those that are symmetrically equivalent. This approach, however, suffers from a combinatorial explosion when the supercell size is large, when there are more than two atom types, or when there are many displaced atoms. This problem persists even when there are only a relatively small number of unique arrangements that survive the elimination process. Here, we extend an existing algorithm to include the extra configurational degrees of freedom from the inclusion of displacement directions. The algorithm uses group theory and a tree-like data structure to eliminate large classes of configurations, avoiding the typical combinatoric explosion. With this approach we can now enumerate previously inaccessible cases, including atomic displacements. © 2017 Elsevier B.V.
277 a57207901363 Hart G. p714 False Journal 349 The AFLOW Library of Crystallographic Prototypes: Part 1 An easily available resource of common crystal structures is essential for researchers, teachers, and students. For many years this was provided by the U.S. Naval Research Laboratory's Crystal Lattice Structures web page, which contained nearly 300 crystal structures, including a majority of those which were given Strukturbericht designations. This article presents the updated version of the database, now including 288 standardized structures in 92 space groups. Similar to what was available on the web page before, we present a complete description of each structure, including the formulas for the primitive vectors, all of the basis vectors, and the AFLOW commands to generate the standardized cells. We also present a brief discussion of crystal systems, space groups, primitive and conventional lattices, Wyckoff positions, Pearson symbols and Strukturbericht designations. The web version of this database is located at http://aflow.org/CrystalDatabase. © 2017 Elsevier B.V.
278 a34873697600 Sunaoshi T. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
279 a56767836200 Lemmon J.P. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
280 a7102900497 Takeuchi I. p66 False Journal 49 High-Throughput Exploration of Lithium-Alloy Protection Layers for High-Performance Lithium-Metal Batteries To realize high specific capacity Li-metal batteries, a protection layer for the Li-metal anode is needed. We are carrying out combinatorial screening of Li-alloy thin films as the protection layer which can undergo significant lithiation with minimum change in volume and crystal structure. Here, we have fabricated lithium-free binary alloy thin film composition spreads of Co1-xSnx on Cu layers on Si substrates. The crystallinity of the thin films was tuned by varying the deposition temperature followed by electrochemical lithiation to form Li-alloy ternary thin films. Synchrotron diffraction is used as the main tool to investigate the crystallinity of the films before and after lithiation. Co3Sn2 alloy thin films are found to exhibit significant lithium uptake capacity while maintaining its structural integrity, and are thus a good candidate of the Li-metal protection layer. © 2020 American Chemical Society.
281 a57196422740 Howell R.G. p67 True Journal 50 Measuring height characteristics of sagebrush (Artemisia sp.) using imagery derived from small unmanned aerial systems (SUAS) In situ measurements of sagebrush have traditionally been expensive and time consuming. Currently, improvements in small Unmanned Aerial Systems (sUAS) technology can be used to quantify sagebrush morphology and community structure with high resolution imagery on western rangelands, especially in sensitive habitat of the Greater sage-grouse (Centrocercus urophasianus). The emergence of photogrammetry algorithms to generate 3D point clouds from true color imagery can potentially increase the efficiency and accuracy of measuring shrub height in sage-grouse habitat. Our objective was to determine optimal parameters for measuring sagebrush height including flight altitude, single-vs. double-pass, and continuous vs. pause features. We acquired imagery using a DJI Mavic Pro 2 multi-rotor Unmanned Aerial Vehicle (UAV) equipped with an RGB camera, flown at 30.5, 45, 75, and 120 m and implementing single-pass and double-pass methods, using continuous flight and paused flight for each photo method. We generated a Digital Surface Model (DSM) from which we derived plant height, and then performed an accuracy assessment using on the ground measurements taken at the time of flight. We found high correlation between field measured heights and estimated heights, with a mean difference of approximately 10 cm (SE = 0.4 cm) and little variability in accuracy between flights with different heights and other parameters after statistical correction using linear regression. We conclude that higher altitude flights using a single-pass method are optimal to measure sagebrush height due to lower requirements in data storage and processing time. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
282 a7403518015 Jensen R.R. p67 False Journal 50 Measuring height characteristics of sagebrush (Artemisia sp.) using imagery derived from small unmanned aerial systems (SUAS) In situ measurements of sagebrush have traditionally been expensive and time consuming. Currently, improvements in small Unmanned Aerial Systems (sUAS) technology can be used to quantify sagebrush morphology and community structure with high resolution imagery on western rangelands, especially in sensitive habitat of the Greater sage-grouse (Centrocercus urophasianus). The emergence of photogrammetry algorithms to generate 3D point clouds from true color imagery can potentially increase the efficiency and accuracy of measuring shrub height in sage-grouse habitat. Our objective was to determine optimal parameters for measuring sagebrush height including flight altitude, single-vs. double-pass, and continuous vs. pause features. We acquired imagery using a DJI Mavic Pro 2 multi-rotor Unmanned Aerial Vehicle (UAV) equipped with an RGB camera, flown at 30.5, 45, 75, and 120 m and implementing single-pass and double-pass methods, using continuous flight and paused flight for each photo method. We generated a Digital Surface Model (DSM) from which we derived plant height, and then performed an accuracy assessment using on the ground measurements taken at the time of flight. We found high correlation between field measured heights and estimated heights, with a mean difference of approximately 10 cm (SE = 0.4 cm) and little variability in accuracy between flights with different heights and other parameters after statistical correction using linear regression. We conclude that higher altitude flights using a single-pass method are optimal to measure sagebrush height due to lower requirements in data storage and processing time. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
283 a36852156000 Petersen S.L. p67 False Journal 50 Measuring height characteristics of sagebrush (Artemisia sp.) using imagery derived from small unmanned aerial systems (SUAS) In situ measurements of sagebrush have traditionally been expensive and time consuming. Currently, improvements in small Unmanned Aerial Systems (sUAS) technology can be used to quantify sagebrush morphology and community structure with high resolution imagery on western rangelands, especially in sensitive habitat of the Greater sage-grouse (Centrocercus urophasianus). The emergence of photogrammetry algorithms to generate 3D point clouds from true color imagery can potentially increase the efficiency and accuracy of measuring shrub height in sage-grouse habitat. Our objective was to determine optimal parameters for measuring sagebrush height including flight altitude, single-vs. double-pass, and continuous vs. pause features. We acquired imagery using a DJI Mavic Pro 2 multi-rotor Unmanned Aerial Vehicle (UAV) equipped with an RGB camera, flown at 30.5, 45, 75, and 120 m and implementing single-pass and double-pass methods, using continuous flight and paused flight for each photo method. We generated a Digital Surface Model (DSM) from which we derived plant height, and then performed an accuracy assessment using on the ground measurements taken at the time of flight. We found high correlation between field measured heights and estimated heights, with a mean difference of approximately 10 cm (SE = 0.4 cm) and little variability in accuracy between flights with different heights and other parameters after statistical correction using linear regression. We conclude that higher altitude flights using a single-pass method are optimal to measure sagebrush height due to lower requirements in data storage and processing time. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
284 a16245238300 Larsen R.T. p67 False Journal 50 Measuring height characteristics of sagebrush (Artemisia sp.) using imagery derived from small unmanned aerial systems (SUAS) In situ measurements of sagebrush have traditionally been expensive and time consuming. Currently, improvements in small Unmanned Aerial Systems (sUAS) technology can be used to quantify sagebrush morphology and community structure with high resolution imagery on western rangelands, especially in sensitive habitat of the Greater sage-grouse (Centrocercus urophasianus). The emergence of photogrammetry algorithms to generate 3D point clouds from true color imagery can potentially increase the efficiency and accuracy of measuring shrub height in sage-grouse habitat. Our objective was to determine optimal parameters for measuring sagebrush height including flight altitude, single-vs. double-pass, and continuous vs. pause features. We acquired imagery using a DJI Mavic Pro 2 multi-rotor Unmanned Aerial Vehicle (UAV) equipped with an RGB camera, flown at 30.5, 45, 75, and 120 m and implementing single-pass and double-pass methods, using continuous flight and paused flight for each photo method. We generated a Digital Surface Model (DSM) from which we derived plant height, and then performed an accuracy assessment using on the ground measurements taken at the time of flight. We found high correlation between field measured heights and estimated heights, with a mean difference of approximately 10 cm (SE = 0.4 cm) and little variability in accuracy between flights with different heights and other parameters after statistical correction using linear regression. We conclude that higher altitude flights using a single-pass method are optimal to measure sagebrush height due to lower requirements in data storage and processing time. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
285 a57202776341 Bahari M. p68 True Journal 51 Oxidation efficiency of glucose using viologen mediators for glucose fuel cell applications with non-precious anodes Glucose is a potential source of energy for fuel cell applications. However, its complete oxidation has been a challenge. Dimethyl viologen, as an electron mediator, has been shown to promote high levels of glucose oxidation under aerobic conditions. Nevertheless, the efficiency of viologen-mediated glucose oxidation has been low in electrochemical experiments. In this study, viologen-mediated oxidation of glucose was investigated under anaerobic electrochemical conditions to understand the factors that impact the oxidation efficiency. Of particular interest was the improvement of electrochemical oxidation for glucose fuel cell applications. An experimental cell was developed to electrochemically reoxidize the mediator as it was homogeneously reduced by glucose under anaerobic conditions. In contrast, the mediator was reoxidized by direct reaction with oxygen under aerobic conditions. The aerobic oxidation efficiency was 75%, three times larger than the maximum efficiency in the electrochemical cell. 13C-NMR results show that the main product formed under aerobic conditions was formic acid, whereas glycolic acid was the principal product formed in the electrochemical cell. Carbonate was only formed under aerobic conditions. Therefore, the use of oxygen to reoxidize the mediator also directly influenced the glucose oxidation pathway. In the electrochemical cell, the oxidation efficiency depended on the electrochemical reaction rate of the mediator and was higher at faster rates. The efficiency also depended on the initial molar ratio of the mediator to glucose. The maximum oxidation efficiency of glucose in the electrochemical cell was approximately 22%, which is about three times larger than the maximum efficiency for precious-metal-based anodes. © 2019
286 a57212879455 Malmberg M.A. p68 False Journal 51 Oxidation efficiency of glucose using viologen mediators for glucose fuel cell applications with non-precious anodes Glucose is a potential source of energy for fuel cell applications. However, its complete oxidation has been a challenge. Dimethyl viologen, as an electron mediator, has been shown to promote high levels of glucose oxidation under aerobic conditions. Nevertheless, the efficiency of viologen-mediated glucose oxidation has been low in electrochemical experiments. In this study, viologen-mediated oxidation of glucose was investigated under anaerobic electrochemical conditions to understand the factors that impact the oxidation efficiency. Of particular interest was the improvement of electrochemical oxidation for glucose fuel cell applications. An experimental cell was developed to electrochemically reoxidize the mediator as it was homogeneously reduced by glucose under anaerobic conditions. In contrast, the mediator was reoxidized by direct reaction with oxygen under aerobic conditions. The aerobic oxidation efficiency was 75%, three times larger than the maximum efficiency in the electrochemical cell. 13C-NMR results show that the main product formed under aerobic conditions was formic acid, whereas glycolic acid was the principal product formed in the electrochemical cell. Carbonate was only formed under aerobic conditions. Therefore, the use of oxygen to reoxidize the mediator also directly influenced the glucose oxidation pathway. In the electrochemical cell, the oxidation efficiency depended on the electrochemical reaction rate of the mediator and was higher at faster rates. The efficiency also depended on the initial molar ratio of the mediator to glucose. The maximum oxidation efficiency of glucose in the electrochemical cell was approximately 22%, which is about three times larger than the maximum efficiency for precious-metal-based anodes. © 2019
287 a57212877661 Brown D.M. p68 False Journal 51 Oxidation efficiency of glucose using viologen mediators for glucose fuel cell applications with non-precious anodes Glucose is a potential source of energy for fuel cell applications. However, its complete oxidation has been a challenge. Dimethyl viologen, as an electron mediator, has been shown to promote high levels of glucose oxidation under aerobic conditions. Nevertheless, the efficiency of viologen-mediated glucose oxidation has been low in electrochemical experiments. In this study, viologen-mediated oxidation of glucose was investigated under anaerobic electrochemical conditions to understand the factors that impact the oxidation efficiency. Of particular interest was the improvement of electrochemical oxidation for glucose fuel cell applications. An experimental cell was developed to electrochemically reoxidize the mediator as it was homogeneously reduced by glucose under anaerobic conditions. In contrast, the mediator was reoxidized by direct reaction with oxygen under aerobic conditions. The aerobic oxidation efficiency was 75%, three times larger than the maximum efficiency in the electrochemical cell. 13C-NMR results show that the main product formed under aerobic conditions was formic acid, whereas glycolic acid was the principal product formed in the electrochemical cell. Carbonate was only formed under aerobic conditions. Therefore, the use of oxygen to reoxidize the mediator also directly influenced the glucose oxidation pathway. In the electrochemical cell, the oxidation efficiency depended on the electrochemical reaction rate of the mediator and was higher at faster rates. The efficiency also depended on the initial molar ratio of the mediator to glucose. The maximum oxidation efficiency of glucose in the electrochemical cell was approximately 22%, which is about three times larger than the maximum efficiency for precious-metal-based anodes. © 2019
288 a57212877401 Hadi Nazari S. p68 False Journal 51 Oxidation efficiency of glucose using viologen mediators for glucose fuel cell applications with non-precious anodes Glucose is a potential source of energy for fuel cell applications. However, its complete oxidation has been a challenge. Dimethyl viologen, as an electron mediator, has been shown to promote high levels of glucose oxidation under aerobic conditions. Nevertheless, the efficiency of viologen-mediated glucose oxidation has been low in electrochemical experiments. In this study, viologen-mediated oxidation of glucose was investigated under anaerobic electrochemical conditions to understand the factors that impact the oxidation efficiency. Of particular interest was the improvement of electrochemical oxidation for glucose fuel cell applications. An experimental cell was developed to electrochemically reoxidize the mediator as it was homogeneously reduced by glucose under anaerobic conditions. In contrast, the mediator was reoxidized by direct reaction with oxygen under aerobic conditions. The aerobic oxidation efficiency was 75%, three times larger than the maximum efficiency in the electrochemical cell. 13C-NMR results show that the main product formed under aerobic conditions was formic acid, whereas glycolic acid was the principal product formed in the electrochemical cell. Carbonate was only formed under aerobic conditions. Therefore, the use of oxygen to reoxidize the mediator also directly influenced the glucose oxidation pathway. In the electrochemical cell, the oxidation efficiency depended on the electrochemical reaction rate of the mediator and was higher at faster rates. The efficiency also depended on the initial molar ratio of the mediator to glucose. The maximum oxidation efficiency of glucose in the electrochemical cell was approximately 22%, which is about three times larger than the maximum efficiency for precious-metal-based anodes. © 2019
289 a35262249500 Lewis R.S. p68 False Journal 51 Oxidation efficiency of glucose using viologen mediators for glucose fuel cell applications with non-precious anodes Glucose is a potential source of energy for fuel cell applications. However, its complete oxidation has been a challenge. Dimethyl viologen, as an electron mediator, has been shown to promote high levels of glucose oxidation under aerobic conditions. Nevertheless, the efficiency of viologen-mediated glucose oxidation has been low in electrochemical experiments. In this study, viologen-mediated oxidation of glucose was investigated under anaerobic electrochemical conditions to understand the factors that impact the oxidation efficiency. Of particular interest was the improvement of electrochemical oxidation for glucose fuel cell applications. An experimental cell was developed to electrochemically reoxidize the mediator as it was homogeneously reduced by glucose under anaerobic conditions. In contrast, the mediator was reoxidized by direct reaction with oxygen under aerobic conditions. The aerobic oxidation efficiency was 75%, three times larger than the maximum efficiency in the electrochemical cell. 13C-NMR results show that the main product formed under aerobic conditions was formic acid, whereas glycolic acid was the principal product formed in the electrochemical cell. Carbonate was only formed under aerobic conditions. Therefore, the use of oxygen to reoxidize the mediator also directly influenced the glucose oxidation pathway. In the electrochemical cell, the oxidation efficiency depended on the electrochemical reaction rate of the mediator and was higher at faster rates. The efficiency also depended on the initial molar ratio of the mediator to glucose. The maximum oxidation efficiency of glucose in the electrochemical cell was approximately 22%, which is about three times larger than the maximum efficiency for precious-metal-based anodes. © 2019
289 a35262249500 Lewis R.S. p317 False Conference 97 Factors leading to sustainable social impact on the affected communities of engineering service learning projects University engineering programs across the USA engage in service learning projects. These projects involve student teams designing and implementing products or solutions for communities in need, often in developing nations. There has been much research done relating to pedagogy and the impact of these programs on student learning. However, less research has been done on measuring the impact of these programs on the affected communities. This paper examines factors that practitioners believe are related to successfully delivering a desirable and transferable solution to affected communities. The authors identified 46 distinct factors from the literature that implicitly or explicitly are suggested to contribute to successful project outcomes. Formed as postulates in this paper, these 46 factors have been separated into 5 categories to assist understanding and implementing these factors into service learning programs. Lastly, different methods of analyzing and measuring project success and impact are discussed. Future methods for proving the viability of the 46 postulates are discussed as well. Copyright © 2019 ASME.
289 a35262249500 Lewis R.S. p487 True Conference 179 Assessment of a global engineering outreach course [No abstract available]
289 a35262249500 Lewis R.S. p734 True Conference 315 Sustainable water filters in southern Peru [No abstract available]
289 a35262249500 Lewis R.S. p735 True Conference 316 Global humanitarian-based projects: A documentation strategy for strengthening project sustainability [No abstract available]
290 a7102405529 Watt G.D. p68 False Journal 51 Oxidation efficiency of glucose using viologen mediators for glucose fuel cell applications with non-precious anodes Glucose is a potential source of energy for fuel cell applications. However, its complete oxidation has been a challenge. Dimethyl viologen, as an electron mediator, has been shown to promote high levels of glucose oxidation under aerobic conditions. Nevertheless, the efficiency of viologen-mediated glucose oxidation has been low in electrochemical experiments. In this study, viologen-mediated oxidation of glucose was investigated under anaerobic electrochemical conditions to understand the factors that impact the oxidation efficiency. Of particular interest was the improvement of electrochemical oxidation for glucose fuel cell applications. An experimental cell was developed to electrochemically reoxidize the mediator as it was homogeneously reduced by glucose under anaerobic conditions. In contrast, the mediator was reoxidized by direct reaction with oxygen under aerobic conditions. The aerobic oxidation efficiency was 75%, three times larger than the maximum efficiency in the electrochemical cell. 13C-NMR results show that the main product formed under aerobic conditions was formic acid, whereas glycolic acid was the principal product formed in the electrochemical cell. Carbonate was only formed under aerobic conditions. Therefore, the use of oxygen to reoxidize the mediator also directly influenced the glucose oxidation pathway. In the electrochemical cell, the oxidation efficiency depended on the electrochemical reaction rate of the mediator and was higher at faster rates. The efficiency also depended on the initial molar ratio of the mediator to glucose. The maximum oxidation efficiency of glucose in the electrochemical cell was approximately 22%, which is about three times larger than the maximum efficiency for precious-metal-based anodes. © 2019
291 a57212107391 Petrie A. p69 True Conference 12 A 0.2-V 10-bit 5-kHz SAR ADC with Dynamic Bulk Biasing and Ultra-Low-Supply-Voltage Comparator This paper describes a 10-bit 5-kHz SAR ADC under an ultra-low-supply-voltage of 0.2 V for low-power applications. To tolerate the severe variations in the subthreshold regime, a novel dynamic bulk biasing circuit senses the NMOS/PMOS strength ratio in the background and applies feedback to recover the circuit functionality. A new comparator relaxes the stringent speed-noise trade-off under the 0.2-V supply. Employing ac-coupling, stacked input pairs, and voltage-boosted load capacitors, the comparator achieves more than threefold improvement in speed with little noise penalty. The measured ADC consumes 22 nW and exhibits an SNDR of 52.8 dB at Nyquist, yielding an FoM of 12.3 fJ/conv.-step. Measurements of multiple chips show the proposed dynamic bulk biasing successfully improves the yield by nearly twofold in the presence of supply variations. © 2020 IEEE.
291 a57212107391 Petrie A. p175 False Journal 119 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW, yielding an FoM of 37 fJ/conv.-step, the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2018 IEEE.
291 a57212107391 Petrie A. p177 False Conference 39 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW,yielding an FoM of 37 fJ/conv.-step,the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2019 IEEE.
292 a57216754583 Kinnison W. p69 False Conference 12 A 0.2-V 10-bit 5-kHz SAR ADC with Dynamic Bulk Biasing and Ultra-Low-Supply-Voltage Comparator This paper describes a 10-bit 5-kHz SAR ADC under an ultra-low-supply-voltage of 0.2 V for low-power applications. To tolerate the severe variations in the subthreshold regime, a novel dynamic bulk biasing circuit senses the NMOS/PMOS strength ratio in the background and applies feedback to recover the circuit functionality. A new comparator relaxes the stringent speed-noise trade-off under the 0.2-V supply. Employing ac-coupling, stacked input pairs, and voltage-boosted load capacitors, the comparator achieves more than threefold improvement in speed with little noise penalty. The measured ADC consumes 22 nW and exhibits an SNDR of 52.8 dB at Nyquist, yielding an FoM of 12.3 fJ/conv.-step. Measurements of multiple chips show the proposed dynamic bulk biasing successfully improves the yield by nearly twofold in the presence of supply variations. © 2020 IEEE.
293 a8342785400 Layton K. p69 False Conference 12 A 0.2-V 10-bit 5-kHz SAR ADC with Dynamic Bulk Biasing and Ultra-Low-Supply-Voltage Comparator This paper describes a 10-bit 5-kHz SAR ADC under an ultra-low-supply-voltage of 0.2 V for low-power applications. To tolerate the severe variations in the subthreshold regime, a novel dynamic bulk biasing circuit senses the NMOS/PMOS strength ratio in the background and applies feedback to recover the circuit functionality. A new comparator relaxes the stringent speed-noise trade-off under the 0.2-V supply. Employing ac-coupling, stacked input pairs, and voltage-boosted load capacitors, the comparator achieves more than threefold improvement in speed with little noise penalty. The measured ADC consumes 22 nW and exhibits an SNDR of 52.8 dB at Nyquist, yielding an FoM of 12.3 fJ/conv.-step. Measurements of multiple chips show the proposed dynamic bulk biasing successfully improves the yield by nearly twofold in the presence of supply variations. © 2020 IEEE.
293 a8342785400 Layton K. p277 False Journal 182 A 9-Bit 10-MHz 28-μW SAR ADC Using Tapered Bit Periods and a Partially Interdigitated DAC A successive-approximation-register (SAR) analogto- digital converter (ADC) incorporates "tapered bit periods" to reduce power consumption by minimizing the digital-to-analog converter (DAC) timing overhead. Utilizing a variable delay line and the standard SAR logic, the proposed technique reduces power by downsizing the DAC drivers and digital logic without decreasing the sampling rate. A detailed analysis derives, for the first time, a closed-form solution of the capacitive DAC settling time accounting for parasitics, and determines the time savings of the proposed design. In addition, this brief proposes a "partially interdigitated" DAC layout to reduce the bottom-plate parasitic capacitance to minimize the DAC power. A 9-bit prototype fabricated in 180-nm technology achieves a signal-to-noise-distortion ratio (SNDR) of 55.5 dB at a 10-MHz sampling rate while consuming 28 μW, yielding a figure-of-merit of 5.7 fJ/conversionstep, the lowest among published ADCs at similar speeds and resolutions. © 2004-2012 IEEE.
294 a57190228554 Taysom B.S. p70 True Journal 52 Controlling martensite and pearlite formation with cooling rate and temperature control in rotary friction welding A major limitation in industrial welding is the undesirable microstructures that form due to high peak temperatures and cooling rates. In particular, martensite and other brittle microstructures often form in steels during rotary friction welding (FW). In order to address this, cooling rate and temperature control is developed for FW. Limits of achievable FW cooling rates are primarily determined by thermal and geometric properties such as thermal diffusivity and length. A controller limits interface temperatures during a weld preheat, changing the thermal profile and slowing post-weld cooling. This method is demonstrated in 1045 steel. Cooling simulations, TTT diagrams, microhardness line scans, and scanning electron microscopy are used for analysis. Without temperature and cooling rate control, martensite readily forms after a weld. With temperature and cooling rate control, martensitic transformations are completely avoided and a pearlitic microstructure is developed. Temperature and cooling rate control is a viable tool in designing post-weld microstructures within achievable cooling rate limitations. © 2019
294 a57190228554 Taysom B.S. p83 True Journal 63 Adaptive relay autotuning under static and non-static disturbances with application to friction stir welding When a traditional relay feedback test is biased, asymmetry is induced, erroneous system identification occurs, and the test may stop oscillating. Adaptive methods which restore symmetry to the relay test are developed, and additional methods are presented to detect and recover from a non-oscillation condition. This is demonstrated both in simulation and in a process with significant transients and disturbances — friction stir welding (FSW). In testing, it is shown that the adaptive method is able to restore symmetry even in the presence of severe and changing disturbances, including after the weld plunge where temperature gradients change rapidly. These improvements enable system identification of systems such as FSW in a more robust and accurate manner. © 2019 ISA
294 a57190228554 Taysom B.S. p326 True Conference 106 Advances in Signal Processing for Friction Stir Welding Temperature Control Precise temperature control of FSW benefits from control and manipulated signals that are responsive and smooth. Accurate measurement of tool temperature and spindle speed feedback are important to temperature control, but often noise in these signals prevents optimal control. Two different methods are developed in this paper to improve signal quality. A series of Bezier curves are used to compensate signals which exhibit a periodic but arbitrarily-shaped offset. Least-squares fitting is used to obtain quality derivatives from discrete or noisy signals. The Bezier method is used to decrease the inaccurate temperature fluctuation measurements reported by telemetry collar error and adds no time delay or phase shift. The least-squares approach is used to estimate spindle speed and temperature derivatives and adds only minimal time delay while substantially reducing noise. © 2019, The Minerals, Metals & Materials Society.
294 a57190228554 Taysom B.S. p686 True Journal 332 A comparison of model predictive control and PID temperature control in friction stir welding Temperature control of friction stir welding (FSW) via model predictive control (MPC) is investigated in Al 7075-T7. Two MPC controllers are compared against two well-tuned PID controllers to obtain a direct comparison of MPC and current FSW controllers. One MPC controller uses a first-order plus dead-time (FOPDT) model derived from a simplified conduction-advection view of the stir zone. The other MPC controller uses the Hybrid Heat Source model that describes heat conduction in the plate and tool. At quasi steady-state conditions, all four controllers can easily hold temperature within 2 °C of the setpoint in the absence of large disturbances. Once the weld is past the initial traverse, the FOPDT controller is superior to the Hybrid Heat Source controller with regards to modeled-disturbance rejection and setpoint changes. The FOPDT controller is competitive with well-tuned PID controllers in this region of the weld. During the initial traverse, the Hybrid Heat Source controller and PID controller with regulator gains were able to control temperature within 5 °C of the setpoint, compared to a typical deviation of 20–30 °C when uncontrolled. During this period, the FOPDT controller and PID controller with servo gains could not maintain satisfactory temperature control. MPC is demonstrated to be a viable control method for FSW. Temperature control before reaching steady state for both MPC and PID is shown to be feasible, but more difficult than for steady state. Recommendations are given for when each controller might be preferred in various circumstances, based upon the results shown herein. © 2017 The Society of Manufacturing Engineers
295 a7102879142 Sorensen C.D. p70 False Journal 52 Controlling martensite and pearlite formation with cooling rate and temperature control in rotary friction welding A major limitation in industrial welding is the undesirable microstructures that form due to high peak temperatures and cooling rates. In particular, martensite and other brittle microstructures often form in steels during rotary friction welding (FW). In order to address this, cooling rate and temperature control is developed for FW. Limits of achievable FW cooling rates are primarily determined by thermal and geometric properties such as thermal diffusivity and length. A controller limits interface temperatures during a weld preheat, changing the thermal profile and slowing post-weld cooling. This method is demonstrated in 1045 steel. Cooling simulations, TTT diagrams, microhardness line scans, and scanning electron microscopy are used for analysis. Without temperature and cooling rate control, martensite readily forms after a weld. With temperature and cooling rate control, martensitic transformations are completely avoided and a pearlitic microstructure is developed. Temperature and cooling rate control is a viable tool in designing post-weld microstructures within achievable cooling rate limitations. © 2019
295 a7102879142 Sorensen C.D. p83 False Journal 63 Adaptive relay autotuning under static and non-static disturbances with application to friction stir welding When a traditional relay feedback test is biased, asymmetry is induced, erroneous system identification occurs, and the test may stop oscillating. Adaptive methods which restore symmetry to the relay test are developed, and additional methods are presented to detect and recover from a non-oscillation condition. This is demonstrated both in simulation and in a process with significant transients and disturbances — friction stir welding (FSW). In testing, it is shown that the adaptive method is able to restore symmetry even in the presence of severe and changing disturbances, including after the weld plunge where temperature gradients change rapidly. These improvements enable system identification of systems such as FSW in a more robust and accurate manner. © 2019 ISA
295 a7102879142 Sorensen C.D. p285 False Journal 186 Product development: Principles and tools for creating desirable and transferable designs Introduction This book explores the evolution of products from the beginning idea through mass-production. Rather than prescribing a one-size-fits-all process, the authors explain the theory behind product development and challenge readers to develop their own customized development process uniquely suited for their individual situation. In addition to theory, the book provides development case studies, exercises and self-evaluation criteria at the end of each chapter, and a product development reference that introduces a wide variety of design tools and methods. Class-tested for three consecutive years by hundreds of students in four different courses, the book is an ideal text for senior design classes in mechanical engineering and related disciplines as well as a reference for practicing engineers/product designers. Focuses on excellent design outcomes, rather than rote activities; Maximizes readers’ contextual understanding with real examples of student design and case studies; Reinforces readers’ grasp of theory and best-practices with exercises at the end of each chapter and self-evaluation criteria; Includes a comprehensive product development reference ordered alphabetically and cross-referenced by stage of development, design skills, and design objective; Adopts a concise and engaging writing style and attractive layout with many informative figures. © Springer Nature Switzerland AG 2020.
295 a7102879142 Sorensen C.D. p326 False Conference 106 Advances in Signal Processing for Friction Stir Welding Temperature Control Precise temperature control of FSW benefits from control and manipulated signals that are responsive and smooth. Accurate measurement of tool temperature and spindle speed feedback are important to temperature control, but often noise in these signals prevents optimal control. Two different methods are developed in this paper to improve signal quality. A series of Bezier curves are used to compensate signals which exhibit a periodic but arbitrarily-shaped offset. Least-squares fitting is used to obtain quality derivatives from discrete or noisy signals. The Bezier method is used to decrease the inaccurate temperature fluctuation measurements reported by telemetry collar error and adds no time delay or phase shift. The least-squares approach is used to estimate spindle speed and temperature derivatives and adds only minimal time delay while substantially reducing noise. © 2019, The Minerals, Metals & Materials Society.
295 a7102879142 Sorensen C.D. p353 False Conference 124 Do capstone students really understand the needs of the customer?: Observations on students’ blind spots left by early program curriculum Student capstone teams have varying degrees of success in meeting the expectations of their project sponsors. Keeping sponsors happy is important to these programs in order to ensure continued support from these industry representatives, so finding ways to improve project outcomes is critical. In order to find blind spots that students may have been left with after their first 6-7 weeks of instruction, we conducted structured interviews with students in capstone programs at Brigham Young University and the US Air Force Academy. These interviews were then transcribed, coded, and analyzed for themes that may have been well understood or misunderstood by students. We found that a significant number of students had not understood concepts such as a design being more than a prototype, that sponsors have expectations for the tradeoffs between product cost and performance, or that they need to be thinking about how their designs might be deployed. It was also interesting to note that most students also reported feeling confident in their understanding despite their apparent lack thereof, indicating that these could represent major blind spots for students. We propose that developing methods for teaching these principles early on will help students see more clearly what their end goals need to be, and thus help them be more successful in delivering desirable designs. Copyright © 2019 ASME.
295 a7102879142 Sorensen C.D. p354 False Conference 125 The technology/tactics (TEC/TAC) plot: Explicit representation of user actions in the product design space The initial phases of the design process – including interactions with stakeholders, ideation of concept candidates, and the selection of the best candidates – have a large impact on the success of a project as a whole. They also tend to be the most unstructured portion of the project, and are often marginalized by teams who assume they already understand stakeholder needs and the best solution paths to pursue. Design researchers have developed methods shown to increase the creativity and divergent thinking of the design team during these initial phases of design. Nevertheless, these methods often rely on only a vague or amorphous representation of the design space (the set of all possible concepts the design team could feasibly select to meet the objective of the project). In this paper, we introduce a particular design-space structure that can help teams ideate and evaluate their ideation, thus improving the early phases of the design process. The design space presented here is a vector space with a basis of technology (the physical product people will use) and tactics (the procedure for using the product). Also presented are definitions, principles, and sub-theories that facilitate the creation and use of technology-tactics plots to represent the design space. Considering the design space in this structured way, the design team can gain valuable insights that improve the effectiveness of the initial stages of design, and may yield additional benefits to the design process as a whole, if further developed. Copyright © 2019 ASME.
295 a7102879142 Sorensen C.D. p514 False Journal 283 Non-dimensional modeling of the effects of weld parameters on peak temperature and cooling rate in friction stir welding Experimental data from friction stir welded Al 7075 and HSLA-65 were used to create dimensionless, empirical models relating critical weld parameters to the peak temperature rise and cooling rate of the weld heat-affected zone. Five different backing plate materials and a wide range of travel speeds and weld powers were used in the experimental design to ensure the models are relevant to a broad range of welding parameters. The resulting models have R-squared values of 0.997 and 0.995 for the dimensionless peak temperature rise and cooling rate correlations, respectively. Demonstrations of the models’ practical applications are provided. Herein is shown how the models can identify welding parameter (i.e. travel speed or power) levels needed to produce a desired weld peak temperature rise or cooling rate. Also demonstrated is how the models can be used to explore the relative effects of travel speed and backing plate thermal diffusivity on weld peak temperature rise and cooling rate. © 2017 Elsevier B.V.
295 a7102879142 Sorensen C.D. p572 False Journal 303 A review of friction stir welding of steels: Tool, material flow, microstructure, and properties Considerable progress has been achieved in friction stir welding (FSW) of steels in every aspect of tool fabrication, microstructure control and properties evaluation in the past two decades. With the development of reliable welding tools and precise control systems, FSW of steels has reached a new level of technical maturity. High-quality, long welds can be produced in many engineering steels. Compared to traditional fusion welding, FSW exhibits unique advantages producing joints with better properties. As a result of active control of the welding temperature and/or cooling rate, FSW has the capability of fabricating steel joints with excellent toughness and strength. For example, unfavorable phase transformations that usually occur during traditional welding can be avoided and favorable phase fractions in advanced steels can be maintained in the weld zone thus avoiding the typical property degradations associated with fusion welding. If phase transformations do occur during FSW of thick steels, optimization of microstructure and properties can be attained by controlling the heat input and post-weld cooling rate. © 2017
295 a7102879142 Sorensen C.D. p686 False Journal 332 A comparison of model predictive control and PID temperature control in friction stir welding Temperature control of friction stir welding (FSW) via model predictive control (MPC) is investigated in Al 7075-T7. Two MPC controllers are compared against two well-tuned PID controllers to obtain a direct comparison of MPC and current FSW controllers. One MPC controller uses a first-order plus dead-time (FOPDT) model derived from a simplified conduction-advection view of the stir zone. The other MPC controller uses the Hybrid Heat Source model that describes heat conduction in the plate and tool. At quasi steady-state conditions, all four controllers can easily hold temperature within 2 °C of the setpoint in the absence of large disturbances. Once the weld is past the initial traverse, the FOPDT controller is superior to the Hybrid Heat Source controller with regards to modeled-disturbance rejection and setpoint changes. The FOPDT controller is competitive with well-tuned PID controllers in this region of the weld. During the initial traverse, the Hybrid Heat Source controller and PID controller with regulator gains were able to control temperature within 5 °C of the setpoint, compared to a typical deviation of 20–30 °C when uncontrolled. During this period, the FOPDT controller and PID controller with servo gains could not maintain satisfactory temperature control. MPC is demonstrated to be a viable control method for FSW. Temperature control before reaching steady state for both MPC and PID is shown to be feasible, but more difficult than for steady state. Recommendations are given for when each controller might be preferred in various circumstances, based upon the results shown herein. © 2017 The Society of Manufacturing Engineers
296 a57211891331 Guo Z. p71 True Journal 42 Smart camera for quality inspection and grading of food products Due to the increasing consumption of food products and demand for food quality and safety, most food processing facilities in the United States utilize machines to automate their processes, such as cleaning, inspection and grading, packing, storing, and shipping. Machine vision technology has been a proven solution for inspection and grading of food products since the late 1980s. The remaining challenges, especially for small to midsize facilities, include the system and operating costs, demand for high-skilled workers for complicated configuration and operation and, in some cases, unsatisfactory results. This paper focuses on the development of an embedded solution with learning capability to alleviate these challenges. Three simple application cases are included to demonstrate the operation of this unique solution. Two datasets of more challenging cases were created to analyze and demonstrate the performance of our visual inspection algorithm. One dataset includes infrared images of Medjool dates of four levels of skin delamination for surface quality grading. The other one consists of grayscale images of oysters with varying shape for shape quality evaluation. Our algorithm achieved a grading accuracy of 95.0% on the date dataset and 98.6% on the oyster dataset, both easily surpassed manual grading, which constantly faces the challenges of human fatigue or other distractions. Details of the design and functions of our smart camera and our simple visual inspection algorithm are discussed in this paper. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
296 a57211891331 Guo Z. p149 True Journal 104 Efficient evolutionary learning algorithm for real-time embedded vision applications This paper reports the development of an efficient evolutionary learning algorithm designed specifically for real-time embedded visual inspection applications. The proposed evolutionary learning algorithm constructs image features as a series of image transforms for image classification and is suitable for resource-limited systems. This algorithm requires only a small number of images and time for training. It does not depend on handcrafted features or manual tuning of parameters and is generalized to be versatile for visual inspection applications. This allows the system to be configured on the fly for different applications and by an operator without extensive experience. An embedded vision system, equipped with an ARM processor running Linux, is capable of performing at roughly one hundred 640 × 480 frames per second which is more than adequate for real-time visual inspection applications. As example applications, three image datasets were created to test the performance of this algorithm. The first dataset was used to demonstrate the suitability of the algorithm for visual inspection automation applications. This experiment combined two applications to make it a more challenging test. One application was for separating fertilized and unfertilized eggs. The other one was for detecting two common defects on the eggshell. Two other datasets were created for road condition classification and pavement quality evaluation. The proposed algorithm was 100% for fertilized egg detection and 98.6% for eggshell quality inspection for a combined 99.1% accuracy. It had an accuracy of 92% for the road condition classification and 100% for pavement quality evaluation. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
297 a57199244740 Zhang M. p71 False Journal 42 Smart camera for quality inspection and grading of food products Due to the increasing consumption of food products and demand for food quality and safety, most food processing facilities in the United States utilize machines to automate their processes, such as cleaning, inspection and grading, packing, storing, and shipping. Machine vision technology has been a proven solution for inspection and grading of food products since the late 1980s. The remaining challenges, especially for small to midsize facilities, include the system and operating costs, demand for high-skilled workers for complicated configuration and operation and, in some cases, unsatisfactory results. This paper focuses on the development of an embedded solution with learning capability to alleviate these challenges. Three simple application cases are included to demonstrate the operation of this unique solution. Two datasets of more challenging cases were created to analyze and demonstrate the performance of our visual inspection algorithm. One dataset includes infrared images of Medjool dates of four levels of skin delamination for surface quality grading. The other one consists of grayscale images of oysters with varying shape for shape quality evaluation. Our algorithm achieved a grading accuracy of 95.0% on the date dataset and 98.6% on the oyster dataset, both easily surpassed manual grading, which constantly faces the challenges of human fatigue or other distractions. Details of the design and functions of our smart camera and our simple visual inspection algorithm are discussed in this paper. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
297 a57199244740 Zhang M. p149 False Journal 104 Efficient evolutionary learning algorithm for real-time embedded vision applications This paper reports the development of an efficient evolutionary learning algorithm designed specifically for real-time embedded visual inspection applications. The proposed evolutionary learning algorithm constructs image features as a series of image transforms for image classification and is suitable for resource-limited systems. This algorithm requires only a small number of images and time for training. It does not depend on handcrafted features or manual tuning of parameters and is generalized to be versatile for visual inspection applications. This allows the system to be configured on the fly for different applications and by an operator without extensive experience. An embedded vision system, equipped with an ARM processor running Linux, is capable of performing at roughly one hundred 640 × 480 frames per second which is more than adequate for real-time visual inspection applications. As example applications, three image datasets were created to test the performance of this algorithm. The first dataset was used to demonstrate the suitability of the algorithm for visual inspection automation applications. This experiment combined two applications to make it a more challenging test. One application was for separating fertilized and unfertilized eggs. The other one was for detecting two common defects on the eggshell. Two other datasets were created for road condition classification and pavement quality evaluation. The proposed algorithm was 100% for fertilized egg detection and 98.6% for eggshell quality inspection for a combined 99.1% accuracy. It had an accuracy of 92% for the road condition classification and 100% for pavement quality evaluation. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
298 a57204433875 Simons T. p71 False Journal 42 Smart camera for quality inspection and grading of food products Due to the increasing consumption of food products and demand for food quality and safety, most food processing facilities in the United States utilize machines to automate their processes, such as cleaning, inspection and grading, packing, storing, and shipping. Machine vision technology has been a proven solution for inspection and grading of food products since the late 1980s. The remaining challenges, especially for small to midsize facilities, include the system and operating costs, demand for high-skilled workers for complicated configuration and operation and, in some cases, unsatisfactory results. This paper focuses on the development of an embedded solution with learning capability to alleviate these challenges. Three simple application cases are included to demonstrate the operation of this unique solution. Two datasets of more challenging cases were created to analyze and demonstrate the performance of our visual inspection algorithm. One dataset includes infrared images of Medjool dates of four levels of skin delamination for surface quality grading. The other one consists of grayscale images of oysters with varying shape for shape quality evaluation. Our algorithm achieved a grading accuracy of 95.0% on the date dataset and 98.6% on the oyster dataset, both easily surpassed manual grading, which constantly faces the challenges of human fatigue or other distractions. Details of the design and functions of our smart camera and our simple visual inspection algorithm are discussed in this paper. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
298 a57204433875 Simons T. p217 True Journal 104 A review of binarized neural networks In this work, we review Binarized Neural Networks (BNNs). BNNs are deep neural networks that use binary values for activations and weights, instead of full precision values. With binary values, BNNs can execute computations using bitwise operations, which reduces execution time. Model sizes of BNNs are much smaller than their full precision counterparts. While the accuracy of a BNN model is generally less than full precision models, BNNs have been closing accuracy gap and are becoming more accurate on larger datasets like ImageNet. BNNs are also good candidates for deep learning implementations on FPGAs and ASICs due to their bitwise efficiency. We give a tutorial of the general BNN methodology and review various contributions, implementations and applications of BNNs. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
298 a57204433875 Simons T. p233 True Journal 104 Jet features: Hardware-friendly, learned convolutional kernels for high-speed image classification This paper explores a set of learned convolutional kernels which we call Jet Features. Jet Features are efficient to compute in software, easy to implement in hardware and perform well on visual inspection tasks. Because Jet Features can be learned, they can be used in machine learning algorithms. Using Jet Features, we make significant improvements on our previous work, the Evolution Constructed Features (ECO Features) algorithm. Not only do we gain a 3.7× speedup in software without loosing any accuracy on the CIFAR-10 and MNIST datasets, but Jet Features also allow us to implement the algorithm in an FPGA using only a fraction of its resources. We hope to apply the benefits of Jet Features to Convolutional Neural Networks in the future. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
299 a57215212754 Fuller S.G. p72 False Journal 42 Optimization and implementation of synthetic basis feature descriptor on FPGA Feature detection, description, and matching are crucial steps for many computer vision algorithms. These steps rely on feature descriptors to match image features across sets of images. Previous work has shown that our SYnthetic BAsis (SYBA) feature descriptor can offer superior performance to other binary descriptors. This paper focused on various optimizations and hardware implementation of the newer and optimized version. The hardware implementation on a field-programmable gate array (FPGA) is a high-throughput low-latency solution which is critical for applications such as high-speed object detection and tracking, stereo vision, visual odometry, structure from motion, and optical flow. We compared our solution to other hardware designs of binary descriptors. We demonstrated that our implementation of SYBA as a feature descriptor in hardware offered superior image feature matching performance and used fewer resources than most binary feature descriptor implementations. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
300 a57215211789 McCown A.S. p72 False Journal 42 Optimization and implementation of synthetic basis feature descriptor on FPGA Feature detection, description, and matching are crucial steps for many computer vision algorithms. These steps rely on feature descriptors to match image features across sets of images. Previous work has shown that our SYnthetic BAsis (SYBA) feature descriptor can offer superior performance to other binary descriptors. This paper focused on various optimizations and hardware implementation of the newer and optimized version. The hardware implementation on a field-programmable gate array (FPGA) is a high-throughput low-latency solution which is critical for applications such as high-speed object detection and tracking, stereo vision, visual odometry, structure from motion, and optical flow. We compared our solution to other hardware designs of binary descriptors. We demonstrated that our implementation of SYBA as a feature descriptor in hardware offered superior image feature matching performance and used fewer resources than most binary feature descriptor implementations. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
301 a57214076898 Clayton M.F. p73 True Journal 53 Nanoparticle orientation distribution analysis and design for polymeric piezoresistive sensors Piezoresistive sensors, with polymer matrices and conductive nanoparticles, are a relatively new addition to the sensor class, with the potential to transform such fields as wearable sensors and the internet of things. The unusual inverse piezoresistive behavior of the sensors has been modeled using quantum tunneling and percolation theory. However, the impact of the distribution of conductive particles in the matrix, and specifically their relative orientation, has not been well studied. The initial and deformed distribution of orientations greatly influences the sensor behavior, since the quantum tunneling model is highly sensitive to the polymer gaps between nanoparticles; the evolution of these gaps under deformation is strongly dependent upon the relative orientation of neighboring particles, and determines electron transport properties, and overall sensor response. In this paper a simple analytical model for isotropic orientation distribution and subsequent Poisson-based gap evolution is compared with a more sophisticated finite element and random resistor network analysis. The new numerical model was able to explain previously unexplained physical behavior and is used to design sensors with specific desired characteristics. The appropriateness of the previously assumed percolation behavior is also examined via the model and generalized effective medium theory. © 2020
302 a57198146081 Bilodeau R.A. p73 False Journal 53 Nanoparticle orientation distribution analysis and design for polymeric piezoresistive sensors Piezoresistive sensors, with polymer matrices and conductive nanoparticles, are a relatively new addition to the sensor class, with the potential to transform such fields as wearable sensors and the internet of things. The unusual inverse piezoresistive behavior of the sensors has been modeled using quantum tunneling and percolation theory. However, the impact of the distribution of conductive particles in the matrix, and specifically their relative orientation, has not been well studied. The initial and deformed distribution of orientations greatly influences the sensor behavior, since the quantum tunneling model is highly sensitive to the polymer gaps between nanoparticles; the evolution of these gaps under deformation is strongly dependent upon the relative orientation of neighboring particles, and determines electron transport properties, and overall sensor response. In this paper a simple analytical model for isotropic orientation distribution and subsequent Poisson-based gap evolution is compared with a more sophisticated finite element and random resistor network analysis. The new numerical model was able to explain previously unexplained physical behavior and is used to design sensors with specific desired characteristics. The appropriateness of the previously assumed percolation behavior is also examined via the model and generalized effective medium theory. © 2020
303 a7006441571 Bowden A.E. p73 False Journal 53 Nanoparticle orientation distribution analysis and design for polymeric piezoresistive sensors Piezoresistive sensors, with polymer matrices and conductive nanoparticles, are a relatively new addition to the sensor class, with the potential to transform such fields as wearable sensors and the internet of things. The unusual inverse piezoresistive behavior of the sensors has been modeled using quantum tunneling and percolation theory. However, the impact of the distribution of conductive particles in the matrix, and specifically their relative orientation, has not been well studied. The initial and deformed distribution of orientations greatly influences the sensor behavior, since the quantum tunneling model is highly sensitive to the polymer gaps between nanoparticles; the evolution of these gaps under deformation is strongly dependent upon the relative orientation of neighboring particles, and determines electron transport properties, and overall sensor response. In this paper a simple analytical model for isotropic orientation distribution and subsequent Poisson-based gap evolution is compared with a more sophisticated finite element and random resistor network analysis. The new numerical model was able to explain previously unexplained physical behavior and is used to design sensors with specific desired characteristics. The appropriateness of the previously assumed percolation behavior is also examined via the model and generalized effective medium theory. © 2020
303 a7006441571 Bowden A.E. p314 False Conference 94 Characteristics of self-deployment in origami-based systems The potential of compliant mechanisms and related origami-based mechanical systems to store strain energy make them ideal candidates for applications requiring an actuation or deployment process, such as space system arrays, minimally invasive surgical devices and deployable barriers. Many origami structures can be thought of as a compliant mechanism because, like compliant mechanisms, its function is performed through the elastic deformation of its members. This stored strain energy could prove useful. There are opportunities using strain energy to develop approaches to deploy particular mechanical systems. In order to better understand the principles of self-actuation and promote the designs of such systems, a taxonomy of deployable origami mechanisms is presented. This taxonomy demonstrates that there are several different types of deployable origami mechanisms and provides an organizational method to better understand the design space. Characteristics of self deployment in concentrated, deployable origami strain energy mechanisms with internal actuation are identified and examples of strain energy based deployment are provided. Copyright © 2019 ASME.
303 a7006441571 Bowden A.E. p315 False Conference 95 Deployable euler spiral connectors (DESCs) Deployable Euler Spiral Connectors (DESCs) are introduced as a way to use compliant flexures that lay flat when under strain in a stowed position. This paper presents the design of DESCs using the Euler spiral equations. An application of a spinal device is presented as a proof-of-concept of the use of DESCs. Copyright © 2019 ASME.
303 a7006441571 Bowden A.E. p505 False Journal 276 Inverse piezoresistive nanocomposite sensors for identifying human sitting posture Sitting posture is the position in which one holds his/her body upright against gravity while sitting. Poor sitting posture is regarded as an aggravating factor for various diseases. In this paper, we present an inverse piezoresistive nanocomposite sensor, and related deciphering neural network, as a new tool to identify human sitting postures accurately. As a low power consumption device, the proposed tool has simple structure, and is easy to use. The strain gauge is attached to the back of the user to acquire sitting data. A three-layer BP neural network is employed to distinguish normal sitting posture, slight hunchback and severe hunchback according to the acquired data. Experimental results show that our method is both realizable and effective, achieving 98.75% posture identification accuracy. This successful application of inverse piezoresistive nanocomposite sensors reveals that the method could potentially be used for monitoring of diverse physiological parameters in the future. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
303 a7006441571 Bowden A.E. p517 False Journal 286 Effect of environmental and material factors on the response of nanocomposite foam impact sensors Nanocomposite foam (NCF) is a multifunctional material that can be used to measure impact. Interactions between the flexible polymer matrix and conductive particles dispersed throughout it produce a voltage signal under dynamic strain, which correlates to the magnitude of impact. Though promising in applications requiring both impact sensing and energy absorption, NCF's voltage response has been observed to suffer from significant signal drift. This paper investigates several causes of variance in the response of NCF sensors to consistent impacts. These effects can be classified into three general types: recoverable transient effects (such as those relating to viscoelasticity or capacitive charging), environmental drift (due to humidity and temperature), and permanent signal decay from material degradation. The motivation for the study arises from various potential repeat-impact applications where periodic recalibration of the sensor would be difficult (such as a gait-tracking insole in use for a marathon event). A cyclic drop testing machine was used to apply consistent impacts to NCF, and drift resulting from each factor (in ranges typical of an insole environment) was experimentally isolated. Models representing each factor's contribution to signal drift are presented. Of the factors investigated, humidity and temperature caused the most significant drift, with permanent material degradation accounting for only minor decay in voltage response. Transient effects were also observed, with a characteristic 'warm-up' (or 'charging') time required for the NCF to achieve steady-state; this phenomenon, and the related 'recovery' time for the material to return to its original state, were determined. The resultant data can be leveraged to implement a correction algorithm or other drift-compensating method to retain an NCF sensor's accuracy in both long and short data collection scenarios. © 2018 IOP Publishing Ltd.
303 a7006441571 Bowden A.E. p546 False Journal 300 Materials selection of flexible open-cell foams in energy absorption applications Foam must be engineered to absorb a particular range of energy in various impact-related applications. Since energy absorption is dependent upon the unique stress-strain response of each foam specimen, it is difficult to quantify analytically; thus, energy absorption cannot be easily compared across materials. Current methods accomplish this using an experimental approach, individually testing foam materials, densities, and geometries to quantify how each influences energy absorption. Such methods require large amounts of time and money to characterize a narrow range of foams. This paper facilitates foam selection by deriving generalized energy absorption material indices. Assuming Euler buckling of columns in the open-cell foam structure, this paper applies equations derived by Maiti et al. to a typical impact scenario wherein the indices are extracted. Using existing Ashby charts, these indices allow polymers to be ranked by the mass and cost each would require as a foamed structure to satisfy specific energy absorption constraints. The presented method allows the energy absorption of a wide range of flexible foams to be compared and relieves the need for extensive factor-specific testing. This method is applied to football helmet foam selection; however, it can be used for many applications where energy absorption is of interest. © 2017 Elsevier Ltd
303 a7006441571 Bowden A.E. p586 False Conference 231 Design and modeling of a prosthetic venous valve Chronic Venous Insufficiency (CVI) is a disease of the lower limbs that affects millions of people in the United States. CVI results from incompetent venous valves. The purpose of venous valves is to prevent retrograde blood flow to the lower limbs. Valve failure can lead to edema, pain, and ulcers. One solution that has great potential is to create an implantable venous valve that could restore function of the venous system. No prosthetic venous valves are clinically used currently because of problems with biocompatiblility and thrombogenicity caused by high shear rates. This paper presents a prosthetic venous valve that could overcome these difficulties by using carbon-infiltrated carbon nanotubes (CI-CNTs). This material has been proven to be thrombo-resistant, biocompatible due to its non-reactive properties, and durable. The valve was designed to be initially open and to close with physiological pressures. Finite element modeling showed that, with a hydrostatic pressure of 20 mmHg (the minimum hydrostatic pressure in the common femoral vein), it fully closed with a maximum stress of 117 MPa, which is below the ultimate strength of CI-CNTs. A computational fluid dynamics analysis demonstrated the valve would cause a maximum shear rate of 225.1 s− 1, which is less than the maximum shear rate in the body. Hence, this valve would be less likely than previous prosthetic valves to develop blood clots. Currently, this is the lowest shear rate reported for a prosthetic venous valve. These results demonstrate that a CI-CNT prosthetic venous valve has the potential to be an effective treatment for CVI. Copyright © 2018 ASME.
303 a7006441571 Bowden A.E. p666 False Journal 320 Nano-Composite Foam Sensor System in Football Helmets American football has both the highest rate of concussion incidences as well as the highest number of concussions of all contact sports due to both the number of athletes and nature of the sport. Recent research has linked concussions with long term health complications such as chronic traumatic encephalopathy and early onset Alzheimer’s. Understanding the mechanical characteristics of concussive impacts is critical to help protect athletes from these debilitating diseases and is now possible using helmet-based sensor systems. To date, real time on-field measurement of head impacts has been almost exclusively measured by devices that rely on accelerometers or gyroscopes attached to the player’s helmet, or embedded in a mouth guard. These systems monitor motion of the head or helmet, but do not directly measure impact energy. This paper evaluates the accuracy of a novel, multifunctional foam-based sensor that replaces a portion of the helmet foam to measure impact. All modified helmets were tested using a National Operating Committee Standards for Athletic Equipment-style drop tower with a total of 24 drop tests (4 locations with 6 impact energies). The impacts were evaluated using a headform, instrumented with a tri-axial accelerometer, mounted to a Hybrid III neck assembly. The resultant accelerations were evaluated for both the peak acceleration and the severity indices. These data were then compared to the voltage response from multiple Nano Composite Foam sensors located throughout the helmet. The foam sensor system proved to be accurate in measuring both the HIC and Gadd severity index, as well as peak acceleration while also providing additional details that were previously difficult to obtain, such as impact energy. © 2017, Biomedical Engineering Society.
303 a7006441571 Bowden A.E. p694 False Journal 320 Estimation of 3D Ground Reaction Force Using Nanocomposite Piezo-Responsive Foam Sensors During Walking This paper describes a method for the estimation of the 3D ground reaction force (GRF) during human walking using novel nanocomposite piezo-responsive foam (NCPF) sensors. Nine subjects (5 male, 4 female) walked on a force-instrumented treadmill at 1.34 m/s for 120 s each while wearing a shoe that was instrumented with four NCPF sensors. GRF data, measured via the treadmill, and sensor data, measured via the NCPF inserts, were used in a tenfold cross validation process to calibrate a separate model for each individual. The calibration model estimated average anterior–posterior, mediolateral and vertical GRF with mean average errors (MAE) of 6.52 N (2.14%), 4.79 N (6.34%), and 15.4 N (2.15%), respectively. Two additional models were created using the sensor data from all subjects and subject demographics. A tenfold cross validation process for this combined data set resulted in models that estimated average anterior–posterior, mediolateral and vertical GRF with less than 8.16 N (2.41%), 6.63 N (7.37%), and 19.4 N (2.31%) errors, respectively. Intra-subject estimates based on the model had a higher accuracy than inter-subject estimates, likely due to the relatively small subject cohort used in creating the model. The novel NCPF sensors demonstrate the ability to accurately estimate 3D GRF during human movement outside of the traditional biomechanics laboratory setting. © 2017, Biomedical Engineering Society.
303 a7006441571 Bowden A.E. p867 False Conference 388 Exploration of carbon-filled carbon nanotube vascular stents The purpose of this research was to design, fabricate, and test coronary stent designs composed of carbon-infiltrated carbon nanotubes (CI-CNTs). Coronary stents currently have two major complications: restenosis and thrombosis. CI-CNT stents may provide improved clinical outcomes for both of these issues. Multiple stent design concepts were generated, evaluated, and two stent designs were selected: one with a semi-auxetic nature, and one designed for maximum force. These designs were further developed and optimized using analytical tools along with finite element analysis. Planar versions of the stent designs were manufactured and mechanically tested to verify performance. The performance of the cylindrical stent configurations was analyzed using finite element modeling. A sample cylindrical stent was also fabricated. This research demonstrates that feasible coronary stent designs can be manufactured from CI-CNTs. However, a major challenge for CI-CNT stent designs is meeting the design requirement of sufficient radial force. © Springer International Publishing Switzerland 2017.
304 a57191873151 Ziaee M. p74 True Journal 54 Optimization of laser sintering for demineralized bone/polycaprolactone composite powder for bone tissue scaffold Demineralized bone matrix (DBM) is an excellent bone scaffold material, but is available in only limited sizes. An additive manufacturing (AM) method that retains these properties while enabling customized geometry fabrication would provide bone scaffolds for a larger range of geometries while maintaining the benefits of DBM. This work examines laser sintering (LS) of a blend of demineralized bone matrix (DBM) and polycaprolactone (PCL) using a CO2 laser beam. A comprehensive experimental study was carried out to find the conditions that form defect-free layers while still retaining the favorable biological features of DBM. The results identify a process setting window over which LS can be utilized to constructing complex patient-specific scaffolds. With the identified setting, first, the DBM/PCL blend was fused in the LS machine. Parts were then were further strengthened through a post-processing heat treatment. The shrinkage level, skeletal density, mechanical testing, and porosimetry of the resultant samples were compared to traditional machined DBM blocks. The maximum tensile strength of the samples and post-processing shrinkage depends on heat treatment duration. The tensile strength measurements demonstrate that the post-processing conditions can be tuned to achieve the tensile strength of the demineralized bone strips. Evaluation of the dimensional change suggests that the shrinkage along the laser paths is ~0.3% while thickness shrinks the most (up to ~20%). The porosimetry and density studies showed that the final part achieved over 40% porosity with a density comparable to blocks of DBM. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
304 a57191873151 Ziaee M. p182 True Journal 124 Binder jetting: A review of process, materials, and methods Binder Jet printing is an additive manufacturing technique that dispenses liquid binding agent on powder to form a two-dimensional pattern on a layer. The layers are stacked to build a physical article. Binder Jetting (BJ) can be adapted to almost any powder with high production rates and the BJ process utilizes a broad range of technologies including printing tehniques, powder deposition, dynamic binder/powder interaction, and post-processing methods. A wide variety of materials including polymers, metals, and ceramics have been processed successfully with Binder Jet. However, developing printing and post-processing methods that maximize part performance is a remaining challenge. This article presents a broad review of technologies and approaches that have been applied in Binder Jet printing and points towards opportunities for future advancement. © 2019 Elsevier B.V.
304 a57191873151 Ziaee M. p226 True Journal 148 Fabrication of demineralized bone matrix/polycaprolactone composites using large area projection sintering (LAPS) Cadaveric decellularized bone tissue is utilized as an allograft in many musculoskeletal surgical procedures. Typically, the allograft acts as a scaffold to guide tissue regeneration with superior biocompatibility relative to synthetic scaffolds. Traditionally these scaffolds are machined into the required dimensions and shapes. However, the geometrical simplicity and, in some cases, limited dimensions of the donated tissue restrict the use of allograft scaffolds. This could be overcome by additive manufacturing using granulated bone that is both decellularized and demineralized. In this study, the large area projection sintering (LAPS) method is evaluated as a fabrication method to build porous structures composed of granulated cortical bone bound by polycaprolactone (PCL). This additive manufacturing method utilizes visible light to selectively cure the deposited material layer-by-layer to create 3D geometry. First, the spreading behavior of the composite mixtures is evaluated and the conditions to attain improved powder bed density to fabricate the test specimens are determined. The tensile strength of the LAPS fabricated samples in both dry and hydrated states are determined and compared to the demineralized cancellous bone allograft and the heat treated demineralized-bone/PCL mixture in mold. The results indicated that the projection sintered composites of 45–55 wt %. Demineralized bone matrix (DBM) particulates produced strength comparable to processed and demineralized cancellous bone. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
305 a57216430816 Mahmood A. p74 False Journal 54 Optimization of laser sintering for demineralized bone/polycaprolactone composite powder for bone tissue scaffold Demineralized bone matrix (DBM) is an excellent bone scaffold material, but is available in only limited sizes. An additive manufacturing (AM) method that retains these properties while enabling customized geometry fabrication would provide bone scaffolds for a larger range of geometries while maintaining the benefits of DBM. This work examines laser sintering (LS) of a blend of demineralized bone matrix (DBM) and polycaprolactone (PCL) using a CO2 laser beam. A comprehensive experimental study was carried out to find the conditions that form defect-free layers while still retaining the favorable biological features of DBM. The results identify a process setting window over which LS can be utilized to constructing complex patient-specific scaffolds. With the identified setting, first, the DBM/PCL blend was fused in the LS machine. Parts were then were further strengthened through a post-processing heat treatment. The shrinkage level, skeletal density, mechanical testing, and porosimetry of the resultant samples were compared to traditional machined DBM blocks. The maximum tensile strength of the samples and post-processing shrinkage depends on heat treatment duration. The tensile strength measurements demonstrate that the post-processing conditions can be tuned to achieve the tensile strength of the demineralized bone strips. Evaluation of the dimensional change suggests that the shrinkage along the laser paths is ~0.3% while thickness shrinks the most (up to ~20%). The porosimetry and density studies showed that the final part achieved over 40% porosity with a density comparable to blocks of DBM. © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
305 a57216430816 Mahmood A. p226 False Journal 148 Fabrication of demineralized bone matrix/polycaprolactone composites using large area projection sintering (LAPS) Cadaveric decellularized bone tissue is utilized as an allograft in many musculoskeletal surgical procedures. Typically, the allograft acts as a scaffold to guide tissue regeneration with superior biocompatibility relative to synthetic scaffolds. Traditionally these scaffolds are machined into the required dimensions and shapes. However, the geometrical simplicity and, in some cases, limited dimensions of the donated tissue restrict the use of allograft scaffolds. This could be overcome by additive manufacturing using granulated bone that is both decellularized and demineralized. In this study, the large area projection sintering (LAPS) method is evaluated as a fabrication method to build porous structures composed of granulated cortical bone bound by polycaprolactone (PCL). This additive manufacturing method utilizes visible light to selectively cure the deposited material layer-by-layer to create 3D geometry. First, the spreading behavior of the composite mixtures is evaluated and the conditions to attain improved powder bed density to fabricate the test specimens are determined. The tensile strength of the LAPS fabricated samples in both dry and hydrated states are determined and compared to the demineralized cancellous bone allograft and the heat treated demineralized-bone/PCL mixture in mold. The results indicated that the projection sintered composites of 45–55 wt %. Demineralized bone matrix (DBM) particulates produced strength comparable to processed and demineralized cancellous bone. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
306 a55971908500 Jin M. p75 True Journal 55 A CPRBM-based method for large-deflection analysis of contact-aided compliant mechanisms considering beam-to-beam contacts Contact-aided compliant mechanisms (CCMs) utilize contact to achieve enhanced functionality. The contact phenomenon of CCMs increases the difficulties of their analysis and design, especially when they exhibit beam-to-beam contact. Considering the particularity of CCMs analysis, which is more about the mechanisms’ deformation, this paper presents a numerical method to analyze the large deflection and stress of the CCMs considering beam-to-beam contacts. Based on our previous work on beam-to-rigid contact, the large deformation of general beams in CCMs is modeled by using the chained pseudo-rigid-body model (CPRBM). An approximation based on the geometric information of CPRBM is proposed in this paper to rapidly determine the moving boundary curve for beam-to-beam contact constraints. The static equilibrium configuration of CCMs is solved by minimizing its potential energy function under the geometric constraints from the boundary curves of contacts. A formulation is also provided to evaluate the normal stress along the deformed beam based on the deformation of CPRBM's torsional springs. Numerical examples and finite element analysis are used to verify the feasibility and accuracy of the proposed method. © 2019 Elsevier Ltd
307 a54415193700 Zhu B. p75 False Journal 55 A CPRBM-based method for large-deflection analysis of contact-aided compliant mechanisms considering beam-to-beam contacts Contact-aided compliant mechanisms (CCMs) utilize contact to achieve enhanced functionality. The contact phenomenon of CCMs increases the difficulties of their analysis and design, especially when they exhibit beam-to-beam contact. Considering the particularity of CCMs analysis, which is more about the mechanisms’ deformation, this paper presents a numerical method to analyze the large deflection and stress of the CCMs considering beam-to-beam contacts. Based on our previous work on beam-to-rigid contact, the large deformation of general beams in CCMs is modeled by using the chained pseudo-rigid-body model (CPRBM). An approximation based on the geometric information of CPRBM is proposed in this paper to rapidly determine the moving boundary curve for beam-to-beam contact constraints. The static equilibrium configuration of CCMs is solved by minimizing its potential energy function under the geometric constraints from the boundary curves of contacts. A formulation is also provided to evaluate the normal stress along the deformed beam based on the deformation of CPRBM's torsional springs. Numerical examples and finite element analysis are used to verify the feasibility and accuracy of the proposed method. © 2019 Elsevier Ltd
308 a56489679500 Mo J. p75 False Journal 55 A CPRBM-based method for large-deflection analysis of contact-aided compliant mechanisms considering beam-to-beam contacts Contact-aided compliant mechanisms (CCMs) utilize contact to achieve enhanced functionality. The contact phenomenon of CCMs increases the difficulties of their analysis and design, especially when they exhibit beam-to-beam contact. Considering the particularity of CCMs analysis, which is more about the mechanisms’ deformation, this paper presents a numerical method to analyze the large deflection and stress of the CCMs considering beam-to-beam contacts. Based on our previous work on beam-to-rigid contact, the large deformation of general beams in CCMs is modeled by using the chained pseudo-rigid-body model (CPRBM). An approximation based on the geometric information of CPRBM is proposed in this paper to rapidly determine the moving boundary curve for beam-to-beam contact constraints. The static equilibrium configuration of CCMs is solved by minimizing its potential energy function under the geometric constraints from the boundary curves of contacts. A formulation is also provided to evaluate the normal stress along the deformed beam based on the deformation of CPRBM's torsional springs. Numerical examples and finite element analysis are used to verify the feasibility and accuracy of the proposed method. © 2019 Elsevier Ltd
309 a55522618700 Yang Z. p75 False Journal 55 A CPRBM-based method for large-deflection analysis of contact-aided compliant mechanisms considering beam-to-beam contacts Contact-aided compliant mechanisms (CCMs) utilize contact to achieve enhanced functionality. The contact phenomenon of CCMs increases the difficulties of their analysis and design, especially when they exhibit beam-to-beam contact. Considering the particularity of CCMs analysis, which is more about the mechanisms’ deformation, this paper presents a numerical method to analyze the large deflection and stress of the CCMs considering beam-to-beam contacts. Based on our previous work on beam-to-rigid contact, the large deformation of general beams in CCMs is modeled by using the chained pseudo-rigid-body model (CPRBM). An approximation based on the geometric information of CPRBM is proposed in this paper to rapidly determine the moving boundary curve for beam-to-beam contact constraints. The static equilibrium configuration of CCMs is solved by minimizing its potential energy function under the geometric constraints from the boundary curves of contacts. A formulation is also provided to evaluate the normal stress along the deformed beam based on the deformation of CPRBM's torsional springs. Numerical examples and finite element analysis are used to verify the feasibility and accuracy of the proposed method. © 2019 Elsevier Ltd
310 a55864283000 Zhang X. p75 False Journal 55 A CPRBM-based method for large-deflection analysis of contact-aided compliant mechanisms considering beam-to-beam contacts Contact-aided compliant mechanisms (CCMs) utilize contact to achieve enhanced functionality. The contact phenomenon of CCMs increases the difficulties of their analysis and design, especially when they exhibit beam-to-beam contact. Considering the particularity of CCMs analysis, which is more about the mechanisms’ deformation, this paper presents a numerical method to analyze the large deflection and stress of the CCMs considering beam-to-beam contacts. Based on our previous work on beam-to-rigid contact, the large deformation of general beams in CCMs is modeled by using the chained pseudo-rigid-body model (CPRBM). An approximation based on the geometric information of CPRBM is proposed in this paper to rapidly determine the moving boundary curve for beam-to-beam contact constraints. The static equilibrium configuration of CCMs is solved by minimizing its potential energy function under the geometric constraints from the boundary curves of contacts. A formulation is also provided to evaluate the normal stress along the deformed beam based on the deformation of CPRBM's torsional springs. Numerical examples and finite element analysis are used to verify the feasibility and accuracy of the proposed method. © 2019 Elsevier Ltd
311 a57209110872 Wu R. p76 True Journal 56 Non-catalytic ash effect on char reactivity This investigation reviews non-catalytic ash effects on char reactivity based on several biomass chars. Biomass ash contents vary substantially among fuel types and are typified by the three fuels compared in this investigation. These fuels have ash-content ratios of about 40:1, which should allow experimental observation of ash effects. In addition, the experiments explore char gasification rates under kinetically controlled conditions that should highlight the effects of ash. By contrast, diffusion controlled burning rates may mask the types of ash effects observed here. The experimental and theoretical results indicate that refractory material such as ash reduces kinetic reaction rates by rendering portions of the surface area inert as char burnout proceeds and ash content increases. Ash also affects particle size in a somewhat compensatory manner. A theoretical model has been developed to quantify the ash effect. This model indicates that all chars from ash-forming fuels should experience similar behavior, which manifests itself as a decrease in the kinetic burning rate in late stages of burnout even though the kinetic reactivity of the char does not change. © 2019 Elsevier Ltd
312 a57206455220 Beutler J. p76 False Journal 56 Non-catalytic ash effect on char reactivity This investigation reviews non-catalytic ash effects on char reactivity based on several biomass chars. Biomass ash contents vary substantially among fuel types and are typified by the three fuels compared in this investigation. These fuels have ash-content ratios of about 40:1, which should allow experimental observation of ash effects. In addition, the experiments explore char gasification rates under kinetically controlled conditions that should highlight the effects of ash. By contrast, diffusion controlled burning rates may mask the types of ash effects observed here. The experimental and theoretical results indicate that refractory material such as ash reduces kinetic reaction rates by rendering portions of the surface area inert as char burnout proceeds and ash content increases. Ash also affects particle size in a somewhat compensatory manner. A theoretical model has been developed to quantify the ash effect. This model indicates that all chars from ash-forming fuels should experience similar behavior, which manifests itself as a decrease in the kinetic burning rate in late stages of burnout even though the kinetic reactivity of the char does not change. © 2019 Elsevier Ltd
313 a7103248108 Baxter L.L. p76 False Journal 56 Non-catalytic ash effect on char reactivity This investigation reviews non-catalytic ash effects on char reactivity based on several biomass chars. Biomass ash contents vary substantially among fuel types and are typified by the three fuels compared in this investigation. These fuels have ash-content ratios of about 40:1, which should allow experimental observation of ash effects. In addition, the experiments explore char gasification rates under kinetically controlled conditions that should highlight the effects of ash. By contrast, diffusion controlled burning rates may mask the types of ash effects observed here. The experimental and theoretical results indicate that refractory material such as ash reduces kinetic reaction rates by rendering portions of the surface area inert as char burnout proceeds and ash content increases. Ash also affects particle size in a somewhat compensatory manner. A theoretical model has been developed to quantify the ash effect. This model indicates that all chars from ash-forming fuels should experience similar behavior, which manifests itself as a decrease in the kinetic burning rate in late stages of burnout even though the kinetic reactivity of the char does not change. © 2019 Elsevier Ltd
313 a7103248108 Baxter L.L. p650 False Conference 281 Improving full-scale models of new carbon capture technologies with uncertainty quantification Carbon capture technologies for combustion power plants aim to remove CO2 from flue gas. One such technology is the novel CO2-Binding Organic Liquid (CO2BOL) process developed at the Pacific Northwest National Laboratory. The process utilizes their anhydrous CO2BOL solvent in place of amine mixtures to reduce the energy penalty. A full-scale model of this system based on NETL's Case 10 power plant is projected to produce 7-16% more net electric power over a traditional MEA system for the same plant. These full-scale model predictions are promising, however full-scale simulations are difficult to validate using only bench-scale data. There are errors in both the measurements and models that need to be considered in addition to uncertainties introduced by up-scaling. Uncertainty quantification (UQ) is a statistical framework used to better understand these uncertainties as well as data gaps in models. By constraining models to data, distributions of model parameters are estimated and then propagated through the model to obtain distributions of key outputs such as carbon capture percent, energy penalty, stripper temperature, etc. The results from this UQ analysis aid the design of experiments (DoE) which identifies data gaps to fill to improve model accuracy. Using UQ and DoE effectively can reduce the development time of new carbon capture by years and save time and money on the path to a pilot, and ultimately full-scale, plant. Copyright © (2018) by AIChE. All Rights Reserved.
313 a7103248108 Baxter L.L. p835 False Conference 363 Field testing of Cryogenic Carbon Capture Sustainable Energy Solutions has been developing Cryogenic Carbon Capture™(CCC) since 2008. In that time two processes have been developed, the External Cooling Loop and Compressed Flue Gas Cryogenic Carbon Capture processes (CCC ECL™ and CCC CFG™ respectively). The CCC ECL™ process has been scaled up to a 1 TPD CO2 system. In this process the flue gas is cooled by an external refrigerant loop. SES has tested CCC ECL™ on real flue gas slip streams from subbituminous coal, bituminous coal, biomass, natural gas, shredded tires, and municipal waste fuels at field sites that include utility power stations, heating plants, cement kilns, and pilot-scale research reactors. The CO2 concentrations from these tests ranged from 5 to 22% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at a modest rate. The CCC CFG™ process has been scaled up to a.25 ton per day system. This system has been tested on real flue gas streams including subbituminous coal, bituminous coal and natural gas at field sites that include utility power stations, heating plants, and pilot-scale research reactors. CO2 concentrations for these tests ranged from 5 to 15% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at 90+%. Hg capture was also verified and the resulting effluent from CCC CFG™ was below a lppt concentration. This paper will focus on discussion of the capabilities of CCC, the results of field testing and the future steps surrounding the development of this technology. Copyright 2017, Carbon Management Technology Conference.
314 a57191108291 Morgan W.S. p77 True Journal 57 Generalized regular k-point grid generation on the fly In the DFT community, it is common practice to use regular k-point grids (Monkhorst-Pack, MP) for Brillioun zone integration. Recently Wisesa et al. (2016) and Morgan et al. (2018) demonstrated that generalized regular (GR) grids offer an advantage over traditional MP grids. The difference is simple but effective. At the same k-point density, GR grids have greater symmetry and 60% fewer irreducible k-points. GR grids have not been widely adopted because one must search through a large number of candidate grids; in many cases, a brute force search could take hours. This work describes an algorithm that can quickly search over GR grids for those that have the most uniform distribution of points and the best symmetry reduction. The grids are ∼60% more efficient, on average, than MP grids and can now be generated on the fly in seconds. © 2019 Elsevier B.V.
314 a57191108291 Morgan W.S. p440 True Journal 245 Efficiency of Generalized Regular k-point grids Most DFT practitioners use regular grids (Monkhorst-Pack, MP) for integrations in the Brillouin zone. Although regular grids are the natural choice and easy to generate, more general grids whose generating vectors are not merely integer divisions of the reciprocal lattice vectors, are usually more efficient (Wisesa et al., 2016). We demonstrate the efficiency of generalized regular (GR) grids compared to Monkhorst-Pack (MP) and simultaneously commensurate (SC) grids. In the case of metals, for total energy accuracies of one meV/atom, GR grids are 60% faster on average than MP grids and 20% faster than SC grids. GR grids also have greater freedom in choosing the k-point density, enabling the practitioner to achieve a target accuracy with the minimum computational cost. © 2018 Elsevier B.V.
314 a57191108291 Morgan W.S. p709 True Journal 349 Generating derivative superstructures for systems with high configurational freedom Modeling alloys requires the exploration of all possible configurations of atoms. Additionally, modeling the thermal properties of materials requires knowledge of the possible ways of displacing the atoms. One solution to finding all symmetrically unique configurations and displacements is to generate the complete list of possible configurations and remove those that are symmetrically equivalent. This approach, however, suffers from a combinatorial explosion when the supercell size is large, when there are more than two atom types, or when there are many displaced atoms. This problem persists even when there are only a relatively small number of unique arrangements that survive the elimination process. Here, we extend an existing algorithm to include the extra configurational degrees of freedom from the inclusion of displacement directions. The algorithm uses group theory and a tree-like data structure to eliminate large classes of configurations, avoiding the typical combinatoric explosion. With this approach we can now enumerate previously inaccessible cases, including atomic displacements. © 2017 Elsevier B.V.
315 a57212383793 Christensen J.E. p77 False Journal 57 Generalized regular k-point grid generation on the fly In the DFT community, it is common practice to use regular k-point grids (Monkhorst-Pack, MP) for Brillioun zone integration. Recently Wisesa et al. (2016) and Morgan et al. (2018) demonstrated that generalized regular (GR) grids offer an advantage over traditional MP grids. The difference is simple but effective. At the same k-point density, GR grids have greater symmetry and 60% fewer irreducible k-points. GR grids have not been widely adopted because one must search through a large number of candidate grids; in many cases, a brute force search could take hours. This work describes an algorithm that can quickly search over GR grids for those that have the most uniform distribution of points and the best symmetry reduction. The grids are ∼60% more efficient, on average, than MP grids and can now be generated on the fly in seconds. © 2019 Elsevier B.V.
316 a57212379321 Hamilton P.K. p77 False Journal 57 Generalized regular k-point grid generation on the fly In the DFT community, it is common practice to use regular k-point grids (Monkhorst-Pack, MP) for Brillioun zone integration. Recently Wisesa et al. (2016) and Morgan et al. (2018) demonstrated that generalized regular (GR) grids offer an advantage over traditional MP grids. The difference is simple but effective. At the same k-point density, GR grids have greater symmetry and 60% fewer irreducible k-points. GR grids have not been widely adopted because one must search through a large number of candidate grids; in many cases, a brute force search could take hours. This work describes an algorithm that can quickly search over GR grids for those that have the most uniform distribution of points and the best symmetry reduction. The grids are ∼60% more efficient, on average, than MP grids and can now be generated on the fly in seconds. © 2019 Elsevier B.V.
317 a57202904399 Jorgensen J.J. p77 False Journal 57 Generalized regular k-point grid generation on the fly In the DFT community, it is common practice to use regular k-point grids (Monkhorst-Pack, MP) for Brillioun zone integration. Recently Wisesa et al. (2016) and Morgan et al. (2018) demonstrated that generalized regular (GR) grids offer an advantage over traditional MP grids. The difference is simple but effective. At the same k-point density, GR grids have greater symmetry and 60% fewer irreducible k-points. GR grids have not been widely adopted because one must search through a large number of candidate grids; in many cases, a brute force search could take hours. This work describes an algorithm that can quickly search over GR grids for those that have the most uniform distribution of points and the best symmetry reduction. The grids are ∼60% more efficient, on average, than MP grids and can now be generated on the fly in seconds. © 2019 Elsevier B.V.
317 a57202904399 Jorgensen J.J. p440 False Journal 245 Efficiency of Generalized Regular k-point grids Most DFT practitioners use regular grids (Monkhorst-Pack, MP) for integrations in the Brillouin zone. Although regular grids are the natural choice and easy to generate, more general grids whose generating vectors are not merely integer divisions of the reciprocal lattice vectors, are usually more efficient (Wisesa et al., 2016). We demonstrate the efficiency of generalized regular (GR) grids compared to Monkhorst-Pack (MP) and simultaneously commensurate (SC) grids. In the case of metals, for total energy accuracies of one meV/atom, GR grids are 60% faster on average than MP grids and 20% faster than SC grids. GR grids also have greater freedom in choosing the k-point density, enabling the practitioner to achieve a target accuracy with the minimum computational cost. © 2018 Elsevier B.V.
318 a7403279876 Campbell B.J. p77 False Journal 57 Generalized regular k-point grid generation on the fly In the DFT community, it is common practice to use regular k-point grids (Monkhorst-Pack, MP) for Brillioun zone integration. Recently Wisesa et al. (2016) and Morgan et al. (2018) demonstrated that generalized regular (GR) grids offer an advantage over traditional MP grids. The difference is simple but effective. At the same k-point density, GR grids have greater symmetry and 60% fewer irreducible k-points. GR grids have not been widely adopted because one must search through a large number of candidate grids; in many cases, a brute force search could take hours. This work describes an algorithm that can quickly search over GR grids for those that have the most uniform distribution of points and the best symmetry reduction. The grids are ∼60% more efficient, on average, than MP grids and can now be generated on the fly in seconds. © 2019 Elsevier B.V.
319 a6507391043 Forcade R.W. p77 False Journal 57 Generalized regular k-point grid generation on the fly In the DFT community, it is common practice to use regular k-point grids (Monkhorst-Pack, MP) for Brillioun zone integration. Recently Wisesa et al. (2016) and Morgan et al. (2018) demonstrated that generalized regular (GR) grids offer an advantage over traditional MP grids. The difference is simple but effective. At the same k-point density, GR grids have greater symmetry and 60% fewer irreducible k-points. GR grids have not been widely adopted because one must search through a large number of candidate grids; in many cases, a brute force search could take hours. This work describes an algorithm that can quickly search over GR grids for those that have the most uniform distribution of points and the best symmetry reduction. The grids are ∼60% more efficient, on average, than MP grids and can now be generated on the fly in seconds. © 2019 Elsevier B.V.
319 a6507391043 Forcade R.W. p709 False Journal 349 Generating derivative superstructures for systems with high configurational freedom Modeling alloys requires the exploration of all possible configurations of atoms. Additionally, modeling the thermal properties of materials requires knowledge of the possible ways of displacing the atoms. One solution to finding all symmetrically unique configurations and displacements is to generate the complete list of possible configurations and remove those that are symmetrically equivalent. This approach, however, suffers from a combinatorial explosion when the supercell size is large, when there are more than two atom types, or when there are many displaced atoms. This problem persists even when there are only a relatively small number of unique arrangements that survive the elimination process. Here, we extend an existing algorithm to include the extra configurational degrees of freedom from the inclusion of displacement directions. The algorithm uses group theory and a tree-like data structure to eliminate large classes of configurations, avoiding the typical combinatoric explosion. With this approach we can now enumerate previously inaccessible cases, including atomic displacements. © 2017 Elsevier B.V.
320 a57196261400 Kunzler J.W. p78 True Journal 58 Compact structure with high TX-RX isolation for frequency domain duplexing on printed circuit boards When developing compact and lightweight antenna systems for unmanned aerial systems, achieving high isolation between transmit and receive signal paths is challenging. To address this issue, we demonstrate a prototype isolation design on a printed circuit board for a frequency division duplexed X band antenna system. Key components include a microstrip defected ground plane notch filter and a copper grating barrier that provides 20 dB higher isolation than free space separation between the transmit and receive antennas. The hardware provides at least 105 dB of transmit isolation into the receiver low noise amplifier in the transmit band. The proposed design is lighter and more compact than traditional machined metal waveguide isolation techniques used for ground-based systems yet achieves similar isolation performance. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.
320 a57196261400 Kunzler J.W. p665 False Journal 319 Sidelobe Level and Aperture Efficiency Optimization for Tiled Aperiodic Array Antennas Array antennas with aperiodic element placement provide a way to mitigate grating lobe level when the array element spacing is larger than one half wavelength. Design techniques for aperiodic arrays include thinning, numerical optimization, and other methods, but even with modern tools, designing electrically large aperiodic arrays remain computationally challenging. To reduce the complexity of the large aperiodic array design problem, we study the use of discrete rotated tiles with element positions and tile orientations optimized to minimize peak sidelobe level (PSLL). The directivity, frequency sensitivity of PSLL, and optimization complexity for uniform arrays, aperiodic arrays, and tiled arrays are compared. Based on many numerical examples, an approximate relationship between PSLL and array element number and density for aperiodic and tiled arrays is proposed as a convergence estimator for the design optimization process. © 2017 IEEE.
321 a57214229367 Bartschi J.M. p78 False Journal 58 Compact structure with high TX-RX isolation for frequency domain duplexing on printed circuit boards When developing compact and lightweight antenna systems for unmanned aerial systems, achieving high isolation between transmit and receive signal paths is challenging. To address this issue, we demonstrate a prototype isolation design on a printed circuit board for a frequency division duplexed X band antenna system. Key components include a microstrip defected ground plane notch filter and a copper grating barrier that provides 20 dB higher isolation than free space separation between the transmit and receive antennas. The hardware provides at least 105 dB of transmit isolation into the receiver low noise amplifier in the transmit band. The proposed design is lighter and more compact than traditional machined metal waveguide isolation techniques used for ground-based systems yet achieves similar isolation performance. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.
322 a57214855898 Schnepf P.D. p79 True Journal 59 Closed-Loop, Axial Temperature Control of Etched Silicon Microcolumn for Tunable Thermal Gradient Gas Chromatography Combining the resolution of conventional gas chromatography systems with the size factor of microGC systems is important for improving the affordability and portability of high performance gas analysis. Recent work has demonstrated the feasibility of high resolution separation of gases in a benchtopscale short column system by controlling thermal gradients through the column. This work reports a microfabricated thermally controllable gas chromatographic column with a small footprint (approximately 6.25 cm2). The design of the 20 cm column utilizes 21 individually controllable thin film heaters and conduction cooling to produce a desired temperature profile. The reported device is capable of heating and cooling rates exceeding 8000 °C/min and can reach temperatures of 350 °C. The control methods allow for excellent disturbance rejection and precision to within +/- 1 °C. Each length of the column between heaters was demonstrated to be individually controllable and displayed quadratic temperature profiles. This paper focuses on the fabrication process and implementation of the thermal control strategy. [2019-0113] © 1992-2012 IEEE.
323 a57215031057 Davis A. p79 False Journal 59 Closed-Loop, Axial Temperature Control of Etched Silicon Microcolumn for Tunable Thermal Gradient Gas Chromatography Combining the resolution of conventional gas chromatography systems with the size factor of microGC systems is important for improving the affordability and portability of high performance gas analysis. Recent work has demonstrated the feasibility of high resolution separation of gases in a benchtopscale short column system by controlling thermal gradients through the column. This work reports a microfabricated thermally controllable gas chromatographic column with a small footprint (approximately 6.25 cm2). The design of the 20 cm column utilizes 21 individually controllable thin film heaters and conduction cooling to produce a desired temperature profile. The reported device is capable of heating and cooling rates exceeding 8000 °C/min and can reach temperatures of 350 °C. The control methods allow for excellent disturbance rejection and precision to within +/- 1 °C. Each length of the column between heaters was demonstrated to be individually controllable and displayed quadratic temperature profiles. This paper focuses on the fabrication process and implementation of the thermal control strategy. [2019-0113] © 1992-2012 IEEE.
324 a6701610428 Vanfleet R. p79 False Journal 59 Closed-Loop, Axial Temperature Control of Etched Silicon Microcolumn for Tunable Thermal Gradient Gas Chromatography Combining the resolution of conventional gas chromatography systems with the size factor of microGC systems is important for improving the affordability and portability of high performance gas analysis. Recent work has demonstrated the feasibility of high resolution separation of gases in a benchtopscale short column system by controlling thermal gradients through the column. This work reports a microfabricated thermally controllable gas chromatographic column with a small footprint (approximately 6.25 cm2). The design of the 20 cm column utilizes 21 individually controllable thin film heaters and conduction cooling to produce a desired temperature profile. The reported device is capable of heating and cooling rates exceeding 8000 °C/min and can reach temperatures of 350 °C. The control methods allow for excellent disturbance rejection and precision to within +/- 1 °C. Each length of the column between heaters was demonstrated to be individually controllable and displayed quadratic temperature profiles. This paper focuses on the fabrication process and implementation of the thermal control strategy. [2019-0113] © 1992-2012 IEEE.
324 a6701610428 Vanfleet R. p363 False Journal 203 High surface-area carbon microcantilevers Microscale porous carbon mechanical resonators were formed using carbon nanotube templated microfabrication. These cantilever resonators exhibited nanoscale porosity resulting in a high surface area to volume ratio which could enable sensitive analyte detection in air. These resonators were shown to be mechanically robust and the porosity could be controllably varied resulting in densities from 102 to 103 kg m-3, with pore diameters on the order of hundreds of nanometers. Cantilevers with lengths ranging from 500 μm to 5 mm were clamped in a fixture for mechanical resonance testing where quality factors from 102 to 103 were observed at atmospheric pressure in air. © 2019 The Royal Society of Chemistry.
324 a6701610428 Vanfleet R. p512 False Journal 281 Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 μm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes. © 2018 American Chemical Society.
324 a6701610428 Vanfleet R. p725 False Journal 354 Carbon monolith scaffolding for high volumetric capacity silicon Li-ion battery anodes A nanoporous carbon monolith structure has been developed for use as a scaffold for silicon anodes for lithium batteries. This scaffold was fabricated by coating vertically aligned carbon nanotubes in a highly conformal coating of nanocrystalline carbon, applied via atmospheric pressure chemical vapor deposition. The coating increases the mechanical stability of the nanotube structure, which provides electrically conductive pathways through the anode. Silicon anodes were fabricated with the monoliths by low pressure chemical vapor infiltration of silicon. This platform allows the carbon and silicon volume fractions to be independently varied in the anode. Anodes with a low silicon content (less than 5% by volume) showed high stability in cycling against lithium with a capacity retention of 89.7% between cycles 2 and 185. Anodes with a high silicon content (∼25% by volume) showed poor capacity retention when the carbon content was low (<40% by volume), and transmission electron microscopy analysis indicated that the anodes failed due to the destruction of the nanocrystalline carbon coating during cycling. However, by increasing the carbon content to ∼60% volume percent in the monolith, capacity retention was substantially stabilized even for anodes with very high silicon loadings. These stabilized electrodes exhibited volumetric capacities as high as ∼1000 mA h/ml and retained over 725 mA h/ml by cycle 100. © 2017 American Vacuum Society.
325 a7403218372 Jensen B.D. p79 False Journal 59 Closed-Loop, Axial Temperature Control of Etched Silicon Microcolumn for Tunable Thermal Gradient Gas Chromatography Combining the resolution of conventional gas chromatography systems with the size factor of microGC systems is important for improving the affordability and portability of high performance gas analysis. Recent work has demonstrated the feasibility of high resolution separation of gases in a benchtopscale short column system by controlling thermal gradients through the column. This work reports a microfabricated thermally controllable gas chromatographic column with a small footprint (approximately 6.25 cm2). The design of the 20 cm column utilizes 21 individually controllable thin film heaters and conduction cooling to produce a desired temperature profile. The reported device is capable of heating and cooling rates exceeding 8000 °C/min and can reach temperatures of 350 °C. The control methods allow for excellent disturbance rejection and precision to within +/- 1 °C. Each length of the column between heaters was demonstrated to be individually controllable and displayed quadratic temperature profiles. This paper focuses on the fabrication process and implementation of the thermal control strategy. [2019-0113] © 1992-2012 IEEE.
325 a7403218372 Jensen B.D. p153 False Journal 108 Heat set creases in polyethylene terephthalate (PET) sheets to enable origami-based applications Polyethylene terephthalate (PET) sheets show promise for application in origami-based engineering design. Origami-based engineering provides advantages that are not readily available in traditional engineering design methods. Several processing methods were examined to identify trends and determine the effect of processing of PET sheets on the crease properties of origami mechanisms in PET. Various annealing times, temperatures, and cooling rates were evaluated and data collected for over 1000 samples. It was determined that annealing temperature plays the largest role in crease response. An increase in the crystallinity of a PET sheet while in the folded state likely increases the force response of the crease in PET sheets. An annealing time of at least 60 min at 160 C-180 C with a quick cooling results in a high force response in the crease. The effectiveness of the processing methods was demonstrated in several origami patterns of various complexities. © 2019 IOP Publishing Ltd.
325 a7403218372 Jensen B.D. p164 False Journal 114 Using non-destructive testing to predict bending modulus of carbon infiltrated-carbon nanotubes Carbon infiltrated carbon nanotubes (CI-CNT) are an important emerging material in several micro-electro-mechanical systems (MEMS) because of their unique mechanical and chemical properties. While CI-CNTs are only roughly conductive they work well in micro springs, levers, and meshes. However, fabrication of CI-CNTs can result in large mechanical property variation, and methods to characterize properties usually involve destructive testing. Destructive testing also assumes the tested specimens are representative of the entire batch which is not always true in the case of CI-CNT production. Finding a non-destructive way to test for stiffness of this material reduces the number of parts that have to be made and increases confidence in the integrity of device being used. It also simplifies testing of complex parts. The stiffness of CI-CNT beams is related to the molecular structure of the carbon material infiltrated between the carbon nanotubes (CNTs), how it interacts with the CNTs, and how much of it there is. The amount of material can be approximated with the density of the beam, and both the type of material and its interaction with the CNTs can be approximated through analysis of the Raman spectra taken at the surface. A combination of these two observations can be related to the effective material stiffness. The relationship can be fitted with a power function, with a variance of 1.41 GPa, which is about 11% of the maximum stiffness of the samples tested. © 2019 IOP Publishing Ltd.
325 a7403218372 Jensen B.D. p322 False Conference 102 Fabrication and testing of a MEMS system for injection of DNA into plant cells This paper describes the fabrication and testing of a system to inject DNA into plant leaves. Arrays of silicon lances were made using photolithographic and STS DRIE Bosch techniques. A nanoinjector device was also made to accept the silicon lance arrays and perform nanoinjections. Nanoinjections were performed on Arabidopsis and cotton cotyledons. Changes in the force applied during a nanoinjection and varying the number of repeated nanoinjections on the same cotyledon were observed. Too much force or too many repeated injections caused physical damage to the cotyledon. An optimal force and number of repeated injections can be performed without causing physical damage to the cotyledon. Several injections using DNA were performed without successful transfection of the leaves. Possible reasons for this failure to transfect were explored. Copyright © 2019 ASME.
325 a7403218372 Jensen B.D. p324 False Conference 104 Simulation of a micro-electro-mechanical system for generating electrical power from pressurized gas This paper presents a novel approach to energy scavenging for a micro-electro-mechanical system (MEMS) device to convert the energy stored in pressurized gas into electrical power. The proposed design uses input pressure to move a piston and magnet through a set of coils while pulling on another mass through non-linear springs to open and close the input air valve. The model demonstrates that the design is capable of staying in motion with continual input pressure (up to at least a time stamp of 1 second), and that an average power output of 9.47 µW over 5 ms can be achieved. We suggest that further research be done to optimize the design parameters and that the optimized design be used to the test the system. Copyright © 2019 ASME.
325 a7403218372 Jensen B.D. p454 False Conference 160 Zipper Tube Reinforcement to Mitigate Flexible Shaft Buckling The Zipper Tube Reinforcement (ZTR) is a novel support system developed to mitigate buckling in thin flexible devices used in robotic surgery. The ZTR was inspired by a construction technique called a Buckling Restrained Braced Frame (BRBF) and deployable booms for space applications. It utilizes a zipper function to allow a rolled sheet to deploy into a variable-length tube and stow in a small volume spooled on a mandrel. The tube envelops the device and allows it to support a much higher compressive load before buckling failure through the insertion stroke. The ZTR also enables the possibility of smaller, more flexible devices due to its design for continuous support and could find application in other fields. © 2018 IEEE.
325 a7403218372 Jensen B.D. p583 False Conference 228 Retractable anti-buckling support systems for flexible medical devices This work presents two novel support systems used to help mitigate flexible device buckling during insertion such as the insertion of medical device into the body. These systems are collapsible to accommodate the changing length of the flexible device as it is inserted. They use tension in wires or geometry to provide systems with lateral stiffness used to support the device. Through modeling, the performance of these systems can be predicted and they can be designed to a desired performance. This was validated in the geometry-based support system. They provide systems with small operating volumes and part counts. Copyright © 2018 ASME.
325 a7403218372 Jensen B.D. p586 False Conference 231 Design and modeling of a prosthetic venous valve Chronic Venous Insufficiency (CVI) is a disease of the lower limbs that affects millions of people in the United States. CVI results from incompetent venous valves. The purpose of venous valves is to prevent retrograde blood flow to the lower limbs. Valve failure can lead to edema, pain, and ulcers. One solution that has great potential is to create an implantable venous valve that could restore function of the venous system. No prosthetic venous valves are clinically used currently because of problems with biocompatiblility and thrombogenicity caused by high shear rates. This paper presents a prosthetic venous valve that could overcome these difficulties by using carbon-infiltrated carbon nanotubes (CI-CNTs). This material has been proven to be thrombo-resistant, biocompatible due to its non-reactive properties, and durable. The valve was designed to be initially open and to close with physiological pressures. Finite element modeling showed that, with a hydrostatic pressure of 20 mmHg (the minimum hydrostatic pressure in the common femoral vein), it fully closed with a maximum stress of 117 MPa, which is below the ultimate strength of CI-CNTs. A computational fluid dynamics analysis demonstrated the valve would cause a maximum shear rate of 225.1 s− 1, which is less than the maximum shear rate in the body. Hence, this valve would be less likely than previous prosthetic valves to develop blood clots. Currently, this is the lowest shear rate reported for a prosthetic venous valve. These results demonstrate that a CI-CNT prosthetic venous valve has the potential to be an effective treatment for CVI. Copyright © 2018 ASME.
325 a7403218372 Jensen B.D. p587 False Conference 232 Patterned carbon nanotube growth on stainless steel This paper presents, for the first time, the process of growing a pattern of carbon nanotubes (CNT(s)) on 316L stainless steel. The data presented is preliminary and requires further investigation to detail the growth behaviors of CNTs on stainless steel in regards to producing a pattern. However, this article presents the viability of producing a pattern on a stainless steel surface that can be used in bio-surfacing and electronic applications, among others. The results show that producing a CNT pattern on stainless steel can be achieved in a similar manner to that of producing a CNT pattern on a silicon wafer, with some vital differences in the photolithography and growth processes. The results also show that long CNT growth can lead to partial overgrowth of the pattern. Copyright © 2018 ASME.
325 a7403218372 Jensen B.D. p600 False Journal 307 Cylindrical cross-axis flexural pivots The cylindrical cross-axis flexural pivot (CCAFP) is proposed as an ultra-compact flexure capable of being integrated into hollow cylindrical shafts, enabling shaft motion without inhibiting cables or other components inside the shaft. Mechanism geometry, materials, and manufacturing are proposed and the results analyzed and tested. A parametric finite element model of the CCAFP was created to analyze the force-deflection and strain-deflection relationships and the predicted behavior was verified by experiment. Analytic models of stress-limiting cam-surfaces suggest even larger motions may be possible when not limited by current practical constraints. The CCAFP is demonstrated and tested at multiple size scales and in multiple materials, ranging from 28.6 mm diameter 4130 steel (achieving 9 degrees of angular deflection) to 3 mm diameter NiTi (achieving an angular deflection of 85 degrees). The results are generalized to apply to a range of applications, and the CCAFP particularly shows promise for implementation in minimally invasive surgical instruments to decrease instrument size while maintaining instrument performance. © 2017 Elsevier Inc.
325 a7403218372 Jensen B.D. p699 False Journal 342 Inverted L-arm gripper compliant mechanism This work exploits the advantages of compliant mechanisms (devices that achieve their motion through the deflection of flexible members) to enable the creation of small instruments for minimally invasive surgery (MIS). Using flexures to achieve motion presents challenges, three of which are considered in this work. First, compliant mechanisms generally perform inadequately in compression. Second, for a 690 deg range of motion desired for each jaw, the bending stresses in the flexures are prohibitive considering materials used in current instruments. Third, for cables attached at fixed points on the mechanism, the mechanical advantage will vary considerably during actuation. Research results are presented that address these challenges using compliant mechanism principles as demonstrated in a two-degree-of-freedom (2DoF) L-Arm gripper. © 2017 by ASME.
325 a7403218372 Jensen B.D. p867 False Conference 388 Exploration of carbon-filled carbon nanotube vascular stents The purpose of this research was to design, fabricate, and test coronary stent designs composed of carbon-infiltrated carbon nanotubes (CI-CNTs). Coronary stents currently have two major complications: restenosis and thrombosis. CI-CNT stents may provide improved clinical outcomes for both of these issues. Multiple stent design concepts were generated, evaluated, and two stent designs were selected: one with a semi-auxetic nature, and one designed for maximum force. These designs were further developed and optimized using analytical tools along with finite element analysis. Planar versions of the stent designs were manufactured and mechanically tested to verify performance. The performance of the cylindrical stent configurations was analyzed using finite element modeling. A sample cylindrical stent was also fabricated. This research demonstrates that feasible coronary stent designs can be manufactured from CI-CNTs. However, a major challenge for CI-CNT stent designs is meeting the design requirement of sufficient radial force. © Springer International Publishing Switzerland 2017.
325 a7403218372 Jensen B.D. p876 False Journal 407 Preface [No abstract available]
326 a57200515115 Kurniawan C. p80 True Journal 60 Grain boundary structure–property model inference using polycrystals: the overdetermined case Efforts to construct predictive grain boundary (GB) structure–property models have historically relied on property measurements or calculations made on bicrystals. Experimental bicrystals can be difficult or expensive to fabricate, and computational constraints limit atomistic bicrystal simulations to high-symmetry GBs (i.e., those with small enough GB periodicity). Although the use of bicrystal property data to construct GB structure–property models is more direct, in many experimental situations the only type of data available may be measurements of the effective properties of polycrystals. In this work, we investigate the possibility of inferring GB structure–property models from measurements of the homogenized effective properties of polycrystals when the form of the structure–property model is unknown. We present an idealized case study in which GB structure–property models for diffusivity are inferred from noisy simulation results of two-dimensional microstructures, under the assumption that the number of polycrystal measurements available is larger than the number of parameters in the inferred model. We also demonstrate how uncertainty quantification for the inferred structure–property models is easily performed within this framework. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
327 a57194698845 Baird S. p80 False Journal 60 Grain boundary structure–property model inference using polycrystals: the overdetermined case Efforts to construct predictive grain boundary (GB) structure–property models have historically relied on property measurements or calculations made on bicrystals. Experimental bicrystals can be difficult or expensive to fabricate, and computational constraints limit atomistic bicrystal simulations to high-symmetry GBs (i.e., those with small enough GB periodicity). Although the use of bicrystal property data to construct GB structure–property models is more direct, in many experimental situations the only type of data available may be measurements of the effective properties of polycrystals. In this work, we investigate the possibility of inferring GB structure–property models from measurements of the homogenized effective properties of polycrystals when the form of the structure–property model is unknown. We present an idealized case study in which GB structure–property models for diffusivity are inferred from noisy simulation results of two-dimensional microstructures, under the assumption that the number of polycrystal measurements available is larger than the number of parameters in the inferred model. We also demonstrate how uncertainty quantification for the inferred structure–property models is easily performed within this framework. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
327 a57194698845 Baird S. p725 False Journal 354 Carbon monolith scaffolding for high volumetric capacity silicon Li-ion battery anodes A nanoporous carbon monolith structure has been developed for use as a scaffold for silicon anodes for lithium batteries. This scaffold was fabricated by coating vertically aligned carbon nanotubes in a highly conformal coating of nanocrystalline carbon, applied via atmospheric pressure chemical vapor deposition. The coating increases the mechanical stability of the nanotube structure, which provides electrically conductive pathways through the anode. Silicon anodes were fabricated with the monoliths by low pressure chemical vapor infiltration of silicon. This platform allows the carbon and silicon volume fractions to be independently varied in the anode. Anodes with a low silicon content (less than 5% by volume) showed high stability in cycling against lithium with a capacity retention of 89.7% between cycles 2 and 185. Anodes with a high silicon content (∼25% by volume) showed poor capacity retention when the carbon content was low (<40% by volume), and transmission electron microscopy analysis indicated that the anodes failed due to the destruction of the nanocrystalline carbon coating during cycling. However, by increasing the carbon content to ∼60% volume percent in the monolith, capacity retention was substantially stabilized even for anodes with very high silicon loadings. These stabilized electrodes exhibited volumetric capacities as high as ∼1000 mA h/ml and retained over 725 mA h/ml by cycle 100. © 2017 American Vacuum Society.
328 a35409277700 Johnson O.K. p80 False Journal 60 Grain boundary structure–property model inference using polycrystals: the overdetermined case Efforts to construct predictive grain boundary (GB) structure–property models have historically relied on property measurements or calculations made on bicrystals. Experimental bicrystals can be difficult or expensive to fabricate, and computational constraints limit atomistic bicrystal simulations to high-symmetry GBs (i.e., those with small enough GB periodicity). Although the use of bicrystal property data to construct GB structure–property models is more direct, in many experimental situations the only type of data available may be measurements of the effective properties of polycrystals. In this work, we investigate the possibility of inferring GB structure–property models from measurements of the homogenized effective properties of polycrystals when the form of the structure–property model is unknown. We present an idealized case study in which GB structure–property models for diffusivity are inferred from noisy simulation results of two-dimensional microstructures, under the assumption that the number of polycrystal measurements available is larger than the number of parameters in the inferred model. We also demonstrate how uncertainty quantification for the inferred structure–property models is easily performed within this framework. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
328 a35409277700 Johnson O.K. p325 False Conference 105 Establishing baseline performance for off-the-shelf nitrile seals for the India Mark II hand pump system Accessing clean water is a persistent, and life threatening, challenge for millions of people in the world. Mechanical hand pumps have a long history of helping people access clean ground water for drinking and daily use. Among the most ubiquitous are the India Mark II and III pump systems, for which there are more than 4,000,000 installed across the world. These are estimated to serve between 600M and 1B people. All pumps degrade in performance over time, requiring service; many do not receive it causing pumps to become dysfunctional. The purpose of this paper is to establish a baseline for nitrile seal performance of India Mark II hand pump systems. Understanding off-the-shelf performance and using it as a baseline is an important step toward understanding degradation of performance over time, which is the focus of a much larger study to understand – mechanically and socially – how hand pumps perform, degrade, and ultimately meet human needs. In this paper, 110 off-the-shelf nitrile seals that were purchased in Uganda were tested and the following was characterized: (i) geometric variation, (ii) material variation, (iii) leak performance, and (iv) correlation between these. The seal leak performance was found to be very robust to variations in geometry and material at zero cycles. This important baseline supports our future work to understand how and to what degree seals become sensitive to geometric and material degradation during use. Copyright © 2019 ASME.
328 a35409277700 Johnson O.K. p532 True Journal 294 Texture mediated grain boundary network design in three dimensions Experimental grain boundary engineering studies have demonstrated the potential for materials properties enhancement via the modification of grain boundary network structure. These techniques apply to materials that readily form annealing twins and are amenable to cyclic thermomechanical processing and have resulted in dramatic property enhancement. In this work we present a theoretical framework that enables the design of grain boundary networks in polycrystalline materials through an alternative approach: exploitation of a relationship between crystallographic texture and grain boundary network structure. Because crystallographic texture is a universal characteristic of polycrystalline materials, this work has the potential to significantly expand the class of materials whose grain boundary networks can be controlled. We demonstrate the utility of the approach by application to a concrete design problem involving competing design objectives for yield strength, elastic compliance, and resistance to electromigration. We construct the first materials properties closure to comprise grain boundary network sensitive properties and identify an optimal microstructure that is predicted to outperform an undesigned isotropic material. © 2017 Elsevier Ltd
329 a57193749678 Searle M. p81 True Journal 61 Thermal transport due to buoyant flow past a vertical, heated superhydrophobic surface with uniform stream-wise slip An analytical investigation of thermal transport due to laminar, buoyant flow past a vertical superhydrophobic (SHPo) surface was performed. The surface temperature is uniform and is greater than the temperature of the surrounding liquid. Uniform stream-wise hydrodynamic slip and temperature jump were imposed at the wall to model the SHPo surface. Applying an integral analysis within the boundary layer results in a system of differential equations, which was solved numerically to obtain boundary layer thickness and local and average values of the Nusselt number. The classical smooth hydrophobic scenario with no-slip and no temperature jump showed excellent agreement with previous analyses of the same problem. Solutions were obtained for laminar Rayleigh number ranging from 104 to 109 at a Prandtl number of 7. There was a modest decrease in the boundary layer thickness due to the increased slip length and the flow velocity decreased due to the increased temperature jump length. The local Nusselt number decreased as the temperature jump length increased, with greater reduction at larger Rayleigh numbers and near the lower edge. The decrease in the average Nusselt number relative to surfaces with no-slip and no temperature jump may be as much as 50%. © 2019
329 a57193749678 Searle M. p169 True Journal 116 Thermal transport due to liquid jet impingement on superhydrophobic surfaces with isotropic slip: Isoflux wall Thermal transport due to a liquid water jet impinging an isoflux superhydrophobic surface with isotropic slip was modeled analytically. An integral analysis of the transport equations resulting in a system of ordinary differential equations was solved numerically. Impingement on superhydrophobic surfaces greatly reduces the heat transfer that occurs relative to a smooth surface due to gas trapped in cavities on the surface. This results in an apparent slip velocity and temperature jump at the surface. Local and average Nusselt numbers are presented as a function of radial position (0 to 45 jet radii), jet Reynolds number (3×103 to 1.5×104), liquid Prandtl number (2 to 11), normalized slip length (0 to 0.2), and normalized temperature jump length (0 to 0.2). All results are compared to classical (no-slip, no temperature jump) behavior on a smooth surface. Although local Nusselt numbers for the isoflux scenario are greater than the corresponding isothermal case, the difference in Nusselt number between these two heating conditions becomes negligible as the temperature jump length increases to quantities realizable on superhydrophobic surfaces. These results may be utilized to explore heat transfer degradation in applications where smooth surfaces are replaced by superhydrophobic surfaces to avoid fouling. © 2019 Elsevier Ltd
329 a57193749678 Searle M. p410 True Journal 220 Influence of microstructure geometry on pool boiling at superhydrophobic surfaces Periodically patterned superhydrophobic surfaces with rectangular rib and circular post arrays were utilized as heat transfer surfaces in a boiling apparatus with the water pool undergoing saturated pool boiling. The surface microstructures were geometrically defined by cavity fraction (the ratio of projected cavity area to surface area), pitch (the center to center distance between microfeatures), and feature height. Surface heat flux and surface superheat, the difference between the heated surface and the pool saturation temperature, were measured for each surface. Ten different micropatterned surfaces with post or rib geometries were considered with cavity fraction varying from 0.5 to 0.98, pitch varying from 8 to 40 μm, and microfeature height at 4 μm or 15 μm. The surface heat flux was measured across a range of surface superheats spanning 2–38 K. It is demonstrated for the first time that the transition from nucleate boiling to film boiling on rib patterned surfaces depends strongly on the cavity fraction. Increasing the microstructure height from 4 μm to 15 μm modestly increases the transition temperature. Nucleate boiling is more suppressed on post patterned surfaces than on rib patterned surfaces. Further, the rib structured surfaces exhibit a sudden transition from nucleate to film boiling while the post structured surfaces exhibit a gradual transition, with the vapor film growing slowly across the surface. Once stable film boiling is reached, the surface microstructure negligibly influences the heat flux for all surfaces. © 2018 Elsevier Ltd
329 a57193749678 Searle M. p821 True Journal 392 Thermal transport due to liquid jet impingement on superhydrophobic surfaces with isotropic slip This paper presents an analytical investigation of thermal transport due to a steady, laminar, axisymmetric liquid jet impinging normally on a superhydrophobic (SHPo) surface maintained at constant surface temperature. At the liquid-surface boundary of the spreading thin film, an isotropic hydrodynamic slip and temperature jump are imposed to approximate the SHPo surface boundary condition. Applying an integral analysis within the thin film results in a system of differential equations which are solved numerically to obtain local hydrodynamic and thermal boundary layer thicknesses, thin film height, and local and radially averaged heat flux. The classical smooth hydrophobic scenario with no-slip and no-temperature jump showed excellent agreement with previous differential analysis of the same problem. The influence of varying temperature jump length on the local Nusselt number was obtained over a range of Reynolds and Prandtl numbers. Increasing temperature jump length results in a dramatic decrease in the local thermal transport near the impingement point. The greatest decrease occurs at small temperature jump lengths. Further, local and average Nusselt numbers are less influenced by the Reynolds and Prandtl numbers as temperature jump length increases. Overall, variations in the temperature jump length exert much more influence than variations in the hydrodynamic slip length. © 2017 Elsevier Ltd
330 a55457444300 Crockett J. p81 False Journal 61 Thermal transport due to buoyant flow past a vertical, heated superhydrophobic surface with uniform stream-wise slip An analytical investigation of thermal transport due to laminar, buoyant flow past a vertical superhydrophobic (SHPo) surface was performed. The surface temperature is uniform and is greater than the temperature of the surrounding liquid. Uniform stream-wise hydrodynamic slip and temperature jump were imposed at the wall to model the SHPo surface. Applying an integral analysis within the boundary layer results in a system of differential equations, which was solved numerically to obtain boundary layer thickness and local and average values of the Nusselt number. The classical smooth hydrophobic scenario with no-slip and no temperature jump showed excellent agreement with previous analyses of the same problem. Solutions were obtained for laminar Rayleigh number ranging from 104 to 109 at a Prandtl number of 7. There was a modest decrease in the boundary layer thickness due to the increased slip length and the flow velocity decreased due to the increased temperature jump length. The local Nusselt number decreased as the temperature jump length increased, with greater reduction at larger Rayleigh numbers and near the lower edge. The decrease in the average Nusselt number relative to surfaces with no-slip and no temperature jump may be as much as 50%. © 2019
330 a55457444300 Crockett J. p169 False Journal 116 Thermal transport due to liquid jet impingement on superhydrophobic surfaces with isotropic slip: Isoflux wall Thermal transport due to a liquid water jet impinging an isoflux superhydrophobic surface with isotropic slip was modeled analytically. An integral analysis of the transport equations resulting in a system of ordinary differential equations was solved numerically. Impingement on superhydrophobic surfaces greatly reduces the heat transfer that occurs relative to a smooth surface due to gas trapped in cavities on the surface. This results in an apparent slip velocity and temperature jump at the surface. Local and average Nusselt numbers are presented as a function of radial position (0 to 45 jet radii), jet Reynolds number (3×103 to 1.5×104), liquid Prandtl number (2 to 11), normalized slip length (0 to 0.2), and normalized temperature jump length (0 to 0.2). All results are compared to classical (no-slip, no temperature jump) behavior on a smooth surface. Although local Nusselt numbers for the isoflux scenario are greater than the corresponding isothermal case, the difference in Nusselt number between these two heating conditions becomes negligible as the temperature jump length increases to quantities realizable on superhydrophobic surfaces. These results may be utilized to explore heat transfer degradation in applications where smooth surfaces are replaced by superhydrophobic surfaces to avoid fouling. © 2019 Elsevier Ltd
330 a55457444300 Crockett J. p202 False Journal 136 Heat transfer to bouncing droplets on superhydrophobic surfaces This study experimentally and theoretically investigates the dynamics and heat transfer to impinging water droplets on superhydrophobic surfaces heated below the boiling temperature. Different from impingement on hydrophilic substrates, the droplets rebound from the surface after the spreading and retraction stages. Experiments are performed using simultaneous high speed video and infrared (IR) imaging to capture droplet dynamics and temperature variation during the transient event. Thermal images allow estimation of bulk droplet temperature change during contact such that the cooling effectiveness for an individual droplet can be estimated. A similarity solution is utilized to yield a model for the transient heat flux at the droplet-wall interface, where convection inside the droplet is accounted for. The experimental and theoretical results for the cooling effectiveness show good agreement. It is revealed that the cooling effectiveness increases with Weber number but decreases with droplet diameter and surface cavity fraction (the ratio of cavity area to total surface area). © 2019 Elsevier Ltd
330 a55457444300 Crockett J. p260 False Journal 170 Turning depths: Evanescent to propagating wave kinetic energy density Tidal flow over oceanic topography generates internal waves when the natural frequency N of the water is greater than the tidal frequency ω. When N<ω, evanescent waves are generated. Although the amplitude and kinetic energy of evanescent waves decay rapidly, if the wave reaches a turning depth, where N=ω, and moves into a region where N>ω, the evanescent wave becomes an internal wave. This work expands upon previous research of varying stratifications by investigating the kinetic energy density in internal waves generated by evanescent waves passing through a turning depth. An analytical model is presented and compared to synthetic schlieren experiments of two Gaussian-shaped topographies. The model and experiments both indicate that the kinetic energy density of internal waves increases with decreasing topographic slope, when the distance between the topography and the turning depth decreases and when the average Froude number in the evanescent region is close to one. The model is used to estimate the normalized kinetic energy density of internal waves generated from an oceanic feature located within an evanescent region. © 2019 American Physical Society.
330 a55457444300 Crockett J. p271 False Journal 178 Influence of micro-structured superhydrophobic surfaces on nucleation and natural convection in a heated pool This work experimentally explores sub-boiling pool nucleation on micro-structured superhydrophobic surfaces. All surfaces tested were submerged in a 20 mm deep pool of water and heated from below to maintain a constant surface temperature, while the side walls of the pool were insulated, and the top was covered. Three thermocouples positioned in the pool obtain the average pool temperature. A heat flux sensor is placed directly beneath the surface to measure the heat flux supplied to the pool. Free convection heat transfer coefficients are obtained for the sub-boiling temperature range of 40–90 °C. Six surface types are studied: smooth hydrophilic, smooth hydrophobic, superhydrophobic with rib/cavity structures, superhydrophobic with rib/cavity structures and additional sparsely spaced ribs to close off the cavities, circular posts, and circular holes. It is found that structured superhydrophobic surfaces provide cavities for nucleation to occur. More dissolved air effervesces from the water as the surface temperature increases due to an increased level of supersaturation and convection. The nucleation leads to large air bubble formations that reduce the overall convection coefficient when compared to the smooth surfaces. For the rib/cavity structured surfaces, the bubbles form in an anisotropic manner and are aligned with the surface structure. More bubbles are observed on the superhydrophobic surfaces where the cavities are bounded. Since water's ability to dissolve air is dependent on temperature, heat and mass transfer cannot be treated independently on any of the superhydrophobic surfaces studied here. © 2018 Elsevier Ltd
330 a55457444300 Crockett J. p392 False Journal 170 Orthogonal liquid-jet impingement on wettability-patterned impermeable substrates Liquid-jet impingement on flat impermeable substrates is important for a multitude of applications ranging from electronic-equipment cooling to fuel atomization and erosion of solid surfaces. On a wettable horizontal surface, where a sufficient downstream liquid depth can be sustained after axisymmetric impingement, the jet forms a thin film on the substrate up to a radial distance where the film height suddenly increases, forming a hydraulic jump. On a superhydrophobic surface, where a downstream liquid depth is not naturally sustained, the thin film expands and breaks up into droplets, which are subsequently ejected in a random fashion outward, as carried by their radial momentum. In the present work, a facile, scalable, wettability-patterning approach is presented for delaying or even eliminating droplet breakup in the case of jet impingement on horizontal superhydrophobic surfaces. Analytical expressions for predicting the hydraulic jump and droplet breakup locations are developed to designate the proper wettability patterns that facilitate alteration and control of the postimpingement liquid behavior. The axisymmetric model is extended to evaluate the radial variation of the competing forces responsible for film breakup, and a design criterion for the effective wettability patterns is proposed. © 2019 American Physical Society.
330 a55457444300 Crockett J. p410 False Journal 220 Influence of microstructure geometry on pool boiling at superhydrophobic surfaces Periodically patterned superhydrophobic surfaces with rectangular rib and circular post arrays were utilized as heat transfer surfaces in a boiling apparatus with the water pool undergoing saturated pool boiling. The surface microstructures were geometrically defined by cavity fraction (the ratio of projected cavity area to surface area), pitch (the center to center distance between microfeatures), and feature height. Surface heat flux and surface superheat, the difference between the heated surface and the pool saturation temperature, were measured for each surface. Ten different micropatterned surfaces with post or rib geometries were considered with cavity fraction varying from 0.5 to 0.98, pitch varying from 8 to 40 μm, and microfeature height at 4 μm or 15 μm. The surface heat flux was measured across a range of surface superheats spanning 2–38 K. It is demonstrated for the first time that the transition from nucleate boiling to film boiling on rib patterned surfaces depends strongly on the cavity fraction. Increasing the microstructure height from 4 μm to 15 μm modestly increases the transition temperature. Nucleate boiling is more suppressed on post patterned surfaces than on rib patterned surfaces. Further, the rib structured surfaces exhibit a sudden transition from nucleate to film boiling while the post structured surfaces exhibit a gradual transition, with the vapor film growing slowly across the surface. Once stable film boiling is reached, the surface microstructure negligibly influences the heat flux for all surfaces. © 2018 Elsevier Ltd
330 a55457444300 Crockett J. p422 False Journal 232 Thermally induced atomization during droplet impingement on superheated hydrophobic and superhydrophobic surfaces This paper presents on thermally induced atomization dynamics during liquid water droplet impingement on superheated hydrophobic and superhydrophobic surfaces. Circular micropillars 4 μm in height with varying center-to-center distances (pitch) of 8 μm, 12 μm and 16 μm, are used to create the superhydrophobic surfaces. The range of surface temperatures explored is 110°C&lt;Ts&lt;337°C. An image processing algorithm was developed to quantify the temporal behavior of thermally induced atomization captured via high-speed photography. Results show thermally induced atomization is initially absent (&lt;1 ms following impact) on all surfaces. The amount of ejected droplets later during droplet spreading is determined as a function of surface structuring and temperature. Atomization ceases when the surface has cooled sufficiently (2.5–4 ms depending on the surface). The maximum amount of atomization for a given scenario is highly dependent on surface temperature and surface microstructure characteristics. At low surface temperatures, atomization increases with increasing surface temperature; however at high surface temperatures atomization decreases with increasing surface temperature. This rise and fall behavior is tantamount to the classical relationship between heat flux and surface temperature for pool boiling. Both droplet impingement and pool boiling depend on vapor bubble formation dynamics and the stability of the so-called Leidenfrost vapor film, which is impacted by surface wettability. Results also show that small surface pitch causes a high atomization intensity, indicating that not all superhydrophobic surfaces sustain Leidenfrost-like behavior at all excess temperatures. © 2018 Elsevier Ltd
330 a55457444300 Crockett J. p500 False Journal 271 Bubble nucleation in superhydrophobic microchannels due to subcritical heating This work experimentally studies the effects of single wall heating on laminar flow in a high-aspect ratio superhydrophobic microchannel. When water that is saturated with air is used as the working liquid, the non-wetted cavities on the superhydrophobic surfaces act as nucleation sites and allow air to effervesce out of the water and onto the surface when heated. Previous works in the literature have only considered the opposite case where the water is undersaturated and absorbs air out the cavities for a microchannel setting. The microchannel considered in this work consists of a rib/cavity structured superhydrophobic surface and a glass surface separated by spacers. The microchannel is 60 mm long by 14 mm wide and two channel heights of nominally 183 μm and 366 μm are explored. The superhydrophobic side is in contact with a heated aluminum block and a camera is used to visualize the flow through the glass side. Thermocouples are embedded in the aluminum to record the temperature profile along the length of the channel. Temperatures are maintained below the boiling temperature of the working liquid. The friction factor-Reynolds product (fRe) is obtained via pressure drop and volumetric flow-rate measurements. Five surface types/configurations are investigated: smooth hydrophilic, smooth hydrophobic, superhydrophobic with ribs perpendicular to the flow, superhydrophobic with ribs parallel to the flow, and superhydrophobic with ribs parallel to the flow with several breaker ridges perpendicular to the flow. The surface type/configuration has a significant impact on the mass transport dynamics. For surfaces with closed cell micro-structures, large bubbles eventually form and adversely affect fRe and lead to higher temperatures along the channel. When degassed water is used, no bubble nucleation is observed and the air initially trapped in the superhydrophobic cavities is quickly absorbed by the water. © 2018 Elsevier Ltd
330 a55457444300 Crockett J. p821 False Journal 392 Thermal transport due to liquid jet impingement on superhydrophobic surfaces with isotropic slip This paper presents an analytical investigation of thermal transport due to a steady, laminar, axisymmetric liquid jet impinging normally on a superhydrophobic (SHPo) surface maintained at constant surface temperature. At the liquid-surface boundary of the spreading thin film, an isotropic hydrodynamic slip and temperature jump are imposed to approximate the SHPo surface boundary condition. Applying an integral analysis within the thin film results in a system of differential equations which are solved numerically to obtain local hydrodynamic and thermal boundary layer thicknesses, thin film height, and local and radially averaged heat flux. The classical smooth hydrophobic scenario with no-slip and no-temperature jump showed excellent agreement with previous differential analysis of the same problem. The influence of varying temperature jump length on the local Nusselt number was obtained over a range of Reynolds and Prandtl numbers. Increasing temperature jump length results in a dramatic decrease in the local thermal transport near the impingement point. The greatest decrease occurs at small temperature jump lengths. Further, local and average Nusselt numbers are less influenced by the Reynolds and Prandtl numbers as temperature jump length increases. Overall, variations in the temperature jump length exert much more influence than variations in the hydrodynamic slip length. © 2017 Elsevier Ltd
330 a55457444300 Crockett J. p822 False Journal 392 Two-phase flow pressure drop in superhydrophobic channels Superhydrophobic surfaces have been shown to reduce drag in single-phase channel flow; however, little work has been done to characterize their drag-reducing ability found in two-phase flows. Adiabatic, air-water mixtures were used to explore the influence of hydrophobicity on two-phase flows and the hydrodynamics which might be present in flow condensation environments. Pressure drop measurements in a rectangular channel with one superhydrophobic wall (cross-section approximately 0.37 × 10 mm) and three transparent hydrophilic walls were obtained. Data for air/water mixtures with superficial Reynolds numbers ranging from 22–215 and 55–220, respectively, were obtained for superhydrophobic surfaces with three different cavity fractions. Agreement between experimentally obtained two-phase pressure drop data and correlations in the literature for conventional smooth control surfaces was better than 20 percent, which is within the accuracy of the correlations. The data reveal a reduction in the pressure drop for two-phase flow in a channel with a single superhydrophobic wall compared to a control scenario. The observed reduction is approximately 10 percent greater than the reduction that is observed for single-phase flow (relative to a classical channel). © 2017 Elsevier Ltd
330 a55457444300 Crockett J. p825 False Journal 394 Hydrodynamics of droplet impingement on hot surfaces of varying wettability This work presents on the hydrodynamics of water droplet impingement on superheated solid surfaces across the entire wettability spectrum: superhydrophilic, hydrophilic, hydrophobic and superhydrophobic. While a large body of work exists on droplet impingement on hydrophilic and superhydrophilic surfaces, impingement on the latter two has been largely neglected and the present results show that dynamics are dramatically different. Experiments ranging in surface temperature from 125°C to 415°C and Weber numbers from 10 to 225 were performed and analyzed using high-speed imaging. Some of the most striking differences are as follows. While atomization is always present for impingement on the hydrophilic and superhydrophilic surfaces at temperatures below the Leidenfrost point, atomization is absent at low Weber numbers and at low excess surface temperatures on the hydrophobic surface. At high surface temperatures, the attraction of vapor bubbles on the hydrophobic surface allows a vapor blanket to form more readily thus leading to Leidenfrost behavior at a much lower temperature than classically observed on a hydrophilic surface. One of the most interesting phenomenon that will be discussed includes what will be described as a “pseudo-Leidenfrost” state for impingement on the superhydrophobic surface. Because water can be suspended at the peaks of the roughness on a superhydrophobic interface, vapor escapes from underneath the droplet thus mimicking Leidenfrost behavior for all excess temperatures. This results in minimal atomization for superhydrophobic impingement over the entire regime explored. Finally, maximum spread diameters for Leidenfrost impingement are tabulated as a function of the Weber number for all surfaces and are shown to be larger on the smooth surfaces than on the textured ones indicating that droplet spreading at the Leidenfrost point is not independent of surface type as previously supposed. © 2016 Elsevier Ltd
331 a6701863708 Maynes D. p81 False Journal 61 Thermal transport due to buoyant flow past a vertical, heated superhydrophobic surface with uniform stream-wise slip An analytical investigation of thermal transport due to laminar, buoyant flow past a vertical superhydrophobic (SHPo) surface was performed. The surface temperature is uniform and is greater than the temperature of the surrounding liquid. Uniform stream-wise hydrodynamic slip and temperature jump were imposed at the wall to model the SHPo surface. Applying an integral analysis within the boundary layer results in a system of differential equations, which was solved numerically to obtain boundary layer thickness and local and average values of the Nusselt number. The classical smooth hydrophobic scenario with no-slip and no temperature jump showed excellent agreement with previous analyses of the same problem. Solutions were obtained for laminar Rayleigh number ranging from 104 to 109 at a Prandtl number of 7. There was a modest decrease in the boundary layer thickness due to the increased slip length and the flow velocity decreased due to the increased temperature jump length. The local Nusselt number decreased as the temperature jump length increased, with greater reduction at larger Rayleigh numbers and near the lower edge. The decrease in the average Nusselt number relative to surfaces with no-slip and no temperature jump may be as much as 50%. © 2019
331 a6701863708 Maynes D. p137 False Journal 96 Contributions of Tip Leakage and Inlet Diffusion on Inducer Backflow Inducers are used as a first stage in pumps to minimize cavitation and allow the pump to operate at lower inlet head conditions. Inlet flow recirculation or backflow in the inducer occurs at low flow conditions and can lead to instabilities and cavitation-induced head breakdown. Backflow of an inducer with a tip clearance (TC) of τ = 0.32% and with no tip clearance (NTC) is examined with a series of computational fluid dynamics simulations. Removing the TC eliminates tip leakage flow; however, backflow is still observed. In fact, the NTC case showed a 37% increase in the length of the upstream backflow penetration. Tip leakage flow does instigate a smaller secondary leading edge tip vortex that is separate from the much larger backflow structure. A comprehensive analysis of these simulations suggests that blade inlet diffusion, not tip leakage flow, is the fundamental mechanism leading to the formation of backflow. © 2019 by ASME.
331 a6701863708 Maynes D. p169 False Journal 116 Thermal transport due to liquid jet impingement on superhydrophobic surfaces with isotropic slip: Isoflux wall Thermal transport due to a liquid water jet impinging an isoflux superhydrophobic surface with isotropic slip was modeled analytically. An integral analysis of the transport equations resulting in a system of ordinary differential equations was solved numerically. Impingement on superhydrophobic surfaces greatly reduces the heat transfer that occurs relative to a smooth surface due to gas trapped in cavities on the surface. This results in an apparent slip velocity and temperature jump at the surface. Local and average Nusselt numbers are presented as a function of radial position (0 to 45 jet radii), jet Reynolds number (3×103 to 1.5×104), liquid Prandtl number (2 to 11), normalized slip length (0 to 0.2), and normalized temperature jump length (0 to 0.2). All results are compared to classical (no-slip, no temperature jump) behavior on a smooth surface. Although local Nusselt numbers for the isoflux scenario are greater than the corresponding isothermal case, the difference in Nusselt number between these two heating conditions becomes negligible as the temperature jump length increases to quantities realizable on superhydrophobic surfaces. These results may be utilized to explore heat transfer degradation in applications where smooth surfaces are replaced by superhydrophobic surfaces to avoid fouling. © 2019 Elsevier Ltd
331 a6701863708 Maynes D. p202 False Journal 136 Heat transfer to bouncing droplets on superhydrophobic surfaces This study experimentally and theoretically investigates the dynamics and heat transfer to impinging water droplets on superhydrophobic surfaces heated below the boiling temperature. Different from impingement on hydrophilic substrates, the droplets rebound from the surface after the spreading and retraction stages. Experiments are performed using simultaneous high speed video and infrared (IR) imaging to capture droplet dynamics and temperature variation during the transient event. Thermal images allow estimation of bulk droplet temperature change during contact such that the cooling effectiveness for an individual droplet can be estimated. A similarity solution is utilized to yield a model for the transient heat flux at the droplet-wall interface, where convection inside the droplet is accounted for. The experimental and theoretical results for the cooling effectiveness show good agreement. It is revealed that the cooling effectiveness increases with Weber number but decreases with droplet diameter and surface cavity fraction (the ratio of cavity area to total surface area). © 2019 Elsevier Ltd
331 a6701863708 Maynes D. p271 False Journal 178 Influence of micro-structured superhydrophobic surfaces on nucleation and natural convection in a heated pool This work experimentally explores sub-boiling pool nucleation on micro-structured superhydrophobic surfaces. All surfaces tested were submerged in a 20 mm deep pool of water and heated from below to maintain a constant surface temperature, while the side walls of the pool were insulated, and the top was covered. Three thermocouples positioned in the pool obtain the average pool temperature. A heat flux sensor is placed directly beneath the surface to measure the heat flux supplied to the pool. Free convection heat transfer coefficients are obtained for the sub-boiling temperature range of 40–90 °C. Six surface types are studied: smooth hydrophilic, smooth hydrophobic, superhydrophobic with rib/cavity structures, superhydrophobic with rib/cavity structures and additional sparsely spaced ribs to close off the cavities, circular posts, and circular holes. It is found that structured superhydrophobic surfaces provide cavities for nucleation to occur. More dissolved air effervesces from the water as the surface temperature increases due to an increased level of supersaturation and convection. The nucleation leads to large air bubble formations that reduce the overall convection coefficient when compared to the smooth surfaces. For the rib/cavity structured surfaces, the bubbles form in an anisotropic manner and are aligned with the surface structure. More bubbles are observed on the superhydrophobic surfaces where the cavities are bounded. Since water's ability to dissolve air is dependent on temperature, heat and mass transfer cannot be treated independently on any of the superhydrophobic surfaces studied here. © 2018 Elsevier Ltd
331 a6701863708 Maynes D. p340 False Journal 96 Increasing Inducer Stability and Suction Performance With a Stability Control Device An inducer is used as the first stage of high suction performance pump. It pressurizes the fluid to delay the onset of cavitation, which can adversely affect performance in a centrifugal pump. In this paper, the performance of a water pump inducer has been explored with and without the implementation of a stability control device (SCD). This device is an inlet cover bleed system that removes high-energy fluid near the blade leading edge and reinjects it back upstream. The research was conducted by running multiphase, time-accurate computational fluid dynamic (CFD) simulations at the design flow coefficient and at low, off-design flow coefficients. The suction performance and stability for the same inducer with and without the implementation of the SCD has been explored. An improvement in stability and suction performance was observed when the SCD was implemented. Without the SCD, the inducer developed backflow at the blade tip, which led to rotating cavitation and larger rotordynamic forces. With the SCD, no significant cavitation instabilities developed, and the rotordynamic forces remained small. The lack of cavitation instabilities also allowed the inducer to operate at lower inlet pressures, increasing the suction performance of the inducer. Copyright © 2018 by ASME.
331 a6701863708 Maynes D. p410 False Journal 220 Influence of microstructure geometry on pool boiling at superhydrophobic surfaces Periodically patterned superhydrophobic surfaces with rectangular rib and circular post arrays were utilized as heat transfer surfaces in a boiling apparatus with the water pool undergoing saturated pool boiling. The surface microstructures were geometrically defined by cavity fraction (the ratio of projected cavity area to surface area), pitch (the center to center distance between microfeatures), and feature height. Surface heat flux and surface superheat, the difference between the heated surface and the pool saturation temperature, were measured for each surface. Ten different micropatterned surfaces with post or rib geometries were considered with cavity fraction varying from 0.5 to 0.98, pitch varying from 8 to 40 μm, and microfeature height at 4 μm or 15 μm. The surface heat flux was measured across a range of surface superheats spanning 2–38 K. It is demonstrated for the first time that the transition from nucleate boiling to film boiling on rib patterned surfaces depends strongly on the cavity fraction. Increasing the microstructure height from 4 μm to 15 μm modestly increases the transition temperature. Nucleate boiling is more suppressed on post patterned surfaces than on rib patterned surfaces. Further, the rib structured surfaces exhibit a sudden transition from nucleate to film boiling while the post structured surfaces exhibit a gradual transition, with the vapor film growing slowly across the surface. Once stable film boiling is reached, the surface microstructure negligibly influences the heat flux for all surfaces. © 2018 Elsevier Ltd
331 a6701863708 Maynes D. p422 False Journal 232 Thermally induced atomization during droplet impingement on superheated hydrophobic and superhydrophobic surfaces This paper presents on thermally induced atomization dynamics during liquid water droplet impingement on superheated hydrophobic and superhydrophobic surfaces. Circular micropillars 4 μm in height with varying center-to-center distances (pitch) of 8 μm, 12 μm and 16 μm, are used to create the superhydrophobic surfaces. The range of surface temperatures explored is 110°C&lt;Ts&lt;337°C. An image processing algorithm was developed to quantify the temporal behavior of thermally induced atomization captured via high-speed photography. Results show thermally induced atomization is initially absent (&lt;1 ms following impact) on all surfaces. The amount of ejected droplets later during droplet spreading is determined as a function of surface structuring and temperature. Atomization ceases when the surface has cooled sufficiently (2.5–4 ms depending on the surface). The maximum amount of atomization for a given scenario is highly dependent on surface temperature and surface microstructure characteristics. At low surface temperatures, atomization increases with increasing surface temperature; however at high surface temperatures atomization decreases with increasing surface temperature. This rise and fall behavior is tantamount to the classical relationship between heat flux and surface temperature for pool boiling. Both droplet impingement and pool boiling depend on vapor bubble formation dynamics and the stability of the so-called Leidenfrost vapor film, which is impacted by surface wettability. Results also show that small surface pitch causes a high atomization intensity, indicating that not all superhydrophobic surfaces sustain Leidenfrost-like behavior at all excess temperatures. © 2018 Elsevier Ltd
331 a6701863708 Maynes D. p500 False Journal 271 Bubble nucleation in superhydrophobic microchannels due to subcritical heating This work experimentally studies the effects of single wall heating on laminar flow in a high-aspect ratio superhydrophobic microchannel. When water that is saturated with air is used as the working liquid, the non-wetted cavities on the superhydrophobic surfaces act as nucleation sites and allow air to effervesce out of the water and onto the surface when heated. Previous works in the literature have only considered the opposite case where the water is undersaturated and absorbs air out the cavities for a microchannel setting. The microchannel considered in this work consists of a rib/cavity structured superhydrophobic surface and a glass surface separated by spacers. The microchannel is 60 mm long by 14 mm wide and two channel heights of nominally 183 μm and 366 μm are explored. The superhydrophobic side is in contact with a heated aluminum block and a camera is used to visualize the flow through the glass side. Thermocouples are embedded in the aluminum to record the temperature profile along the length of the channel. Temperatures are maintained below the boiling temperature of the working liquid. The friction factor-Reynolds product (fRe) is obtained via pressure drop and volumetric flow-rate measurements. Five surface types/configurations are investigated: smooth hydrophilic, smooth hydrophobic, superhydrophobic with ribs perpendicular to the flow, superhydrophobic with ribs parallel to the flow, and superhydrophobic with ribs parallel to the flow with several breaker ridges perpendicular to the flow. The surface type/configuration has a significant impact on the mass transport dynamics. For surfaces with closed cell micro-structures, large bubbles eventually form and adversely affect fRe and lead to higher temperatures along the channel. When degassed water is used, no bubble nucleation is observed and the air initially trapped in the superhydrophobic cavities is quickly absorbed by the water. © 2018 Elsevier Ltd
331 a6701863708 Maynes D. p821 False Journal 392 Thermal transport due to liquid jet impingement on superhydrophobic surfaces with isotropic slip This paper presents an analytical investigation of thermal transport due to a steady, laminar, axisymmetric liquid jet impinging normally on a superhydrophobic (SHPo) surface maintained at constant surface temperature. At the liquid-surface boundary of the spreading thin film, an isotropic hydrodynamic slip and temperature jump are imposed to approximate the SHPo surface boundary condition. Applying an integral analysis within the thin film results in a system of differential equations which are solved numerically to obtain local hydrodynamic and thermal boundary layer thicknesses, thin film height, and local and radially averaged heat flux. The classical smooth hydrophobic scenario with no-slip and no-temperature jump showed excellent agreement with previous differential analysis of the same problem. The influence of varying temperature jump length on the local Nusselt number was obtained over a range of Reynolds and Prandtl numbers. Increasing temperature jump length results in a dramatic decrease in the local thermal transport near the impingement point. The greatest decrease occurs at small temperature jump lengths. Further, local and average Nusselt numbers are less influenced by the Reynolds and Prandtl numbers as temperature jump length increases. Overall, variations in the temperature jump length exert much more influence than variations in the hydrodynamic slip length. © 2017 Elsevier Ltd
331 a6701863708 Maynes D. p822 False Journal 392 Two-phase flow pressure drop in superhydrophobic channels Superhydrophobic surfaces have been shown to reduce drag in single-phase channel flow; however, little work has been done to characterize their drag-reducing ability found in two-phase flows. Adiabatic, air-water mixtures were used to explore the influence of hydrophobicity on two-phase flows and the hydrodynamics which might be present in flow condensation environments. Pressure drop measurements in a rectangular channel with one superhydrophobic wall (cross-section approximately 0.37 × 10 mm) and three transparent hydrophilic walls were obtained. Data for air/water mixtures with superficial Reynolds numbers ranging from 22–215 and 55–220, respectively, were obtained for superhydrophobic surfaces with three different cavity fractions. Agreement between experimentally obtained two-phase pressure drop data and correlations in the literature for conventional smooth control surfaces was better than 20 percent, which is within the accuracy of the correlations. The data reveal a reduction in the pressure drop for two-phase flow in a channel with a single superhydrophobic wall compared to a control scenario. The observed reduction is approximately 10 percent greater than the reduction that is observed for single-phase flow (relative to a classical channel). © 2017 Elsevier Ltd
331 a6701863708 Maynes D. p825 False Journal 394 Hydrodynamics of droplet impingement on hot surfaces of varying wettability This work presents on the hydrodynamics of water droplet impingement on superheated solid surfaces across the entire wettability spectrum: superhydrophilic, hydrophilic, hydrophobic and superhydrophobic. While a large body of work exists on droplet impingement on hydrophilic and superhydrophilic surfaces, impingement on the latter two has been largely neglected and the present results show that dynamics are dramatically different. Experiments ranging in surface temperature from 125°C to 415°C and Weber numbers from 10 to 225 were performed and analyzed using high-speed imaging. Some of the most striking differences are as follows. While atomization is always present for impingement on the hydrophilic and superhydrophilic surfaces at temperatures below the Leidenfrost point, atomization is absent at low Weber numbers and at low excess surface temperatures on the hydrophobic surface. At high surface temperatures, the attraction of vapor bubbles on the hydrophobic surface allows a vapor blanket to form more readily thus leading to Leidenfrost behavior at a much lower temperature than classically observed on a hydrophilic surface. One of the most interesting phenomenon that will be discussed includes what will be described as a “pseudo-Leidenfrost” state for impingement on the superhydrophobic surface. Because water can be suspended at the peaks of the roughness on a superhydrophobic interface, vapor escapes from underneath the droplet thus mimicking Leidenfrost behavior for all excess temperatures. This results in minimal atomization for superhydrophobic impingement over the entire regime explored. Finally, maximum spread diameters for Leidenfrost impingement are tabulated as a function of the Weber number for all surfaces and are shown to be larger on the smooth surfaces than on the textured ones indicating that droplet spreading at the Leidenfrost point is not independent of surface type as previously supposed. © 2016 Elsevier Ltd
332 a57201666213 Park J.L. p82 True Journal 62 The effects of doping alumina with silica in alumina-supported NiO catalysts for oxidative dehydrogenation of ethane The production of ethylene via the oxidative dehydrogenation of ethane is well-documented as an energy efficient process. Alumina-supported NiO catalysts make the oxidative dehydrogenation of ethane more selective to ethylene and operate at low reaction temperatures (&lt;500 °C). The addition of silica to the alumina supports of these NiO catalysts formed higher amounts of the NiAl2O4 spinel phase and had adjustable acidities and surface areas with calcination temperature, leading to increases in ethylene productivity. A 5 wt% silica-doped alumina support calcined at 1100 °C with 16 wt% NiO exhibited low acidity and a stable, low surface area, resulting in an ethylene productivity of 13.6 μmolethylene/s·gnickel or 1.32 × 10−2 μmolethylene/s·m2 at 500 °C. © 2019
332 a57201666213 Park J.L. p518 True Journal 287 Low Temperature Oxidative Dehydrogenation of Ethane by Ce-Modified NiNb Catalysts Low temperature oxidative dehydrogenation catalysts are becoming a viable material for drastically altering the production of small chain alkenes. Among materials used, bimetallic and trimetallic nickel catalysts have shown great promise. In this study, we report a 38% increase in the rate of ethylene production with the addition of Ce to NiNb catalysts. Oxidative dehydrogenation of ethane was performed in the temperature range of 250-350 °C. At 300 °C, the rate of ethylene production was maximized with a rate of 6.91 × 10-4 mmol gcat-1 s-1. At higher temperatures, the rate of deep oxidation to CO2 outcompeted the rate of ethylene formation. The improved rate due to the addition of Ce is attributed to ceria's ability to rapidly transport oxygen to the NiO active sites. © 2018 American Chemical Society.
333 a55694540600 Canizales K.A. p82 False Journal 62 The effects of doping alumina with silica in alumina-supported NiO catalysts for oxidative dehydrogenation of ethane The production of ethylene via the oxidative dehydrogenation of ethane is well-documented as an energy efficient process. Alumina-supported NiO catalysts make the oxidative dehydrogenation of ethane more selective to ethylene and operate at low reaction temperatures (&lt;500 °C). The addition of silica to the alumina supports of these NiO catalysts formed higher amounts of the NiAl2O4 spinel phase and had adjustable acidities and surface areas with calcination temperature, leading to increases in ethylene productivity. A 5 wt% silica-doped alumina support calcined at 1100 °C with 16 wt% NiO exhibited low acidity and a stable, low surface area, resulting in an ethylene productivity of 13.6 μmolethylene/s·gnickel or 1.32 × 10−2 μmolethylene/s·m2 at 500 °C. © 2019
334 a7003545107 Woodfield B.F. p82 False Journal 62 The effects of doping alumina with silica in alumina-supported NiO catalysts for oxidative dehydrogenation of ethane The production of ethylene via the oxidative dehydrogenation of ethane is well-documented as an energy efficient process. Alumina-supported NiO catalysts make the oxidative dehydrogenation of ethane more selective to ethylene and operate at low reaction temperatures (&lt;500 °C). The addition of silica to the alumina supports of these NiO catalysts formed higher amounts of the NiAl2O4 spinel phase and had adjustable acidities and surface areas with calcination temperature, leading to increases in ethylene productivity. A 5 wt% silica-doped alumina support calcined at 1100 °C with 16 wt% NiO exhibited low acidity and a stable, low surface area, resulting in an ethylene productivity of 13.6 μmolethylene/s·gnickel or 1.32 × 10−2 μmolethylene/s·m2 at 500 °C. © 2019
334 a7003545107 Woodfield B.F. p181 False Journal 123 Thermal and hydrothermal stability of pure and silica-doped mesoporous aluminas Thermal and hydrothermal stabilities of solvent deficient derived pure alumina (PA) as well as silica-doped aluminas (SDA) with three different dopant concentrations (5, 15, 27% by weight) have been investigated for changes in phase and pore structure after calcination at high temperatures under air and steam/air atmospheres. For all aluminas, heat treatment results in decreased surface area and increased pore diameter. Starting at 700 °C, metastable to stable phase transformation occurs, causing a substantial change in the pore structure of all aluminas. By 1100 (PA), 1200 (15 SDA) and 1200 °C (27 SDA), the transition to α-Al2O3 was complete, respectively. No α-Al2O3 is observed for 5 wt % silica doped alumina (5SDA) under thermal calcination. Calcination in steam and air, instead of in air only, results in enlarged pore size and depressed temperature of alpha phase transformation for all aluminas. Results show that the silica dopant modifies the pores of the alumina, stabilizes the oxygen lattice of γ-Al2O3, and retards α-Al2O3 formation. This study of the thermal and hydrothermal stability not only suggests the applicability of 5SDA for catalytic reactions occurring at high temperature in the presence of steam, but also contributes to a better understanding of the structural features responsible for the improved thermal stability of these aluminas. © 2019 Elsevier Inc.
334 a7003545107 Woodfield B.F. p384 False Journal 210 Review of surface water interactions with metal oxide nanoparticles Surface water can affect the properties of metal oxide nanoparticles. Investigations on several systems revealed that nanoparticles have different thermodynamic properties than their bulk counterparts due to adsorbed water on their surfaces. Some thermodynamically metastable phases of bulk metal oxides become stable when reduced to the nanoscale, partially due to interactions between high energy surfaces and surface water. Water adsorption microcalorimetry and high-temperature oxide melt solution calorimetry, low-temperature specific heat calorimetry, and inelastic neutron scattering are used to understand the interactions of surface water with metal oxide nanoparticles. Computational methods, such as molecular dynamics simulations and density functional theory calculations, have been used to study these interactions. Investigations on titania, cassiterite, and alumina illustrate the insights gained by these measurements. The energetics of water on metal oxide surfaces are different from those of either liquid water or hexagonal ice, and there is substantial variation in water interactions on different metal oxide surfaces. Copyright © Materials Research Society 2019.
335 a13406135400 Stowers K.J. p82 False Journal 62 The effects of doping alumina with silica in alumina-supported NiO catalysts for oxidative dehydrogenation of ethane The production of ethylene via the oxidative dehydrogenation of ethane is well-documented as an energy efficient process. Alumina-supported NiO catalysts make the oxidative dehydrogenation of ethane more selective to ethylene and operate at low reaction temperatures (&lt;500 °C). The addition of silica to the alumina supports of these NiO catalysts formed higher amounts of the NiAl2O4 spinel phase and had adjustable acidities and surface areas with calcination temperature, leading to increases in ethylene productivity. A 5 wt% silica-doped alumina support calcined at 1100 °C with 16 wt% NiO exhibited low acidity and a stable, low surface area, resulting in an ethylene productivity of 13.6 μmolethylene/s·gnickel or 1.32 × 10−2 μmolethylene/s·m2 at 500 °C. © 2019
335 a13406135400 Stowers K.J. p449 False Journal 253 Synthesis of high-specific volume carbon nanotube structures for gas-phase applications A novel and efficient gas-phase method has been developed for synthesizing carbon nanotube (CNT) structures with very high specific volume, high surface area and high porosity. The resulting material has potential application as a catalyst and adsorbent support for gas-phase chemical processes and has several advantages over the conventional liquid-phase approach that involves multiple steps and takes many hours to days resulting in a dense mat of CNTs. Multi-walled CNTs were initially nucleated and grown on alumina nanoparticles using a liquid precursor of ferrocene dissolved in xylene. The CNT seeds were extended using ethylene as the gas precursor. Forces generated by CNT growth separated the alumina support clusters to result in a porous entangled structure with a 60 times gain in weight and a 1300 times gain in volume, compared to the original alumina particles. Effects of ferrocene injection rate, alumina particle sizes, and CNT growth parameters on the volume of the structure were analyzed and it was determined that high ferrocene input, moderate temperatures, and small alumina particles all favor the synthesis of high-volume CNT structures. © 2018 Elsevier B.V.
335 a13406135400 Stowers K.J. p518 False Journal 287 Low Temperature Oxidative Dehydrogenation of Ethane by Ce-Modified NiNb Catalysts Low temperature oxidative dehydrogenation catalysts are becoming a viable material for drastically altering the production of small chain alkenes. Among materials used, bimetallic and trimetallic nickel catalysts have shown great promise. In this study, we report a 38% increase in the rate of ethylene production with the addition of Ce to NiNb catalysts. Oxidative dehydrogenation of ethane was performed in the temperature range of 250-350 °C. At 300 °C, the rate of ethylene production was maximized with a rate of 6.91 × 10-4 mmol gcat-1 s-1. At higher temperatures, the rate of deep oxidation to CO2 outcompeted the rate of ethylene formation. The improved rate due to the addition of Ce is attributed to ceria's ability to rapidly transport oxygen to the NiO active sites. © 2018 American Chemical Society.
336 a57203017789 Smiley A.J. p84 True Journal 64 Postprocessing the outputs of an interacting multiple-model Kalman filter using a Markovian trellis to estimate parameter values of aged Li-ion cells Lithium-ion battery modeling for use in battery management systems requires models that can adapt to the changing behavior of a cell as it ages. One method to enable this adaptivity is to select the most representative model from a set of “pre-aged” models that represent the characteristics of the cell as different cyclic and calendar aging processes occur. By modeling the aging of a cell as a Markovian process, an interacting multiple-model Kalman filter (IMM) can be utilized to determine a time-varying probability mass function that specifies the probability that each of the models under consideration is the best representation of the cell under observation. While the output of the IMM is useful by itself, its predictions can be improved by post-processing. In this paper, we present methods to analyze the time-series probability mass function produced by the IMM using the Viterbi and BCJR algorithms in common use in the digital-communications discipline. These algorithms seek to identify the “best path” through the space of available models over time, based on the likelihoods produced by the IMM and the Markovian transition probabilities. Through the use of these post-processing algorithms, confidence in the best-fitting model can be improved. © 2019 Elsevier Ltd
337 a6701609778 Plett G.L. p84 False Journal 64 Postprocessing the outputs of an interacting multiple-model Kalman filter using a Markovian trellis to estimate parameter values of aged Li-ion cells Lithium-ion battery modeling for use in battery management systems requires models that can adapt to the changing behavior of a cell as it ages. One method to enable this adaptivity is to select the most representative model from a set of “pre-aged” models that represent the characteristics of the cell as different cyclic and calendar aging processes occur. By modeling the aging of a cell as a Markovian process, an interacting multiple-model Kalman filter (IMM) can be utilized to determine a time-varying probability mass function that specifies the probability that each of the models under consideration is the best representation of the cell under observation. While the output of the IMM is useful by itself, its predictions can be improved by post-processing. In this paper, we present methods to analyze the time-series probability mass function produced by the IMM using the Viterbi and BCJR algorithms in common use in the digital-communications discipline. These algorithms seek to identify the “best path” through the space of available models over time, based on the likelihoods produced by the IMM and the Markovian transition probabilities. Through the use of these post-processing algorithms, confidence in the best-fitting model can be improved. © 2019 Elsevier Ltd
338 a7005052477 Godfrey P.C. p87 True Journal 66 The biotech living and the walking dead [No abstract available]
339 a8750608700 Allen G.N. p87 False Journal 66 The biotech living and the walking dead [No abstract available]
340 a57214071214 Benson D. p87 False Journal 66 The biotech living and the walking dead [No abstract available]
341 a57193518829 Hansen L.T. p88 True Journal 67 An investigation of geometrically necessary dislocations and back stress in large grained tantalum via EBSD and CPFEM This study explores the evolution of GNDs and their effects on back stress through experimental and computational methods. Four large-grained tantalum tensile specimens were strained in uniaxial tension, electron backscatter diffraction (EBSD) data were collected, and geometrically necessary dislocation (GND) maps of the four specimens in the unloaded state were produced. EBSD-based GND maps revealed several types of features with high GND content which caused back stress in the specimens. Correlations between five geometrically-based grain boundary (GB) transmission factors and the GB GND content were evaluated, and statistically significant correlations were found for transmission factors based on Livingston and Chalmer's N factor, Werner and Prantl's slip transfer number, and GB misorientation. The sign of individual components of the Nye tensor were used to visually and quantitatively identify clustering of GNDs of the same sign, thus giving additional evidence of increasing back stress due to deformation. Deformation of one of the specimens was simulated using multiple CPFEM based modeling approaches and predicted stress-strain responses are compared. The super dislocation model (SD model) — a crystal plasticity finite element method (CPFEM) which incorporates elastic dislocation interactions — was able to isolate impact of back stress on the overall flow stress. The SD model predicted correct stresses when compared with experimental data; however, when the elastic interactions in the SD model were turned off, stress predictions were 25% too low. Thus, demonstrating the importance of incorporating back stress into the model. © 2019 Elsevier B.V.
342 a7006583274 Wagoner R.H. p88 False Journal 67 An investigation of geometrically necessary dislocations and back stress in large grained tantalum via EBSD and CPFEM This study explores the evolution of GNDs and their effects on back stress through experimental and computational methods. Four large-grained tantalum tensile specimens were strained in uniaxial tension, electron backscatter diffraction (EBSD) data were collected, and geometrically necessary dislocation (GND) maps of the four specimens in the unloaded state were produced. EBSD-based GND maps revealed several types of features with high GND content which caused back stress in the specimens. Correlations between five geometrically-based grain boundary (GB) transmission factors and the GB GND content were evaluated, and statistically significant correlations were found for transmission factors based on Livingston and Chalmer's N factor, Werner and Prantl's slip transfer number, and GB misorientation. The sign of individual components of the Nye tensor were used to visually and quantitatively identify clustering of GNDs of the same sign, thus giving additional evidence of increasing back stress due to deformation. Deformation of one of the specimens was simulated using multiple CPFEM based modeling approaches and predicted stress-strain responses are compared. The super dislocation model (SD model) — a crystal plasticity finite element method (CPFEM) which incorporates elastic dislocation interactions — was able to isolate impact of back stress on the overall flow stress. The SD model predicted correct stresses when compared with experimental data; however, when the elastic interactions in the SD model were turned off, stress predictions were 25% too low. Thus, demonstrating the importance of incorporating back stress into the model. © 2019 Elsevier B.V.
342 a7006583274 Wagoner R.H. p208 False Journal 141 Atomistic survey of grain boundary-dislocation interactions in FCC nickel It is well known that grain boundaries (GBs) have a strong influence on mechanical properties of polycrystalline materials. Not as well-known is how different GBs interact with dislocations to influence dislocation movement. This work presents a molecular dynamics study of 33 different FCC Ni bicrystals, each subjected to four different loading conditions to induce incident dislocation-GB interactions in 132 unique configurations. The resulting simulations produce 189 dislocation-GB interactions. Each interaction is analyzed to determine properties that affect the likelihood of transmission, reflection, or absorption of the dislocation at the GB of interest. The results confirm the ability to predict the slip system of a transmitted dislocation using common geometric criteria. Furthermore, machine learning reveals that geometric properties, such as the minimum residual Burgers vector (RBV) and the disorientation angle between the two grains, are strong indicators of whether or not a dislocation will transmit through a GB. © 2019 Elsevier B.V.
342 a7006583274 Wagoner R.H. p748 False Journal 362 An RVE procedure for micromechanical prediction of mechanical behavior of dual-phase steel A “bottom-up” representative volume element (RVE) for a dual phase steel was constructed based on measured microstructural properties (“microproperties”). This differs from the common procedure of inferring hypothetical microproperties by fitting to macroscopic behavior using an assumed micro-to-macrolaw. The bottom-up approach allows the assessment of the law itself by comparing RVE-predicted mechanical behavior with independent macroscopic measurements, thus revealing the nature of the controlling micromechanisms. An RVE for DP980 steel was constructed using actual microproperties. Finite element (FE) simulations of elastic-plastic transitions were compared with independent loading-unloading-loading and compression-tension experiments. Constitutive models of three types were utilized: 1) a standard continuum model, 2) a standard Crystal Plasticity (CP) model, and 3) a SuperDislocation (SD) model similar to CP but including the elastic interactions of discrete dislocations. These comparisons led to following conclusions: 1) While a constitutive model that ignores elastic interaction of defects can be fit to macroscopic or microscopic behavior, it cannot represent both accurately, 2) Elastic interactions among dislocations are the predominant source of nonlinearity in the nominally-elastic region (i.e. at stresses below the standard yield stress), and 3) Continuum stress inhomogeneity arising from the hard martensite / soft ferrite microstructure has a minor role in the observed transitional nonlinearity in the absence of discrete dislocation interactions. © 2017 Elsevier B.V.
343 a55359526600 Lim H. p88 False Journal 67 An investigation of geometrically necessary dislocations and back stress in large grained tantalum via EBSD and CPFEM This study explores the evolution of GNDs and their effects on back stress through experimental and computational methods. Four large-grained tantalum tensile specimens were strained in uniaxial tension, electron backscatter diffraction (EBSD) data were collected, and geometrically necessary dislocation (GND) maps of the four specimens in the unloaded state were produced. EBSD-based GND maps revealed several types of features with high GND content which caused back stress in the specimens. Correlations between five geometrically-based grain boundary (GB) transmission factors and the GB GND content were evaluated, and statistically significant correlations were found for transmission factors based on Livingston and Chalmer's N factor, Werner and Prantl's slip transfer number, and GB misorientation. The sign of individual components of the Nye tensor were used to visually and quantitatively identify clustering of GNDs of the same sign, thus giving additional evidence of increasing back stress due to deformation. Deformation of one of the specimens was simulated using multiple CPFEM based modeling approaches and predicted stress-strain responses are compared. The super dislocation model (SD model) — a crystal plasticity finite element method (CPFEM) which incorporates elastic dislocation interactions — was able to isolate impact of back stress on the overall flow stress. The SD model predicted correct stresses when compared with experimental data; however, when the elastic interactions in the SD model were turned off, stress predictions were 25% too low. Thus, demonstrating the importance of incorporating back stress into the model. © 2019 Elsevier B.V.
343 a55359526600 Lim H. p748 False Journal 362 An RVE procedure for micromechanical prediction of mechanical behavior of dual-phase steel A “bottom-up” representative volume element (RVE) for a dual phase steel was constructed based on measured microstructural properties (“microproperties”). This differs from the common procedure of inferring hypothetical microproperties by fitting to macroscopic behavior using an assumed micro-to-macrolaw. The bottom-up approach allows the assessment of the law itself by comparing RVE-predicted mechanical behavior with independent macroscopic measurements, thus revealing the nature of the controlling micromechanisms. An RVE for DP980 steel was constructed using actual microproperties. Finite element (FE) simulations of elastic-plastic transitions were compared with independent loading-unloading-loading and compression-tension experiments. Constitutive models of three types were utilized: 1) a standard continuum model, 2) a standard Crystal Plasticity (CP) model, and 3) a SuperDislocation (SD) model similar to CP but including the elastic interactions of discrete dislocations. These comparisons led to following conclusions: 1) While a constitutive model that ignores elastic interaction of defects can be fit to macroscopic or microscopic behavior, it cannot represent both accurately, 2) Elastic interactions among dislocations are the predominant source of nonlinearity in the nominally-elastic region (i.e. at stresses below the standard yield stress), and 3) Continuum stress inhomogeneity arising from the hard martensite / soft ferrite microstructure has a minor role in the observed transitional nonlinearity in the absence of discrete dislocation interactions. © 2017 Elsevier B.V.
344 a56911636200 Carroll J.D. p88 False Journal 67 An investigation of geometrically necessary dislocations and back stress in large grained tantalum via EBSD and CPFEM This study explores the evolution of GNDs and their effects on back stress through experimental and computational methods. Four large-grained tantalum tensile specimens were strained in uniaxial tension, electron backscatter diffraction (EBSD) data were collected, and geometrically necessary dislocation (GND) maps of the four specimens in the unloaded state were produced. EBSD-based GND maps revealed several types of features with high GND content which caused back stress in the specimens. Correlations between five geometrically-based grain boundary (GB) transmission factors and the GB GND content were evaluated, and statistically significant correlations were found for transmission factors based on Livingston and Chalmer's N factor, Werner and Prantl's slip transfer number, and GB misorientation. The sign of individual components of the Nye tensor were used to visually and quantitatively identify clustering of GNDs of the same sign, thus giving additional evidence of increasing back stress due to deformation. Deformation of one of the specimens was simulated using multiple CPFEM based modeling approaches and predicted stress-strain responses are compared. The super dislocation model (SD model) — a crystal plasticity finite element method (CPFEM) which incorporates elastic dislocation interactions — was able to isolate impact of back stress on the overall flow stress. The SD model predicted correct stresses when compared with experimental data; however, when the elastic interactions in the SD model were turned off, stress predictions were 25% too low. Thus, demonstrating the importance of incorporating back stress into the model. © 2019 Elsevier B.V.
345 a55272011900 Zhou G. p88 False Journal 67 An investigation of geometrically necessary dislocations and back stress in large grained tantalum via EBSD and CPFEM This study explores the evolution of GNDs and their effects on back stress through experimental and computational methods. Four large-grained tantalum tensile specimens were strained in uniaxial tension, electron backscatter diffraction (EBSD) data were collected, and geometrically necessary dislocation (GND) maps of the four specimens in the unloaded state were produced. EBSD-based GND maps revealed several types of features with high GND content which caused back stress in the specimens. Correlations between five geometrically-based grain boundary (GB) transmission factors and the GB GND content were evaluated, and statistically significant correlations were found for transmission factors based on Livingston and Chalmer's N factor, Werner and Prantl's slip transfer number, and GB misorientation. The sign of individual components of the Nye tensor were used to visually and quantitatively identify clustering of GNDs of the same sign, thus giving additional evidence of increasing back stress due to deformation. Deformation of one of the specimens was simulated using multiple CPFEM based modeling approaches and predicted stress-strain responses are compared. The super dislocation model (SD model) — a crystal plasticity finite element method (CPFEM) which incorporates elastic dislocation interactions — was able to isolate impact of back stress on the overall flow stress. The SD model predicted correct stresses when compared with experimental data; however, when the elastic interactions in the SD model were turned off, stress predictions were 25% too low. Thus, demonstrating the importance of incorporating back stress into the model. © 2019 Elsevier B.V.
346 a57203486012 Bong H.J. p88 False Journal 67 An investigation of geometrically necessary dislocations and back stress in large grained tantalum via EBSD and CPFEM This study explores the evolution of GNDs and their effects on back stress through experimental and computational methods. Four large-grained tantalum tensile specimens were strained in uniaxial tension, electron backscatter diffraction (EBSD) data were collected, and geometrically necessary dislocation (GND) maps of the four specimens in the unloaded state were produced. EBSD-based GND maps revealed several types of features with high GND content which caused back stress in the specimens. Correlations between five geometrically-based grain boundary (GB) transmission factors and the GB GND content were evaluated, and statistically significant correlations were found for transmission factors based on Livingston and Chalmer's N factor, Werner and Prantl's slip transfer number, and GB misorientation. The sign of individual components of the Nye tensor were used to visually and quantitatively identify clustering of GNDs of the same sign, thus giving additional evidence of increasing back stress due to deformation. Deformation of one of the specimens was simulated using multiple CPFEM based modeling approaches and predicted stress-strain responses are compared. The super dislocation model (SD model) — a crystal plasticity finite element method (CPFEM) which incorporates elastic dislocation interactions — was able to isolate impact of back stress on the overall flow stress. The SD model predicted correct stresses when compared with experimental data; however, when the elastic interactions in the SD model were turned off, stress predictions were 25% too low. Thus, demonstrating the importance of incorporating back stress into the model. © 2019 Elsevier B.V.
346 a57203486012 Bong H.J. p748 True Journal 362 An RVE procedure for micromechanical prediction of mechanical behavior of dual-phase steel A “bottom-up” representative volume element (RVE) for a dual phase steel was constructed based on measured microstructural properties (“microproperties”). This differs from the common procedure of inferring hypothetical microproperties by fitting to macroscopic behavior using an assumed micro-to-macrolaw. The bottom-up approach allows the assessment of the law itself by comparing RVE-predicted mechanical behavior with independent macroscopic measurements, thus revealing the nature of the controlling micromechanisms. An RVE for DP980 steel was constructed using actual microproperties. Finite element (FE) simulations of elastic-plastic transitions were compared with independent loading-unloading-loading and compression-tension experiments. Constitutive models of three types were utilized: 1) a standard continuum model, 2) a standard Crystal Plasticity (CP) model, and 3) a SuperDislocation (SD) model similar to CP but including the elastic interactions of discrete dislocations. These comparisons led to following conclusions: 1) While a constitutive model that ignores elastic interaction of defects can be fit to macroscopic or microscopic behavior, it cannot represent both accurately, 2) Elastic interactions among dislocations are the predominant source of nonlinearity in the nominally-elastic region (i.e. at stresses below the standard yield stress), and 3) Continuum stress inhomogeneity arising from the hard martensite / soft ferrite microstructure has a minor role in the observed transitional nonlinearity in the absence of discrete dislocation interactions. © 2017 Elsevier B.V.
347 a57202293242 Ogbeibu S. p89 True Journal 68 Technological turbulence and greening of team creativity, product innovation, and human resource management: Implications for sustainability Given the overwhelming increase in technological advancements and global warming concerns, our study attempts to investigate the predictive powers of green human resource management (GHRM) bundles and green team creativity on green product innovation. Additionally, we examine the roles of technological turbulence and environmental dynamic capability. We have administered a cross-sectional (time lag) survey design with 229 respondents from 31 manufacturing organisations in Malaysia and employed the partial least square path modelling (SmartPLS3) for data analysis. Results indicate that technological turbulence, green recruitment and selection and green training, involvement and development are positive predictors of green team creativity. Green performance and compensation negatively predict green team creativity. While green team creativity positively predicts green product innovation, environmental dynamic capability negatively predicts green product innovation. Technological turbulence reinforces the positive impact of green recruitment and selection on green team creativity and dampens the positive impact of green training, involvement and development on green team creativity. Furthermore, green team creativity is a complementary and competitive mediator. By simultaneously investigating the predictive powers of technological turbulence, green team creativity and environmental dynamic capability in our study, we offer novel insights that extend traditional HRM conceptualisations to reflect a more environmentally sustainable GHRM framework. Policy implications and future directions are also discussed. © 2019 Elsevier Ltd
348 a57203024588 Emelifeonwu J. p89 False Journal 68 Technological turbulence and greening of team creativity, product innovation, and human resource management: Implications for sustainability Given the overwhelming increase in technological advancements and global warming concerns, our study attempts to investigate the predictive powers of green human resource management (GHRM) bundles and green team creativity on green product innovation. Additionally, we examine the roles of technological turbulence and environmental dynamic capability. We have administered a cross-sectional (time lag) survey design with 229 respondents from 31 manufacturing organisations in Malaysia and employed the partial least square path modelling (SmartPLS3) for data analysis. Results indicate that technological turbulence, green recruitment and selection and green training, involvement and development are positive predictors of green team creativity. Green performance and compensation negatively predict green team creativity. While green team creativity positively predicts green product innovation, environmental dynamic capability negatively predicts green product innovation. Technological turbulence reinforces the positive impact of green recruitment and selection on green team creativity and dampens the positive impact of green training, involvement and development on green team creativity. Furthermore, green team creativity is a complementary and competitive mediator. By simultaneously investigating the predictive powers of technological turbulence, green team creativity and environmental dynamic capability in our study, we offer novel insights that extend traditional HRM conceptualisations to reflect a more environmentally sustainable GHRM framework. Policy implications and future directions are also discussed. © 2019 Elsevier Ltd
349 a57160053200 Senadjki A. p89 False Journal 68 Technological turbulence and greening of team creativity, product innovation, and human resource management: Implications for sustainability Given the overwhelming increase in technological advancements and global warming concerns, our study attempts to investigate the predictive powers of green human resource management (GHRM) bundles and green team creativity on green product innovation. Additionally, we examine the roles of technological turbulence and environmental dynamic capability. We have administered a cross-sectional (time lag) survey design with 229 respondents from 31 manufacturing organisations in Malaysia and employed the partial least square path modelling (SmartPLS3) for data analysis. Results indicate that technological turbulence, green recruitment and selection and green training, involvement and development are positive predictors of green team creativity. Green performance and compensation negatively predict green team creativity. While green team creativity positively predicts green product innovation, environmental dynamic capability negatively predicts green product innovation. Technological turbulence reinforces the positive impact of green recruitment and selection on green team creativity and dampens the positive impact of green training, involvement and development on green team creativity. Furthermore, green team creativity is a complementary and competitive mediator. By simultaneously investigating the predictive powers of technological turbulence, green team creativity and environmental dynamic capability in our study, we offer novel insights that extend traditional HRM conceptualisations to reflect a more environmentally sustainable GHRM framework. Policy implications and future directions are also discussed. © 2019 Elsevier Ltd
350 a36006215900 Gaskin J. p89 False Journal 68 Technological turbulence and greening of team creativity, product innovation, and human resource management: Implications for sustainability Given the overwhelming increase in technological advancements and global warming concerns, our study attempts to investigate the predictive powers of green human resource management (GHRM) bundles and green team creativity on green product innovation. Additionally, we examine the roles of technological turbulence and environmental dynamic capability. We have administered a cross-sectional (time lag) survey design with 229 respondents from 31 manufacturing organisations in Malaysia and employed the partial least square path modelling (SmartPLS3) for data analysis. Results indicate that technological turbulence, green recruitment and selection and green training, involvement and development are positive predictors of green team creativity. Green performance and compensation negatively predict green team creativity. While green team creativity positively predicts green product innovation, environmental dynamic capability negatively predicts green product innovation. Technological turbulence reinforces the positive impact of green recruitment and selection on green team creativity and dampens the positive impact of green training, involvement and development on green team creativity. Furthermore, green team creativity is a complementary and competitive mediator. By simultaneously investigating the predictive powers of technological turbulence, green team creativity and environmental dynamic capability in our study, we offer novel insights that extend traditional HRM conceptualisations to reflect a more environmentally sustainable GHRM framework. Policy implications and future directions are also discussed. © 2019 Elsevier Ltd
351 a55944615300 Kaivo-oja J. p89 False Journal 68 Technological turbulence and greening of team creativity, product innovation, and human resource management: Implications for sustainability Given the overwhelming increase in technological advancements and global warming concerns, our study attempts to investigate the predictive powers of green human resource management (GHRM) bundles and green team creativity on green product innovation. Additionally, we examine the roles of technological turbulence and environmental dynamic capability. We have administered a cross-sectional (time lag) survey design with 229 respondents from 31 manufacturing organisations in Malaysia and employed the partial least square path modelling (SmartPLS3) for data analysis. Results indicate that technological turbulence, green recruitment and selection and green training, involvement and development are positive predictors of green team creativity. Green performance and compensation negatively predict green team creativity. While green team creativity positively predicts green product innovation, environmental dynamic capability negatively predicts green product innovation. Technological turbulence reinforces the positive impact of green recruitment and selection on green team creativity and dampens the positive impact of green training, involvement and development on green team creativity. Furthermore, green team creativity is a complementary and competitive mediator. By simultaneously investigating the predictive powers of technological turbulence, green team creativity and environmental dynamic capability in our study, we offer novel insights that extend traditional HRM conceptualisations to reflect a more environmentally sustainable GHRM framework. Policy implications and future directions are also discussed. © 2019 Elsevier Ltd
352 a57191995369 Chen K. p90 True Journal 69 Optimising the design of phased array feeds for survey speed The scientific capability of an astronomical phased array feed receiver can be quantified by combining the bandwidth, sensitivity, and field of view into the overall survey speed of the instrument. The authors investigate the relationships between survey speed and reflector geometry, array layout, element spacing and element configuration using numerical simulations, to determine the values of these parameters that lead to optimal system performance. They characterise the array element spacing that leads to maximum survey speed as a function of the reflector f/D. To further improve survey speed in relation to the overall number of array elements, the authors explore the possibility of using elements with modest levels of superdirectivity to sample more of the focal plane Airy pattern and increase optimal spacing for survey speed figure of merit. The results explain how optimal survey speed is controlled primarily by the influence of element type and array layout on the peak achievable aperture efficiency. © The Institution of Engineering and Technology 2020
353 a57195515828 Horne R.R. p91 True Journal 70 Latanoprost uptake and release from commercial contact lenses This study investigated the potential of delivering an anti-glaucoma drug using commercial silicone hydrogel (SiHy) contact lenses. The moderately hydrophobic drug latanoprost was rapidly loaded in 4 min by swelling contact lenses in a solution of the drug in n-propanol. A fraction of the drug was radiolabeled, thus allowing measurement of the uptake and subsequent release of drug into artificial tear fluid. Three questions were addressed: (1) how much drug can be loaded into each type of lens, (2) how fast is drug release, and (3) how are these values related to the contact lens chemistry. The results showed that much more latanoprost could be loaded into SiHy lenses than a conventional contact lens of poly(hydroxyethyl methacrylate). The drug uptake correlated with the amount of swelling in n-propanol, with Galyfilcon lenses having the greatest swelling and highest drug uptake. The drug release from the SiHy lenses occurred over days, whereas the conventional lens released nearly all drug in a burst over a few hours. To examine correlations between lens chemistry, drug chemistry and uptake, and solvent chemistry, the Hansen solubility parameters were calculated using estimates of contact lens chemistry. These results showed that drug uptake in SiHy lenses correlated with favorable solubility parameter interactions between the n-propanol and the lens material, but did not correlate with interactions between the drug and the lens materials. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
354 a57211443769 Rich J.T. p91 False Journal 70 Latanoprost uptake and release from commercial contact lenses This study investigated the potential of delivering an anti-glaucoma drug using commercial silicone hydrogel (SiHy) contact lenses. The moderately hydrophobic drug latanoprost was rapidly loaded in 4 min by swelling contact lenses in a solution of the drug in n-propanol. A fraction of the drug was radiolabeled, thus allowing measurement of the uptake and subsequent release of drug into artificial tear fluid. Three questions were addressed: (1) how much drug can be loaded into each type of lens, (2) how fast is drug release, and (3) how are these values related to the contact lens chemistry. The results showed that much more latanoprost could be loaded into SiHy lenses than a conventional contact lens of poly(hydroxyethyl methacrylate). The drug uptake correlated with the amount of swelling in n-propanol, with Galyfilcon lenses having the greatest swelling and highest drug uptake. The drug release from the SiHy lenses occurred over days, whereas the conventional lens released nearly all drug in a burst over a few hours. To examine correlations between lens chemistry, drug chemistry and uptake, and solvent chemistry, the Hansen solubility parameters were calculated using estimates of contact lens chemistry. These results showed that drug uptake in SiHy lenses correlated with favorable solubility parameter interactions between the n-propanol and the lens material, but did not correlate with interactions between the drug and the lens materials. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
355 a57211435896 Bradley M.W. p91 False Journal 70 Latanoprost uptake and release from commercial contact lenses This study investigated the potential of delivering an anti-glaucoma drug using commercial silicone hydrogel (SiHy) contact lenses. The moderately hydrophobic drug latanoprost was rapidly loaded in 4 min by swelling contact lenses in a solution of the drug in n-propanol. A fraction of the drug was radiolabeled, thus allowing measurement of the uptake and subsequent release of drug into artificial tear fluid. Three questions were addressed: (1) how much drug can be loaded into each type of lens, (2) how fast is drug release, and (3) how are these values related to the contact lens chemistry. The results showed that much more latanoprost could be loaded into SiHy lenses than a conventional contact lens of poly(hydroxyethyl methacrylate). The drug uptake correlated with the amount of swelling in n-propanol, with Galyfilcon lenses having the greatest swelling and highest drug uptake. The drug release from the SiHy lenses occurred over days, whereas the conventional lens released nearly all drug in a burst over a few hours. To examine correlations between lens chemistry, drug chemistry and uptake, and solvent chemistry, the Hansen solubility parameters were calculated using estimates of contact lens chemistry. These results showed that drug uptake in SiHy lenses correlated with favorable solubility parameter interactions between the n-propanol and the lens material, but did not correlate with interactions between the drug and the lens materials. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
356 a7005408810 Pitt W.G. p91 False Journal 70 Latanoprost uptake and release from commercial contact lenses This study investigated the potential of delivering an anti-glaucoma drug using commercial silicone hydrogel (SiHy) contact lenses. The moderately hydrophobic drug latanoprost was rapidly loaded in 4 min by swelling contact lenses in a solution of the drug in n-propanol. A fraction of the drug was radiolabeled, thus allowing measurement of the uptake and subsequent release of drug into artificial tear fluid. Three questions were addressed: (1) how much drug can be loaded into each type of lens, (2) how fast is drug release, and (3) how are these values related to the contact lens chemistry. The results showed that much more latanoprost could be loaded into SiHy lenses than a conventional contact lens of poly(hydroxyethyl methacrylate). The drug uptake correlated with the amount of swelling in n-propanol, with Galyfilcon lenses having the greatest swelling and highest drug uptake. The drug release from the SiHy lenses occurred over days, whereas the conventional lens released nearly all drug in a burst over a few hours. To examine correlations between lens chemistry, drug chemistry and uptake, and solvent chemistry, the Hansen solubility parameters were calculated using estimates of contact lens chemistry. These results showed that drug uptake in SiHy lenses correlated with favorable solubility parameter interactions between the n-propanol and the lens material, but did not correlate with interactions between the drug and the lens materials. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.
356 a7005408810 Pitt W.G. p153 False Journal 108 Heat set creases in polyethylene terephthalate (PET) sheets to enable origami-based applications Polyethylene terephthalate (PET) sheets show promise for application in origami-based engineering design. Origami-based engineering provides advantages that are not readily available in traditional engineering design methods. Several processing methods were examined to identify trends and determine the effect of processing of PET sheets on the crease properties of origami mechanisms in PET. Various annealing times, temperatures, and cooling rates were evaluated and data collected for over 1000 samples. It was determined that annealing temperature plays the largest role in crease response. An increase in the crystallinity of a PET sheet while in the folded state likely increases the force response of the crease in PET sheets. An annealing time of at least 60 min at 160 C-180 C with a quick cooling results in a high force response in the crease. The effectiveness of the processing methods was demonstrated in several origami patterns of various complexities. © 2019 IOP Publishing Ltd.
356 a7005408810 Pitt W.G. p172 False Conference 36 Multiplexed Detection of Single Antibiotic Drug-Resistant Plasmids using Multimode Interference Waveguide Based Optofluidic Chip A single multimode interference waveguide is used to create distinct spectral spot patterns on two liquid-core waveguides on an optofluidic chip. This device is used for multiplexed detection of antibiotic-resistant plasmids with single nucleic acid sensitivity. © 2019 IEEE.
357 a56685601500 Wnorowska U. p92 True Journal 71 Nanoantibiotics containing membrane-active human cathelicidin LL-37 or synthetic ceragenins attached to the surface of magnetic nanoparticles as novel and innovative therapeutic tools: Current status and potential future applications Nanotechnology-based therapeutic approaches have attracted attention of scientists, in particular due to the special features of nanomaterials, such as adequate biocompatibility, ability to improve therapeutic efficiency of incorporated drugs and to limit their adverse effects. Among a variety of reported nanomaterials for biomedical applications, metal and metal oxide-based nanoparticles offer unique physicochemical properties allowing their use in combination with conventional antimicrobials and as magnetic field-controlled drug delivery nanocarriers. An ever-growing number of studies demonstrate that by combining magnetic nanoparticles with membrane-active, natural human cathelicidin-derived LL-37 peptide, and its synthetic mimics such as ceragenins, innovative nanoagents might be developed. Between others, they demonstrate high clinical potential as antimicrobial, anti-cancer, immunomodulatory and regenerative agents. Due to continuous research, knowledge on pleiotropic character of natural antibacterial peptides and their mimics is growing, and it is justifying to stay that the therapeutic potential of nanosystems containing membrane active compounds has not been exhausted yet. © 2020 The Author(s).
358 a16549438300 Fiedoruk K. p92 False Journal 71 Nanoantibiotics containing membrane-active human cathelicidin LL-37 or synthetic ceragenins attached to the surface of magnetic nanoparticles as novel and innovative therapeutic tools: Current status and potential future applications Nanotechnology-based therapeutic approaches have attracted attention of scientists, in particular due to the special features of nanomaterials, such as adequate biocompatibility, ability to improve therapeutic efficiency of incorporated drugs and to limit their adverse effects. Among a variety of reported nanomaterials for biomedical applications, metal and metal oxide-based nanoparticles offer unique physicochemical properties allowing their use in combination with conventional antimicrobials and as magnetic field-controlled drug delivery nanocarriers. An ever-growing number of studies demonstrate that by combining magnetic nanoparticles with membrane-active, natural human cathelicidin-derived LL-37 peptide, and its synthetic mimics such as ceragenins, innovative nanoagents might be developed. Between others, they demonstrate high clinical potential as antimicrobial, anti-cancer, immunomodulatory and regenerative agents. Due to continuous research, knowledge on pleiotropic character of natural antibacterial peptides and their mimics is growing, and it is justifying to stay that the therapeutic potential of nanosystems containing membrane active compounds has not been exhausted yet. © 2020 The Author(s).
359 a56685789300 Piktel E. p92 False Journal 71 Nanoantibiotics containing membrane-active human cathelicidin LL-37 or synthetic ceragenins attached to the surface of magnetic nanoparticles as novel and innovative therapeutic tools: Current status and potential future applications Nanotechnology-based therapeutic approaches have attracted attention of scientists, in particular due to the special features of nanomaterials, such as adequate biocompatibility, ability to improve therapeutic efficiency of incorporated drugs and to limit their adverse effects. Among a variety of reported nanomaterials for biomedical applications, metal and metal oxide-based nanoparticles offer unique physicochemical properties allowing their use in combination with conventional antimicrobials and as magnetic field-controlled drug delivery nanocarriers. An ever-growing number of studies demonstrate that by combining magnetic nanoparticles with membrane-active, natural human cathelicidin-derived LL-37 peptide, and its synthetic mimics such as ceragenins, innovative nanoagents might be developed. Between others, they demonstrate high clinical potential as antimicrobial, anti-cancer, immunomodulatory and regenerative agents. Due to continuous research, knowledge on pleiotropic character of natural antibacterial peptides and their mimics is growing, and it is justifying to stay that the therapeutic potential of nanosystems containing membrane active compounds has not been exhausted yet. © 2020 The Author(s).
360 a57212757453 Prasad S.V. p92 False Journal 71 Nanoantibiotics containing membrane-active human cathelicidin LL-37 or synthetic ceragenins attached to the surface of magnetic nanoparticles as novel and innovative therapeutic tools: Current status and potential future applications Nanotechnology-based therapeutic approaches have attracted attention of scientists, in particular due to the special features of nanomaterials, such as adequate biocompatibility, ability to improve therapeutic efficiency of incorporated drugs and to limit their adverse effects. Among a variety of reported nanomaterials for biomedical applications, metal and metal oxide-based nanoparticles offer unique physicochemical properties allowing their use in combination with conventional antimicrobials and as magnetic field-controlled drug delivery nanocarriers. An ever-growing number of studies demonstrate that by combining magnetic nanoparticles with membrane-active, natural human cathelicidin-derived LL-37 peptide, and its synthetic mimics such as ceragenins, innovative nanoagents might be developed. Between others, they demonstrate high clinical potential as antimicrobial, anti-cancer, immunomodulatory and regenerative agents. Due to continuous research, knowledge on pleiotropic character of natural antibacterial peptides and their mimics is growing, and it is justifying to stay that the therapeutic potential of nanosystems containing membrane active compounds has not been exhausted yet. © 2020 The Author(s).
361 a57212871890 Sulik M. p92 False Journal 71 Nanoantibiotics containing membrane-active human cathelicidin LL-37 or synthetic ceragenins attached to the surface of magnetic nanoparticles as novel and innovative therapeutic tools: Current status and potential future applications Nanotechnology-based therapeutic approaches have attracted attention of scientists, in particular due to the special features of nanomaterials, such as adequate biocompatibility, ability to improve therapeutic efficiency of incorporated drugs and to limit their adverse effects. Among a variety of reported nanomaterials for biomedical applications, metal and metal oxide-based nanoparticles offer unique physicochemical properties allowing their use in combination with conventional antimicrobials and as magnetic field-controlled drug delivery nanocarriers. An ever-growing number of studies demonstrate that by combining magnetic nanoparticles with membrane-active, natural human cathelicidin-derived LL-37 peptide, and its synthetic mimics such as ceragenins, innovative nanoagents might be developed. Between others, they demonstrate high clinical potential as antimicrobial, anti-cancer, immunomodulatory and regenerative agents. Due to continuous research, knowledge on pleiotropic character of natural antibacterial peptides and their mimics is growing, and it is justifying to stay that the therapeutic potential of nanosystems containing membrane active compounds has not been exhausted yet. © 2020 The Author(s).
362 a57215487696 Janion M. p92 False Journal 71 Nanoantibiotics containing membrane-active human cathelicidin LL-37 or synthetic ceragenins attached to the surface of magnetic nanoparticles as novel and innovative therapeutic tools: Current status and potential future applications Nanotechnology-based therapeutic approaches have attracted attention of scientists, in particular due to the special features of nanomaterials, such as adequate biocompatibility, ability to improve therapeutic efficiency of incorporated drugs and to limit their adverse effects. Among a variety of reported nanomaterials for biomedical applications, metal and metal oxide-based nanoparticles offer unique physicochemical properties allowing their use in combination with conventional antimicrobials and as magnetic field-controlled drug delivery nanocarriers. An ever-growing number of studies demonstrate that by combining magnetic nanoparticles with membrane-active, natural human cathelicidin-derived LL-37 peptide, and its synthetic mimics such as ceragenins, innovative nanoagents might be developed. Between others, they demonstrate high clinical potential as antimicrobial, anti-cancer, immunomodulatory and regenerative agents. Due to continuous research, knowledge on pleiotropic character of natural antibacterial peptides and their mimics is growing, and it is justifying to stay that the therapeutic potential of nanosystems containing membrane active compounds has not been exhausted yet. © 2020 The Author(s).
363 a16548815300 Daniluk T. p92 False Journal 71 Nanoantibiotics containing membrane-active human cathelicidin LL-37 or synthetic ceragenins attached to the surface of magnetic nanoparticles as novel and innovative therapeutic tools: Current status and potential future applications Nanotechnology-based therapeutic approaches have attracted attention of scientists, in particular due to the special features of nanomaterials, such as adequate biocompatibility, ability to improve therapeutic efficiency of incorporated drugs and to limit their adverse effects. Among a variety of reported nanomaterials for biomedical applications, metal and metal oxide-based nanoparticles offer unique physicochemical properties allowing their use in combination with conventional antimicrobials and as magnetic field-controlled drug delivery nanocarriers. An ever-growing number of studies demonstrate that by combining magnetic nanoparticles with membrane-active, natural human cathelicidin-derived LL-37 peptide, and its synthetic mimics such as ceragenins, innovative nanoagents might be developed. Between others, they demonstrate high clinical potential as antimicrobial, anti-cancer, immunomodulatory and regenerative agents. Due to continuous research, knowledge on pleiotropic character of natural antibacterial peptides and their mimics is growing, and it is justifying to stay that the therapeutic potential of nanosystems containing membrane active compounds has not been exhausted yet. © 2020 The Author(s).
364 a7202875039 Savage P.B. p92 False Journal 71 Nanoantibiotics containing membrane-active human cathelicidin LL-37 or synthetic ceragenins attached to the surface of magnetic nanoparticles as novel and innovative therapeutic tools: Current status and potential future applications Nanotechnology-based therapeutic approaches have attracted attention of scientists, in particular due to the special features of nanomaterials, such as adequate biocompatibility, ability to improve therapeutic efficiency of incorporated drugs and to limit their adverse effects. Among a variety of reported nanomaterials for biomedical applications, metal and metal oxide-based nanoparticles offer unique physicochemical properties allowing their use in combination with conventional antimicrobials and as magnetic field-controlled drug delivery nanocarriers. An ever-growing number of studies demonstrate that by combining magnetic nanoparticles with membrane-active, natural human cathelicidin-derived LL-37 peptide, and its synthetic mimics such as ceragenins, innovative nanoagents might be developed. Between others, they demonstrate high clinical potential as antimicrobial, anti-cancer, immunomodulatory and regenerative agents. Due to continuous research, knowledge on pleiotropic character of natural antibacterial peptides and their mimics is growing, and it is justifying to stay that the therapeutic potential of nanosystems containing membrane active compounds has not been exhausted yet. © 2020 The Author(s).
365 a6701383359 Bucki R. p92 False Journal 71 Nanoantibiotics containing membrane-active human cathelicidin LL-37 or synthetic ceragenins attached to the surface of magnetic nanoparticles as novel and innovative therapeutic tools: Current status and potential future applications Nanotechnology-based therapeutic approaches have attracted attention of scientists, in particular due to the special features of nanomaterials, such as adequate biocompatibility, ability to improve therapeutic efficiency of incorporated drugs and to limit their adverse effects. Among a variety of reported nanomaterials for biomedical applications, metal and metal oxide-based nanoparticles offer unique physicochemical properties allowing their use in combination with conventional antimicrobials and as magnetic field-controlled drug delivery nanocarriers. An ever-growing number of studies demonstrate that by combining magnetic nanoparticles with membrane-active, natural human cathelicidin-derived LL-37 peptide, and its synthetic mimics such as ceragenins, innovative nanoagents might be developed. Between others, they demonstrate high clinical potential as antimicrobial, anti-cancer, immunomodulatory and regenerative agents. Due to continuous research, knowledge on pleiotropic character of natural antibacterial peptides and their mimics is growing, and it is justifying to stay that the therapeutic potential of nanosystems containing membrane active compounds has not been exhausted yet. © 2020 The Author(s).
366 a57191570988 Orme A.D. p93 True Conference 13 Analysis of distortion phase shift in a highly loaded fan stage Full annulus URANS simulations are presented to investigate distortion phase shift in a single stage transonic fan. The fan is subject to a 90°sector inlet total pressure distortion. Simulation results are presented for choke, design, and near-stall operating conditions. Circumferential profiles of swirl, total pressure, total temperature, power, and phase shift are analyzed at 10%, 30%, 50%, 70%, and 90% span. Phase shift is a measure of the rotational translation of a distortion profile and is valuable for understanding the translational motion of distortion as it passes through the fan. At choke and design operating conditions the phase shift is positive in the direction of rotor rotation. At near-stall the phase shift is negative opposite rotor rotation for the outer 30% span. Local power reaches a maximum value, resulting in the generation of a uniform pressure region. This region causes increased distortion content in the near-stall case over a wide circumferential extent resulting in a negative phase shift. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
366 a57191570988 Orme A.D. p337 False Conference 113 Radial variation in distortion transfer and generation in a highly loaded fan stage from near-stall to choke Understanding distortion transfer and generation through fan and compressor blade rows is able to assist in blade design and performance prediction. Using full annulus URANS simulations, the effects of distortion as it passes through the rotor of a transonic fan at five radial locations (10%, 30%, 50%, 70%, and 90% span) are analyzed. The inlet distortion profile is a 90-degree sector with a 15% total pressure deficit. Fourier distortion descriptors are used in this study to quantitatively describe distortion transfer and generation. Results are presented and compared for three operating points (near-stall, design, and choke). These results are used to explain the relationship between inlet total pressure distortion, pressure-induced swirl, total pressure distortion transfer, total temperature distortion generation, and circumferential rotor power variation. It is shown that very large changes in pressure-induced swirl and distortion transfer and generation occur between near-stall and design, but only small changes are seen between design and choke. The greatest changes are shown to be near the tip. Local power variations are shown to correlate with total pressure distortion transfer and total temperature distortion generation. Copyright © 2019 ASME.
366 a57191570988 Orme A.D. p884 False Conference 397 Formability of magnesium alloy AZ31B from room temperature to 125, °C under biaxial tension Magnesium AZ31B sheets of 2, mm thickness were stretch formed using a 101.6, mm diameter punch at room temperature and subsequent increments from 25 to 125, °C. Surface strains were measured using a digital image correlation method in order to ensure that biaxial stretching was achieved. The punch height versus load curve was found to be the same for temperatures of 25 and for 50, °C, while at 75, °C the load for a given punch height was less. This difference seems to indicate a change in deformation mechanism between 50 and 75, °C. Electron Backscatter Diffraction (EBSD) was used to quantify features of the microstructure in the as-received and the strained specimens. Rather than a sudden transition from twinning to slip at low temperatures, it appears that twinning gradually decreases and slip activity increases as temperatures rise across the range from 25 to 125, °C. This confirms recent predictions found in the literature. The twin activity predominantly involves the formation of compression twins which rapidly transform further to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
367 a57201357657 Soderquist D.R. p93 False Conference 13 Analysis of distortion phase shift in a highly loaded fan stage Full annulus URANS simulations are presented to investigate distortion phase shift in a single stage transonic fan. The fan is subject to a 90°sector inlet total pressure distortion. Simulation results are presented for choke, design, and near-stall operating conditions. Circumferential profiles of swirl, total pressure, total temperature, power, and phase shift are analyzed at 10%, 30%, 50%, 70%, and 90% span. Phase shift is a measure of the rotational translation of a distortion profile and is valuable for understanding the translational motion of distortion as it passes through the fan. At choke and design operating conditions the phase shift is positive in the direction of rotor rotation. At near-stall the phase shift is negative opposite rotor rotation for the outer 30% span. Local power reaches a maximum value, resulting in the generation of a uniform pressure region. This region causes increased distortion content in the near-stall case over a wide circumferential extent resulting in a negative phase shift. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
367 a57201357657 Soderquist D.R. p337 True Conference 113 Radial variation in distortion transfer and generation in a highly loaded fan stage from near-stall to choke Understanding distortion transfer and generation through fan and compressor blade rows is able to assist in blade design and performance prediction. Using full annulus URANS simulations, the effects of distortion as it passes through the rotor of a transonic fan at five radial locations (10%, 30%, 50%, 70%, and 90% span) are analyzed. The inlet distortion profile is a 90-degree sector with a 15% total pressure deficit. Fourier distortion descriptors are used in this study to quantitatively describe distortion transfer and generation. Results are presented and compared for three operating points (near-stall, design, and choke). These results are used to explain the relationship between inlet total pressure distortion, pressure-induced swirl, total pressure distortion transfer, total temperature distortion generation, and circumferential rotor power variation. It is shown that very large changes in pressure-induced swirl and distortion transfer and generation occur between near-stall and design, but only small changes are seen between design and choke. The greatest changes are shown to be near the tip. Local power variations are shown to correlate with total pressure distortion transfer and total temperature distortion generation. Copyright © 2019 ASME.
367 a57201357657 Soderquist D.R. p595 True Conference 238 Radial variation in distortion transfer and generation through a highly loaded fan stage An important consideration for fan and compressor design is quantifying distortion transfer and generation blade row by blade row. Detailed information about the magnitude of distortion and the shape of the distortion profile and how it changes through blade rows increases the understanding of flow physics and helps predict aerodynamic performance. Using full annulus URANS simulations, this paper analyzes what happens to distortion as it passes through the rotor and stator blade rows at 10%, 30%, 50%, 70%, and 90% span. Fourier distortion descriptors are used in this study to quantitatively describe distortion transfer and generation. With these descriptors, evidence of pressure-induced swirl is shown at the fan inlet. It is also shown that although there is very little distortion at the 10% span of the inlet, after passing through the rotor blade row the 10% span has the greatest amount of total pressure and total temperature distortion. This radial migration of distortion is attributed to the high hade angle of the hub. The total pressure and total temperature profiles have significant circumferential phase shifts after passing through the rotor and slight phase shifts after passing through the stator. In general, the calculated phase shifts are greatest at the 10% and 90% spans, the nearest locations to the hub and the tip clearance gap, respectively. Copyright © 2018 ASME.
367 a57201357657 Soderquist D.R. p597 True Conference 240 Analysis of distortion transfer and generation through a compressor using the harmonic balance approach Inlet flow distortion significantly affects an engine’s overall performance. It can be difficult to predict the transfer of distortion through a compressor because traditional experimental and computational methods are very expensive and time consuming. The Harmonic Balance approach is a promising alternative which uses Fourier techniques to represent fluid flow solutions. Relatively little work has been done to assess how much Fourier information is necessary to calculate a sufficiently accurate solution with the Harmonic Balance Solver. This study focuses on analyzing the effects of varying the amount of modal content that is used in Harmonic Balance simulations. Inlet distortion profiles with varying magnitudes are used in order to analyze trends and provide insight into the distortion flow physics for various inlet conditions. The geometry is a single stage axial compressor that consists of an inlet guide vane followed by the NASA Stage 37 rotor. It is shown that simulations with greater magnitudes of distortion require more modal content in order to achieve sufficiently accurate results. Harmonic Balance simulations are shown to have significantly lower computational costs than simulations with a conventional unsteady solver. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
368 a57210289242 Greenwood J.R. p94 False Journal 72 Using Cyclic Quadrilaterals to Design Cylindrical Developable Mechanisms Developable mechanisms on regular cylindrical surfaces can be described using cyclic quadrilaterals. Mechanisms can exist in either an open or crossed configuration, and these configurations correspond to convex and crossed cyclic quadrilaterals. Using equations developed for both convex and crossed cyclic quadrilaterals, the geometry of the reference surface to which a four-bar mechanism can be mapped is found. Grashof mechanisms can be mapped to two surfaces in open or crossed configurations. The only way to map a non-Grashof mechanism to a cylindrical surface is in its open configuration. Extramobile and intramobile behavior can be achieved depending on selected pairs within a cyclic quadrilateral and its position within the circumcircle. Selecting different sets of links as the ground link changes the potential behavior of the mechanism. Different cases are tabulated to represent all possibilities. A non-Grashof developable mechanism can only exhibit extramobile or intramobile behavior if all of the joints lie on one half of the circumcircle. © 2020, Springer Nature Switzerland AG.
368 a57210289242 Greenwood J.R. p136 True Journal 95 Developable mechanisms on regular cylindrical surfaces Developable mechanisms can provide high functionality and compact stowability. This paper presents engineering models to aid in the design of cylindrical developable mechanisms. These models take into account the added spatial restrictions imposed by the developable surface. Equations are provided for the kinematic analysis of cylindrical developable mechanisms. A new classification for developable mechanisms is also presented (intramobile, extramobile, and transmobile) and two graphical methods are provided for determining this classification for single-DOF planar cylindrical developable mechanisms. Characteristics specific to four-bar cylindrical developable mechanisms are also discussed. © 2019 Elsevier Ltd
368 a57210289242 Greenwood J.R. p318 False Conference 98 Conceptualizing stable states in origami-based devices using an energy visualization approach In many origami-based applications a device needs to be maintained in one or more fold states. The origami stability integration method (OSIM) presented in this paper provides an approach for graphically combining various techniques to achieve stability. Techniques are divided into four groups based on whether they are intrinsic or extrinsic to the origami pattern and whether they exhibit differentiable or non-differentiable energy storage behaviors. These categorizations can help designers select appropriate techniques for their application. The paper also contains design considerations and resources for several intrinsic techniques. Finally, two case studies are presented which use the OSIM and the technique guidelines to conceptualize stability in origami-based devices. Copyright © 2019 ASME.
369 a57192710054 Butler J.J. p94 False Journal 72 Using Cyclic Quadrilaterals to Design Cylindrical Developable Mechanisms Developable mechanisms on regular cylindrical surfaces can be described using cyclic quadrilaterals. Mechanisms can exist in either an open or crossed configuration, and these configurations correspond to convex and crossed cyclic quadrilaterals. Using equations developed for both convex and crossed cyclic quadrilaterals, the geometry of the reference surface to which a four-bar mechanism can be mapped is found. Grashof mechanisms can be mapped to two surfaces in open or crossed configurations. The only way to map a non-Grashof mechanism to a cylindrical surface is in its open configuration. Extramobile and intramobile behavior can be achieved depending on selected pairs within a cyclic quadrilateral and its position within the circumcircle. Selecting different sets of links as the ground link changes the potential behavior of the mechanism. Different cases are tabulated to represent all possibilities. A non-Grashof developable mechanism can only exhibit extramobile or intramobile behavior if all of the joints lie on one half of the circumcircle. © 2020, Springer Nature Switzerland AG.
369 a57192710054 Butler J.J. p319 True Conference 99 Thick folding through regionally-sandwiched compliant sheets The regional-sandwiching of compliant sheets (ReCS) technique presented in this work creates flat-foldable, rigid-foldable, and self-deploying thick origami-based mechanisms. Regional-sandwiching of the compliant sheet is used to create mountain/valley assignments for each fold about a vertex, constraining motion to a single branch of folding. Strain energy in deflected flexible members is used to enable self-deployment. This work presents the methods to design origami-based mechanisms using the ReCS technique, including volume trimming at the vertex of the compliant sheet and of the panels used in the sandwich. Physical models of a simple single fold mechanism and a degree-four vertex mechanism are presented to demonstrate the ReCS technique using acrylic panels and spring steel. Consideration is given to the risk of yielding of the compliant sheet due to parasitic motion with possible mitigation of yielding by decreasing the thickness of the sheet. Copyright © 2019 ASME.
369 a57192710054 Butler J.J. p321 False Conference 101 Kirigami-based deployable transcrease hard stop models usable in origami patterns Stopping origami in arbitrary fold states can present a challenge for origami-based design. In this paper two categories of kirigami-based models are presented for stopping the fold motion of individual creases using deployable hard stops. These models are transcrease (across a crease) and deploy from a flat sheet. The first category is planar and has behavior similar to a four-bar linkage. The second category is spherical and behaves like a degree-4 origami vertex. These models are based on the zero-thickness assumption of paper and can be applied to origami patterns made from thin materials, limiting the motion of the base origami pattern through self-interference within the original facets. Model parameters are based on a desired fold or dihedral angle, as well as facet dimensions. Examples show model benefits and limitations. Copyright © 2019 ASME.
369 a57192710054 Butler J.J. p412 True Journal 222 A model for multi-input mechanical advantage in origami-based mechanisms Mechanical advantage is traditionally defined for single-input and single-output rigidbody mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origamibased mechanisms are capable of offering unique solutions to engineering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi-input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. © 2018 by ASME.
369 a57192710054 Butler J.J. p455 False Conference 161 Modified Material Properties in Curved Panels Through Lamina Emergent Torsional Joints Compliant joints have a number of advantages that make them suitable for highly constrained design problems. While much work has been done on the design of compliant joints manufactured from planar sheet materials, this work focuses on the design of cylindrically-curved joints. A method for using lamina emergent torsional (LET) joints to increase energy storage efficiency in curved sheet materials is presented. A numerical model is provided for predicting the stiffness and maximum applied moment of a curved LET joint. Predicted curved LET joint stiffnesses and maximum moments are utilized to create shape factors that produce an effective modulus of elasticity and an effective modulus of resilience. For a given case, the effective modulus of elasticity is shown to decrease by about three orders of magnitude while the effective resilience decreases by approximately one order of magnitude. Designers can use this information to tailor materials to fit design requirements or to select alternative materials that were previously unsuited for an application. © 2018 IEEE.
369 a57192710054 Butler J.J. p881 True Conference 396 Highly compressible origami bellows for microgravity drilling-debris containment The design and testing of an origami-based bellows for microgravity drilling is described. The potential benefits of an origami-based solution created an opportunity for application on NASA’s Asteroid Redirect Mission (ARM) to protect sensitive parts from debris. Origami-based bellows were designed to fit spatial limitations and meet needed compression ratios. Designs have demonstrated high mass reductions, improved stroke length, greatly decreased stowed volume, improved flexibility, and reduced reaction forces in comparison with traditional metal bellows. A nylon-reinforced polyvinyl fluoride based bellows with an aramid fiber stitched seam is well suited for debris containment in space conditions. Various epoxies maintained an adequate bond with polyvinyl fluoride below expected environmental temperature for bellows mounting. Asymmetric compression of the bellows occurs at extreme low temperatures and is preventable by balancing stiffness within the structure. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
370 a57219015425 Lystrup C. p95 True Journal 73 Optical measurement of voids in situ during infusion of carbon reinforcements Liquid composite molding (LCM) is growing in importance as an alternative to traditional prepreg-autoclave methods for manufacture high-performance composites. The most significant roadblock to industry’s implementation of LCM is the usually higher void content compared with prepreg processing. One tool for reducing void levels in LCM involves optimization of flow velocity, which requires models to be developed to describe void formation at a given velocity. To help solve this problem, the following research illustrates the first known method for optical void measurement in situ during infusion in a carbon fiber reinforcement. Similar to previous studies on glass fiber, this work utilizes fluorescent dye and a digital camera to produce sufficient contrast and resolution for image analysis. Visible bubbles are photographed against the opaque carbon fiber background. An automated method of image analysis is outlined, which was used to analyze 230 images for three different flow orientations of a single fabric, producing the highest amount of experimental data seen so far on in situ void measurement. The resulting data identifies a minimum velocity threshold for minimal macro-void formation. The resultant void characterization framework will better enable optimization of LCM processing for high-performance composites based on carbon reinforcements. © The Author(s) 2020.
371 a55813139600 George A. p95 False Journal 73 Optical measurement of voids in situ during infusion of carbon reinforcements Liquid composite molding (LCM) is growing in importance as an alternative to traditional prepreg-autoclave methods for manufacture high-performance composites. The most significant roadblock to industry’s implementation of LCM is the usually higher void content compared with prepreg processing. One tool for reducing void levels in LCM involves optimization of flow velocity, which requires models to be developed to describe void formation at a given velocity. To help solve this problem, the following research illustrates the first known method for optical void measurement in situ during infusion in a carbon fiber reinforcement. Similar to previous studies on glass fiber, this work utilizes fluorescent dye and a digital camera to produce sufficient contrast and resolution for image analysis. Visible bubbles are photographed against the opaque carbon fiber background. An automated method of image analysis is outlined, which was used to analyze 230 images for three different flow orientations of a single fabric, producing the highest amount of experimental data seen so far on in situ void measurement. The resulting data identifies a minimum velocity threshold for minimal macro-void formation. The resultant void characterization framework will better enable optimization of LCM processing for high-performance composites based on carbon reinforcements. © The Author(s) 2020.
371 a55813139600 George A. p140 False Journal 98 The effects of voids in quasi-static indentation of resin-infused reinforced polymers The focus of this study is the influence of voids on the damage behaviour in quasi-static loading of resin-infused carbon fibre-reinforced polymers. Experimental results are presented for quasi-static loading in combination with high-resolution tomographic imaging and statistical analysis (homology of pores or voids and induced cracks). Three distinct mechanisms were observed to control delamination growth in the presence of sharp and blunt voids. Delamination cracks interact with the supporting yarns, especially in combination with air pockets trapped in the resin in the form of long, sharp voids. This resulted in crack growth that coalesces with delamination cracks from neighbouring yarn-voids during increased out-of-plane load–displacement, with almost no presence of intralaminar transverse cracks. This highlights the benefits and drawbacks of the supporting yarn during out-of-plane loading. © The Author(s) 2019.
371 a55813139600 George A. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
371 a55813139600 George A. p313 True Conference 93 Characterization and validation of in situ void formation during resin infusion An experimental methodology to photograph bubbles in-situ during infusion of carbon reinforcements has been developed and demonstrated previously. This method is based on fluorescent photography of bubbles at the surface of the reinforcement during infusion. Previous work with this experimental methodology was done with test oils, but has now been characterized with a curing epoxy resin. The results of in-situ bubble photography at the surface are now compared to standard defect characterization methods including ultrasound and image analysis of polished cross-section micrographs. Such experimental results are meant to provide the data required to build process optimization models capable of prediction of the final void distribution and morphology of voids. © 2019 by Ever J. Barbero. Published by CAMX - The Composites and Advanced Materials Expo.
371 a55813139600 George A. p675 False Journal 326 Continuous permeability measurement during unidirectional vacuum infusion processing Flow simulation for liquid composite molding is often performed to assist in process optimization and requires the permeability of the reinforcement to be characterized. For infusion under a flexible membrane, such as vacuum infusion, or for simulation of a part with non-uniform thickness, one must test the permeability at various levels of compaction. This process is time consuming and often relies on interpolation or extrapolation around a few experimental permeability measurements. To accelerate the process of permeability characterization, a small number of methodologies have been previously presented in the literature, in which the permeability may be tested at multiple fiber volume contents in a single test. Some of the methods even measure the permeability over a continuous range of thicknesses, thus requiring no later interpolation of permeability values. A novel method is presented here for the rapid measurement of permeability over a continuous range of fiber volume content, in a single unidirectional vacuum infusion flow experiment. The thickness gradient across the vacuum bag, as well as the fluid pressure at several locations in the mold were concurrently measured to calculate the fabric compressibility. An analytical flow model, which accounts for the compressibility, is then used by iterating the fitting constant in a permeability model until the predicted flow front progression matches empirical measurement. The method is demonstrated here for two reinforcement materials: (1) a fiberglass unbalanced weave and (2) a carbon biax non-crimped fabric. The standard deviation across the multiple experiments for each material and flow orientation ranged from 12.8% to 29.7%. Validation of these results was performed by comparing the resulting permeability with multiple non-continuous permeability measurement methods. © 2017, © The Author(s) 2017.
371 a55813139600 George A. p792 False Conference 329 In situ bubble characterization during resin infusion for process simulation of voids Optimization of liquid composite molding processes would greatly benefit from an understanding of how voids form and move during processing. While theoretical models exist in the literature for such phenomena, little experimental validation exists due to the difficulties of characterizing voids inside the mold, in a fluid state. The best experimental methodologies presented so far involve light transmission and thus only work for fiberglass reinforcements. An experimental methodology is presented in this paper, in which a proper lighting scheme allows for in situ photography of bubbles during liquid composite molding of carbon reinforcements. The resulting images were processed using image analysis software to identify key parameters such as grey level threshold, and size and circularity limits, which best allow for automated identification of bubbles in the images. No script achieved complete identification of all of the bubbles, but a methodology was developed and implemented to iterate the analysis parameters, evaluate the resulting bubble identification performance, and identify a range of analysis parameters that would provide the best possible results for automated in situ void detection. © 2017 International Committee on Composite Materials. All rights reserved.
372 a57203836305 Zobell B. p95 False Journal 73 Optical measurement of voids in situ during infusion of carbon reinforcements Liquid composite molding (LCM) is growing in importance as an alternative to traditional prepreg-autoclave methods for manufacture high-performance composites. The most significant roadblock to industry’s implementation of LCM is the usually higher void content compared with prepreg processing. One tool for reducing void levels in LCM involves optimization of flow velocity, which requires models to be developed to describe void formation at a given velocity. To help solve this problem, the following research illustrates the first known method for optical void measurement in situ during infusion in a carbon fiber reinforcement. Similar to previous studies on glass fiber, this work utilizes fluorescent dye and a digital camera to produce sufficient contrast and resolution for image analysis. Visible bubbles are photographed against the opaque carbon fiber background. An automated method of image analysis is outlined, which was used to analyze 230 images for three different flow orientations of a single fabric, producing the highest amount of experimental data seen so far on in situ void measurement. The resulting data identifies a minimum velocity threshold for minimal macro-void formation. The resultant void characterization framework will better enable optimization of LCM processing for high-performance composites based on carbon reinforcements. © The Author(s) 2020.
372 a57203836305 Zobell B. p792 True Conference 329 In situ bubble characterization during resin infusion for process simulation of voids Optimization of liquid composite molding processes would greatly benefit from an understanding of how voids form and move during processing. While theoretical models exist in the literature for such phenomena, little experimental validation exists due to the difficulties of characterizing voids inside the mold, in a fluid state. The best experimental methodologies presented so far involve light transmission and thus only work for fiberglass reinforcements. An experimental methodology is presented in this paper, in which a proper lighting scheme allows for in situ photography of bubbles during liquid composite molding of carbon reinforcements. The resulting images were processed using image analysis software to identify key parameters such as grey level threshold, and size and circularity limits, which best allow for automated identification of bubbles in the images. No script achieved complete identification of all of the bubbles, but a methodology was developed and implemented to iterate the analysis parameters, evaluate the resulting bubble identification performance, and identify a range of analysis parameters that would provide the best possible results for automated in situ void detection. © 2017 International Committee on Composite Materials. All rights reserved.
373 a57219009389 Boster K. p95 False Journal 73 Optical measurement of voids in situ during infusion of carbon reinforcements Liquid composite molding (LCM) is growing in importance as an alternative to traditional prepreg-autoclave methods for manufacture high-performance composites. The most significant roadblock to industry’s implementation of LCM is the usually higher void content compared with prepreg processing. One tool for reducing void levels in LCM involves optimization of flow velocity, which requires models to be developed to describe void formation at a given velocity. To help solve this problem, the following research illustrates the first known method for optical void measurement in situ during infusion in a carbon fiber reinforcement. Similar to previous studies on glass fiber, this work utilizes fluorescent dye and a digital camera to produce sufficient contrast and resolution for image analysis. Visible bubbles are photographed against the opaque carbon fiber background. An automated method of image analysis is outlined, which was used to analyze 230 images for three different flow orientations of a single fabric, producing the highest amount of experimental data seen so far on in situ void measurement. The resulting data identifies a minimum velocity threshold for minimal macro-void formation. The resultant void characterization framework will better enable optimization of LCM processing for high-performance composites based on carbon reinforcements. © The Author(s) 2020.
374 a57219005376 Childs C. p95 False Journal 73 Optical measurement of voids in situ during infusion of carbon reinforcements Liquid composite molding (LCM) is growing in importance as an alternative to traditional prepreg-autoclave methods for manufacture high-performance composites. The most significant roadblock to industry’s implementation of LCM is the usually higher void content compared with prepreg processing. One tool for reducing void levels in LCM involves optimization of flow velocity, which requires models to be developed to describe void formation at a given velocity. To help solve this problem, the following research illustrates the first known method for optical void measurement in situ during infusion in a carbon fiber reinforcement. Similar to previous studies on glass fiber, this work utilizes fluorescent dye and a digital camera to produce sufficient contrast and resolution for image analysis. Visible bubbles are photographed against the opaque carbon fiber background. An automated method of image analysis is outlined, which was used to analyze 230 images for three different flow orientations of a single fabric, producing the highest amount of experimental data seen so far on in situ void measurement. The resulting data identifies a minimum velocity threshold for minimal macro-void formation. The resultant void characterization framework will better enable optimization of LCM processing for high-performance composites based on carbon reinforcements. © The Author(s) 2020.
375 a57219006078 Girod H. p95 False Journal 73 Optical measurement of voids in situ during infusion of carbon reinforcements Liquid composite molding (LCM) is growing in importance as an alternative to traditional prepreg-autoclave methods for manufacture high-performance composites. The most significant roadblock to industry’s implementation of LCM is the usually higher void content compared with prepreg processing. One tool for reducing void levels in LCM involves optimization of flow velocity, which requires models to be developed to describe void formation at a given velocity. To help solve this problem, the following research illustrates the first known method for optical void measurement in situ during infusion in a carbon fiber reinforcement. Similar to previous studies on glass fiber, this work utilizes fluorescent dye and a digital camera to produce sufficient contrast and resolution for image analysis. Visible bubbles are photographed against the opaque carbon fiber background. An automated method of image analysis is outlined, which was used to analyze 230 images for three different flow orientations of a single fabric, producing the highest amount of experimental data seen so far on in situ void measurement. The resulting data identifies a minimum velocity threshold for minimal macro-void formation. The resultant void characterization framework will better enable optimization of LCM processing for high-performance composites based on carbon reinforcements. © The Author(s) 2020.
376 a57218481091 Ploeg S. p96 True Journal 74 Simphony: An open-source photonic integrated circuit simulation framework We present Simphony, a free and open-source software toolbox for abstracting and simulating photonic integrated circuits, implemented in Python. The toolbox is both fast and easily extensible; plugins can be written to provide compatibility with existing layout tools, and device libraries can be easily created without a deep knowledge of programming. We include several examples of photonic circuit simulations with novel features and demonstrate a speedup of more than 20x over a leading commercially available software tool. IEEE
377 a57217024741 Gunther H. p96 False Journal 74 Simphony: An open-source photonic integrated circuit simulation framework We present Simphony, a free and open-source software toolbox for abstracting and simulating photonic integrated circuits, implemented in Python. The toolbox is both fast and easily extensible; plugins can be written to provide compatibility with existing layout tools, and device libraries can be easily created without a deep knowledge of programming. We include several examples of photonic circuit simulations with novel features and demonstrate a speedup of more than 20x over a leading commercially available software tool. IEEE
378 a57218482479 Camacho R. p96 False Journal 74 Simphony: An open-source photonic integrated circuit simulation framework We present Simphony, a free and open-source software toolbox for abstracting and simulating photonic integrated circuits, implemented in Python. The toolbox is both fast and easily extensible; plugins can be written to provide compatibility with existing layout tools, and device libraries can be easily created without a deep knowledge of programming. We include several examples of photonic circuit simulations with novel features and demonstrate a speedup of more than 20x over a leading commercially available software tool. IEEE
379 a34873482400 Skaggs P. p97 True Conference 14 Designer Thinking, A Unique Combination of Cognitive Modes The theory of cognitive modes states that individuals have unique and dominant ways of receiving, processing, and using information and that these styles influence behaviors and abilities. These abilities are natural talents. Every profession uses different. The work someone is most likely to enjoy and be successful in is work that uses his or her specific abilities. Research identifies three dominant cognitive modes for industrial designers: creative thinking, visual thinking, and adaptive thinking. This paper describes a series of experiences developed to help assess creative, visual, and adaptive thinking in students that are considering the industrial design program at Brigham Young University. © 2020, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.
379 a34873482400 Skaggs P. p695 False Journal 338 The need, development, and validation of the innovation test instrument This study discusses the need, development, and validation of the Innovation Test Instrument (ITI). This article outlines how the researchers identified the content domain of the assessment and created test items. Then, it describes initial validation testing of the instrument. The findings suggest that the ITI is a good first step in creating an innovation assessment because it is more inclusive of both divergent and convergent thinking. In comparison, past innovation assessments have only assessed either divergence or convergence. The ITI still needs further validation and improvement to make strong claims about its ability to determine the effectiveness of an innovation course. © 2017, Virginia Polytechnic Institute. All rights reserved.
380 a6507317548 Fulda N. p98 True Conference 15 Rethinking Our Assumptions About Language Model Evaluation Many applications of pre-trained language models use their learned internal representations, also known as word- or sentence embeddings, as input features for other language-based tasks. Over recent years, this has led to the implicit assumption that the quality of such embeddings is determined solely by their ability to facilitate transfer learning. In this position paper we argue that pre-trained linguistic embeddings have value above and beyond their utility as input features for downstream tasks. We adopt a paradigm in which they are instead treated as implicit knowledge repositories that can be used to solve common-sense reasoning problems via linear operations on embedded text. To validate this paradigm, we apply our methodology to tasks such as threat detection, emotional classification, and sentiment analysis, and demonstrate that linguistic embeddings show strong potential at solving such tasks directly, without the need for additional training. Motivated by these results, we advocate for empirical evaluations of language models that include vector-based reasoning tasks in addition to more traditional benchmarks, with the ultimate goal of facilitating language-based reasoning, or ‘reasoning in the linguistic domain’. We conclude by analyzing the structure of currently available embedding models and identifying several shortcomings which must be overcome in order to realize the full potential of this approach. © 2020, Springer Nature Switzerland AG.
380 a6507317548 Fulda N. p108 False Conference 18 Machine Learning for Offensive Security: Sandbox Classification Using Decision Trees and Artificial Neural Networks The merits of machine learning in information security have primarily focused on bolstering defenses. However, machine learning (ML) techniques are not reserved for organizations with deep pockets and massive data repositories; the democratization of ML has lead to a rise in the number of security teams using ML to support offensive operations. The research presented here will explore two models that our team has used to solve a single offensive task, detecting a sandbox. Using process list data gathered with phishing emails, we will demonstrate the use of Decision Trees and Artificial Neural Networks to successfully classify sandboxes, thereby avoiding unsafe execution. This paper aims to give unique insight into how a real offensive team is using machine learning to support offensive operations. © 2020, Springer Nature Switzerland AG.
381 a54781821400 Stout J.M. p99 True Journal 37 Nanofluidic peristaltic pumps made from silica thin films We present theory for operation and experimental results for a nanoscale pump implemented in silica thin films that uses electrostatic actuation. The devices were implemented on silicon substrates using standard microfabrication recipes. Using pressures induced by capillary forces, the pressures exerted on pump membranes through electrostatic forces, and the approximate displacement per stroke we predict the pump speed operating the device over a range of frequencies and voltages. For membranes 100 nm thick, 170 V was required for pump actuation, providing exquisite control of pumping rates of less than 1 fl s-1 per nanochannel. © 2019 IOP Publishing Ltd.
382 a57215052018 Baumgarten T.E. p99 False Journal 37 Nanofluidic peristaltic pumps made from silica thin films We present theory for operation and experimental results for a nanoscale pump implemented in silica thin films that uses electrostatic actuation. The devices were implemented on silicon substrates using standard microfabrication recipes. Using pressures induced by capillary forces, the pressures exerted on pump membranes through electrostatic forces, and the approximate displacement per stroke we predict the pump speed operating the device over a range of frequencies and voltages. For membranes 100 nm thick, 170 V was required for pump actuation, providing exquisite control of pumping rates of less than 1 fl s-1 per nanochannel. © 2019 IOP Publishing Ltd.
383 a57215058041 Stagg G.G. p99 False Journal 37 Nanofluidic peristaltic pumps made from silica thin films We present theory for operation and experimental results for a nanoscale pump implemented in silica thin films that uses electrostatic actuation. The devices were implemented on silicon substrates using standard microfabrication recipes. Using pressures induced by capillary forces, the pressures exerted on pump membranes through electrostatic forces, and the approximate displacement per stroke we predict the pump speed operating the device over a range of frequencies and voltages. For membranes 100 nm thick, 170 V was required for pump actuation, providing exquisite control of pumping rates of less than 1 fl s-1 per nanochannel. © 2019 IOP Publishing Ltd.
384 a56957771800 Cannon M.J. p100 True Conference 16 Modeling common cause failures in systems with triple modular redundancy and repair Triple modular redundancy (TMR) is commonly employed to increase the reliability and mean time to failure (MTTF) of a system. This improvement can be shown by using a continuous time Markov chain. However, typical Markov chain models do not model common cause failures (CCF), which is a singular event that simultaneously causes failure in multiple redundant modules. This paper introduces a new Markov chain to model CCF in TMR with repair systems. This new model is compared to the idealized models of TMR with repair without CCF. The fundamental limitations that CCF imposes on the system are shown and discussed. In a motivating example, it is seen that CCF imposes a limitation of 51× on the reliability improvement in a system with TMR and repair compared to a simplex system, (i.e., without TMR). A case study is also presented where the likelihood of CCF is reduced by a factor of 18× using various mitigation techniques. Reducing the CCF compounds the reliability improvement of TMR with repair and leads to a overall system reliability improvement of 10,000× compared to the simplex system as supported by the proposed model. © 2020 IEEE.
384 a56957771800 Cannon M.J. p112 True Journal 29 Improving the Reliability of TMR with Nontriplicated I/O on SRAM FPGAs Triple modular redundancy (TMR) with repair is a commonly employed mitigation strategy used on SRAM field-programmable gate arrays (FPGAs) to reduce the effects of ionizing radiation and improve a circuit's sensitive cross section. This article examines TMR circuits, where the I/O ports of the circuit have not been triplicated, but the internal circuitry has. Such circuits introduce single-point failures (SPFs) into the circuit that limit the neutron cross-sectional improvement offered by TMR to only 3× for the b13 benchmark circuit used in this article. This article proposes two different mitigation techniques to address SPFs, which alter the placement and routing of the circuit. These mitigation techniques reduce the neutron cross section by 26× over the unmitigated circuit while minimally affecting the circuit's maximum clock frequency and resource utilization. © 1963-2012 IEEE.
384 a56957771800 Cannon M.J. p362 True Journal 202 Strategies for Removing Common Mode Failures from TMR Designs Deployed on SRAM FPGAs Triple modular redundancy (TMR) with repair has proven to be an effective strategy for mitigating the effects of single-event upsets within the configuration memory of static random access memory field-programmable gate arrays. Applying TMR to the design successfully reduces the design's neutron cross section by 80×. The effectiveness of TMR, however, is limited by the presence of single bits in the configuration memory which cause more than one TMR domain to fail simultaneously. We present three strategies to mitigate against these failures and improve the effectiveness of TMR: incremental routing, incremental placement, and striping. These techniques were tested using both fault injection and a wide spectrum neutron beam with the best technique offering a 400× reduction to the design's sensitive neutron cross section. An analysis from the radiation test shows that no single bits caused failure and that multicell upsets were the main cause of failure for these mitigation strategies. © 1963-2012 IEEE.
384 a56957771800 Cannon M.J. p405 False Conference 151 Single-Event Characterization of 16 nm FinFET Xilinx UltraScale+ Devices with Heavy Ion and Neutron Irradiation This study examines the single-event response of Xilinx 16nm FinFET UltraScale+ FPGA and MPSoC device families. Heavy-ion single-event latch-up, single-event upsets in configuration SRAM, BlockRAM™ memories, and flip-flops, and neutron-induced single-event latch-up results are provided. © 2018 IEEE.
384 a56957771800 Cannon M.J. p690 False Journal 336 Mitigated FPGA design of multi-gigabit transceivers for application in high radiation environments of High Energy Physics experiments SRAM-based Field Programmable Gate Array (FPGA) logic devices are very attractive in applications where high data throughput is needed, such as the latest generation of High Energy Physics (HEP) experiments. FPGAs have been rarely used in such experiments because of their sensitivity to radiation. The present paper proposes a mitigation approach applied to commercial FPGA devices to meet the reliability requirements for the front-end electronics of the Liquid Argon (LAr) electromagnetic calorimeter of the ATLAS experiment, located at CERN. Particular attention will be devoted to define a proper mitigation scheme of the multi-gigabit transceivers embedded in the FPGA, which is a critical part of the LAr data acquisition chain. A demonstrator board is being developed to validate the proposed methodology. Mitigation techniques such as Triple Modular Redundancy (TMR) and scrubbing will be used to increase the robustness of the design and to maximize the fault tolerance from Single-Event Upsets (SEUs). © 2017 Elsevier Ltd
384 a56957771800 Cannon M.J. p721 True Conference 305 Move the Laser Spot, Not the DUT: Investigating the New Micro-mirror Capability and Challenges for Localizing SEE Sites on Large Modern ICs Small spot size laser testing for single-event effects has proven to be a particularly productive path to insights on the physics of charge collection and circuit response that are difficult or impossible to obtain through broad ion beam tests. As a result, there are a number of such laser facilities; for example, four of them were compared in 2012 [1], but a relatively new facility at the facility at the University of Saskatchewan offers a unique galvo-mirror, laser-spot scanning capability in addition to the usual micrometer-based DUT motion stage [2]. Operating in a fashion similar to LASIX eye surgery, fast pin-point redirection of the laser beam makes tractable (seconds, not hours or days) comprehensive scanning of a millimeter size field-of-view. Combined with auto-stepping the field-of-view, this new spot scanning capability opens up the possibility of comprehensively covering a large die and finding all SEE sites, including the rare, but important, ones such as SEFIs. © 2017 IEEE.
385 a57204469757 Perez-Celis A. p100 False Conference 16 Modeling common cause failures in systems with triple modular redundancy and repair Triple modular redundancy (TMR) is commonly employed to increase the reliability and mean time to failure (MTTF) of a system. This improvement can be shown by using a continuous time Markov chain. However, typical Markov chain models do not model common cause failures (CCF), which is a singular event that simultaneously causes failure in multiple redundant modules. This paper introduces a new Markov chain to model CCF in TMR with repair systems. This new model is compared to the idealized models of TMR with repair without CCF. The fundamental limitations that CCF imposes on the system are shown and discussed. In a motivating example, it is seen that CCF imposes a limitation of 51× on the reliability improvement in a system with TMR and repair compared to a simplex system, (i.e., without TMR). A case study is also presented where the likelihood of CCF is reduced by a factor of 18× using various mitigation techniques. Reducing the CCF compounds the reliability improvement of TMR with repair and leads to a overall system reliability improvement of 10,000× compared to the simplex system as supported by the proposed model. © 2020 IEEE.
385 a57204469757 Perez-Celis A. p112 False Journal 29 Improving the Reliability of TMR with Nontriplicated I/O on SRAM FPGAs Triple modular redundancy (TMR) with repair is a commonly employed mitigation strategy used on SRAM field-programmable gate arrays (FPGAs) to reduce the effects of ionizing radiation and improve a circuit's sensitive cross section. This article examines TMR circuits, where the I/O ports of the circuit have not been triplicated, but the internal circuitry has. Such circuits introduce single-point failures (SPFs) into the circuit that limit the neutron cross-sectional improvement offered by TMR to only 3× for the b13 benchmark circuit used in this article. This article proposes two different mitigation techniques to address SPFs, which alter the placement and routing of the circuit. These mitigation techniques reduce the neutron cross section by 26× over the unmitigated circuit while minimally affecting the circuit's maximum clock frequency and resource utilization. © 1963-2012 IEEE.
385 a57204469757 Perez-Celis A. p113 True Journal 29 Statistical method to extract radiation-induced multiple-cell upsets in SRAM-Based FPGAs Radiation-induced multiple-cell upsets (MCUs) are a concern because they can overcome the protection of error correction code and triplicated designs. Extracting MCU data from radiation tests is helpful to perform more accurate fault injection tests, where MCUs could be simulated with the injection of bits based on the MCUs shapes, sizes, and frequencies. This article presents a statistical method to extract MCU shapes and frequencies from components with no information regarding their physical layout. The proposed method can be used to extract MCU information from BRAM and CRAM alike. The results show the MCU data for three families of Xilinx field-programmable gate arrays (FPGAs). © 1963-2012 IEEE.
385 a57204469757 Perez-Celis A. p362 False Journal 202 Strategies for Removing Common Mode Failures from TMR Designs Deployed on SRAM FPGAs Triple modular redundancy (TMR) with repair has proven to be an effective strategy for mitigating the effects of single-event upsets within the configuration memory of static random access memory field-programmable gate arrays. Applying TMR to the design successfully reduces the design's neutron cross section by 80×. The effectiveness of TMR, however, is limited by the presence of single bits in the configuration memory which cause more than one TMR domain to fail simultaneously. We present three strategies to mitigate against these failures and improve the effectiveness of TMR: incremental routing, incremental placement, and striping. These techniques were tested using both fault injection and a wide spectrum neutron beam with the best technique offering a 400× reduction to the design's sensitive neutron cross section. An analysis from the radiation test shows that no single bits caused failure and that multicell upsets were the main cause of failure for these mitigation strategies. © 1963-2012 IEEE.
385 a57204469757 Perez-Celis A. p405 False Conference 151 Single-Event Characterization of 16 nm FinFET Xilinx UltraScale+ Devices with Heavy Ion and Neutron Irradiation This study examines the single-event response of Xilinx 16nm FinFET UltraScale+ FPGA and MPSoC device families. Heavy-ion single-event latch-up, single-event upsets in configuration SRAM, BlockRAM™ memories, and flip-flops, and neutron-induced single-event latch-up results are provided. © 2018 IEEE.
385 a57204469757 Perez-Celis A. p721 False Conference 305 Move the Laser Spot, Not the DUT: Investigating the New Micro-mirror Capability and Challenges for Localizing SEE Sites on Large Modern ICs Small spot size laser testing for single-event effects has proven to be a particularly productive path to insights on the physics of charge collection and circuit response that are difficult or impossible to obtain through broad ion beam tests. As a result, there are a number of such laser facilities; for example, four of them were compared in 2012 [1], but a relatively new facility at the facility at the University of Saskatchewan offers a unique galvo-mirror, laser-spot scanning capability in addition to the usual micrometer-based DUT motion stage [2]. Operating in a fashion similar to LASIX eye surgery, fast pin-point redirection of the laser beam makes tractable (seconds, not hours or days) comprehensive scanning of a millimeter size field-of-view. Combined with auto-stepping the field-of-view, this new spot scanning capability opens up the possibility of comprehensively covering a large die and finding all SEE sites, including the rare, but important, ones such as SEFIs. © 2017 IEEE.
385 a57204469757 Perez-Celis A. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
386 a57188691775 Best C.M. p101 True Journal 75 Comparing model-based control methods for simultaneous stiffness and position control of inflatable soft robots Inflatable robots are naturally lightweight and compliant, which may make them well suited for operating in unstructured environments or in close proximity to people. The inflatable joints used in this article consist of a strong fabric exterior that constrains two opposing compliant air bladders that generate torque (unlike McKibben actuators where pressure changes cause translation). This antagonistic structure allows the simultaneous control of position and stiffness. However, dynamic models of soft robots that allow variable stiffness control have not been well developed. In this work, a model that includes stiffness as a state variable is developed and validated. Using the stiffness model, a sliding mode controller and model predictive controller are developed to control stiffness and position simultaneously. For sliding mode control (SMC), the joint stiffness was controlled to within 0.07 Nm/rad of a 45 Nm/rad command. For model predictive control (MPC) the joint stiffness was controlled to within 0.045 Nm/rad of the same stiffness command. Both SMC and MPC were able to control to within 0.5° of a desired position at steady state. Stiffness control was extended to a multiple-degree-of-freedom soft robot using MPC. Controlling stiffness of a 4-DOF arm reduced the end-effector deflection by approximately 50% (from 17.9 to 12.2cm) with a 4 lb (1.8 kg) step input applied at the end effector when higher joint stiffness (40 Nm/rad) was used compared with low stiffness (30 Nm/rad). This work shows that the derived stiffness model can enable effective position and stiffness control. © The Author(s) 2020.
386 a57188691775 Best C.M. p717 False Conference 301 Variable stiffness adaptation to mitigate system failure in inflatable robots Although inflatable soft robots are not yet a common robot platform, air leaking from the internal structure is a common and undesirable mode of failure for these platforms. In this paper we demonstrate a method to detect leaks in the structural chamber of an inflatable, pneumatically actuated robot. We then show that our method can adaptively lower commanded joint stiffness which slows the mass flow rate of the leak. This extends the operational life of the robot by decreasing long term error during operation by as much as 50% of the steady state error at the end effector when compared to the same leak if our adaptation method is not used. In future applications where we expect soft, inflatable robots to be useful, our methods can enable failure mitigation in resource-limited situations such as space exploration or disaster response. © 2017 IEEE.
387 a57188173800 Rupert L. p101 False Journal 75 Comparing model-based control methods for simultaneous stiffness and position control of inflatable soft robots Inflatable robots are naturally lightweight and compliant, which may make them well suited for operating in unstructured environments or in close proximity to people. The inflatable joints used in this article consist of a strong fabric exterior that constrains two opposing compliant air bladders that generate torque (unlike McKibben actuators where pressure changes cause translation). This antagonistic structure allows the simultaneous control of position and stiffness. However, dynamic models of soft robots that allow variable stiffness control have not been well developed. In this work, a model that includes stiffness as a state variable is developed and validated. Using the stiffness model, a sliding mode controller and model predictive controller are developed to control stiffness and position simultaneously. For sliding mode control (SMC), the joint stiffness was controlled to within 0.07 Nm/rad of a 45 Nm/rad command. For model predictive control (MPC) the joint stiffness was controlled to within 0.045 Nm/rad of the same stiffness command. Both SMC and MPC were able to control to within 0.5° of a desired position at steady state. Stiffness control was extended to a multiple-degree-of-freedom soft robot using MPC. Controlling stiffness of a 4-DOF arm reduced the end-effector deflection by approximately 50% (from 17.9 to 12.2cm) with a 4 lb (1.8 kg) step input applied at the end effector when higher joint stiffness (40 Nm/rad) was used compared with low stiffness (30 Nm/rad). This work shows that the derived stiffness model can enable effective position and stiffness control. © The Author(s) 2020.
387 a57188173800 Rupert L. p270 False Journal 177 Configuration estimation for accurate position control of large-scale soft robots There is a significant trend in robotics of exploring passively compliant and low inertia systems that can safely make contact with the environment. This paper defines many of the problems associated with developing effective control of soft, pneumatically actuated, inflatable robots, and proposes an approach to solving a subset of these problems. We show that we can obtain a global measurement of orientation for a given soft-robot link using two different types of sensors (not including motion capture). Given the orientation measurement, it is possible to estimate relative configurations of the soft actuators and joints. In order to validate the ability to control position and orientation at the end effector, we show a new method for calibrating the coordinate frames of two unrelated measurement systems. Then, using one of our configuration estimation methods, we demonstrate its viability by performing simple behaviors with a large-scale (approximately 1.5 m long) soft-robot platform attached to the K-Rex rover at NASA Ames in an outdoor environment. Our results also show the importance of soft-robot kinematic calibration and the sensitivity of a soft robot to simple perturbations in the structure like deflation and reinflation. Finally, we show that end effector error can be significantly reduced by doing a form of servoing. In summary, our approach and demonstrations show effective soft-robot configuration estimation and control for large-scale soft robots capable of performing manipulation tasks. © 1996-2012 IEEE.
388 a57202579348 Ong J. p102 True Journal 76 Analysis and evaluation of partitioning techniques for multi-user CAD Recent advances into multi-user computer-aided design environments have enabled designers and engineers to work simultaneously on the same model in different locations. This technology enables different individuals and companies across the globe to share 3D model data in more direct ways. However, intellectual property becomes a larger issue when sharing potentially sensitive data with others in real-time. Partitioning techniques are one strategy to mitigate this risk within multi-user CAD environments. This study explores and evaluates six different partitioning techniques across various metrics identified in the literature and performed a user study to assess the methods' capabilities to hide or suppress data from others. Best practices are suggested and survey data from the participants are analyzed. Overall, the Planar Decomposition technique was found to offer the best trade between protecting data, facilitating multi-user design, and encouraging users to focus only on the relevant information for a design activity. © 2020 CAD Solutions, LLC.
389 a57214718289 Richards D. p102 False Journal 76 Analysis and evaluation of partitioning techniques for multi-user CAD Recent advances into multi-user computer-aided design environments have enabled designers and engineers to work simultaneously on the same model in different locations. This technology enables different individuals and companies across the globe to share 3D model data in more direct ways. However, intellectual property becomes a larger issue when sharing potentially sensitive data with others in real-time. Partitioning techniques are one strategy to mitigate this risk within multi-user CAD environments. This study explores and evaluates six different partitioning techniques across various metrics identified in the literature and performed a user study to assess the methods' capabilities to hide or suppress data from others. Best practices are suggested and survey data from the participants are analyzed. Overall, the Planar Decomposition technique was found to offer the best trade between protecting data, facilitating multi-user design, and encouraging users to focus only on the relevant information for a design activity. © 2020 CAD Solutions, LLC.
390 a57193706327 Larsen J.L. p103 True Journal 77 Automated sounding for concrete bridge deck inspection through a multi-channel, continuously moving platform A new multi-channel, automated, air-coupled, impact-echo sounding device was designed, constructed, and demonstrated in this work. The apparatus includes seven replicated impactor and recording units, a moving trailer platform, a distance measurement instrument, and signal processing modules. A series of computer algorithms is used to determine the presence of delamination on concrete bridge decks based on the bandlimited acoustic energy value computed from the acoustic response associated with each impact. Compared to traditional sounding methods, this device significantly decreases the required inspection time, eliminates subjectivity, and increases safety by substantially reducing the exposure of inspectors to live traffic. © 2019
390 a57193706327 Larsen J.L. p258 False Journal 169 Automated Air-Coupled Impact-Echo Testing of a Concrete Bridge Deck from a Continuously Moving Platform The objective of this work was to develop an automated air-coupled impact-echo testing device for mapping the occurrence of delamination in a concrete bridge deck from a continuously moving platform with a fast, repeatable excitation mechanism and algorithms for collecting and analyzing the acoustic data. The apparatus developed in this research included an impactor unit, a moving platform, a microphone for air-coupled sensing, a distance measurement instrument, and signal processing modules. Given the absence of an existing universal threshold for differentiating among intact and delaminated areas using the new device, a delamination detection threshold value was determined in a first field demonstration also involving chain dragging and coring of a concrete bridge deck. While the maps of the air-coupled impact-echo data and chain-dragging data exhibit a high degree of similarity and are highly consistent with the results of coring, a quantitative method of comparison also demonstrates the utility of the new device across a broad range of delamination percentages. Specifically, the results indicate that the percentage of the deck area determined to be delaminated using impact-echo testing was within 3 percentage points of that determined to be delaminated using chain dragging for 10 of the 13 deck test sections, which generally exhibited delamination percentages ranging from 7 to 21%. Finally, testing with the new device was more than seven times faster than chain dragging. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
391 a57193715705 McElderry J. p103 False Journal 77 Automated sounding for concrete bridge deck inspection through a multi-channel, continuously moving platform A new multi-channel, automated, air-coupled, impact-echo sounding device was designed, constructed, and demonstrated in this work. The apparatus includes seven replicated impactor and recording units, a moving trailer platform, a distance measurement instrument, and signal processing modules. A series of computer algorithms is used to determine the presence of delamination on concrete bridge decks based on the bandlimited acoustic energy value computed from the acoustic response associated with each impact. Compared to traditional sounding methods, this device significantly decreases the required inspection time, eliminates subjectivity, and increases safety by substantially reducing the exposure of inspectors to live traffic. © 2019
392 a57188833818 Pehrson N.A. p104 True Conference 17 Design and analysis of self-deployable, self-stiffening, and retractable arrays Self-deployable, self-stiffening, and retractable (SDSR) arrays were introduced by the authors as a novel architecture of deployable space structures which leverages array surface topology, as opposed to dedicated structures, to achieve desirable deployed structural performance. The application of the technology to solar electric propulsion is discussed. The effects of array shape are discussed, concluding that circular arrays are more structurally efficient than several smaller rectangular arrays, especially for large scales. A system architecture is proposed that considers circular origami-based flasher SDSR arrays integrated with a spacecraft: stowage restraints during launch, deployment, and repeatable retraction. This paper studies the design and analysis of such arrays for scalability, including the performance metrics of specific power, power density, stiffness, and strength. Key advantages of the architecture are the trends of performance metrics which indicate increased performance with increased array power. The limiting constraint is found to be the stowed height dimension and another candidate folding pattern is discussed that eliminates the height constraint violation. Strengths and weaknesses of the architecture are discussed. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
392 a57188833818 Pehrson N.A. p106 True Journal 78 Self-deployable, self-stiffening, and retractable origami-based arrays for spacecraft Spacecraft with large arrays sometimes have deployed sizes that are much larger than the launch volumes; in this case, deployable arrays are used. Several methods exist for stowing, deploying, and stiffening large space arrays. Often these functions are performed by separate systems. This work presents a novel array system that integrates these functions into one system, without the need for external deployment or stiffening structures. The integration comes from the combination of the kinematics of origami-based folding approaches, stored strain energy of compliant hinges, and tension cables. Additionally, due to the origami-based folding approach used, tunable deployed shapes and retraction are possible using reeled cables. The result is a new array architecture that is self-deployable, self-stiffening, and retractable (SDSR) and is described in this work. To understand the behavior of such systems, this work presents the modeling and testing of an SDSR array using an origami flasher pattern and discusses the results for the performance considerations of deployment motion, deployment stiffness, and dynamics. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
392 a57188833818 Pehrson N.A. p238 False Journal 157 Kinetostatic and dynamic analyses of planar compliant mechanisms via a two-port dynamic stiffness model Serial-parallel configurations are widely designed in compliant mechanisms. In this paper, the transfer matrix method is combined with D'Alembert's principle to develop a two-port dynamic stiffness model for analyzing the kinetostatics and dynamics of complex compliant mechanisms with serial-parallel configurations. In detail, two kinds of improved transfer matrices for parallel sub-chains are derived in a unified form by summarizing the common serial-parallel substructures in compliant mechanisms. Then, a two-port dynamic stiffness model describing the frequency-dependent input and output force-displacement relationship of compliant mechanisms is established. Based on the two-port dynamic stiffness model, procedures for solving the static and dynamic performances of compliant mechanisms are presented. The proposed approach is demonstrated by calculating the displacement amplification ratio, input/output stiffness, natural frequencies and forced dynamic response of two typical precision flexure manipulators. The advantage of the proposed approach lies in its capability to describe the simultaneous kinetostatics and dynamics for a large class of serial-parallel configurations with very few degrees of freedom (DOFs), differing from the previous Lagrange-based dynamic modeling methods in the context of compliant mechanisms and should be of interest to designers. © 2019 Elsevier Inc.
392 a57188833818 Pehrson N.A. p246 False Journal 161 Origami-Based Design of Conceal-and-Reveal Systems This work introduces a type of motion termed "conceal-and-reveal" which is characterized by a state that protects a payload, a state that exposes the payload, and coupled motions between these two states. As techniques for thick, rigid origami-based engineering designs are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design similar thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns can be used to initiate viable approaches to achieving conceal-and-reveal motion. © 2019 by ASME.
392 a57188833818 Pehrson N.A. p319 False Conference 99 Thick folding through regionally-sandwiched compliant sheets The regional-sandwiching of compliant sheets (ReCS) technique presented in this work creates flat-foldable, rigid-foldable, and self-deploying thick origami-based mechanisms. Regional-sandwiching of the compliant sheet is used to create mountain/valley assignments for each fold about a vertex, constraining motion to a single branch of folding. Strain energy in deflected flexible members is used to enable self-deployment. This work presents the methods to design origami-based mechanisms using the ReCS technique, including volume trimming at the vertex of the compliant sheet and of the panels used in the sandwich. Physical models of a simple single fold mechanism and a degree-four vertex mechanism are presented to demonstrate the ReCS technique using acrylic panels and spring steel. Consideration is given to the risk of yielding of the compliant sheet due to parasitic motion with possible mitigation of yielding by decreasing the thickness of the sheet. Copyright © 2019 ASME.
392 a57188833818 Pehrson N.A. p367 True Conference 129 Self-deployable, self-stiffening, and retractable origami-based arrays for spacecraft Large deployable arrays are needed for spacecraft that require small stowed volumes. Several methods exist for stowing, deploying, and stiffening large space arrays. Often these functions are performed by separate systems. This paper presents a novel array system that integrates these functions into one system, without the need for external deployment or stiffening structures. The integration comes from the combination of the kinematics of origami-based folding approaches, stored strain energy of compliant hinges, and tension cables. Additionally, due to the origami-based folding approach used, tunable deployed shapes and retraction are possible using reeled cables. The result is a new class of arrays that are self-deployable, self-stiffening, and retractable (SDSR), which are described in this work. To understand the behavior of such systems, this paper presents the modeling and testing of an SDSR array using an origami flasher pattern and discusses the results for the performance metrics of stiffness and shape. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
392 a57188833818 Pehrson N.A. p393 True Conference 142 Folding approaches for tensioned precision planar shell structures An origami-based engineering approach is applied to the folding design of tensioned precision space structures. Tension is a viable means of stiffening a flat antenna aperture, especially when stowed volume is paramount. Three folding patterns are described, and the design guidelines are developed. Deployment kinematics follow the simplicity of a single-degree-of-freedom mechanism for two of the three patterns. The panels are rigid, and articulations occur along the prescribed lines. These deployment architectures are compatible with storable tubular extendible member booms, articulated trusses, or continuous longeron coilable trusses, all commonly used to deploy spacecraft structures. High areal packaging densities were demonstrated: 1.0 m2∕l for a diamond pattern with a high deployed aspect ratio and 0.5 m2∕l for spiral and serpentine patterns compatible with high and low deployed aspect ratios. A double-layer material hinge method is also presented and used to enable the structures to fold, deploy, and be tensioned to a planar state. Copyright © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
392 a57188833818 Pehrson N.A. p456 True Conference 162 An Origami-based Thickness-Accommodating Bistable Mechanism in Monolithic Thick-sheet Materials Origami-based mechanisms can provide useful capabilities in folding large structures to stow in small volumes. However, when using monolithic thick-sheet materials for these types of mechanisms, accommodating the thickness proves challenging. One approach to solve this is to create compliant mechanisms along the fold lines that inherently store energy when actuated and causes the mechanism to tend toward its low energy state. This tendency can be used to create bistable states. We outline a method to use this stored energy to achieve bistable states and name the resulting mechanism an origami-based "Thickness-accommodating bistable interior vertex" (TABIV) in monolithic thick-sheet materials. The kinematics and energy-displacement relationships of this mechanism are derived. Prototypes are shown to exhibit the predicted bistable behavior and the mechanism is integrated and prototyped into origami-based mechanisms demonstrating advantageous multi-stable behaviors. © 2018 IEEE.
392 a57188833818 Pehrson N.A. p581 False Conference 226 Origami-based design of conceal-and-reveal systems This work introduces a type of motion termed “conceal-and-reveal” which is characterized by a state that protects a payload, a state that exposes the payload, and continuous motion between these two states. As techniques for thick, rigid origami-based engineering design are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design other thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns represent viable approaches to achieving conceal-and-reveal motion. Copyright © 2018 ASME
392 a57188833818 Pehrson N.A. p634 True Conference 269 Folding approaches for tensioned precision planar shell structures An origami-based engineering approach is applied to the folding design of tensioned precision space structures. Tension is a viable means of stiffening a flat antenna aperture especially when stowed volume is paramount. Three folding patterns are introduced and the design guidelines are developed. Deployment kinematics follow the simplicity of a single degree of freedom mechanism for two of the three patterns. The panels are rigid, and articulations occur along the prescribed lines. These deployment architectures are compatible with storable tubular extendible member booms, articulated trusses, or continuous longeron coilable trusses, all commonly used to deploy spacecraft structures. High areal packaging densities were demonstrated: 1.0 m2/L for a diamond pattern with a high deployed aspect ratio and 0.5 m2/L for spiral and serpentine patterns compatible with high and low deployed aspect ratios. A double-layer material hinge method is also presented and used to enable the structures to fold, deploy, and be tensioned to a planar state. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
393 a57209881955 Ames D.C. p104 False Conference 17 Design and analysis of self-deployable, self-stiffening, and retractable arrays Self-deployable, self-stiffening, and retractable (SDSR) arrays were introduced by the authors as a novel architecture of deployable space structures which leverages array surface topology, as opposed to dedicated structures, to achieve desirable deployed structural performance. The application of the technology to solar electric propulsion is discussed. The effects of array shape are discussed, concluding that circular arrays are more structurally efficient than several smaller rectangular arrays, especially for large scales. A system architecture is proposed that considers circular origami-based flasher SDSR arrays integrated with a spacecraft: stowage restraints during launch, deployment, and repeatable retraction. This paper studies the design and analysis of such arrays for scalability, including the performance metrics of specific power, power density, stiffness, and strength. Key advantages of the architecture are the trends of performance metrics which indicate increased performance with increased array power. The limiting constraint is found to be the stowed height dimension and another candidate folding pattern is discussed that eliminates the height constraint violation. Strengths and weaknesses of the architecture are discussed. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
393 a57209881955 Ames D.C. p106 False Journal 78 Self-deployable, self-stiffening, and retractable origami-based arrays for spacecraft Spacecraft with large arrays sometimes have deployed sizes that are much larger than the launch volumes; in this case, deployable arrays are used. Several methods exist for stowing, deploying, and stiffening large space arrays. Often these functions are performed by separate systems. This work presents a novel array system that integrates these functions into one system, without the need for external deployment or stiffening structures. The integration comes from the combination of the kinematics of origami-based folding approaches, stored strain energy of compliant hinges, and tension cables. Additionally, due to the origami-based folding approach used, tunable deployed shapes and retraction are possible using reeled cables. The result is a new array architecture that is self-deployable, self-stiffening, and retractable (SDSR) and is described in this work. To understand the behavior of such systems, this work presents the modeling and testing of an SDSR array using an origami flasher pattern and discusses the results for the performance considerations of deployment motion, deployment stiffness, and dynamics. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
393 a57209881955 Ames D.C. p367 False Conference 129 Self-deployable, self-stiffening, and retractable origami-based arrays for spacecraft Large deployable arrays are needed for spacecraft that require small stowed volumes. Several methods exist for stowing, deploying, and stiffening large space arrays. Often these functions are performed by separate systems. This paper presents a novel array system that integrates these functions into one system, without the need for external deployment or stiffening structures. The integration comes from the combination of the kinematics of origami-based folding approaches, stored strain energy of compliant hinges, and tension cables. Additionally, due to the origami-based folding approach used, tunable deployed shapes and retraction are possible using reeled cables. The result is a new class of arrays that are self-deployable, self-stiffening, and retractable (SDSR), which are described in this work. To understand the behavior of such systems, this paper presents the modeling and testing of an SDSR array using an origami flasher pattern and discusses the results for the performance metrics of stiffness and shape. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
394 a57212345817 Ignaut B. p104 False Conference 17 Design and analysis of self-deployable, self-stiffening, and retractable arrays Self-deployable, self-stiffening, and retractable (SDSR) arrays were introduced by the authors as a novel architecture of deployable space structures which leverages array surface topology, as opposed to dedicated structures, to achieve desirable deployed structural performance. The application of the technology to solar electric propulsion is discussed. The effects of array shape are discussed, concluding that circular arrays are more structurally efficient than several smaller rectangular arrays, especially for large scales. A system architecture is proposed that considers circular origami-based flasher SDSR arrays integrated with a spacecraft: stowage restraints during launch, deployment, and repeatable retraction. This paper studies the design and analysis of such arrays for scalability, including the performance metrics of specific power, power density, stiffness, and strength. Key advantages of the architecture are the trends of performance metrics which indicate increased performance with increased array power. The limiting constraint is found to be the stowed height dimension and another candidate folding pattern is discussed that eliminates the height constraint violation. Strengths and weaknesses of the architecture are discussed. © 2020, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
394 a57212345817 Ignaut B. p381 False Conference 139 Rigidly foldable thick origami using designed-offset linkages We present new families of thick origami mechanisms that achieve rigid foldability and parallel stacking of panels in the flat-folded state using linkages for some or all of the hinges between panels. A degree-four vertex results in a multi-loop eight-bar spatial mechanism that can be analyzed as separate linkages. The individual linkages are designed so that they introduce offsets perpendicular to the panels that are mutually compatible around each vertex. This family of mechanisms offers the unique combination of a planar unfolded state, parallel-stacked panels in the flat folded state, and kinematic single-degree-of-freedom motion from the flat-unfolded to the flat-folded state. Copyright © 2019 ASME.
395 a57218689472 Broyles Z. p105 True Journal 72 Unpacking the Mathematics of Modeling Origami Folding Transformations with Quaternions This paper seeks to bring mathematical clarity to the modelling of rigid motion origami involving quaternions and dual quaternions. We illustrate with an analysis of a single vertex Muria-ori pattern utilizing quaternions and an analysis of a multi-vertex Muria-ori pattern utilizing dual quaternions. We construct a complete lists of formulas that determine the edge vectors, normal vectors and fold angles throughout the folding transformations. In addition we provide explicit functional representations of the resulting folding transformations. © 2020, Springer Nature Switzerland AG.
396 a57218687826 Talbot S. p105 False Journal 72 Unpacking the Mathematics of Modeling Origami Folding Transformations with Quaternions This paper seeks to bring mathematical clarity to the modelling of rigid motion origami involving quaternions and dual quaternions. We illustrate with an analysis of a single vertex Muria-ori pattern utilizing quaternions and an analysis of a multi-vertex Muria-ori pattern utilizing dual quaternions. We construct a complete lists of formulas that determine the edge vectors, normal vectors and fold angles throughout the folding transformations. In addition we provide explicit functional representations of the resulting folding transformations. © 2020, Springer Nature Switzerland AG.
397 a57218685971 Johnson J. p105 False Journal 72 Unpacking the Mathematics of Modeling Origami Folding Transformations with Quaternions This paper seeks to bring mathematical clarity to the modelling of rigid motion origami involving quaternions and dual quaternions. We illustrate with an analysis of a single vertex Muria-ori pattern utilizing quaternions and an analysis of a multi-vertex Muria-ori pattern utilizing dual quaternions. We construct a complete lists of formulas that determine the edge vectors, normal vectors and fold angles throughout the folding transformations. In addition we provide explicit functional representations of the resulting folding transformations. © 2020, Springer Nature Switzerland AG.
398 a7006533953 Halverson D.M. p105 False Journal 72 Unpacking the Mathematics of Modeling Origami Folding Transformations with Quaternions This paper seeks to bring mathematical clarity to the modelling of rigid motion origami involving quaternions and dual quaternions. We illustrate with an analysis of a single vertex Muria-ori pattern utilizing quaternions and an analysis of a multi-vertex Muria-ori pattern utilizing dual quaternions. We construct a complete lists of formulas that determine the edge vectors, normal vectors and fold angles throughout the folding transformations. In addition we provide explicit functional representations of the resulting folding transformations. © 2020, Springer Nature Switzerland AG.
398 a7006533953 Halverson D.M. p201 False Journal 135 Normalized Coordinate Equations and an Energy Method for Predicting Natural Curved-Fold Configurations Of the many valid configurations that a curved fold may assume, it is of particular interest to identify natural - or lowest energy - configurations that physical models will preferentially assume. We present normalized coordinate equations - equations that relate fold surface properties to their edge of regression - to simplify curved-fold relationships. An energy method based on these normalized coordinate equations is developed to identify natural configurations of general curved folds. While it has been noted that natural configurations have nearly planar creases for curved folds, we show that nonplanar behavior near the crease ends substantially reduces the energy of a fold. © 2019 ASME.
399 a57209889565 Smith S.P. p106 False Journal 78 Self-deployable, self-stiffening, and retractable origami-based arrays for spacecraft Spacecraft with large arrays sometimes have deployed sizes that are much larger than the launch volumes; in this case, deployable arrays are used. Several methods exist for stowing, deploying, and stiffening large space arrays. Often these functions are performed by separate systems. This work presents a novel array system that integrates these functions into one system, without the need for external deployment or stiffening structures. The integration comes from the combination of the kinematics of origami-based folding approaches, stored strain energy of compliant hinges, and tension cables. Additionally, due to the origami-based folding approach used, tunable deployed shapes and retraction are possible using reeled cables. The result is a new array architecture that is self-deployable, self-stiffening, and retractable (SDSR) and is described in this work. To understand the behavior of such systems, this work presents the modeling and testing of an SDSR array using an origami flasher pattern and discusses the results for the performance considerations of deployment motion, deployment stiffness, and dynamics. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
399 a57209889565 Smith S.P. p367 False Conference 129 Self-deployable, self-stiffening, and retractable origami-based arrays for spacecraft Large deployable arrays are needed for spacecraft that require small stowed volumes. Several methods exist for stowing, deploying, and stiffening large space arrays. Often these functions are performed by separate systems. This paper presents a novel array system that integrates these functions into one system, without the need for external deployment or stiffening structures. The integration comes from the combination of the kinematics of origami-based folding approaches, stored strain energy of compliant hinges, and tension cables. Additionally, due to the origami-based folding approach used, tunable deployed shapes and retraction are possible using reeled cables. The result is a new class of arrays that are self-deployable, self-stiffening, and retractable (SDSR), which are described in this work. To understand the behavior of such systems, this paper presents the modeling and testing of an SDSR array using an origami flasher pattern and discusses the results for the performance metrics of stiffness and shape. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
400 a56045493000 Arya M. p106 False Journal 78 Self-deployable, self-stiffening, and retractable origami-based arrays for spacecraft Spacecraft with large arrays sometimes have deployed sizes that are much larger than the launch volumes; in this case, deployable arrays are used. Several methods exist for stowing, deploying, and stiffening large space arrays. Often these functions are performed by separate systems. This work presents a novel array system that integrates these functions into one system, without the need for external deployment or stiffening structures. The integration comes from the combination of the kinematics of origami-based folding approaches, stored strain energy of compliant hinges, and tension cables. Additionally, due to the origami-based folding approach used, tunable deployed shapes and retraction are possible using reeled cables. The result is a new array architecture that is self-deployable, self-stiffening, and retractable (SDSR) and is described in this work. To understand the behavior of such systems, this work presents the modeling and testing of an SDSR array using an origami flasher pattern and discusses the results for the performance considerations of deployment motion, deployment stiffness, and dynamics. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
400 a56045493000 Arya M. p367 False Conference 129 Self-deployable, self-stiffening, and retractable origami-based arrays for spacecraft Large deployable arrays are needed for spacecraft that require small stowed volumes. Several methods exist for stowing, deploying, and stiffening large space arrays. Often these functions are performed by separate systems. This paper presents a novel array system that integrates these functions into one system, without the need for external deployment or stiffening structures. The integration comes from the combination of the kinematics of origami-based folding approaches, stored strain energy of compliant hinges, and tension cables. Additionally, due to the origami-based folding approach used, tunable deployed shapes and retraction are possible using reeled cables. The result is a new class of arrays that are self-deployable, self-stiffening, and retractable (SDSR), which are described in this work. To understand the behavior of such systems, this paper presents the modeling and testing of an SDSR array using an origami flasher pattern and discusses the results for the performance metrics of stiffness and shape. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
401 a57217866402 Adamson M. p107 True Journal 79 Developing Decision Boundaries for Left-Turn Treatments The purpose of this research was to evaluate the interaction of left-turn and opposing through traffic volumes for permitted and protected left-turn phasing at intersections and develop boundaries that help identify when to switch from permitted to protected phasing at signalized intersections. Permitted phasing allows vehicles to turn left after yielding to opposing vehicles; protected phasing provides an exclusive phase for vehicles to turn left without opposition; and protected-permitted phasing combines these phasing alternatives, allowing both permitted and protected turning movements. Intersections with 1, 2, and 3 opposing-lane configurations with permitted and protected-permitted models (split into green times of 10, 15, and 20 s) were analyzed for a total of 12 simulation models. Each model was divided into 100–225 different volume scenarios, with incremental increases in left-turn and opposing volumes. By exporting trajectory files from VISSIM and importing these into the Surrogate Safety Assessment Model, crossing conflicts for each volume combination in each model were extracted. MATLAB was then used to create contour maps representing the number of crossing conflicts per hour associated with different combinations of left-turn and opposing volume. Basic decision boundaries were examined in each contour map. Statistical analysis software was used to perform a linear regression analysis on transformed data and to develop natural log-based equations that form the decision boundaries for each configuration and phase alternative. These equations were graphed and final decision boundaries developed for the 1-, 2-, and 3-lane configurations between permitted and protected-permitted phasing as well as between protected-permitted and protected phasing. © National Academy of Sciences: Transportation Research Board 2020.
402 a8244752200 Schultz G.G. p107 False Journal 79 Developing Decision Boundaries for Left-Turn Treatments The purpose of this research was to evaluate the interaction of left-turn and opposing through traffic volumes for permitted and protected left-turn phasing at intersections and develop boundaries that help identify when to switch from permitted to protected phasing at signalized intersections. Permitted phasing allows vehicles to turn left after yielding to opposing vehicles; protected phasing provides an exclusive phase for vehicles to turn left without opposition; and protected-permitted phasing combines these phasing alternatives, allowing both permitted and protected turning movements. Intersections with 1, 2, and 3 opposing-lane configurations with permitted and protected-permitted models (split into green times of 10, 15, and 20 s) were analyzed for a total of 12 simulation models. Each model was divided into 100–225 different volume scenarios, with incremental increases in left-turn and opposing volumes. By exporting trajectory files from VISSIM and importing these into the Surrogate Safety Assessment Model, crossing conflicts for each volume combination in each model were extracted. MATLAB was then used to create contour maps representing the number of crossing conflicts per hour associated with different combinations of left-turn and opposing volume. Basic decision boundaries were examined in each contour map. Statistical analysis software was used to perform a linear regression analysis on transformed data and to develop natural log-based equations that form the decision boundaries for each configuration and phase alternative. These equations were graphed and final decision boundaries developed for the 1-, 2-, and 3-lane configurations between permitted and protected-permitted phasing as well as between protected-permitted and protected phasing. © National Academy of Sciences: Transportation Research Board 2020.
402 a8244752200 Schultz G.G. p118 True Journal 79 Measuring Compliance of Driver Yielding at Enhanced Pedestrian Crossings in Utah In the 2000s, the Utah Department of Transportation (UDOT) began implementing technological enhancements to reduce the fatality rate of pedestrians involved in crashes. Although these enhancements appeared to be successful at improving safety, there was a need to evaluate their effectiveness. This research evaluates the safety impacts of several pedestrian crossing enhancements using Utah-specific compliance rates of drivers as a surrogate safety measure. This study analyzes enhanced pedestrian crossings to determine the factors that affect the compliance of driver yielding in Utah and provides a statistical analysis to prove the significance of each factor on compliance. The results show that the “High-intensity Activated crossWalK” (HAWK) is more effective at reducing the probability of a non-compliant event compared with an overhead flashing beacon (OFB), and that an OFB is more effective at reducing the probability of a non-compliant event compared with a rectangular rapid flashing beacon (RRFB) or an overhead rectangular rapid flashing beacon (ORRFB). The results show that adding a pedestrian enhancement to a marked crosswalk at a location with five lanes and speed limit between 35 mph and 45 mph can increase compliance rate by 97% for the HAWK, 77% for the OFB, and 57% for the RRFB and ORRFB. © National Academy of Sciences: Transportation Research Board 2020.
402 a8244752200 Schultz G.G. p304 False Conference 85 Analyzing the safety impacts of raised medians A hierarchical Bayesian statistical before-after model was used to analyze locations where raised medians have been installed. Twenty locations where raised medians were installed in Utah from 2002 to 2014 were used in this analysis. A model was developed that analyzed raised medians by access category (AC). Only three AC were represented in the data. Regression plots depicting a decrease in crashes before and after installation and crash modification factor (CMF) plots presenting the CMF values estimated for different vehicle miles traveled values were created as output from the before-after model. Overall, installing a raised median gives an approximate average reduction of 53 percent for all crashes. Individual AC analysis yielded results ranging from 32 to 44 percent reduction for all severity groups except severity 4 and 5. When the model was only run for crash severity 4 and 5, a larger reduction of 57 to 58 percent was found. © 2019 American Society of Civil Engineers.
402 a8244752200 Schultz G.G. p345 False Conference 118 A methodology for analyzing intersection safety This paper summarizes the development of the Utah intersection crash prediction model (UICPM) and the intersection safety analysis methodology (ISAM). The UICPM is a Bayesian generalized linear model that creates distributions of the expected number of crashes at each intersection, compares the actual number of crashes to the distribution, and ranks the intersections based on safety concern. The ISAM is the process that was developed to execute the UICPM. The first step is to prepare the model input by combining the roadway and crash data files. Crashes are assigned to intersections if they are located with the functional area of an intersection. The second step is to execute the UICPM using the R graphical user interface (GUI) tool and R software. The third step is to create a two-page intersection safety analysis report (ISAR) for intersections of interest and maps of the state, regions, and counties to visualize the model results. © 2019 American Society of Civil Engineers.
402 a8244752200 Schultz G.G. p408 False Journal 218 Evaluating Safety Impacts of Access Management Alternatives with the Surrogate Safety Assessment Model In a traditional safety impact analysis, it is necessary to have crash data on existing roadway conditions and a few years must pass before accumulating additional crash data to evaluate the safety impact of an improvement. This is a time-consuming approach and there remains uncertainty in the crash data integrity. The surrogate safety assessment model (SSAM) was developed for resolving these issues. With SSAM, a conflict analysis is performed in a simulated environment. A planned improvement alternative is modeled and no physical installation of the alternative is needed. This study evaluated if SSAM can be used to assess the safety of a highway segment in terms of the number and type of conflicts and to compare the safety effects of multiple access management alternatives. An evaluation of the effect of converting a two-way left-turn lane (TWLTL) into a raised median on a section of an urban street was performed using SSAM working on VISSIM simulation’s trajectory files. The analysis showed that a raised median would be much safer than a TWLTL median for the same level of traffic volume, with approximately 32 to 50 percent reduction in the number of crossing conflicts. The analysis showed that about 34,000 to 38,000 veh/day would be the demand level where the median conversion is recommended for the four-lane study section. The study concluded that the combination of a simulation software program with SSAM could be a viable surrogate analysis approach for evaluating and comparing the safety effects of multiple access management alternatives. © National Academy of Sciences: Transportation Research Board 2018.
402 a8244752200 Schultz G.G. p527 False Journal 292 Investigating the safety impact of roadway network features of suburban arterials in Shanghai With rapid changes in land use development along suburban arterials in Shanghai, there is a corresponding increase in traffic demand on these arterials. To accommodate the local traffic needs of high accessibility and efficiency, an increased number of signalized intersections and accesses have been installed. However, the absence of a defined hierarchical road network, together with irregular signal spacing and access density, tends to deteriorate arterial safety. Previous studies on arterial safety were generally based on a single type of road entity, either intersection or roadway segment, and they analyzed the safety contributing factors (e.g. signal density and access density) on only that type of road entity, while these suburban arterial characteristics could significantly influence the safety performance of both intersections and roadway segments. Macro-level safety modeling was usually applied to investigate the relationships between zonal crash frequencies and demographics, road network features, and traffic characteristics, but the previous researchers did not consider the specific arterial characteristics of signal density and access density. In this study, a new modeling strategy was proposed to analyze the safety impacts of zonal roadway network features (i.e., road network patterns and road network density) along with the suburban arterial characteristics of signal density and access density. Bayesian Conditional Autoregressive Poisson Log-normal models were developed for suburban arterials in 173 traffic analysis zones in the suburban area of Shanghai. Results identified that the grid pattern road network with collector roads parallel to arterials was associated with fewer crashes than networks without parallel collectors. On the other hand, lower road network density, higher signal density and higher access density tended to increase the crash occurrence on suburban arterials. © 2018 Elsevier Ltd
402 a8244752200 Schultz G.G. p570 False Conference 218 High Accuracy Achieved in Determining Lengths and Locations of Horizontal Curves Using Light Detection and Ranging Point Cloud Data The Utah Department of Transportation (UDOT) began collecting asset management data using light detection and ranging (LiDAR) technology in 2012, which included horizontal curve data. However, its horizontal curve data were highly segmented and not ready for crash prediction model development for curve segments. In 2014, an algorithm named the horizontal alignment finder (HAF) algorithm was developed to identify horizontal curves on rural two-lane two-way highways. Its accuracy was about 85 percent with 2012 data. The HAF was recently recalibrated for all other types of UDOT's highways and found to be applicable to them without any modifications in its main algorithm. During the calibration, six types of errors were identified. Four of the six errors were fixed and the HAF was calibrated with new 2015 LiDAR data. The improved HAF's accuracy now ranges from 97 to 98 percent for curve length and 87 to 100 percent for curve location identification. © 2018 American Society of Civil Engineers.
402 a8244752200 Schultz G.G. p687 False Journal 333 Use of Hi-resolution data for evaluating accuracy of traffic volume counts collected by microwave sensors Over the past few years, the Utah Department of Transportation has developed the signal performance metrics (SPMs) system to evaluate the performance of signalized intersections dynamically. This system currently provides data summaries for several performance measures, one of them being turning movement counts collected by microwave sensors. As this system became public, there was a need to evaluate the accuracy of the data placed on the SPMs. A large-scale data collection was carried out to meet this need. Vehicles in the Hi-resolution data from microwave sensors were matched with the vehicles by ground-truth volume count data. Matching vehicles from the microwave sensor data and the ground-truth data manually collected required significant effort. A spreadsheet-based data analysis procedure was developed to carry out the task. A mixed model analysis of variance was used to analyze the effects of the factors considered on turning volume count accuracy. The analysis found that approach volume level and number of approach lanes would have significant effect on the accuracy of turning volume counts but the location of the sensors did not significantly affect the accuracy of turning volume counts. In addition, it was found that the location of lanes in relation to the sensor did not significantly affect the accuracy of lane-by-lane volume counts. This indicated that accuracy analysis could be performed by using total approach volumes without comparing specific turning counts, that is, left-turn, through and right-turn movements. In general, the accuracy of approach volume counts collected by microwave sensors were within the margin of error that traffic engineers could accept. The procedure taken to perform the analysis and a summary of accuracy of volume counts for the factor combinations considered are presented in this paper. © 2017 The Authors
402 a8244752200 Schultz G.G. p829 False Journal 396 Implementing highway safety manual life-cycle benefit–cost analysis of safety improvements The Highway Safety Manual (HSM) lists four methods for determining the change in crash severity in order of reliability. The life-cycle benefit– cost analysis currently used by the Utah Department of Transportation is similar to the least reliable method. To provide a tool to perform the most reliable method defined by the HSM—the predictive method— this research developed a spreadsheet-based tool to allow department engineers to perform life-cycle benefit–cost analyses for the 11 roadway segment types included in the HSM. The tool can be used to analyze the cost-effectiveness of safety-related improvements identified by the Utah crash prediction model, which was previously developed to identify safety hot spots on the state highway system. The concept and the spreadsheet layout are presented by using the rural two-lane, two-way highway spreadsheet as an example. Then a case of a rural two-lane, two-way highway with two selected countermeasures is presented to demonstrate the use of this spreadsheet to compare their benefit–cost ratios. One important aspect associated with life-cycle benefit–cost analyses of safety-related improvements is the cost of implementing such improvements. Safety-related improvements are often included in larger construction contracts and such costs vary significantly, depending on the way they are included in the larger contracts. Hence, construction costs of safety-related improvements—such as initial cost, periodic rehabilitation cost, and annual maintenance costs—must be prepared outside this spreadsheet by the user. © 2017, SAGE Publications Ltd. All rights reserved.
403 a55727966500 Saito M. p107 False Journal 79 Developing Decision Boundaries for Left-Turn Treatments The purpose of this research was to evaluate the interaction of left-turn and opposing through traffic volumes for permitted and protected left-turn phasing at intersections and develop boundaries that help identify when to switch from permitted to protected phasing at signalized intersections. Permitted phasing allows vehicles to turn left after yielding to opposing vehicles; protected phasing provides an exclusive phase for vehicles to turn left without opposition; and protected-permitted phasing combines these phasing alternatives, allowing both permitted and protected turning movements. Intersections with 1, 2, and 3 opposing-lane configurations with permitted and protected-permitted models (split into green times of 10, 15, and 20 s) were analyzed for a total of 12 simulation models. Each model was divided into 100–225 different volume scenarios, with incremental increases in left-turn and opposing volumes. By exporting trajectory files from VISSIM and importing these into the Surrogate Safety Assessment Model, crossing conflicts for each volume combination in each model were extracted. MATLAB was then used to create contour maps representing the number of crossing conflicts per hour associated with different combinations of left-turn and opposing volume. Basic decision boundaries were examined in each contour map. Statistical analysis software was used to perform a linear regression analysis on transformed data and to develop natural log-based equations that form the decision boundaries for each configuration and phase alternative. These equations were graphed and final decision boundaries developed for the 1-, 2-, and 3-lane configurations between permitted and protected-permitted phasing as well as between protected-permitted and protected phasing. © National Academy of Sciences: Transportation Research Board 2020.
403 a55727966500 Saito M. p304 False Conference 85 Analyzing the safety impacts of raised medians A hierarchical Bayesian statistical before-after model was used to analyze locations where raised medians have been installed. Twenty locations where raised medians were installed in Utah from 2002 to 2014 were used in this analysis. A model was developed that analyzed raised medians by access category (AC). Only three AC were represented in the data. Regression plots depicting a decrease in crashes before and after installation and crash modification factor (CMF) plots presenting the CMF values estimated for different vehicle miles traveled values were created as output from the before-after model. Overall, installing a raised median gives an approximate average reduction of 53 percent for all crashes. Individual AC analysis yielded results ranging from 32 to 44 percent reduction for all severity groups except severity 4 and 5. When the model was only run for crash severity 4 and 5, a larger reduction of 57 to 58 percent was found. © 2019 American Society of Civil Engineers.
403 a55727966500 Saito M. p345 False Conference 118 A methodology for analyzing intersection safety This paper summarizes the development of the Utah intersection crash prediction model (UICPM) and the intersection safety analysis methodology (ISAM). The UICPM is a Bayesian generalized linear model that creates distributions of the expected number of crashes at each intersection, compares the actual number of crashes to the distribution, and ranks the intersections based on safety concern. The ISAM is the process that was developed to execute the UICPM. The first step is to prepare the model input by combining the roadway and crash data files. Crashes are assigned to intersections if they are located with the functional area of an intersection. The second step is to execute the UICPM using the R graphical user interface (GUI) tool and R software. The third step is to create a two-page intersection safety analysis report (ISAR) for intersections of interest and maps of the state, regions, and counties to visualize the model results. © 2019 American Society of Civil Engineers.
403 a55727966500 Saito M. p408 False Journal 218 Evaluating Safety Impacts of Access Management Alternatives with the Surrogate Safety Assessment Model In a traditional safety impact analysis, it is necessary to have crash data on existing roadway conditions and a few years must pass before accumulating additional crash data to evaluate the safety impact of an improvement. This is a time-consuming approach and there remains uncertainty in the crash data integrity. The surrogate safety assessment model (SSAM) was developed for resolving these issues. With SSAM, a conflict analysis is performed in a simulated environment. A planned improvement alternative is modeled and no physical installation of the alternative is needed. This study evaluated if SSAM can be used to assess the safety of a highway segment in terms of the number and type of conflicts and to compare the safety effects of multiple access management alternatives. An evaluation of the effect of converting a two-way left-turn lane (TWLTL) into a raised median on a section of an urban street was performed using SSAM working on VISSIM simulation’s trajectory files. The analysis showed that a raised median would be much safer than a TWLTL median for the same level of traffic volume, with approximately 32 to 50 percent reduction in the number of crossing conflicts. The analysis showed that about 34,000 to 38,000 veh/day would be the demand level where the median conversion is recommended for the four-lane study section. The study concluded that the combination of a simulation software program with SSAM could be a viable surrogate analysis approach for evaluating and comparing the safety effects of multiple access management alternatives. © National Academy of Sciences: Transportation Research Board 2018.
403 a55727966500 Saito M. p570 False Conference 218 High Accuracy Achieved in Determining Lengths and Locations of Horizontal Curves Using Light Detection and Ranging Point Cloud Data The Utah Department of Transportation (UDOT) began collecting asset management data using light detection and ranging (LiDAR) technology in 2012, which included horizontal curve data. However, its horizontal curve data were highly segmented and not ready for crash prediction model development for curve segments. In 2014, an algorithm named the horizontal alignment finder (HAF) algorithm was developed to identify horizontal curves on rural two-lane two-way highways. Its accuracy was about 85 percent with 2012 data. The HAF was recently recalibrated for all other types of UDOT's highways and found to be applicable to them without any modifications in its main algorithm. During the calibration, six types of errors were identified. Four of the six errors were fixed and the HAF was calibrated with new 2015 LiDAR data. The improved HAF's accuracy now ranges from 97 to 98 percent for curve length and 87 to 100 percent for curve location identification. © 2018 American Society of Civil Engineers.
403 a55727966500 Saito M. p687 False Journal 333 Use of Hi-resolution data for evaluating accuracy of traffic volume counts collected by microwave sensors Over the past few years, the Utah Department of Transportation has developed the signal performance metrics (SPMs) system to evaluate the performance of signalized intersections dynamically. This system currently provides data summaries for several performance measures, one of them being turning movement counts collected by microwave sensors. As this system became public, there was a need to evaluate the accuracy of the data placed on the SPMs. A large-scale data collection was carried out to meet this need. Vehicles in the Hi-resolution data from microwave sensors were matched with the vehicles by ground-truth volume count data. Matching vehicles from the microwave sensor data and the ground-truth data manually collected required significant effort. A spreadsheet-based data analysis procedure was developed to carry out the task. A mixed model analysis of variance was used to analyze the effects of the factors considered on turning volume count accuracy. The analysis found that approach volume level and number of approach lanes would have significant effect on the accuracy of turning volume counts but the location of the sensors did not significantly affect the accuracy of turning volume counts. In addition, it was found that the location of lanes in relation to the sensor did not significantly affect the accuracy of lane-by-lane volume counts. This indicated that accuracy analysis could be performed by using total approach volumes without comparing specific turning counts, that is, left-turn, through and right-turn movements. In general, the accuracy of approach volume counts collected by microwave sensors were within the margin of error that traffic engineers could accept. The procedure taken to perform the analysis and a summary of accuracy of volume counts for the factor combinations considered are presented in this paper. © 2017 The Authors
403 a55727966500 Saito M. p829 False Journal 396 Implementing highway safety manual life-cycle benefit–cost analysis of safety improvements The Highway Safety Manual (HSM) lists four methods for determining the change in crash severity in order of reliability. The life-cycle benefit– cost analysis currently used by the Utah Department of Transportation is similar to the least reliable method. To provide a tool to perform the most reliable method defined by the HSM—the predictive method— this research developed a spreadsheet-based tool to allow department engineers to perform life-cycle benefit–cost analyses for the 11 roadway segment types included in the HSM. The tool can be used to analyze the cost-effectiveness of safety-related improvements identified by the Utah crash prediction model, which was previously developed to identify safety hot spots on the state highway system. The concept and the spreadsheet layout are presented by using the rural two-lane, two-way highway spreadsheet as an example. Then a case of a rural two-lane, two-way highway with two selected countermeasures is presented to demonstrate the use of this spreadsheet to compare their benefit–cost ratios. One important aspect associated with life-cycle benefit–cost analyses of safety-related improvements is the cost of implementing such improvements. Safety-related improvements are often included in larger construction contracts and such costs vary significantly, depending on the way they are included in the larger contracts. Hence, construction costs of safety-related improvements—such as initial cost, periodic rehabilitation cost, and annual maintenance costs—must be prepared outside this spreadsheet by the user. © 2017, SAGE Publications Ltd. All rights reserved.
404 a57217871738 Stevens M.D. p107 False Journal 79 Developing Decision Boundaries for Left-Turn Treatments The purpose of this research was to evaluate the interaction of left-turn and opposing through traffic volumes for permitted and protected left-turn phasing at intersections and develop boundaries that help identify when to switch from permitted to protected phasing at signalized intersections. Permitted phasing allows vehicles to turn left after yielding to opposing vehicles; protected phasing provides an exclusive phase for vehicles to turn left without opposition; and protected-permitted phasing combines these phasing alternatives, allowing both permitted and protected turning movements. Intersections with 1, 2, and 3 opposing-lane configurations with permitted and protected-permitted models (split into green times of 10, 15, and 20 s) were analyzed for a total of 12 simulation models. Each model was divided into 100–225 different volume scenarios, with incremental increases in left-turn and opposing volumes. By exporting trajectory files from VISSIM and importing these into the Surrogate Safety Assessment Model, crossing conflicts for each volume combination in each model were extracted. MATLAB was then used to create contour maps representing the number of crossing conflicts per hour associated with different combinations of left-turn and opposing volume. Basic decision boundaries were examined in each contour map. Statistical analysis software was used to perform a linear regression analysis on transformed data and to develop natural log-based equations that form the decision boundaries for each configuration and phase alternative. These equations were graphed and final decision boundaries developed for the 1-, 2-, and 3-lane configurations between permitted and protected-permitted phasing as well as between protected-permitted and protected phasing. © National Academy of Sciences: Transportation Research Board 2020.
405 a57218270296 Pearce W. p108 True Conference 18 Machine Learning for Offensive Security: Sandbox Classification Using Decision Trees and Artificial Neural Networks The merits of machine learning in information security have primarily focused on bolstering defenses. However, machine learning (ML) techniques are not reserved for organizations with deep pockets and massive data repositories; the democratization of ML has lead to a rise in the number of security teams using ML to support offensive operations. The research presented here will explore two models that our team has used to solve a single offensive task, detecting a sandbox. Using process list data gathered with phishing emails, we will demonstrate the use of Decision Trees and Artificial Neural Networks to successfully classify sandboxes, thereby avoiding unsafe execution. This paper aims to give unique insight into how a real offensive team is using machine learning to support offensive operations. © 2020, Springer Nature Switzerland AG.
406 a57218269408 Landers N. p108 False Conference 18 Machine Learning for Offensive Security: Sandbox Classification Using Decision Trees and Artificial Neural Networks The merits of machine learning in information security have primarily focused on bolstering defenses. However, machine learning (ML) techniques are not reserved for organizations with deep pockets and massive data repositories; the democratization of ML has lead to a rise in the number of security teams using ML to support offensive operations. The research presented here will explore two models that our team has used to solve a single offensive task, detecting a sandbox. Using process list data gathered with phishing emails, we will demonstrate the use of Decision Trees and Artificial Neural Networks to successfully classify sandboxes, thereby avoiding unsafe execution. This paper aims to give unique insight into how a real offensive team is using machine learning to support offensive operations. © 2020, Springer Nature Switzerland AG.
407 a56215007300 Francom D. p109 True Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
408 a50162863000 Walters D.J. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
409 a55422614200 Barber J.L. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
410 a6603288835 Luscher D.J. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
411 a13405030000 Lawrence E. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
412 a55904183100 Biswas A. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
413 a55279219900 Biwer C.M. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
414 a57211205845 Banesh D. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
415 a38662818500 Lazarz J. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
416 a57203219105 Vogel S.C. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
417 a14059027500 Ramos K. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
418 a6505524737 Bolme C. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
419 a7103004161 Ahrens J. p109 False Journal 80 Simulation and Emulation of X-Ray Diffraction from Dynamic Compression Experiments Many important aspects of the dynamic thermo-mechanical response of materials occur at the mesoscale, i.e. a physical scale of interactions smaller than what can be adequately described by homogenous behaviors, yet larger than the scale of the atomic lattice. Concurrent advancements in computational power, continuum theory, and experimental diagnostics are enabling unprecedented understanding of such interactions. However, we cannot develop a sufficient level of confidence in such mesoscale capability until the constitutive description of the underlying constituents is reliably representative of their actual physical behavior. Therefore, there is a strong need to combine experimental, modeling, and data-science techniques to validate models of the thermomechanical response of individual single crystals. One experimental diagnostic with high potential impact to shock physics and materials science is in-situ x-ray diffraction. This paper is primarily focused on simulation of x-ray diffraction in shock physics, but with an aim toward quantifying parametric uncertainty of simulation models. We develop and demonstrate a data-science and model-driven approach to constrain the parameterization of continuum models of crystal lattice deformation associated with the shock response of crystalline materials. The framework is built around the connection between continuum hydrodynamic simulations of lattice deformation and a new Bragg diffraction simulation code, BarberShop. The dynamic deformation of a crystal lattice is modeled using the DiscoFlux model within an arbitrary Lagrangian-Eulerian hydrodynamic code, FLAG. These detailed continuum simulations of lattice deformation can be computationally slow, thus a statistical model is used to emulate the evolution of lattice deformation fields in time and across the considered model parameter space. Emulated lattice deformation fields can then be generated rapidly for any combination of physics model parameters. In turn, these fields can be fed into BarberShop to realize a rapid prediction of Bragg diffraction patterns associated with particular values of physics model parameters. The framework enables parameterization of the single crystal model to obtain Bragg diffraction patterns that most closely resemble a corresponding measurement. Furthermore, the framework naturally provides sensitivities of the lattice deformation to the physics parameters. We highlight the utility of this framework through the application to a synthetic closed-loop inverse problem leading to the parameterization of a single crystal material model. As a model problem, we consider the dynamic response of the energetic molecular crystal, cyclotrimethylenetrinitramine (or RDX), under dynamic compression induced by simulated flyer plate impact experiments. © 2020, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.
420 a57202612841 Willey L.C. p110 False Journal 81 Single pursuer and two cooperative evaders in the border defense differential game An interest in border defense, surveillance, and interdiction has recently increased for a variety of reasons related to issues of illegal immigration, terrorism, drug and human trafficking, and other potential threats. Unmanned aerial vehicles (UAVs) offer an attractive alternative to supporting and defending various threats at borders. This paper applies a differential game to define a border defense scenario where one UAV (pursuer) seeks to capture two intruders (evaders) before they reach a designated border. The evaders can be UAVs, marine or ground vehicles, or human agents, but they have a lower maximum speed than the pursuer throughout the game. Simple motion is assumed for the pursuer and evaders with complete state information shared across all agents. The game is played within a rectangular area with a parallel top and bottom border of length L and left and right borders with a length of W, for a game aspect ratio of L∕W. The value of the game is the minimum distance to the bottom border achieved by the evaders at any time before capture of both evaders. Within the region where the pursuer wins, the game of degree is explored and the optimal policy for both the evaders and pursuer is derived using geometric properties. © 2020 by John Salmon. Published by the American Institute of Aeronautics and Astronautics, Inc.
420 a57202612841 Willey L.C. p508 False Conference 188 Systems analysis of EV adoption and criteria pollutant accumulation during inversion events Exploring the system-level interactions between vehicle exhaust criteria pollutants, human health, and natural weather patterns such as inversion events is increasingly expedient given the accelerated growth and concentration of human populations in recent years. Pollutants often accumulate to unhealthy concentrations during winter inversion events like those that commonly occur in the state of Utah and other mountainous regions. Electric vehicles (EV) are a potential solution to reduce harmful tail-pipe emissions that accumulate during inversions. This work represents a systems-level analysis of the degree to which replacing internal combustion engine vehicles (ICE) with EVs would reduce the near-road accumulation of criteria pollutants. The analysis draws on vehicle miles travelled data from major highways in Utah, vehicle fuel efficiency data, EPA-specified vehicle pollution emission standards, and local weather pattern trends. It employs two models, built in MATLAB and the agent-based modeling environment NetLogo, to determine pollutant concentrations, accumulation, and dispersion rates. These results are processed to determine changes in the Air Quality Index (AQI) caused by adjusting the percentage of EVs present within the vehicle population. The analysis concludes that replacing a significant percentage (80-100%) of the existing, fossil-fuel powered vehicle population with EVs would improve local AQI by 13 points. During extreme inversion events in Utah, these reductions would delay AQI levels from reaching 'red,' or unhealthy, status for enough time to allow local weather patterns to shift and dissipate the inversion event and accompanying pollution. Such a drastic reduction in AQI translates into better adolescent and elderly health and could minimize the risk of early onset asthma and other respiratory illnesses in regions negatively affected by high traffic pollution and winter inversion events. © 2018 IEEE.
421 a36499438800 Garcia E. p110 False Journal 81 Single pursuer and two cooperative evaders in the border defense differential game An interest in border defense, surveillance, and interdiction has recently increased for a variety of reasons related to issues of illegal immigration, terrorism, drug and human trafficking, and other potential threats. Unmanned aerial vehicles (UAVs) offer an attractive alternative to supporting and defending various threats at borders. This paper applies a differential game to define a border defense scenario where one UAV (pursuer) seeks to capture two intruders (evaders) before they reach a designated border. The evaders can be UAVs, marine or ground vehicles, or human agents, but they have a lower maximum speed than the pursuer throughout the game. Simple motion is assumed for the pursuer and evaders with complete state information shared across all agents. The game is played within a rectangular area with a parallel top and bottom border of length L and left and right borders with a length of W, for a game aspect ratio of L∕W. The value of the game is the minimum distance to the bottom border achieved by the evaders at any time before capture of both evaders. Within the region where the pursuer wins, the game of degree is explored and the optimal policy for both the evaders and pursuer is derived using geometric properties. © 2020 by John Salmon. Published by the American Institute of Aeronautics and Astronautics, Inc.
422 a55860312700 Von Moll A. p110 False Journal 81 Single pursuer and two cooperative evaders in the border defense differential game An interest in border defense, surveillance, and interdiction has recently increased for a variety of reasons related to issues of illegal immigration, terrorism, drug and human trafficking, and other potential threats. Unmanned aerial vehicles (UAVs) offer an attractive alternative to supporting and defending various threats at borders. This paper applies a differential game to define a border defense scenario where one UAV (pursuer) seeks to capture two intruders (evaders) before they reach a designated border. The evaders can be UAVs, marine or ground vehicles, or human agents, but they have a lower maximum speed than the pursuer throughout the game. Simple motion is assumed for the pursuer and evaders with complete state information shared across all agents. The game is played within a rectangular area with a parallel top and bottom border of length L and left and right borders with a length of W, for a game aspect ratio of L∕W. The value of the game is the minimum distance to the bottom border achieved by the evaders at any time before capture of both evaders. Within the region where the pursuer wins, the game of degree is explored and the optimal policy for both the evaders and pursuer is derived using geometric properties. © 2020 by John Salmon. Published by the American Institute of Aeronautics and Astronautics, Inc.
423 a57201618074 Trapuzzano M. p111 True Journal 82 Volume and frequency-independent spreading of droplets driven by ultrasonic surface vibration Many industrial processes depend on the wetting of liquids on various surfaces. Understanding the wetting effects due to ultrasonic vibration could provide a means for changing the behavior of liquids on any surface. In previous studies, low-frequency surface vibrations have been used to alter wetting states of droplets by exciting droplet volume modes. While high-frequency (>20 kHz) surface vibration can also cause droplets to wet or spread on a surface, this effect is relatively uncharacterized. In this study, droplets of various liquids with volumes ranging from 2 to 70 μL were vibrated on hydrophobic-coated (FluoroSyl) glass substrates fixed to a piezoelectric transducer at varying amplitudes and at a range of frequencies between 21 and 42 kHz. The conditions for contact line motion were evaluated, and the change in droplet diameter under vibration was measured. Droplets of all tested liquids initially begin to spread out at a similar surface acceleration level. The results show that the increase in diameter is proportional to the maximum acceleration of the surface. Finally, liquid properties and surface roughness may also produce some secondary effects, but droplet volume and excitation frequency do not significantly change the droplet spreading behavior within the parameter range studied. © 2020 by the authors.
424 a6506325894 Tejada-Martínez A. p111 False Journal 82 Volume and frequency-independent spreading of droplets driven by ultrasonic surface vibration Many industrial processes depend on the wetting of liquids on various surfaces. Understanding the wetting effects due to ultrasonic vibration could provide a means for changing the behavior of liquids on any surface. In previous studies, low-frequency surface vibrations have been used to alter wetting states of droplets by exciting droplet volume modes. While high-frequency (>20 kHz) surface vibration can also cause droplets to wet or spread on a surface, this effect is relatively uncharacterized. In this study, droplets of various liquids with volumes ranging from 2 to 70 μL were vibrated on hydrophobic-coated (FluoroSyl) glass substrates fixed to a piezoelectric transducer at varying amplitudes and at a range of frequencies between 21 and 42 kHz. The conditions for contact line motion were evaluated, and the change in droplet diameter under vibration was measured. Droplets of all tested liquids initially begin to spread out at a similar surface acceleration level. The results show that the increase in diameter is proportional to the maximum acceleration of the surface. Finally, liquid properties and surface roughness may also produce some secondary effects, but droplet volume and excitation frequency do not significantly change the droplet spreading behavior within the parameter range studied. © 2020 by the authors.
425 a8608764300 Guldiken R. p111 False Journal 82 Volume and frequency-independent spreading of droplets driven by ultrasonic surface vibration Many industrial processes depend on the wetting of liquids on various surfaces. Understanding the wetting effects due to ultrasonic vibration could provide a means for changing the behavior of liquids on any surface. In previous studies, low-frequency surface vibrations have been used to alter wetting states of droplets by exciting droplet volume modes. While high-frequency (>20 kHz) surface vibration can also cause droplets to wet or spread on a surface, this effect is relatively uncharacterized. In this study, droplets of various liquids with volumes ranging from 2 to 70 μL were vibrated on hydrophobic-coated (FluoroSyl) glass substrates fixed to a piezoelectric transducer at varying amplitudes and at a range of frequencies between 21 and 42 kHz. The conditions for contact line motion were evaluated, and the change in droplet diameter under vibration was measured. Droplets of all tested liquids initially begin to spread out at a similar surface acceleration level. The results show that the increase in diameter is proportional to the maximum acceleration of the surface. Finally, liquid properties and surface roughness may also produce some secondary effects, but droplet volume and excitation frequency do not significantly change the droplet spreading behavior within the parameter range studied. © 2020 by the authors.
426 a57204470823 Thurlow C.A. p112 False Journal 29 Improving the Reliability of TMR with Nontriplicated I/O on SRAM FPGAs Triple modular redundancy (TMR) with repair is a commonly employed mitigation strategy used on SRAM field-programmable gate arrays (FPGAs) to reduce the effects of ionizing radiation and improve a circuit's sensitive cross section. This article examines TMR circuits, where the I/O ports of the circuit have not been triplicated, but the internal circuitry has. Such circuits introduce single-point failures (SPFs) into the circuit that limit the neutron cross-sectional improvement offered by TMR to only 3× for the b13 benchmark circuit used in this article. This article proposes two different mitigation techniques to address SPFs, which alter the placement and routing of the circuit. These mitigation techniques reduce the neutron cross section by 26× over the unmitigated circuit while minimally affecting the circuit's maximum clock frequency and resource utilization. © 1963-2012 IEEE.
426 a57204470823 Thurlow C.A. p362 False Journal 202 Strategies for Removing Common Mode Failures from TMR Designs Deployed on SRAM FPGAs Triple modular redundancy (TMR) with repair has proven to be an effective strategy for mitigating the effects of single-event upsets within the configuration memory of static random access memory field-programmable gate arrays. Applying TMR to the design successfully reduces the design's neutron cross section by 80×. The effectiveness of TMR, however, is limited by the presence of single bits in the configuration memory which cause more than one TMR domain to fail simultaneously. We present three strategies to mitigate against these failures and improve the effectiveness of TMR: incremental routing, incremental placement, and striping. These techniques were tested using both fault injection and a wide spectrum neutron beam with the best technique offering a 400× reduction to the design's sensitive neutron cross section. An analysis from the radiation test shows that no single bits caused failure and that multicell upsets were the main cause of failure for these mitigation strategies. © 1963-2012 IEEE.
427 a57211518929 Gregg J.F. p114 True Journal 77 Electromagnetic excitation technique for nonlinear resonant ultrasound spectroscopy Nonlinear resonant ultrasound spectroscopy (NRUS) is a method that can be used to determine the amount of microcracking in structures. The nonlinear parameter extracted in NRUS is based on the dependence of the resonance frequency on vibration amplitude in the presence of damage. NRUS measurements typically are excited with a piezoelectric transducer, but here the application of an electromagnetic transducer is explored as an alternative. The electromagnetic transducer, unlike a single piezoelectric, allows selective excitation of longitudinal, torsional, and bending vibrations in a rod-shaped sample. Measurement of the nonlinear properties of the sample for each type of vibration is therefore possible. This electromagnetic technique involves gluing a coil of wire onto the end of a rod sample and placing it in a magnetic field. By controlling which part of the coil is inside the strongest region of the magnetic field, the principal direction of the driven oscillations in the rod can be controlled. Both piezoelectric and electromagnetic excitation techniques are tested by measuring the parameter of nonlinearity for longitudinal motion, αE, in a sample of Berea sandstone. The electromagnetic technique was shown to measure a 30% higher mean value for αE than the piezoelectric technique. © 2019 Elsevier Ltd
428 a56036628100 Anderson B.E. p114 False Journal 77 Electromagnetic excitation technique for nonlinear resonant ultrasound spectroscopy Nonlinear resonant ultrasound spectroscopy (NRUS) is a method that can be used to determine the amount of microcracking in structures. The nonlinear parameter extracted in NRUS is based on the dependence of the resonance frequency on vibration amplitude in the presence of damage. NRUS measurements typically are excited with a piezoelectric transducer, but here the application of an electromagnetic transducer is explored as an alternative. The electromagnetic transducer, unlike a single piezoelectric, allows selective excitation of longitudinal, torsional, and bending vibrations in a rod-shaped sample. Measurement of the nonlinear properties of the sample for each type of vibration is therefore possible. This electromagnetic technique involves gluing a coil of wire onto the end of a rod sample and placing it in a magnetic field. By controlling which part of the coil is inside the strongest region of the magnetic field, the principal direction of the driven oscillations in the rod can be controlled. Both piezoelectric and electromagnetic excitation techniques are tested by measuring the parameter of nonlinearity for longitudinal motion, αE, in a sample of Berea sandstone. The electromagnetic technique was shown to measure a 30% higher mean value for αE than the piezoelectric technique. © 2019 Elsevier Ltd
428 a56036628100 Anderson B.E. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
428 a56036628100 Anderson B.E. p265 False Journal 174 Nonlinear resonant ultrasound spectroscopy of stress corrosion cracking in stainless steel rods Stainless steel containers are susceptible to stress corrosion cracking (SCC) under certain stress and corrosion conditions. Nonlinear ultrasonic techniques are very sensitive to the early presence of damage, more so than linear techniques. Nonlinear Resonant Ultrasound Spectroscopy (NRUS) is used here to measure a nonlinear shift in the resonance frequency due to a cumulative amount of SCC. Steel rods are immersed in a heated magnesium chloride solution and removed after different exposure times. NRUS measurements are conducted using the fundamental longitudinal mode of vibration. Rods exposed longer generally have a larger resonance frequency shift and are therefore more nonlinear. Thus NRUS might offer a means of detecting a cumulative SCC damage in a sample. © 2018 Elsevier Ltd
428 a56036628100 Anderson B.E. p620 True Journal 310 Time reversal techniques Time reversal is a technique to focus wave energy to a selected point in space and time, localize and characterize a source of wave propagation, and/or communicate information between two points. This chapter will introduce the reader to the concept of time reversal and different implementations of this concept. The focus will then be directed to non-destructive evaluation applications using nonlinear elasto-dynamics together with time reversal. © Springer Nature Switzerland AG 2019.
429 a16033650300 Remillieux M.C. p114 False Journal 77 Electromagnetic excitation technique for nonlinear resonant ultrasound spectroscopy Nonlinear resonant ultrasound spectroscopy (NRUS) is a method that can be used to determine the amount of microcracking in structures. The nonlinear parameter extracted in NRUS is based on the dependence of the resonance frequency on vibration amplitude in the presence of damage. NRUS measurements typically are excited with a piezoelectric transducer, but here the application of an electromagnetic transducer is explored as an alternative. The electromagnetic transducer, unlike a single piezoelectric, allows selective excitation of longitudinal, torsional, and bending vibrations in a rod-shaped sample. Measurement of the nonlinear properties of the sample for each type of vibration is therefore possible. This electromagnetic technique involves gluing a coil of wire onto the end of a rod sample and placing it in a magnetic field. By controlling which part of the coil is inside the strongest region of the magnetic field, the principal direction of the driven oscillations in the rod can be controlled. Both piezoelectric and electromagnetic excitation techniques are tested by measuring the parameter of nonlinearity for longitudinal motion, αE, in a sample of Berea sandstone. The electromagnetic technique was shown to measure a 30% higher mean value for αE than the piezoelectric technique. © 2019 Elsevier Ltd
429 a16033650300 Remillieux M.C. p130 True Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
429 a16033650300 Remillieux M.C. p265 False Journal 174 Nonlinear resonant ultrasound spectroscopy of stress corrosion cracking in stainless steel rods Stainless steel containers are susceptible to stress corrosion cracking (SCC) under certain stress and corrosion conditions. Nonlinear ultrasonic techniques are very sensitive to the early presence of damage, more so than linear techniques. Nonlinear Resonant Ultrasound Spectroscopy (NRUS) is used here to measure a nonlinear shift in the resonance frequency due to a cumulative amount of SCC. Steel rods are immersed in a heated magnesium chloride solution and removed after different exposure times. NRUS measurements are conducted using the fundamental longitudinal mode of vibration. Rods exposed longer generally have a larger resonance frequency shift and are therefore more nonlinear. Thus NRUS might offer a means of detecting a cumulative SCC damage in a sample. © 2018 Elsevier Ltd
429 a16033650300 Remillieux M.C. p620 False Journal 310 Time reversal techniques Time reversal is a technique to focus wave energy to a selected point in space and time, localize and characterize a source of wave propagation, and/or communicate information between two points. This chapter will introduce the reader to the concept of time reversal and different implementations of this concept. The focus will then be directed to non-destructive evaluation applications using nonlinear elasto-dynamics together with time reversal. © Springer Nature Switzerland AG 2019.
430 a57195804520 Bilancia P. p115 True Journal 83 On the modeling of a contact-aided cross-axis flexural pivot This paper reports the study of a planar Cross-Axis Flexural Pivot (CAFP) comprising an additional contact pair. The proposed device may be useful for applications requiring a revolute joint that behaves differently when deflecting clockwise/anti-clockwise. The presence of the contact pair reduces the free length of one flexures, resulting in a considerable increment of the overall joint stiffness. The pivot behaviour is investigated, for different load cases, via the Chained-Beam-Constraint Model (CBCM), namely an accurate method to be applied in large deflection problems. A framework comprising Matlab and ANSYS is developed for testing the CAFP performances in terms of rotational stiffness, parasitic shift and maximum stress, with different combinations of geometrical aspect ratios and contact extensions. Results achieved via CBCM for a pure rotation applied to the CAFP's output link are then verified through Finite Element Analysis. The resulting performance maps show good agreement between the numerical results. Furthermore, the CBCM shows an improved computational efficiency, which is a crucial aspect for preliminary design steps. At last, direct comparison between simulations and experiments, developed by means of two custom test rigs, confirms the efficacy of the proposed design method for the modeling of contacts in large deflection problems. © 2019
431 a24483038000 Berselli G. p115 False Journal 83 On the modeling of a contact-aided cross-axis flexural pivot This paper reports the study of a planar Cross-Axis Flexural Pivot (CAFP) comprising an additional contact pair. The proposed device may be useful for applications requiring a revolute joint that behaves differently when deflecting clockwise/anti-clockwise. The presence of the contact pair reduces the free length of one flexures, resulting in a considerable increment of the overall joint stiffness. The pivot behaviour is investigated, for different load cases, via the Chained-Beam-Constraint Model (CBCM), namely an accurate method to be applied in large deflection problems. A framework comprising Matlab and ANSYS is developed for testing the CAFP performances in terms of rotational stiffness, parasitic shift and maximum stress, with different combinations of geometrical aspect ratios and contact extensions. Results achieved via CBCM for a pure rotation applied to the CAFP's output link are then verified through Finite Element Analysis. The resulting performance maps show good agreement between the numerical results. Furthermore, the CBCM shows an improved computational efficiency, which is a crucial aspect for preliminary design steps. At last, direct comparison between simulations and experiments, developed by means of two custom test rigs, confirms the efficacy of the proposed design method for the modeling of contacts in large deflection problems. © 2019
432 a57189375802 Park J. p116 True Journal 84 Model predictive control and estimation of managed pressure drilling using a real-time high fidelity flow model When drilling an oil or gas well, well pressures may be controlled using a technology called managed pressure drilling. This technology often relies on model predictive control schemes; however, practical limitations have generally led to the use of simplified controller models that do not optimally handle certain perturbations in the physical system. The present work reports on the first implementation of a highly accurate system model that has been adapted for real-time use in a controller. This real-time high-fidelity model approximates the results of offline high-fidelity models without requiring operation by model experts. The effectiveness of the model is demonstrated through simulation studies of controller behavior under various drilling conditions, including an evaluation of the impact of sparse downhole feedback measurements. © 2020
432 a57189375802 Park J. p356 True Conference 126 Closed-Loop PID Re-Tuning in a Digital Twin by Re-Playing Past Setpoint and Load Disturbance Data [No abstract available]
432 a57189375802 Park J. p834 True Conference 362 Improved bottomhole pressure control with wired drillpipe and physics-based models Wired Drillpipe (WDP) technology provides two-way and high speed measurements from bottom hole and along-string sensors. The data offered by WDP technology has maximum benefit when applied in an automation system or as a real-time advisory tool. Improved control is demonstrated for Managed Pressure Drilling (MPD) with the use of high-speed telemetry and physics-based models. Stabilizing and minimizing pressure within an acceptable bound leads to higher and more consistent Rate of Penetration (ROP). MPD control is challenging due to tight pressure windows and the nonlinearity of the choke and pump response on Bottom Hole Pressure (BHP). This work demonstrates a new Hammerstein-Wiener nonlinear model predictive controller for BHP regulation in drilling. Hammerstein-Wiener models employ input and output static nonlinear blocks before and after linear dynamics blocks and thereby simplify the controller design. The control performance is evaluated in scenarios such as drilling, pipe connections, and kick attenuation. A physics-based drilling simulator, WeMod, is used for model identification and control performance evaluation. The control performance of the new nonlinear controller is compared to conventional controllers in various scenarios. Because of the interconnected multivariable and nonlinear nature of the drilling operation, conventional controllers show severe limitations. In a first scenario, the performance of set point tracking during normal drilling operation is compared. By changing the set point of the BHP, the conventional controller manipulates only the choke valve opening while the nonlinear controller moves choke valve opening, mud pump, and back pressure pump simultaneously. In a second scenario, a pipe connection of a typical drillpipe stand is demonstrated. The conventional controller is not able to regulate the BHP by adjusting the choke valve only. Although a linear version of the controller is able to exploit multivariable relationships, absence of the nonlinear relationships results in severe oscillation when the operational range is shifted outside of the training region. The nonlinear controller maintains a BHP within ±1 bar of the requested set point. A third scenario investigates the kick attenuation performance of conventional and nonlinear control algorithms. The nonlinear controller attenuates the kick within well control conditions, without requiring a well shut-in procedure. Recent advances in drilling simulators and the reliability of the WDP data highway have enabled tighter BHP control. This study presents a robust method to control BHP by applying Hammerstein-Wiener models in an efficient model predictive controller. The proposed methods have been validated in the downstream industry, but are applied for the first time to drilling with nonlinear control functionality. The multivariable control adjusts three main manipulated variables in MPD simultaneously. Copyright © 2017, SPE/IADC Drilling Conference and Exhibition.
433 a57212455523 Price C. p116 False Journal 84 Model predictive control and estimation of managed pressure drilling using a real-time high fidelity flow model When drilling an oil or gas well, well pressures may be controlled using a technology called managed pressure drilling. This technology often relies on model predictive control schemes; however, practical limitations have generally led to the use of simplified controller models that do not optimally handle certain perturbations in the physical system. The present work reports on the first implementation of a highly accurate system model that has been adapted for real-time use in a controller. This real-time high-fidelity model approximates the results of offline high-fidelity models without requiring operation by model experts. The effectiveness of the model is demonstrated through simulation studies of controller behavior under various drilling conditions, including an evaluation of the impact of sparse downhole feedback measurements. © 2020
434 a6603286802 Pixton D. p116 False Journal 84 Model predictive control and estimation of managed pressure drilling using a real-time high fidelity flow model When drilling an oil or gas well, well pressures may be controlled using a technology called managed pressure drilling. This technology often relies on model predictive control schemes; however, practical limitations have generally led to the use of simplified controller models that do not optimally handle certain perturbations in the physical system. The present work reports on the first implementation of a highly accurate system model that has been adapted for real-time use in a controller. This real-time high-fidelity model approximates the results of offline high-fidelity models without requiring operation by model experts. The effectiveness of the model is demonstrated through simulation studies of controller behavior under various drilling conditions, including an evaluation of the impact of sparse downhole feedback measurements. © 2020
435 a57023931200 Aghito M. p116 False Journal 84 Model predictive control and estimation of managed pressure drilling using a real-time high fidelity flow model When drilling an oil or gas well, well pressures may be controlled using a technology called managed pressure drilling. This technology often relies on model predictive control schemes; however, practical limitations have generally led to the use of simplified controller models that do not optimally handle certain perturbations in the physical system. The present work reports on the first implementation of a highly accurate system model that has been adapted for real-time use in a controller. This real-time high-fidelity model approximates the results of offline high-fidelity models without requiring operation by model experts. The effectiveness of the model is demonstrated through simulation studies of controller behavior under various drilling conditions, including an evaluation of the impact of sparse downhole feedback measurements. © 2020
435 a57023931200 Aghito M. p859 True Conference 381 Automatic model calibration for drilling automation Physics-based hydraulic models are essential for proceeding to a high level of automation in drilling. Mathematical models can facilitate process understanding and problem detection, and determine appropriate actions in case of mismatch between model and data. Furthermore, calculations may replace measurements where and when the latter are not available, as normally occurs during connections or when instruments or signal transmissions fail. However, advanced hydraulic models rely on a large set of inputs, such as pipe and wellbore geometry, various tuning parameters and fluid properties. The models are therefore time-consuming and difficult to configure in the field, where third-party experts may be needed at each well, to properly initiate the automation system and adjust it during the drilling process. Although the methods described in this paper are relevant to any critical drilling operation, they are applied to Managed Pressure Drilling (MPD) as a widely deployed example of drilling automation. In MPD, hydraulic models predict downhole conditions and determine the requisite choke pressure for automatic adjustment. A new method for automatic configuration of key model parameters simplifies the tedious job of setting up the model and ensures that the automation system remains tuned to the well, even without onsite model tuning expertise. The proposed scheme is based on a simple method for separating inaccuracies due to co-linearity in frictional pressure losses and static mud weight. The search for optimal correction factors is based on a sequence of small oscillations of pump rate that can be applied during drilling without interrupting the operation. A massively parallel computing architecture improves the speed of the calibration algorithm proportional to the number of available CPU cores. A set of hydraulic model instances runs in parallel, allowing for efficient testing of changes in input signals within ranges of uncertainty. A method for selecting a subset of the best models that more accurately represent a given well is proposed. Computer simulations demonstrate how the novel calibration scheme allows automatic tuning of the friction factor and density correction factor, giving accurate prediction of the bottom hole pressure (BHP). The tuning scheme is run with a parallel architecture to demonstrate that correct values of unknown configuration parameters can be automatically determined sufficiently fast for real-time drilling control or as an advisory tool. The deployment of automation systems in drilling is hampered by the need for dedicated expert personnel to maintain systems that could have reduced the personnel needed on the rig. The proposed automated physics-based model tuning contributes to removing this roadblock, aiming at making automation systems a more cost-efficient option for drilling operations. Copyright 2017, Society of Petroleum Engineers.
436 a24830555500 Nybø R. p116 False Journal 84 Model predictive control and estimation of managed pressure drilling using a real-time high fidelity flow model When drilling an oil or gas well, well pressures may be controlled using a technology called managed pressure drilling. This technology often relies on model predictive control schemes; however, practical limitations have generally led to the use of simplified controller models that do not optimally handle certain perturbations in the physical system. The present work reports on the first implementation of a highly accurate system model that has been adapted for real-time use in a controller. This real-time high-fidelity model approximates the results of offline high-fidelity models without requiring operation by model experts. The effectiveness of the model is demonstrated through simulation studies of controller behavior under various drilling conditions, including an evaluation of the impact of sparse downhole feedback measurements. © 2020
436 a24830555500 Nybø R. p859 False Conference 381 Automatic model calibration for drilling automation Physics-based hydraulic models are essential for proceeding to a high level of automation in drilling. Mathematical models can facilitate process understanding and problem detection, and determine appropriate actions in case of mismatch between model and data. Furthermore, calculations may replace measurements where and when the latter are not available, as normally occurs during connections or when instruments or signal transmissions fail. However, advanced hydraulic models rely on a large set of inputs, such as pipe and wellbore geometry, various tuning parameters and fluid properties. The models are therefore time-consuming and difficult to configure in the field, where third-party experts may be needed at each well, to properly initiate the automation system and adjust it during the drilling process. Although the methods described in this paper are relevant to any critical drilling operation, they are applied to Managed Pressure Drilling (MPD) as a widely deployed example of drilling automation. In MPD, hydraulic models predict downhole conditions and determine the requisite choke pressure for automatic adjustment. A new method for automatic configuration of key model parameters simplifies the tedious job of setting up the model and ensures that the automation system remains tuned to the well, even without onsite model tuning expertise. The proposed scheme is based on a simple method for separating inaccuracies due to co-linearity in frictional pressure losses and static mud weight. The search for optimal correction factors is based on a sequence of small oscillations of pump rate that can be applied during drilling without interrupting the operation. A massively parallel computing architecture improves the speed of the calibration algorithm proportional to the number of available CPU cores. A set of hydraulic model instances runs in parallel, allowing for efficient testing of changes in input signals within ranges of uncertainty. A method for selecting a subset of the best models that more accurately represent a given well is proposed. Computer simulations demonstrate how the novel calibration scheme allows automatic tuning of the friction factor and density correction factor, giving accurate prediction of the bottom hole pressure (BHP). The tuning scheme is run with a parallel architecture to demonstrate that correct values of unknown configuration parameters can be automatically determined sufficiently fast for real-time drilling control or as an advisory tool. The deployment of automation systems in drilling is hampered by the need for dedicated expert personnel to maintain systems that could have reduced the personnel needed on the rig. The proposed automated physics-based model tuning contributes to removing this roadblock, aiming at making automation systems a more cost-efficient option for drilling operations. Copyright 2017, Society of Petroleum Engineers.
437 a6602776615 Bjørkevoll K. p116 False Journal 84 Model predictive control and estimation of managed pressure drilling using a real-time high fidelity flow model When drilling an oil or gas well, well pressures may be controlled using a technology called managed pressure drilling. This technology often relies on model predictive control schemes; however, practical limitations have generally led to the use of simplified controller models that do not optimally handle certain perturbations in the physical system. The present work reports on the first implementation of a highly accurate system model that has been adapted for real-time use in a controller. This real-time high-fidelity model approximates the results of offline high-fidelity models without requiring operation by model experts. The effectiveness of the model is demonstrated through simulation studies of controller behavior under various drilling conditions, including an evaluation of the impact of sparse downhole feedback measurements. © 2020
437 a6602776615 Bjørkevoll K. p859 False Conference 381 Automatic model calibration for drilling automation Physics-based hydraulic models are essential for proceeding to a high level of automation in drilling. Mathematical models can facilitate process understanding and problem detection, and determine appropriate actions in case of mismatch between model and data. Furthermore, calculations may replace measurements where and when the latter are not available, as normally occurs during connections or when instruments or signal transmissions fail. However, advanced hydraulic models rely on a large set of inputs, such as pipe and wellbore geometry, various tuning parameters and fluid properties. The models are therefore time-consuming and difficult to configure in the field, where third-party experts may be needed at each well, to properly initiate the automation system and adjust it during the drilling process. Although the methods described in this paper are relevant to any critical drilling operation, they are applied to Managed Pressure Drilling (MPD) as a widely deployed example of drilling automation. In MPD, hydraulic models predict downhole conditions and determine the requisite choke pressure for automatic adjustment. A new method for automatic configuration of key model parameters simplifies the tedious job of setting up the model and ensures that the automation system remains tuned to the well, even without onsite model tuning expertise. The proposed scheme is based on a simple method for separating inaccuracies due to co-linearity in frictional pressure losses and static mud weight. The search for optimal correction factors is based on a sequence of small oscillations of pump rate that can be applied during drilling without interrupting the operation. A massively parallel computing architecture improves the speed of the calibration algorithm proportional to the number of available CPU cores. A set of hydraulic model instances runs in parallel, allowing for efficient testing of changes in input signals within ranges of uncertainty. A method for selecting a subset of the best models that more accurately represent a given well is proposed. Computer simulations demonstrate how the novel calibration scheme allows automatic tuning of the friction factor and density correction factor, giving accurate prediction of the bottom hole pressure (BHP). The tuning scheme is run with a parallel architecture to demonstrate that correct values of unknown configuration parameters can be automatically determined sufficiently fast for real-time drilling control or as an advisory tool. The deployment of automation systems in drilling is hampered by the need for dedicated expert personnel to maintain systems that could have reduced the personnel needed on the rig. The proposed automated physics-based model tuning contributes to removing this roadblock, aiming at making automation systems a more cost-efficient option for drilling operations. Copyright 2017, Society of Petroleum Engineers.
438 a56857577200 Leete K.M. p117 True Journal 78 Coherence analysis of the noise from a simulated highly heated laboratory-scale jet Measurements of full-scale high-performance military aircraft reveal phenomena that are not widely seen at laboratory scales. However, recent modifications to large eddy-simulation (LES) methods allow for simulations of jets operating at a high-temperature ratio in a similar regime as military aircraft operating at afterburner. This work applies coherence analyses that have been previously used to study the jet noise field produced by military aircraft to the LES of a highly heated laboratory-scale jet. The coherence of the complex pressures along a near-field line approximately parallel to the shear layer as well as along the nozzle lip line shows evidence of distinct noise production mechanisms that transfer information differently from the flow to the field. A phenomenological comparison between the LES and measurements of an afterburning F-35 aircraft is then made. Although the LES is not run at the exact same conditions as the aircraft and does not reproduce all of the phenomena present in the aircraft’s jet noise field, differences between noise production mechanisms observed in the LES may describe some of the spatiospectral lobe phenomena observed in the measurements of the F-35. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
438 a56857577200 Leete K.M. p373 False Conference 134 Crackle-related beamforming of military jet aircraft noise Crackle is a perceptual feature of supersonic jet noise that is related to the presence of acoustic shocks. This study investigates the apparent source locations of events related to crackle for a high-performance military jet aircraft using an event-based, time-domain beamforming method. This method utilizes the cross correlation between adjacent microphones to determine the angle of propagation of an ensemble of shock-related events within the time waveform. This angle of propagation is then traced back towards the source to find the apparent source location. Based on the angle of propagation, derivative skewness, and overall sound pressure level, the microphone pairs along the array can be sorted into six groups. With increasing engine condition, groups related to the presence of crackle tend to shift downstream and broaden, in qualitative agreement with the general aeroacoustic source locations. However, a comparison with near-field acoustical holography shows that the apparent source region of crackle-related events appears upstream of the overall energy at intermediate power but appear to converge at maximum afterburner. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
438 a56857577200 Leete K.M. p374 True Conference 135 Coherence analysis of the noise from a simulated highly-heated laboratory-scale jet Large-eddy simulations (LES) have been shown to reproduce the flow and acoustic fields of laboratory-scale jets with increasing accuracy. However, measurements of full-scale, high-performance military aircraft reveal phenomena that are not widely seen at laboratory scales. Recent modifications to LES methods allow for simulations of jets operating at a high temperature ratio, in a similar regime as military aircraft operating at afterburner. This work applies coherence analyses that have been previously used to study the jet noise field produced by military aircraft to the LES of a highly-heated, laboratory-scale jet. The coherence of the complex pressures along a near-field line approximately parallel to the shear layer shows evidence of four distinct field regions. The coherence between this line and complex pressures along the simulated jet lipline provide source regions in the jet plume corresponding to each field region. Differences in how information is transferred from the flow to the field suggests that the source regions represent different noise production mechanisms. The field regions compare favorably to some spatiospectral lobe features observed in measurements of an F-35B aircraft operating at afterburner, though do not reproduce all of the phenomena present in the aircraft’s jet noise field. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
438 a56857577200 Leete K.M. p624 True Conference 260 Dependence of high-performance military aircraft noise on frequency and engine power To further understand the unique characteristics of military aircraft noise, the sound field in the vicinity of a tied-down F-35B was measured for various engine powers, from 25% to 150% Engine Thrust Request (ETR). Synchronous measurements along a linear ground array approximately parallel to the shear layer were used to image the entire field through multisource statistically optimized near-field acoustical holography (M-SONAH). The field in the direction of maximum radiation consists of multiple lobes in the spatiospectral domain, which are manifest as multiple local maxima in space for a fixed frequency or multiple peaks in the spectra at a fixed location. Multiple lobes are observed at non-afterburning and afterburning engine conditions. As frequency increases for a given engine power, lobes appear towards the sideline and shift aft until they disappear beyond the measurement aperture and new lobe(s) take their place. As engine power is increased at a fixed frequency, the forwardmost lobe increases in its relative contribution to the field, which is a major contributing factor to the forward shift in overall directivity with increasing engine power. Field reconstructions and data in the forward direction outside of the region of maximum radiation show the presence of broadband shock-associated noise (BBSAN) for 75% ETR and above. Reconstructions along the nozzle lipline of the jet indicate the BBSAN originates from approximately the same region as the sources for the main radiation direction. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
438 a56857577200 Leete K.M. p865 False Conference 386 Preliminary investigation of multilobe fighter jet noise sources using acoustical holography An understanding of jet noise source mechanisms can facilitate targeted noise reduction efforts. This understanding has been enhanced with acoustic imaging technologies, such as near-field acoustical holography (NAH). In this study, multisource statistically optimized NAH (M-SONAH) was used to image the sound field near a tethered F-35 aircraft at multiple frequencies. A linear microphone array, placed along the ground, spanned the length of the jet exhaust plume. A multisource model of the sound field was included in the algorithm to incorporate the effects of the ground reflection on the measurement. Narrowband reconstructions elucidated fine details of the radiation patterns, such as multilobe radiation patterns (which may supersede “dual-lobe” patterns shown in previous studies), and broadband shock-associated noise. [Work supported by F-35 JPO.] © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
439 a16643231700 Liu J. p117 False Journal 78 Coherence analysis of the noise from a simulated highly heated laboratory-scale jet Measurements of full-scale high-performance military aircraft reveal phenomena that are not widely seen at laboratory scales. However, recent modifications to large eddy-simulation (LES) methods allow for simulations of jets operating at a high-temperature ratio in a similar regime as military aircraft operating at afterburner. This work applies coherence analyses that have been previously used to study the jet noise field produced by military aircraft to the LES of a highly heated laboratory-scale jet. The coherence of the complex pressures along a near-field line approximately parallel to the shear layer as well as along the nozzle lip line shows evidence of distinct noise production mechanisms that transfer information differently from the flow to the field. A phenomenological comparison between the LES and measurements of an afterburning F-35 aircraft is then made. Although the LES is not run at the exact same conditions as the aircraft and does not reproduce all of the phenomena present in the aircraft’s jet noise field, differences between noise production mechanisms observed in the LES may describe some of the spatiospectral lobe phenomena observed in the measurements of the F-35. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
439 a16643231700 Liu J. p374 False Conference 135 Coherence analysis of the noise from a simulated highly-heated laboratory-scale jet Large-eddy simulations (LES) have been shown to reproduce the flow and acoustic fields of laboratory-scale jets with increasing accuracy. However, measurements of full-scale, high-performance military aircraft reveal phenomena that are not widely seen at laboratory scales. Recent modifications to LES methods allow for simulations of jets operating at a high temperature ratio, in a similar regime as military aircraft operating at afterburner. This work applies coherence analyses that have been previously used to study the jet noise field produced by military aircraft to the LES of a highly-heated, laboratory-scale jet. The coherence of the complex pressures along a near-field line approximately parallel to the shear layer shows evidence of four distinct field regions. The coherence between this line and complex pressures along the simulated jet lipline provide source regions in the jet plume corresponding to each field region. Differences in how information is transferred from the flow to the field suggests that the source regions represent different noise production mechanisms. The field regions compare favorably to some spatiospectral lobe features observed in measurements of an F-35B aircraft operating at afterburner, though do not reproduce all of the phenomena present in the aircraft’s jet noise field. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
440 a55359090100 Wall A.T. p117 False Journal 78 Coherence analysis of the noise from a simulated highly heated laboratory-scale jet Measurements of full-scale high-performance military aircraft reveal phenomena that are not widely seen at laboratory scales. However, recent modifications to large eddy-simulation (LES) methods allow for simulations of jets operating at a high-temperature ratio in a similar regime as military aircraft operating at afterburner. This work applies coherence analyses that have been previously used to study the jet noise field produced by military aircraft to the LES of a highly heated laboratory-scale jet. The coherence of the complex pressures along a near-field line approximately parallel to the shear layer as well as along the nozzle lip line shows evidence of distinct noise production mechanisms that transfer information differently from the flow to the field. A phenomenological comparison between the LES and measurements of an afterburning F-35 aircraft is then made. Although the LES is not run at the exact same conditions as the aircraft and does not reproduce all of the phenomena present in the aircraft’s jet noise field, differences between noise production mechanisms observed in the LES may describe some of the spatiospectral lobe phenomena observed in the measurements of the F-35. © 2020 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
440 a55359090100 Wall A.T. p370 False Conference 132 Three-way spectral decompositions of high-performance military aircraft noise High-performance military aircraft noise contains large- and fine-scale turbulent mixing noise and broadband shock-associated noise. A three-way spectral decomposition quantifies the contribution from each noise type in the sound of a tied-down F-35B aircraft on a linear ground-based array spanning 35–152 deg. This large spatial aperture allows for detailed investigation into the spatial variation in broadband shock-associated noise and fine- and large-scale turbulent mixing noise. The spectral models used in the decomposition capture the main features of the measured spectra with three exceptions: 1) that the F-35B engine noise contains multiple spectral peaks in the maximum radiation region, 2) that the nonlinear propagation increases the high-frequency spectral levels, and 3) that the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The F-35B broadband shock-associated noise has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. However, the peak level and width exhibit different trends than laboratory-scale broadband shock-associated noise and those recently reported for the F/A-18E aircraft. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
440 a55359090100 Wall A.T. p373 False Conference 134 Crackle-related beamforming of military jet aircraft noise Crackle is a perceptual feature of supersonic jet noise that is related to the presence of acoustic shocks. This study investigates the apparent source locations of events related to crackle for a high-performance military jet aircraft using an event-based, time-domain beamforming method. This method utilizes the cross correlation between adjacent microphones to determine the angle of propagation of an ensemble of shock-related events within the time waveform. This angle of propagation is then traced back towards the source to find the apparent source location. Based on the angle of propagation, derivative skewness, and overall sound pressure level, the microphone pairs along the array can be sorted into six groups. With increasing engine condition, groups related to the presence of crackle tend to shift downstream and broaden, in qualitative agreement with the general aeroacoustic source locations. However, a comparison with near-field acoustical holography shows that the apparent source region of crackle-related events appears upstream of the overall energy at intermediate power but appear to converge at maximum afterburner. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
440 a55359090100 Wall A.T. p374 False Conference 135 Coherence analysis of the noise from a simulated highly-heated laboratory-scale jet Large-eddy simulations (LES) have been shown to reproduce the flow and acoustic fields of laboratory-scale jets with increasing accuracy. However, measurements of full-scale, high-performance military aircraft reveal phenomena that are not widely seen at laboratory scales. Recent modifications to LES methods allow for simulations of jets operating at a high temperature ratio, in a similar regime as military aircraft operating at afterburner. This work applies coherence analyses that have been previously used to study the jet noise field produced by military aircraft to the LES of a highly-heated, laboratory-scale jet. The coherence of the complex pressures along a near-field line approximately parallel to the shear layer shows evidence of four distinct field regions. The coherence between this line and complex pressures along the simulated jet lipline provide source regions in the jet plume corresponding to each field region. Differences in how information is transferred from the flow to the field suggests that the source regions represent different noise production mechanisms. The field regions compare favorably to some spatiospectral lobe features observed in measurements of an F-35B aircraft operating at afterburner, though do not reproduce all of the phenomena present in the aircraft’s jet noise field. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
440 a55359090100 Wall A.T. p623 False Conference 259 Spatiotemporal correlation analysis of jet noise from a round-nozzle supersonic aircraft Spatiotemporal analysis of noise from a tethered F-35B provides insight into the spatial, spectral and temporal relationships within the sound field. Six engine power conditions ranging from 25% to 150% engine thrust request were measured using a 71-microphone linear ground array located approximately 8 m from the estimated shear layer. Mixing noise trends with engine power for the round-nozzle F-35B are similar to those of a nominally rectangular-nozzle high-performance jet aircraft [Harker et al, AIAA, 2016]. Cross-correlation and coherence measures are used to corroborate and confirm identifications of fine- and large-scale turbulent mixing noise contributions from a concurrent study of the F-35B dataset [Neilsen et al., AIAA, 2018]. The relationships observed between multiple spatiospectral lobes seen in the maximum radiation regions of prior and concurrent high-performance aircraft noise studies [Leete et al., AIAA, 2018] are confirmed and expanded upon. Correlograms help identify how the multiple spatiospectral lobes have different apparent phase speeds across the array, corresponding to different directionality, some components of which also change with engine power. Increased overlap of lobes with increased engine power appears to drive global decreases in field coherence. Finally, the structure of the spatiospectral lobes appears to be more visible in nondimensionalized coherence length than in the spectrum itself. Broadband shock-associated noise (BBSAN) is found in the upstream direction at engine powers of 75% engine thrust request and above. Coherence is also used to separate BBSAN from jet mixing noise because the BBSAN is coherent within the relevant frequency range while adjacent fine-scale mixing noise is not. However, correlation and coherence analyses show that the upstream BBSAN signature is related to sound received in the peak radiation region dominated by the spatiospectral lobes. Possible links between the shock-associated noise and the spatiospectral lobes are discussed. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
440 a55359090100 Wall A.T. p624 False Conference 260 Dependence of high-performance military aircraft noise on frequency and engine power To further understand the unique characteristics of military aircraft noise, the sound field in the vicinity of a tied-down F-35B was measured for various engine powers, from 25% to 150% Engine Thrust Request (ETR). Synchronous measurements along a linear ground array approximately parallel to the shear layer were used to image the entire field through multisource statistically optimized near-field acoustical holography (M-SONAH). The field in the direction of maximum radiation consists of multiple lobes in the spatiospectral domain, which are manifest as multiple local maxima in space for a fixed frequency or multiple peaks in the spectra at a fixed location. Multiple lobes are observed at non-afterburning and afterburning engine conditions. As frequency increases for a given engine power, lobes appear towards the sideline and shift aft until they disappear beyond the measurement aperture and new lobe(s) take their place. As engine power is increased at a fixed frequency, the forwardmost lobe increases in its relative contribution to the field, which is a major contributing factor to the forward shift in overall directivity with increasing engine power. Field reconstructions and data in the forward direction outside of the region of maximum radiation show the presence of broadband shock-associated noise (BBSAN) for 75% ETR and above. Reconstructions along the nozzle lipline of the jet indicate the BBSAN originates from approximately the same region as the sources for the main radiation direction. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
440 a55359090100 Wall A.T. p625 False Conference 261 Inclusion of broadband shock-associated noise in spectral decomposition of noise from highperformance military aircraft Attempts to reduce the noise from high-performance military aircraft requires an understanding of the different jet noise generation mechanisms. The primary noise sources originate from interactions between turbulent mixing noise associated with large and finescale turbulent structures and the ambient air. A nonideally expanded jet also contains broadband shock-associated noise. A three-way decomposition of the spectral density measured near a tied-down F-35B quantifies the contribution from each type of noise. The decomposition is performed on noise from a ground-based, linear array of microphones, approximately 8 m from the estimated shear layer, which spanned an angular aperture of 35° to 152° (relative to engine inlet). This large spatial aperture allows for a detailed investigation into the spatial variation in broadband shock-associated noise and fine and large-scale turbulent mixing noise. The spectral decompositions match the measured spectral levels with three main exceptions: 1) the F-35B noise contains multiple spectral peaks in the maximum radiation region, 2) nonlinear propagation increases the high-frequency spectral levels, and 3) the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The main peak of the F-35B broadband shock-associated noise, evident from 35°-70°, has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. The F-35B broadband shockassociated noise peak level and width exhibit different trends than laboratory-scale BBSAN and those recently reported for the F/A-18E [Tam et al., Journal of Sound and Vibration, Vol. 422, 2018, pp. 92-111]. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation from high-performance military aircraft. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
440 a55359090100 Wall A.T. p626 False Conference 262 Comparison of noise from high-performance military aircraft for ground run-up and flyover operations While the majority of jet noise analysis takes place with a static jet or aircraft, airbase and community military jet noise exposure happens for the most part when the aircraft is in flight. Comparisons between flyover and ground run-up measurements for high-performance military aircraft have not been previously published. This paper presents comparisons between static ground run-up and flyover measurements for the F-35 operating at 150% Engine Thrust Request. The overall sound pressure levels and spectra are shown for the two scenarios, as well as indicators of nonlinear propagation and shock content, specifically the derivative skewness and average steepening factor. The overall sound pressure level is reduced in the peak radiation direction aft of the aircraft but increased in the forward direction. The peak frequency of the noise is relatively unaffected by flight effects, though the amplitude of each frequency may vary. The increase in level in the forward direction results in shock formation that is absent during ground run-up measurements. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
440 a55359090100 Wall A.T. p861 False Conference 382 Acoustic shock formation in noise propagation during ground run-up operations of military aircraft A distinctive feature of many propagating, high-amplitude jet noise waveforms is the presence of acoustic shocks. Metrics indicative of shock presence, specifically the skewness of the time derivative of the waveform, the average steepening factor, and a new wavelet-based metric called the shock energy fraction (SEF), are used to quantify the strength and prevalence of acoustic shocks within waveforms recorded 10-305 m from a tethered military aircraft. The derivative skewness is more sensitive to the presence of the largest and steepest shocks, while the ASF and SEF tend to emphasize aggregate behavior of the entire waveform. These metrics are applied at engine conditions ranging from 50% to 150% engine thrust request, over a wide range of angles and distances, to assess the growth and decay of shock waves. The responses of these metrics point to significant shock formation occurring through nonlinear propagation out to 76 m from the microphone array reference position. Although these strongest shocks decay, the metrics point to continued nonlinear propagation in the far-field, out to 305 m. Many of these features are accurately characterized using a nonlinear propagation scheme based on the Burgers equation, but this scheme fails to account for multipath interference and significant atmospheric effects over the long propagation distances, resulting in an overestimation of nonlinearity metrics. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
440 a55359090100 Wall A.T. p863 False Conference 384 Beamforming-based wavepacket model for noise environment predictions of tactical aircraft Jet noise consists of extended, partially correlated sources such that a single-wavepacket source representation is inadequate. A multiple-wavepacket (MWP) model provides an analytical framework for jet-noise-like radiation to simulate jet noise field levels as well as the corresponding spatial coherence properties within the field. Here, a beamforming method with regularization is applied to noise measured by a linear array near a high-performance military aircraft. Beamforming results are decomposed into a reduced-order MWP model and the predicted radiation is validated in terms of level and coherence properties using benchmark measurements. Sound levels and coherence lengths generated by the beamforming results show good agreement with benchmark measurements over a range of frequencies that contribute significantly to the overall radiation. The MWP model is shown to predict full-scale specific features such as multilobe directivity patterns, and the addition of an uncorrelated distribution (UD) model adequately predicts the sideline radiation that is otherwise difficult to reproduce from wavepacket radiation. The MWP model predicted radiation characteristics are an improvement over single-wavepacket models, which do not incorporate spatiotemporal features of the radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
440 a55359090100 Wall A.T. p865 True Conference 386 Preliminary investigation of multilobe fighter jet noise sources using acoustical holography An understanding of jet noise source mechanisms can facilitate targeted noise reduction efforts. This understanding has been enhanced with acoustic imaging technologies, such as near-field acoustical holography (NAH). In this study, multisource statistically optimized NAH (M-SONAH) was used to image the sound field near a tethered F-35 aircraft at multiple frequencies. A linear microphone array, placed along the ground, spanned the length of the jet exhaust plume. A multisource model of the sound field was included in the algorithm to incorporate the effects of the ground reflection on the measurement. Narrowband reconstructions elucidated fine details of the radiation patterns, such as multilobe radiation patterns (which may supersede “dual-lobe” patterns shown in previous studies), and broadband shock-associated noise. [Work supported by F-35 JPO.] © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
441 a57217872286 Galvez de Leon P. p118 False Journal 79 Measuring Compliance of Driver Yielding at Enhanced Pedestrian Crossings in Utah In the 2000s, the Utah Department of Transportation (UDOT) began implementing technological enhancements to reduce the fatality rate of pedestrians involved in crashes. Although these enhancements appeared to be successful at improving safety, there was a need to evaluate their effectiveness. This research evaluates the safety impacts of several pedestrian crossing enhancements using Utah-specific compliance rates of drivers as a surrogate safety measure. This study analyzes enhanced pedestrian crossings to determine the factors that affect the compliance of driver yielding in Utah and provides a statistical analysis to prove the significance of each factor on compliance. The results show that the “High-intensity Activated crossWalK” (HAWK) is more effective at reducing the probability of a non-compliant event compared with an overhead flashing beacon (OFB), and that an OFB is more effective at reducing the probability of a non-compliant event compared with a rectangular rapid flashing beacon (RRFB) or an overhead rectangular rapid flashing beacon (ORRFB). The results show that adding a pedestrian enhancement to a marked crosswalk at a location with five lanes and speed limit between 35 mph and 45 mph can increase compliance rate by 97% for the HAWK, 77% for the OFB, and 57% for the RRFB and ORRFB. © National Academy of Sciences: Transportation Research Board 2020.
442 a57217867341 Shahandashti S.K.F. p118 False Journal 79 Measuring Compliance of Driver Yielding at Enhanced Pedestrian Crossings in Utah In the 2000s, the Utah Department of Transportation (UDOT) began implementing technological enhancements to reduce the fatality rate of pedestrians involved in crashes. Although these enhancements appeared to be successful at improving safety, there was a need to evaluate their effectiveness. This research evaluates the safety impacts of several pedestrian crossing enhancements using Utah-specific compliance rates of drivers as a surrogate safety measure. This study analyzes enhanced pedestrian crossings to determine the factors that affect the compliance of driver yielding in Utah and provides a statistical analysis to prove the significance of each factor on compliance. The results show that the “High-intensity Activated crossWalK” (HAWK) is more effective at reducing the probability of a non-compliant event compared with an overhead flashing beacon (OFB), and that an OFB is more effective at reducing the probability of a non-compliant event compared with a rectangular rapid flashing beacon (RRFB) or an overhead rectangular rapid flashing beacon (ORRFB). The results show that adding a pedestrian enhancement to a marked crosswalk at a location with five lanes and speed limit between 35 mph and 45 mph can increase compliance rate by 97% for the HAWK, 77% for the OFB, and 57% for the RRFB and ORRFB. © National Academy of Sciences: Transportation Research Board 2020.
443 a36893877000 Chamberlin R. p118 False Journal 79 Measuring Compliance of Driver Yielding at Enhanced Pedestrian Crossings in Utah In the 2000s, the Utah Department of Transportation (UDOT) began implementing technological enhancements to reduce the fatality rate of pedestrians involved in crashes. Although these enhancements appeared to be successful at improving safety, there was a need to evaluate their effectiveness. This research evaluates the safety impacts of several pedestrian crossing enhancements using Utah-specific compliance rates of drivers as a surrogate safety measure. This study analyzes enhanced pedestrian crossings to determine the factors that affect the compliance of driver yielding in Utah and provides a statistical analysis to prove the significance of each factor on compliance. The results show that the “High-intensity Activated crossWalK” (HAWK) is more effective at reducing the probability of a non-compliant event compared with an overhead flashing beacon (OFB), and that an OFB is more effective at reducing the probability of a non-compliant event compared with a rectangular rapid flashing beacon (RRFB) or an overhead rectangular rapid flashing beacon (ORRFB). The results show that adding a pedestrian enhancement to a marked crosswalk at a location with five lanes and speed limit between 35 mph and 45 mph can increase compliance rate by 97% for the HAWK, 77% for the OFB, and 57% for the RRFB and ORRFB. © National Academy of Sciences: Transportation Research Board 2020.
444 a57189218211 Liu L. p119 True Journal 85 Array Antenna Gain Enhancement with the Poynting Streamline Method Streamlines of the Poynting vector field connect antenna figures of merit with the energy flow characteristics near a receiving antenna. Poynting streamlines properties and absorption aperture of antenna under different load conditions have been studied in this letter. Based on its Poynting streamline characteristics, the short-circuit dipole can be used as a parasitic element to direct the flow of energy, increase the absorption aperture, and enhance the gain of the array. Numerical examples show that this strategy can not only enhance the gain of dipole array, but also improve the gain of circularly polarized antenna array without deteriorating the axial ratio. Poynting streamline-based methods augment commonly used radiation-mode antenna analysis techniques by providing an intuitive and visual way to guide the design of antenna arrays. © 2002-2011 IEEE.
444 a57189218211 Liu L. p276 False Journal 101 An intuitive way to understand mutual coupling effects in antenna arrays using the poynting streamline method The flow of energy around array antenna in receiving mode can be modeled by generating streamlines of the Poynting vector field. From the streamlines that terminate on the array element loads, a geometrical shape can be assigned to the effective area of the array. These concepts provide an intuitive tool for understanding mutual coupling effects in antenna arrays. The decrease in directivity associated with mutual coupling effects, the so-called element-gain paradox, can be explained by the overlap of the element effective area shapes. The critical element spacing for the element-gain paradox effect can be predicted from the effective area shape for a single isolated array element. Antenna design for minimizing mutual coupling, which is of interest in multiple input multiple output communications systems, magnetic resonance imaging arrays, astronomical arrays, and other applications, can be guided by analysing the effective area shape for a single isolated array element. © 1963-2012 IEEE.
445 a48361087900 Diao J. p119 False Journal 85 Array Antenna Gain Enhancement with the Poynting Streamline Method Streamlines of the Poynting vector field connect antenna figures of merit with the energy flow characteristics near a receiving antenna. Poynting streamlines properties and absorption aperture of antenna under different load conditions have been studied in this letter. Based on its Poynting streamline characteristics, the short-circuit dipole can be used as a parasitic element to direct the flow of energy, increase the absorption aperture, and enhance the gain of the array. Numerical examples show that this strategy can not only enhance the gain of dipole array, but also improve the gain of circularly polarized antenna array without deteriorating the axial ratio. Poynting streamline-based methods augment commonly used radiation-mode antenna analysis techniques by providing an intuitive and visual way to guide the design of antenna arrays. © 2002-2011 IEEE.
445 a48361087900 Diao J. p276 True Journal 101 An intuitive way to understand mutual coupling effects in antenna arrays using the poynting streamline method The flow of energy around array antenna in receiving mode can be modeled by generating streamlines of the Poynting vector field. From the streamlines that terminate on the array element loads, a geometrical shape can be assigned to the effective area of the array. These concepts provide an intuitive tool for understanding mutual coupling effects in antenna arrays. The decrease in directivity associated with mutual coupling effects, the so-called element-gain paradox, can be explained by the overlap of the element effective area shapes. The critical element spacing for the element-gain paradox effect can be predicted from the effective area shape for a single isolated array element. Antenna design for minimizing mutual coupling, which is of interest in multiple input multiple output communications systems, magnetic resonance imaging arrays, astronomical arrays, and other applications, can be guided by analysing the effective area shape for a single isolated array element. © 1963-2012 IEEE.
445 a48361087900 Diao J. p556 True Journal 263 Practical Superdirectivity with Resonant Screened Apertures Motivated by a Poynting Streamlines Analysis Fundamental limits on the degree of practical achievable superdirectivity for antennas include narrow bandwidth, large antenna loss, and sensitivity to excitation and fabrication errors. Superdirective antennas are commonly considered as transmitters, but thinking of the antenna as a receiver may help to understand and overcome some of these limits on practical superdirectivity. We directly model a superdirective antenna in receive mode by calculating streamlines of Poynting vector field near the receiving antennas. Superdirectivity is achieved by expanding the shape of the effective area beyond the antenna physical aperture area. The degree of superdirectivity is parameterized by an effective area expansion distance. The theory predicts that superdirectivity is practical for electrically small and middle size antennas and electrically large antennas with a large aspect ratio. With this motivation, a 1.5 λ × 2 λ superdirective horn antenna with resonant screen structure in front of the antenna aperture is designed and fabricated. The superdirective horn achieves a measured antenna efficiency of 115% over a reasonable bandwidth and with moderate sensitivity to fabrication errors. © 1963-2012 IEEE.
445 a48361087900 Diao J. p665 True Journal 319 Sidelobe Level and Aperture Efficiency Optimization for Tiled Aperiodic Array Antennas Array antennas with aperiodic element placement provide a way to mitigate grating lobe level when the array element spacing is larger than one half wavelength. Design techniques for aperiodic arrays include thinning, numerical optimization, and other methods, but even with modern tools, designing electrically large aperiodic arrays remain computationally challenging. To reduce the complexity of the large aperiodic array design problem, we study the use of discrete rotated tiles with element positions and tile orientations optimized to minimize peak sidelobe level (PSLL). The directivity, frequency sensitivity of PSLL, and optimization complexity for uniform arrays, aperiodic arrays, and tiled arrays are compared. Based on many numerical examples, an approximate relationship between PSLL and array element number and density for aperiodic and tiled arrays is proposed as a convergence estimator for the design optimization process. © 2017 IEEE.
445 a48361087900 Diao J. p674 True Journal 319 Antenna Loss and Receiving Efficiency for Mutually Coupled Arrays For phased arrays used in satellite communications and radio astronomy, high sensitivity is required, and minimizing antenna losses is critical. Losses for single antennas can be minimized using high conductivity materials. It is less well understood that loss for array antennas is also influenced by mutual coupling between array elements and the beamformer weights applied to the signal from each element. In this paper, we study the antenna loss and receiving efficiency for phased array antennas and focal plane phased array feeds. To better elucidate the physics of array antenna loss related to mutual coupling and beamformer weights, losses for a coupled array can be lumped into an array effective resistance similar to the loss resistance of an equivalent single antenna. Numerical results show that although the antenna loss for a single isolated array element is low, the array antenna loss can be significantly increased by mutual coupling, particularly for beams with a large scan angle. © 2017 IEEE.
445 a48361087900 Diao J. p779 True Journal 319 Poynting Streamlines, Effective Area Shape, and the Design of Superdirective Antennas A receiving antenna alters an incident field in such a way that the field is concentrated at the terminals of the antenna. The Poynting power flux density vector associated with the field carries to the antenna the power dissipated in the antenna structure and the load. Streamlines of the Poynting vector field can be used to understand electromagnetic energy flow near linear and aperture antennas. Poynting streamlines provide a way to understand and guide the design of superdirective antennas. Directivity-enhancing screens that attract Poynting streamlines and increase the aperture efficiency of a horn antenna to almost 200% are studied. Superdirective antennas generally have limited practical value due to poor radiation efficiency, narrow bandwidth, and extreme sensitivity to fabrication errors. We show that these limitations can be mitigated by using metal-only structures that are optimized for broadband operation. The tradeoff between peak achievable aperture efficiency and bandwidth is explored. © 1963-2012 IEEE.
446 a7005241866 Eckhardt B. p120 True Journal 86 Exact relations between Rayleigh-Bénard and rotating plane Couette flow in two dimensions Rayleigh-Bénard convection (RBC) and Taylor-Couette flow (TCF) are two paradigmatic fluid dynamical systems frequently discussed together because of their many similarities despite their different geometries and forcing. Often these analogies require approximations, but in the limit of large radii where TCF becomes rotating plane Couette flow (RPC) exact relations can be established. When the flows are restricted to two spatial independent variables, there is an exact specification that maps the three velocity components in RPC to the two velocity components and one temperature field in RBC. Using this, we deduce several relations between both flows: (i) heat and angular momentum transport differ by, explaining why angular momentum transport is not symmetric around even though the relation between, the Rayleigh number, and, a non-dimensional measure of the rotation, has this symmetry. This relationship leads to a predicted value of that maximizes the angular momentum transport that agrees remarkably well with existing numerical simulations of the full three-dimensional system. (ii) One variable in both flows satisfies a maximum principle, i.e. the fields' extrema occur at the walls. Accordingly, backflow events in shear flow cannot occur in this quasi two-dimensional setting. (iii) For free-slip boundary conditions on the axial and radial velocity components, previous rigorous analysis for RBC implies that the azimuthal momentum transport in RPC is bounded from above by, where is the shear Reynolds number, with a scaling exponent smaller than the anticipated. © 2020 Cambridge University Press. All rights reserved.
447 a7006815587 Doering C.R. p120 False Journal 86 Exact relations between Rayleigh-Bénard and rotating plane Couette flow in two dimensions Rayleigh-Bénard convection (RBC) and Taylor-Couette flow (TCF) are two paradigmatic fluid dynamical systems frequently discussed together because of their many similarities despite their different geometries and forcing. Often these analogies require approximations, but in the limit of large radii where TCF becomes rotating plane Couette flow (RPC) exact relations can be established. When the flows are restricted to two spatial independent variables, there is an exact specification that maps the three velocity components in RPC to the two velocity components and one temperature field in RBC. Using this, we deduce several relations between both flows: (i) heat and angular momentum transport differ by, explaining why angular momentum transport is not symmetric around even though the relation between, the Rayleigh number, and, a non-dimensional measure of the rotation, has this symmetry. This relationship leads to a predicted value of that maximizes the angular momentum transport that agrees remarkably well with existing numerical simulations of the full three-dimensional system. (ii) One variable in both flows satisfies a maximum principle, i.e. the fields' extrema occur at the walls. Accordingly, backflow events in shear flow cannot occur in this quasi two-dimensional setting. (iii) For free-slip boundary conditions on the axial and radial velocity components, previous rigorous analysis for RBC implies that the azimuthal momentum transport in RPC is bounded from above by, where is the shear Reynolds number, with a scaling exponent smaller than the anticipated. © 2020 Cambridge University Press. All rights reserved.
448 a36154754400 Whitehead J.P. p120 False Journal 86 Exact relations between Rayleigh-Bénard and rotating plane Couette flow in two dimensions Rayleigh-Bénard convection (RBC) and Taylor-Couette flow (TCF) are two paradigmatic fluid dynamical systems frequently discussed together because of their many similarities despite their different geometries and forcing. Often these analogies require approximations, but in the limit of large radii where TCF becomes rotating plane Couette flow (RPC) exact relations can be established. When the flows are restricted to two spatial independent variables, there is an exact specification that maps the three velocity components in RPC to the two velocity components and one temperature field in RBC. Using this, we deduce several relations between both flows: (i) heat and angular momentum transport differ by, explaining why angular momentum transport is not symmetric around even though the relation between, the Rayleigh number, and, a non-dimensional measure of the rotation, has this symmetry. This relationship leads to a predicted value of that maximizes the angular momentum transport that agrees remarkably well with existing numerical simulations of the full three-dimensional system. (ii) One variable in both flows satisfies a maximum principle, i.e. the fields' extrema occur at the walls. Accordingly, backflow events in shear flow cannot occur in this quasi two-dimensional setting. (iii) For free-slip boundary conditions on the axial and radial velocity components, previous rigorous analysis for RBC implies that the azimuthal momentum transport in RPC is bounded from above by, where is the shear Reynolds number, with a scaling exponent smaller than the anticipated. © 2020 Cambridge University Press. All rights reserved.
448 a36154754400 Whitehead J.P. p418 True Journal 228 The effect of two distinct fast time scales in the rotating, stratified Boussinesq equations: variations from quasi-geostrophy Inspired by the use of fast singular limits in time-parallel numerical methods for a single fast frequency, we consider the limiting, nonlinear dynamics for a system of partial differential equations when two fast, distinct time scales are present. First-order slow equations are derived via the method of multiple time scales when the two small parameters are related by a rational power. We find that the resultant system depends only on the relationship of the two fast time scales, i.e. which fast time is fastest? Using the theory of cancellation of fast oscillations, we show that with the appropriate assumptions on the nonlinear operator of the full system, this reduced slow system is exactly that which the solution will converge to if each asymptotic limit is considered sequentially. The same result is also obtained via the method of renormalization. The specific example of the rotating, stratified Boussinesq equations is explored in detail, indicating that the most common distinguished limit of this system—quasi-geostrophy, is not the only limiting asymptotic system. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
449 a57193226888 Huang Z. p122 True Journal 87 Convolutional Neural Network Based on Complex Networks for Brain Tumor Image Classification with a Modified Activation Function The diagnosis of brain tumor types generally depends on the clinical experience of doctors, and computer-assisted diagnosis improves the accuracy of diagnosing tumor types. Therefore, a convolutional neural network based on complex networks (CNNBCN) with a modified activation function for the magnetic resonance imaging classification of brain tumors is presented. The network structure is not manually designed and optimized, but is generated by randomly generated graph algorithms. These randomly generated graphs are mapped into a computable neural network by a network generator. The accuracy of the modified CNNBCN model for brain tumor classification reaches 95.49%, which is higher than several models presented by other works. In addition, the test loss of brain tumor classification of the modified CNNBCN model is lower than those of the ResNet, DenseNet and MobileNet models in the experiments. The modified CNNBCN model not only achieves satisfactory results in brain tumor image classification, but also enriches the methodology of neural network design. © 2013 IEEE.
450 a57216966389 Du X. p122 False Journal 87 Convolutional Neural Network Based on Complex Networks for Brain Tumor Image Classification with a Modified Activation Function The diagnosis of brain tumor types generally depends on the clinical experience of doctors, and computer-assisted diagnosis improves the accuracy of diagnosing tumor types. Therefore, a convolutional neural network based on complex networks (CNNBCN) with a modified activation function for the magnetic resonance imaging classification of brain tumors is presented. The network structure is not manually designed and optimized, but is generated by randomly generated graph algorithms. These randomly generated graphs are mapped into a computable neural network by a network generator. The accuracy of the modified CNNBCN model for brain tumor classification reaches 95.49%, which is higher than several models presented by other works. In addition, the test loss of brain tumor classification of the modified CNNBCN model is lower than those of the ResNet, DenseNet and MobileNet models in the experiments. The modified CNNBCN model not only achieves satisfactory results in brain tumor image classification, but also enriches the methodology of neural network design. © 2013 IEEE.
451 a57208015963 Chen L. p122 False Journal 87 Convolutional Neural Network Based on Complex Networks for Brain Tumor Image Classification with a Modified Activation Function The diagnosis of brain tumor types generally depends on the clinical experience of doctors, and computer-assisted diagnosis improves the accuracy of diagnosing tumor types. Therefore, a convolutional neural network based on complex networks (CNNBCN) with a modified activation function for the magnetic resonance imaging classification of brain tumors is presented. The network structure is not manually designed and optimized, but is generated by randomly generated graph algorithms. These randomly generated graphs are mapped into a computable neural network by a network generator. The accuracy of the modified CNNBCN model for brain tumor classification reaches 95.49%, which is higher than several models presented by other works. In addition, the test loss of brain tumor classification of the modified CNNBCN model is lower than those of the ResNet, DenseNet and MobileNet models in the experiments. The modified CNNBCN model not only achieves satisfactory results in brain tumor image classification, but also enriches the methodology of neural network design. © 2013 IEEE.
452 a57193230951 Li Y. p122 False Journal 87 Convolutional Neural Network Based on Complex Networks for Brain Tumor Image Classification with a Modified Activation Function The diagnosis of brain tumor types generally depends on the clinical experience of doctors, and computer-assisted diagnosis improves the accuracy of diagnosing tumor types. Therefore, a convolutional neural network based on complex networks (CNNBCN) with a modified activation function for the magnetic resonance imaging classification of brain tumors is presented. The network structure is not manually designed and optimized, but is generated by randomly generated graph algorithms. These randomly generated graphs are mapped into a computable neural network by a network generator. The accuracy of the modified CNNBCN model for brain tumor classification reaches 95.49%, which is higher than several models presented by other works. In addition, the test loss of brain tumor classification of the modified CNNBCN model is lower than those of the ResNet, DenseNet and MobileNet models in the experiments. The modified CNNBCN model not only achieves satisfactory results in brain tumor image classification, but also enriches the methodology of neural network design. © 2013 IEEE.
453 a56584993700 Liu M. p122 False Journal 87 Convolutional Neural Network Based on Complex Networks for Brain Tumor Image Classification with a Modified Activation Function The diagnosis of brain tumor types generally depends on the clinical experience of doctors, and computer-assisted diagnosis improves the accuracy of diagnosing tumor types. Therefore, a convolutional neural network based on complex networks (CNNBCN) with a modified activation function for the magnetic resonance imaging classification of brain tumors is presented. The network structure is not manually designed and optimized, but is generated by randomly generated graph algorithms. These randomly generated graphs are mapped into a computable neural network by a network generator. The accuracy of the modified CNNBCN model for brain tumor classification reaches 95.49%, which is higher than several models presented by other works. In addition, the test loss of brain tumor classification of the modified CNNBCN model is lower than those of the ResNet, DenseNet and MobileNet models in the experiments. The modified CNNBCN model not only achieves satisfactory results in brain tumor image classification, but also enriches the methodology of neural network design. © 2013 IEEE.
454 a55367023500 Chou Y. p122 False Journal 87 Convolutional Neural Network Based on Complex Networks for Brain Tumor Image Classification with a Modified Activation Function The diagnosis of brain tumor types generally depends on the clinical experience of doctors, and computer-assisted diagnosis improves the accuracy of diagnosing tumor types. Therefore, a convolutional neural network based on complex networks (CNNBCN) with a modified activation function for the magnetic resonance imaging classification of brain tumors is presented. The network structure is not manually designed and optimized, but is generated by randomly generated graph algorithms. These randomly generated graphs are mapped into a computable neural network by a network generator. The accuracy of the modified CNNBCN model for brain tumor classification reaches 95.49%, which is higher than several models presented by other works. In addition, the test loss of brain tumor classification of the modified CNNBCN model is lower than those of the ResNet, DenseNet and MobileNet models in the experiments. The modified CNNBCN model not only achieves satisfactory results in brain tumor image classification, but also enriches the methodology of neural network design. © 2013 IEEE.
454 a55367023500 Chou Y. p237 False Journal 156 Recognition of Chinese food using convolutional neural network Food recognition is the first step for dietary assessment. Computer vision technology is being viewed as an effective tool for automatic food recognition for monitoring nutrition intake. Of the many food recognition algorithms in the literature, Bag-of-Features model is a proven approach that has shown impressive recognition accuracy. In this paper, we propose a small and efficient convolutional neural network architecture for Chinese food recognition, which is more applicable for resources limited platforms. Our network architecture is designed to model and perform a pipeline of processing similar to the Bag-of-Features approach. The main advantage of the proposed architecture, like other convolutional neural networks, is its ability to unifiedly optimize the entire network through back propagation, which is critical to recognition accuracy. We further compare and correlate our architecture with the traditional Bag-of-Features model in an attempt to investigate the similarities between them and identify factors that influence the recognition accuracy. The proposed architecture with a 5-layer deep convolutional neural network achieves the top-1 accuracy of 97.12% and the top-5 accuracy of 99.86% on a newly created Chinese food image dataset that is composed of 8734 images of 25 food categories. Our experimental result demonstrates the feasibility of applying the proposed compact CNN architecture to a challenging problem and achieve real-time performance. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
455 a7403329173 Jin L. p122 False Journal 87 Convolutional Neural Network Based on Complex Networks for Brain Tumor Image Classification with a Modified Activation Function The diagnosis of brain tumor types generally depends on the clinical experience of doctors, and computer-assisted diagnosis improves the accuracy of diagnosing tumor types. Therefore, a convolutional neural network based on complex networks (CNNBCN) with a modified activation function for the magnetic resonance imaging classification of brain tumors is presented. The network structure is not manually designed and optimized, but is generated by randomly generated graph algorithms. These randomly generated graphs are mapped into a computable neural network by a network generator. The accuracy of the modified CNNBCN model for brain tumor classification reaches 95.49%, which is higher than several models presented by other works. In addition, the test loss of brain tumor classification of the modified CNNBCN model is lower than those of the ResNet, DenseNet and MobileNet models in the experiments. The modified CNNBCN model not only achieves satisfactory results in brain tumor image classification, but also enriches the methodology of neural network design. © 2013 IEEE.
456 a57204964732 James B. p123 True Journal 29 Applying Compiler-Automated Software Fault Tolerance to Multiple Processor Platforms Several recent works have explored the feasibility of using commercial off-the-shelf (COTS) processing systems in radiation-prone environments, such as spacecraft. Typically, this approach requires some form of protection to ensure that the software can tolerate radiation upsets without compromising the system. Our recent work, COmpiler Assisted Software fault Tolerance (COAST), provides automated compiler modification of software programs to insert dual-or triple-modular redundancy. In this article, we extend COAST to support several new processing platforms, including RISC-V and Xilinx, San Jose, CA, USA, SoC-based products. The automated software protection mechanisms are tested for a variety of configurations, altering the benchmark and cache configuration. Across the different configurations, the cross sections were improved by 4× to 106×. In addition, a hardware-mitigation technique is tested using dual-lock-step cores on the Texas Instruments, Dallas, TX, USA, Hercules platform, which is compared with the software-only mitigation approach. © 1963-2012 IEEE.
456 a57204964732 James B. p385 False Journal 202 Microcontroller compiler-assisted software fault tolerance Commercial off-the-shelf microcontrollers can be useful for noncritical processing on spaceborne platforms. These microprocessors can be inexpensive and consume small amounts of power. However, the software running on these processors is vulnerable to radiation upsets. In this paper, we present a fully automated, configurable, software-based tool to increase the reliability of microprocessors in high-radiation environments. This tool consists of a set of open-source LLVM compiler passes to automatically implement software-based mitigation techniques. We duplicate or triplicate computations and insert voting mechanisms into software during the compilation process, allowing for runtime error correction. While the techniques we implement are not novel, previous work has typically been closed source, processor architecture dependent, not automated, and not tested in real high-radiation environments. In contrast, the compiler passes presented in this paper are publicly available, highly customizable, and are platform independent and language independent. We have tested our modified software using both fault injection and through neutron beam radiation on a Texas Instruments MSP430 microcontroller. When tested by a neutron beam, we were able to decrease the cross section of programs by 17-29 × , increasing mean-work-to-failure by 4-7 ×. © 1963-2012 IEEE.
457 a12544690900 Quinn H. p123 False Journal 29 Applying Compiler-Automated Software Fault Tolerance to Multiple Processor Platforms Several recent works have explored the feasibility of using commercial off-the-shelf (COTS) processing systems in radiation-prone environments, such as spacecraft. Typically, this approach requires some form of protection to ensure that the software can tolerate radiation upsets without compromising the system. Our recent work, COmpiler Assisted Software fault Tolerance (COAST), provides automated compiler modification of software programs to insert dual-or triple-modular redundancy. In this article, we extend COAST to support several new processing platforms, including RISC-V and Xilinx, San Jose, CA, USA, SoC-based products. The automated software protection mechanisms are tested for a variety of configurations, altering the benchmark and cache configuration. Across the different configurations, the cross sections were improved by 4× to 106×. In addition, a hardware-mitigation technique is tested using dual-lock-step cores on the Texas Instruments, Dallas, TX, USA, Hercules platform, which is compared with the software-only mitigation approach. © 1963-2012 IEEE.
457 a12544690900 Quinn H. p385 False Journal 202 Microcontroller compiler-assisted software fault tolerance Commercial off-the-shelf microcontrollers can be useful for noncritical processing on spaceborne platforms. These microprocessors can be inexpensive and consume small amounts of power. However, the software running on these processors is vulnerable to radiation upsets. In this paper, we present a fully automated, configurable, software-based tool to increase the reliability of microprocessors in high-radiation environments. This tool consists of a set of open-source LLVM compiler passes to automatically implement software-based mitigation techniques. We duplicate or triplicate computations and insert voting mechanisms into software during the compilation process, allowing for runtime error correction. While the techniques we implement are not novel, previous work has typically been closed source, processor architecture dependent, not automated, and not tested in real high-radiation environments. In contrast, the compiler passes presented in this paper are publicly available, highly customizable, and are platform independent and language independent. We have tested our modified software using both fault injection and through neutron beam radiation on a Texas Instruments MSP430 microcontroller. When tested by a neutron beam, we were able to decrease the cross section of programs by 17-29 × , increasing mean-work-to-failure by 4-7 ×. © 1963-2012 IEEE.
458 a54978625300 Goeders J. p123 False Journal 29 Applying Compiler-Automated Software Fault Tolerance to Multiple Processor Platforms Several recent works have explored the feasibility of using commercial off-the-shelf (COTS) processing systems in radiation-prone environments, such as spacecraft. Typically, this approach requires some form of protection to ensure that the software can tolerate radiation upsets without compromising the system. Our recent work, COmpiler Assisted Software fault Tolerance (COAST), provides automated compiler modification of software programs to insert dual-or triple-modular redundancy. In this article, we extend COAST to support several new processing platforms, including RISC-V and Xilinx, San Jose, CA, USA, SoC-based products. The automated software protection mechanisms are tested for a variety of configurations, altering the benchmark and cache configuration. Across the different configurations, the cross sections were improved by 4× to 106×. In addition, a hardware-mitigation technique is tested using dual-lock-step cores on the Texas Instruments, Dallas, TX, USA, Hercules platform, which is compared with the software-only mitigation approach. © 1963-2012 IEEE.
458 a54978625300 Goeders J. p268 False Conference 63 On-chip FPGA debug instrumentation for machine learning applications FPGAs provide a promising implementation option for many machine learning applications. Although simulations or software models can be used to explore the design space of these applications, often the final behaviour can not be evaluated until the design is mapped to the FPGA and integrated into the target system. This may be because long run-times are required, or because the environment can not be adequately described using a software model. Once unexpected behaviour is observed, on-chip debug is notoriously difficult; typically a design is instrumented with on-chip trace buffers that record the run-time behaviour for later interrogation. In this paper, we describe instrumentation that can accelerate the process of debugging machine learning applications implemented on an FPGA. Unlike previous work, our instrumentation is optimized to take advantage of characteristics of this application domain. Our instruments gather useful domain-specific information about the observed variables instead of recording the raw values of those elements. Results show that the proposed instruments provide at least 17.8x longer visibility in the most conservative of our experiments at a low area and latency cost. © 2019 Association for Computing Machinery.
458 a54978625300 Goeders J. p385 False Journal 202 Microcontroller compiler-assisted software fault tolerance Commercial off-the-shelf microcontrollers can be useful for noncritical processing on spaceborne platforms. These microprocessors can be inexpensive and consume small amounts of power. However, the software running on these processors is vulnerable to radiation upsets. In this paper, we present a fully automated, configurable, software-based tool to increase the reliability of microprocessors in high-radiation environments. This tool consists of a set of open-source LLVM compiler passes to automatically implement software-based mitigation techniques. We duplicate or triplicate computations and insert voting mechanisms into software during the compilation process, allowing for runtime error correction. While the techniques we implement are not novel, previous work has typically been closed source, processor architecture dependent, not automated, and not tested in real high-radiation environments. In contrast, the compiler passes presented in this paper are publicly available, highly customizable, and are platform independent and language independent. We have tested our modified software using both fault injection and through neutron beam radiation on a Texas Instruments MSP430 microcontroller. When tested by a neutron beam, we were able to decrease the cross section of programs by 17-29 × , increasing mean-work-to-failure by 4-7 ×. © 1963-2012 IEEE.
458 a54978625300 Goeders J. p429 False Conference 154 Using physical and functional comparisons to assure 3rd-party IP for modern FPGAs In modern FPGA design, 3rd-party IP is commonly used to reduce costs and time-to-market. However, the complexity of IP and associated CAD tools makes it easier for attackers to maliciously tamper with the IP (i.e. insert Hardware Trojans) in ways that are hard to detect. This work proposes techniques that allows a user to incorporate trusted 3rd-party IP into a design and verify that the incorporation occurs tamper-free. We present comparative results from utilizing this framework across a benchmark suite of 22 designs. We show that the approach reliably detects tampering without giving any false positives. © 2018 IEEE.
458 a54978625300 Goeders J. p538 False Conference 194 Architecture exploration for HLS-oriented FPGA debug overlays High-Level Synthesis (HLS) promises improved designer productivity, but requires a debug ecosystem that allows designers to debug in the context of the original source code. Recent work has presented in-system debug frameworks where instrumentation added to the design collects trace data as the circuit runs, and a software tool that allows the user to replay the execution using the captured data. When searching for the root cause of a bug, the designer may need to modify the instrumentation to collect data from a new part of the design, requiring a lengthy recompile. In this paper, we propose a flexible debug overlay family that provides software-like debug turn-around times for HLS generated circuits. At compile time, the overlay is added to the design and compiled. At debug time, the overlay can be configured many times to implement specific debug scenarios without a recompilation. This paper first outlines a number of “capabilities” that such an overlay should have, and then describes architectural support for each of these capabilities. The cheapest overlay variant allows selective variable tracing with only a 1.7% increase in area overhead from the baseline debug instrumentation, while the deluxe variant offers 2x-7x improvement in trace buffer memory utilization with conditional buffer freeze support. © 2018 Association for Computing Machinery.
459 a57201759181 Ling M. p124 True Journal 88 Kinetostatic and dynamic modeling of flexure-based compliant mechanisms: A survey Flexure-based compliant mechanisms are becoming increasingly promising in precision engineering, robotics, and other applications due to the excellent advantages of no friction, no backlash, no wear, and minimal requirement of assembly. Because compliant mechanisms have inherent coupling of kinematic-mechanical behaviors with large deflections and/or complex serial-parallel configurations, the kinetostatic and dynamic analyses are challenging in comparison to their rigid-body counterparts. To address these challenges, a variety of techniques have been reported in a growing stream of publications. This paper surveys and compares the conceptual ideas, key advances, and applicable scopes, and open problems of the state-of-the-art kinetostatic and dynamic modeling methods for compliant mechanisms in terms of small and large deflections. Future challenges are discussed and new opportunities for extended study are highlighted as well. The presented review provides a guide on how to select suitable modeling approaches for those engaged in the field of compliant mechanisms. © 2020 Oxford University Press. All rights reserved.
459 a57201759181 Ling M. p238 True Journal 157 Kinetostatic and dynamic analyses of planar compliant mechanisms via a two-port dynamic stiffness model Serial-parallel configurations are widely designed in compliant mechanisms. In this paper, the transfer matrix method is combined with D'Alembert's principle to develop a two-port dynamic stiffness model for analyzing the kinetostatics and dynamics of complex compliant mechanisms with serial-parallel configurations. In detail, two kinds of improved transfer matrices for parallel sub-chains are derived in a unified form by summarizing the common serial-parallel substructures in compliant mechanisms. Then, a two-port dynamic stiffness model describing the frequency-dependent input and output force-displacement relationship of compliant mechanisms is established. Based on the two-port dynamic stiffness model, procedures for solving the static and dynamic performances of compliant mechanisms are presented. The proposed approach is demonstrated by calculating the displacement amplification ratio, input/output stiffness, natural frequencies and forced dynamic response of two typical precision flexure manipulators. The advantage of the proposed approach lies in its capability to describe the simultaneous kinetostatics and dynamics for a large class of serial-parallel configurations with very few degrees of freedom (DOFs), differing from the previous Lagrange-based dynamic modeling methods in the context of compliant mechanisms and should be of interest to designers. © 2019 Elsevier Inc.
459 a57201759181 Ling M. p443 True Journal 222 A pseudo-static model for dynamic analysis on frequency domain of distributed compliant mechanisms This paper presents a pseudo-static modeling methodology for dynamic analysis of distributed compliant mechanisms to provide accurate and efficient solutions. First, a dynamic stiffness matrix of the flexible beam is deduced, which has the same definition and a similar form as the traditional static compliance/stiffness matrix but is frequency dependent. Second, the pseudo-static modeling procedure for the dynamic analysis is implemented in a statics-similar way based on D'alembert's principle. Then, all the kinematic, static and dynamic performances of compliant mechanisms can be analyzed based on the pseudo-static model. The superiority of the proposed method is that when it is used for the dynamic modeling of compliant mechanisms, the traditional dynamic modeling procedures, such as calculation of the elastic and kinetic energies as well as using Lagrange's equation, are avoided and the dynamic modeling is converted to a staticssimilar problem. Comparison of the proposed method with an elastic-beam-based model in previous literature and finite element analysis for an exemplary XY precision positioning stage reveals its high accuracy and easy operation. © 2018 by ASME.
459 a57201759181 Ling M. p479 True Journal 265 Kinetostatic modeling of complex compliant mechanisms with serial-parallel substructures: A semi-analytical matrix displacement method Kinetostatic analysis of compliant mechanisms are crucial at the early stage of design, and it can be difficult and laborsome for complex configurations with distributed compliance. In this paper, a kinetostatic modeling method for flexure-hinge-based compliant mechanisms with hybrid serial-parallel substructures is presented to provide accurate and concise solutions by combining the matrix displacement method with the transfer matrix method. The transition between the elemental stiffness matrix and the transfer matrix of flexure hinges/flexible beams is straightforward, enabling the condensation of a hybrid serial-parallel substructure into one equivalent two-node element simple. A general kinetostatic model of the whole compliant mechanisms is first established based on the equilibrium equation of the nodal force. Then, a condensed two-port mechanical network representing the input/output force-displacement relations of single-degree-of-freedom (DOF) compliant mechanisms and the Jacobian matrix for multi-DOF compliant mechanisms are respectively built. Comparison of the proposed method with the compliance matrix method in previous literature, finite element analysis and experiment for three exemplary mechanisms reveals good prediction accuracy, suggesting its feasibility for fast performance evaluation and parameter optimization at the initial stage of design. © 2018 Elsevier Ltd
460 a16548784600 Cao J. p124 False Journal 88 Kinetostatic and dynamic modeling of flexure-based compliant mechanisms: A survey Flexure-based compliant mechanisms are becoming increasingly promising in precision engineering, robotics, and other applications due to the excellent advantages of no friction, no backlash, no wear, and minimal requirement of assembly. Because compliant mechanisms have inherent coupling of kinematic-mechanical behaviors with large deflections and/or complex serial-parallel configurations, the kinetostatic and dynamic analyses are challenging in comparison to their rigid-body counterparts. To address these challenges, a variety of techniques have been reported in a growing stream of publications. This paper surveys and compares the conceptual ideas, key advances, and applicable scopes, and open problems of the state-of-the-art kinetostatic and dynamic modeling methods for compliant mechanisms in terms of small and large deflections. Future challenges are discussed and new opportunities for extended study are highlighted as well. The presented review provides a guide on how to select suitable modeling approaches for those engaged in the field of compliant mechanisms. © 2020 Oxford University Press. All rights reserved.
460 a16548784600 Cao J. p238 False Journal 157 Kinetostatic and dynamic analyses of planar compliant mechanisms via a two-port dynamic stiffness model Serial-parallel configurations are widely designed in compliant mechanisms. In this paper, the transfer matrix method is combined with D'Alembert's principle to develop a two-port dynamic stiffness model for analyzing the kinetostatics and dynamics of complex compliant mechanisms with serial-parallel configurations. In detail, two kinds of improved transfer matrices for parallel sub-chains are derived in a unified form by summarizing the common serial-parallel substructures in compliant mechanisms. Then, a two-port dynamic stiffness model describing the frequency-dependent input and output force-displacement relationship of compliant mechanisms is established. Based on the two-port dynamic stiffness model, procedures for solving the static and dynamic performances of compliant mechanisms are presented. The proposed approach is demonstrated by calculating the displacement amplification ratio, input/output stiffness, natural frequencies and forced dynamic response of two typical precision flexure manipulators. The advantage of the proposed approach lies in its capability to describe the simultaneous kinetostatics and dynamics for a large class of serial-parallel configurations with very few degrees of freedom (DOFs), differing from the previous Lagrange-based dynamic modeling methods in the context of compliant mechanisms and should be of interest to designers. © 2019 Elsevier Inc.
460 a16548784600 Cao J. p443 False Journal 222 A pseudo-static model for dynamic analysis on frequency domain of distributed compliant mechanisms This paper presents a pseudo-static modeling methodology for dynamic analysis of distributed compliant mechanisms to provide accurate and efficient solutions. First, a dynamic stiffness matrix of the flexible beam is deduced, which has the same definition and a similar form as the traditional static compliance/stiffness matrix but is frequency dependent. Second, the pseudo-static modeling procedure for the dynamic analysis is implemented in a statics-similar way based on D'alembert's principle. Then, all the kinematic, static and dynamic performances of compliant mechanisms can be analyzed based on the pseudo-static model. The superiority of the proposed method is that when it is used for the dynamic modeling of compliant mechanisms, the traditional dynamic modeling procedures, such as calculation of the elastic and kinetic energies as well as using Lagrange's equation, are avoided and the dynamic modeling is converted to a staticssimilar problem. Comparison of the proposed method with an elastic-beam-based model in previous literature and finite element analysis for an exemplary XY precision positioning stage reveals its high accuracy and easy operation. © 2018 by ASME.
460 a16548784600 Cao J. p479 False Journal 265 Kinetostatic modeling of complex compliant mechanisms with serial-parallel substructures: A semi-analytical matrix displacement method Kinetostatic analysis of compliant mechanisms are crucial at the early stage of design, and it can be difficult and laborsome for complex configurations with distributed compliance. In this paper, a kinetostatic modeling method for flexure-hinge-based compliant mechanisms with hybrid serial-parallel substructures is presented to provide accurate and concise solutions by combining the matrix displacement method with the transfer matrix method. The transition between the elemental stiffness matrix and the transfer matrix of flexure hinges/flexible beams is straightforward, enabling the condensation of a hybrid serial-parallel substructure into one equivalent two-node element simple. A general kinetostatic model of the whole compliant mechanisms is first established based on the equilibrium equation of the nodal force. Then, a condensed two-port mechanical network representing the input/output force-displacement relations of single-degree-of-freedom (DOF) compliant mechanisms and the Jacobian matrix for multi-DOF compliant mechanisms are respectively built. Comparison of the proposed method with the compliance matrix method in previous literature, finite element analysis and experiment for three exemplary mechanisms reveals good prediction accuracy, suggesting its feasibility for fast performance evaluation and parameter optimization at the initial stage of design. © 2018 Elsevier Ltd
461 a8922674200 Chen G. p124 False Journal 88 Kinetostatic and dynamic modeling of flexure-based compliant mechanisms: A survey Flexure-based compliant mechanisms are becoming increasingly promising in precision engineering, robotics, and other applications due to the excellent advantages of no friction, no backlash, no wear, and minimal requirement of assembly. Because compliant mechanisms have inherent coupling of kinematic-mechanical behaviors with large deflections and/or complex serial-parallel configurations, the kinetostatic and dynamic analyses are challenging in comparison to their rigid-body counterparts. To address these challenges, a variety of techniques have been reported in a growing stream of publications. This paper surveys and compares the conceptual ideas, key advances, and applicable scopes, and open problems of the state-of-the-art kinetostatic and dynamic modeling methods for compliant mechanisms in terms of small and large deflections. Future challenges are discussed and new opportunities for extended study are highlighted as well. The presented review provides a guide on how to select suitable modeling approaches for those engaged in the field of compliant mechanisms. © 2020 Oxford University Press. All rights reserved.
461 a8922674200 Chen G. p390 False Journal 213 A design approach to fully compliant multistable mechanisms employing a single bistable mechanism A fully compliant multistable mechanism is a monolithic structure that is capable of staying at multiple positions without power input, and has many applications including switches, valves, positioners. However, it is difficult to design such a mechanism because of the complexities of the multistable behavior, the practical stress limits and the buckling constraints. This paper discusses the design approach for fully compliant multistable mechanisms which employs a single bistable mechanism and several end-effectors connected in series. The force-displacement characteristics of the end-effectors are derived using the pseudo-rigid-body model. The design approach to the fully compliant multistable mechanism is provided to determine the design parameters for the flexible segments considering the critical buckling load and the bending strength. Two design examples are presented to demonstrate the feasibility of the approach. © 2019, © 2019 Taylor & Francis Group, LLC.
461 a8922674200 Chen G. p413 True Journal 223 Symmetric Equations for Evaluating Maximum Torsion Stress of Rectangular Beams in Compliant Mechanisms There are several design equations available for calculating the torsional compliance and the maximum torsion stress of a rectangular cross-section beam, but most depend on the relative magnitude of the two dimensions of the cross-section (i.e., the thickness and the width). After reviewing the available equations, two thickness-to-width ratio independent equations that are symmetric with respect to the two dimensions are obtained for evaluating the maximum torsion stress of rectangular cross-section beams. Based on the resulting equations, outside lamina emergent torsional joints are analyzed and some useful design insights are obtained. These equations, together with the previous work on symmetric equations for calculating torsional compliance, provide a convenient and effective way for designing and optimizing torsional beams in compliant mechanisms. © 2018, The Author(s).
461 a8922674200 Chen G. p503 True Journal 274 Membrane-Enhanced Lamina Emergent Torsional Joints for Surrogate Folds Lamina emergent compliant mechanisms (including origami-adapted compliant mechanisms) are mechanical devices that can be fabricated from a planar material (a lamina) and have motion that emerges out of the fabrication plane. Lamina emergent compliant mechanisms often exhibit undesirable parasitic motions due to the planar fabrication constraint. This work introduces a type of lamina emergent torsion (LET) joint that reduces parasitic motions of lamina emergent mechanisms, and presents equations for modeling parasitic motion of LET joints. The membrane joint also makes possible one-way joints that can ensure origami-based mechanisms emerge from their flat state (a change point) into the desired configuration. Membrane-enhanced LET (M-LET) joints, including one-way surrogate folds, are described here and show promise for use in a wide range of compliant mechanisms and origami-based compliant mechanisms. They are demonstrated as individual joints and in mechanisms such as a kaleidocycle (a 6R Bricard linkage), degree-4 origami vertices (spherical mechanisms), and waterbomb base mechanisms (an 8R multi-degrees-of-freedom origami-based mechanism). © 2018 by ASME.
461 a8922674200 Chen G. p853 True Conference 377 A framework for energy-based kinetostatic modeling of compliant mechanisms Although energy-based methods have advantages over the Newtonian methods for kinetostatic modeling, the geometric nonlinearities inherent in deflections of compliant mechanisms preclude most of the energy-based theorems. Castigliano's first theorem and the Crotti-Engesser theorem, which don't require the problem being solved to be linear, are selected to construct the energy-based kinetostatic modeling framework for compliant mechanisms in this work. Utilization of these two theorems requires explicitly formulating the strain energy in terms of deflections and the complementary strain energy in terms of loads, which are derived based on the beam constraint model. The kinetostatic modeling of two compliant mechanisms are provided to demonstrate the effectiveness of using Castigliano's first theorem and the Crotti-Engesser theorem with the explicit formulations in this framework. Future work will be focused on incorporating use of the principle of minimum strain energy and the principle of minimum complementary strain energy. Copyright © 2017 ASME.
462 a55764938300 Wilson P.S. p125 True Journal 89 Guest editorial an overview of the seabed characterization experiment [No abstract available]
463 a6701550039 Knobles D.P. p125 False Journal 89 Guest editorial an overview of the seabed characterization experiment [No abstract available]
464 a6506328689 Neilsen T.B. p125 False Journal 89 Guest editorial an overview of the seabed characterization experiment [No abstract available]
464 a6506328689 Neilsen T.B. p370 True Conference 132 Three-way spectral decompositions of high-performance military aircraft noise High-performance military aircraft noise contains large- and fine-scale turbulent mixing noise and broadband shock-associated noise. A three-way spectral decomposition quantifies the contribution from each noise type in the sound of a tied-down F-35B aircraft on a linear ground-based array spanning 35–152 deg. This large spatial aperture allows for detailed investigation into the spatial variation in broadband shock-associated noise and fine- and large-scale turbulent mixing noise. The spectral models used in the decomposition capture the main features of the measured spectra with three exceptions: 1) that the F-35B engine noise contains multiple spectral peaks in the maximum radiation region, 2) that the nonlinear propagation increases the high-frequency spectral levels, and 3) that the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The F-35B broadband shock-associated noise has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. However, the peak level and width exhibit different trends than laboratory-scale broadband shock-associated noise and those recently reported for the F/A-18E aircraft. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
464 a6506328689 Neilsen T.B. p623 False Conference 259 Spatiotemporal correlation analysis of jet noise from a round-nozzle supersonic aircraft Spatiotemporal analysis of noise from a tethered F-35B provides insight into the spatial, spectral and temporal relationships within the sound field. Six engine power conditions ranging from 25% to 150% engine thrust request were measured using a 71-microphone linear ground array located approximately 8 m from the estimated shear layer. Mixing noise trends with engine power for the round-nozzle F-35B are similar to those of a nominally rectangular-nozzle high-performance jet aircraft [Harker et al, AIAA, 2016]. Cross-correlation and coherence measures are used to corroborate and confirm identifications of fine- and large-scale turbulent mixing noise contributions from a concurrent study of the F-35B dataset [Neilsen et al., AIAA, 2018]. The relationships observed between multiple spatiospectral lobes seen in the maximum radiation regions of prior and concurrent high-performance aircraft noise studies [Leete et al., AIAA, 2018] are confirmed and expanded upon. Correlograms help identify how the multiple spatiospectral lobes have different apparent phase speeds across the array, corresponding to different directionality, some components of which also change with engine power. Increased overlap of lobes with increased engine power appears to drive global decreases in field coherence. Finally, the structure of the spatiospectral lobes appears to be more visible in nondimensionalized coherence length than in the spectrum itself. Broadband shock-associated noise (BBSAN) is found in the upstream direction at engine powers of 75% engine thrust request and above. Coherence is also used to separate BBSAN from jet mixing noise because the BBSAN is coherent within the relevant frequency range while adjacent fine-scale mixing noise is not. However, correlation and coherence analyses show that the upstream BBSAN signature is related to sound received in the peak radiation region dominated by the spatiospectral lobes. Possible links between the shock-associated noise and the spatiospectral lobes are discussed. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
464 a6506328689 Neilsen T.B. p624 False Conference 260 Dependence of high-performance military aircraft noise on frequency and engine power To further understand the unique characteristics of military aircraft noise, the sound field in the vicinity of a tied-down F-35B was measured for various engine powers, from 25% to 150% Engine Thrust Request (ETR). Synchronous measurements along a linear ground array approximately parallel to the shear layer were used to image the entire field through multisource statistically optimized near-field acoustical holography (M-SONAH). The field in the direction of maximum radiation consists of multiple lobes in the spatiospectral domain, which are manifest as multiple local maxima in space for a fixed frequency or multiple peaks in the spectra at a fixed location. Multiple lobes are observed at non-afterburning and afterburning engine conditions. As frequency increases for a given engine power, lobes appear towards the sideline and shift aft until they disappear beyond the measurement aperture and new lobe(s) take their place. As engine power is increased at a fixed frequency, the forwardmost lobe increases in its relative contribution to the field, which is a major contributing factor to the forward shift in overall directivity with increasing engine power. Field reconstructions and data in the forward direction outside of the region of maximum radiation show the presence of broadband shock-associated noise (BBSAN) for 75% ETR and above. Reconstructions along the nozzle lipline of the jet indicate the BBSAN originates from approximately the same region as the sources for the main radiation direction. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
464 a6506328689 Neilsen T.B. p625 True Conference 261 Inclusion of broadband shock-associated noise in spectral decomposition of noise from highperformance military aircraft Attempts to reduce the noise from high-performance military aircraft requires an understanding of the different jet noise generation mechanisms. The primary noise sources originate from interactions between turbulent mixing noise associated with large and finescale turbulent structures and the ambient air. A nonideally expanded jet also contains broadband shock-associated noise. A three-way decomposition of the spectral density measured near a tied-down F-35B quantifies the contribution from each type of noise. The decomposition is performed on noise from a ground-based, linear array of microphones, approximately 8 m from the estimated shear layer, which spanned an angular aperture of 35° to 152° (relative to engine inlet). This large spatial aperture allows for a detailed investigation into the spatial variation in broadband shock-associated noise and fine and large-scale turbulent mixing noise. The spectral decompositions match the measured spectral levels with three main exceptions: 1) the F-35B noise contains multiple spectral peaks in the maximum radiation region, 2) nonlinear propagation increases the high-frequency spectral levels, and 3) the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The main peak of the F-35B broadband shock-associated noise, evident from 35°-70°, has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. The F-35B broadband shockassociated noise peak level and width exhibit different trends than laboratory-scale BBSAN and those recently reported for the F/A-18E [Tam et al., Journal of Sound and Vibration, Vol. 422, 2018, pp. 92-111]. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation from high-performance military aircraft. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
464 a6506328689 Neilsen T.B. p626 False Conference 262 Comparison of noise from high-performance military aircraft for ground run-up and flyover operations While the majority of jet noise analysis takes place with a static jet or aircraft, airbase and community military jet noise exposure happens for the most part when the aircraft is in flight. Comparisons between flyover and ground run-up measurements for high-performance military aircraft have not been previously published. This paper presents comparisons between static ground run-up and flyover measurements for the F-35 operating at 150% Engine Thrust Request. The overall sound pressure levels and spectra are shown for the two scenarios, as well as indicators of nonlinear propagation and shock content, specifically the derivative skewness and average steepening factor. The overall sound pressure level is reduced in the peak radiation direction aft of the aircraft but increased in the forward direction. The peak frequency of the noise is relatively unaffected by flight effects, though the amplitude of each frequency may vary. The increase in level in the forward direction results in shock formation that is absent during ground run-up measurements. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
464 a6506328689 Neilsen T.B. p640 False Journal 312 Effect of nozzle–plate distance on acoustic phenomena from supersonic impinging jet For an adequate understanding of the broadband acoustic phenomena generated by a rocket exhaust jet impinging on a flame deflector, this study experimentally clarifies the factors that cause the difference in the broadband acoustic field of a supersonic ideally expanded jet impinging on an inclined flat plate for various nozzle–plate distances. According to previous studies, there are two possible factors: the Mach waves, which are radiated from the free-jet region and reflected by the plate, and the acoustic waves generated in the impingement region. To distinguish the effects of these factors, this study compares the following three results: the overall sound pressure level distribution, images extracted from the schlieren visualization movies using acoustic-triggered conditional sampling, and tracing lines of the acoustic intensity vectors of the Mach waves. The results reveal that the nozzle–plate distance affects the fraction of the Mach waves that are generated in the free-jet region and reflected by the plate, resulting in a higher overall sound pressure level in the upstream direction for larger nozzle–plate distances. It is concluded that the location of the plate relative to the source region of the Mach waves significantly affects the acoustic phenomena, owing to the variation in the nozzle–plate distances. Copyright © 2018 by Masahito Akamine, Koji Okamoto, Kent L. Gee, Tracianne B. Neilsen, Susumu Teramoto, Takeo Okunuki, and Seiji Tsutsumi.
464 a6506328689 Neilsen T.B. p861 False Conference 382 Acoustic shock formation in noise propagation during ground run-up operations of military aircraft A distinctive feature of many propagating, high-amplitude jet noise waveforms is the presence of acoustic shocks. Metrics indicative of shock presence, specifically the skewness of the time derivative of the waveform, the average steepening factor, and a new wavelet-based metric called the shock energy fraction (SEF), are used to quantify the strength and prevalence of acoustic shocks within waveforms recorded 10-305 m from a tethered military aircraft. The derivative skewness is more sensitive to the presence of the largest and steepest shocks, while the ASF and SEF tend to emphasize aggregate behavior of the entire waveform. These metrics are applied at engine conditions ranging from 50% to 150% engine thrust request, over a wide range of angles and distances, to assess the growth and decay of shock waves. The responses of these metrics point to significant shock formation occurring through nonlinear propagation out to 76 m from the microphone array reference position. Although these strongest shocks decay, the metrics point to continued nonlinear propagation in the far-field, out to 305 m. Many of these features are accurately characterized using a nonlinear propagation scheme based on the Burgers equation, but this scheme fails to account for multipath interference and significant atmospheric effects over the long propagation distances, resulting in an overestimation of nonlinearity metrics. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
464 a6506328689 Neilsen T.B. p862 True Conference 383 Level-educed wavepacket representation of Mach 1.8 laboratory-scale jet noise The search for an equivalent acoustic source model for high-speed jet noise has recently focused on wavepacket representations. A wavepacket is defined as a spatially extended source with an axial amplitude distribution that grows, saturates and decays, an axial phase relationship that produces directional noise, and correlation lengths longer than the integral length scales of the turbulent structures. This definition of a wavepacket has the same characteristics as the large-scale turbulent mixing noise; if the turbulent mixing noise can be isolated, the associate equivalent acoustic wavepacket—defined as a pressure fluctuation on a cylinder around the jet nozzle—can be found. An estimate of the frequencydependent, spatial variation in the large-scale turbulent mixing noise comes from a similarity spectra decomposition of the measured autospectral density, which in turn leads to data-educed wavenumber axial spectra associated with the frequency-dependent equivalent wavepackets. This wavepacket eduction technique has been applied to acoustical measurements of an unheated, Mach 1.8 jet in the near and far fields. At both locations, the resulting frequency-dependent, data-educed wavenumber spectra exhibit different types of self-similarity for low and high frequency regimes that become apparent when the axial wavenumber is scaled by the acoustic wavenumber, with a transition band between the two regimes. As expected, the data-educed wavenumber spectra can be used to predict field levels in the dominant radiation lobe. Addition of an uncorrelated source distribution, derived from the similarity spectra decomposition associated with the fine-scale turbulent mixing noise, creates a model that accounts for the sideline levels. This field-prediction ability of the wavepacket-plus-uncorrelated-distribution model is tested using the near and far field measurements. When predicting the field at the other location, the model’s average error is less than 2 dB for St = 0.04-0.25 but increases for larger St because the apparent directivity changes from near to far field, likely due to the frequency dependence of the extended source region. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
464 a6506328689 Neilsen T.B. p863 False Conference 384 Beamforming-based wavepacket model for noise environment predictions of tactical aircraft Jet noise consists of extended, partially correlated sources such that a single-wavepacket source representation is inadequate. A multiple-wavepacket (MWP) model provides an analytical framework for jet-noise-like radiation to simulate jet noise field levels as well as the corresponding spatial coherence properties within the field. Here, a beamforming method with regularization is applied to noise measured by a linear array near a high-performance military aircraft. Beamforming results are decomposed into a reduced-order MWP model and the predicted radiation is validated in terms of level and coherence properties using benchmark measurements. Sound levels and coherence lengths generated by the beamforming results show good agreement with benchmark measurements over a range of frequencies that contribute significantly to the overall radiation. The MWP model is shown to predict full-scale specific features such as multilobe directivity patterns, and the addition of an uncorrelated distribution (UD) model adequately predicts the sideline radiation that is otherwise difficult to reproduce from wavepacket radiation. The MWP model predicted radiation characteristics are an improvement over single-wavepacket models, which do not incorporate spatiotemporal features of the radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
464 a6506328689 Neilsen T.B. p864 False Conference 385 Characterization of supersonic laboratory-scale jet noise with vector acoustic intensity A new method for the calculation of vector acoustic intensity from pressure microphone measurements has been applied to the aeroacoustic source characterization of an unheated, Mach 1.8 laboratory-scale jet. Because of the ability to unwrap the phase of the transfer functions between microphone pairs in the measurement of a radiating, broadband source, physically meaningful near-field intensity vectors are calculated up to the maximum analysis frequency of 32 kHz. The new intensity method is used to obtain a detailed description of the sound energy flow near the jet. The resulting intensity vectors have been used with a ray-tracing technique to identify the dominant source region over a broad range of frequencies. Additional aeroacoustics analyses provide insight into the frequency-dependent characteristics of jet noise radiation, including the nature of the hydrodynamic field and the transition between the principal lobe and sideline radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
464 a6506328689 Neilsen T.B. p865 False Conference 386 Preliminary investigation of multilobe fighter jet noise sources using acoustical holography An understanding of jet noise source mechanisms can facilitate targeted noise reduction efforts. This understanding has been enhanced with acoustic imaging technologies, such as near-field acoustical holography (NAH). In this study, multisource statistically optimized NAH (M-SONAH) was used to image the sound field near a tethered F-35 aircraft at multiple frequencies. A linear microphone array, placed along the ground, spanned the length of the jet exhaust plume. A multisource model of the sound field was included in the algorithm to incorporate the effects of the ground reflection on the measurement. Narrowband reconstructions elucidated fine details of the radiation patterns, such as multilobe radiation patterns (which may supersede “dual-lobe” patterns shown in previous studies), and broadband shock-associated noise. [Work supported by F-35 JPO.] © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
465 a57201947722 Manring L. p126 True Conference 19 Augmented Reality for Interactive Robot Control Robots are widely used to support mission-critical, high-risk and complex operations. Human supervision and remote robot control are often required to operate robots in unpredictable and changing scenarios. Often, robots are controlled remotely by technicians via joystick interfaces which require training and experience to operate. To improve robot usage and practicality, we propose using augmented reality (AR) to create a more intuitive, less training-intensive means of controlling robots than traditional joystick control. AR is a creative platform for developing robot control systems, because AR combines the real world (the environment around the user, the physical robot, etc.) with the digital world (holograms, digital displays, etc.); it can even interpret physical gestures, such as pinching two fingers. In this research, a Microsoft Hololens headset is used to create an AR environment to control a Yaskawa Motoman SIA5D robot. The control process begins with the user placing an interactable holographic robot in 3D space. The user can then select between two control methods: manual control and automatic control. In manual control, the user can move the end effector of the holographic robot and the physical robot will respond immediately. In automatic control, the user can move the end effector of the holographic robot to a desired location, view a holographic preview of the motion, and select execute if the motion plan is satisfactory. In this preview mode, the user is able to preview both the motion of the robot and the torques experienced by the joints of the manipulator. This gives the user additional feedback on the planned motion. In this project we succeeded in creating an AR control system that makes controlling a robotic manipulator intuitive and effective. © 2020, Society for Experimental Mechanics, Inc.
466 a57209567638 Pederson J. p126 False Conference 19 Augmented Reality for Interactive Robot Control Robots are widely used to support mission-critical, high-risk and complex operations. Human supervision and remote robot control are often required to operate robots in unpredictable and changing scenarios. Often, robots are controlled remotely by technicians via joystick interfaces which require training and experience to operate. To improve robot usage and practicality, we propose using augmented reality (AR) to create a more intuitive, less training-intensive means of controlling robots than traditional joystick control. AR is a creative platform for developing robot control systems, because AR combines the real world (the environment around the user, the physical robot, etc.) with the digital world (holograms, digital displays, etc.); it can even interpret physical gestures, such as pinching two fingers. In this research, a Microsoft Hololens headset is used to create an AR environment to control a Yaskawa Motoman SIA5D robot. The control process begins with the user placing an interactable holographic robot in 3D space. The user can then select between two control methods: manual control and automatic control. In manual control, the user can move the end effector of the holographic robot and the physical robot will respond immediately. In automatic control, the user can move the end effector of the holographic robot to a desired location, view a holographic preview of the motion, and select execute if the motion plan is satisfactory. In this preview mode, the user is able to preview both the motion of the robot and the torques experienced by the joints of the manipulator. This gives the user additional feedback on the planned motion. In this project we succeeded in creating an AR control system that makes controlling a robotic manipulator intuitive and effective. © 2020, Society for Experimental Mechanics, Inc.
467 a57209581042 Potts D. p126 False Conference 19 Augmented Reality for Interactive Robot Control Robots are widely used to support mission-critical, high-risk and complex operations. Human supervision and remote robot control are often required to operate robots in unpredictable and changing scenarios. Often, robots are controlled remotely by technicians via joystick interfaces which require training and experience to operate. To improve robot usage and practicality, we propose using augmented reality (AR) to create a more intuitive, less training-intensive means of controlling robots than traditional joystick control. AR is a creative platform for developing robot control systems, because AR combines the real world (the environment around the user, the physical robot, etc.) with the digital world (holograms, digital displays, etc.); it can even interpret physical gestures, such as pinching two fingers. In this research, a Microsoft Hololens headset is used to create an AR environment to control a Yaskawa Motoman SIA5D robot. The control process begins with the user placing an interactable holographic robot in 3D space. The user can then select between two control methods: manual control and automatic control. In manual control, the user can move the end effector of the holographic robot and the physical robot will respond immediately. In automatic control, the user can move the end effector of the holographic robot to a desired location, view a holographic preview of the motion, and select execute if the motion plan is satisfactory. In this preview mode, the user is able to preview both the motion of the robot and the torques experienced by the joints of the manipulator. This gives the user additional feedback on the planned motion. In this project we succeeded in creating an AR control system that makes controlling a robotic manipulator intuitive and effective. © 2020, Society for Experimental Mechanics, Inc.
468 a55845968200 Boardman B. p126 False Conference 19 Augmented Reality for Interactive Robot Control Robots are widely used to support mission-critical, high-risk and complex operations. Human supervision and remote robot control are often required to operate robots in unpredictable and changing scenarios. Often, robots are controlled remotely by technicians via joystick interfaces which require training and experience to operate. To improve robot usage and practicality, we propose using augmented reality (AR) to create a more intuitive, less training-intensive means of controlling robots than traditional joystick control. AR is a creative platform for developing robot control systems, because AR combines the real world (the environment around the user, the physical robot, etc.) with the digital world (holograms, digital displays, etc.); it can even interpret physical gestures, such as pinching two fingers. In this research, a Microsoft Hololens headset is used to create an AR environment to control a Yaskawa Motoman SIA5D robot. The control process begins with the user placing an interactable holographic robot in 3D space. The user can then select between two control methods: manual control and automatic control. In manual control, the user can move the end effector of the holographic robot and the physical robot will respond immediately. In automatic control, the user can move the end effector of the holographic robot to a desired location, view a holographic preview of the motion, and select execute if the motion plan is satisfactory. In this preview mode, the user is able to preview both the motion of the robot and the torques experienced by the joints of the manipulator. This gives the user additional feedback on the planned motion. In this project we succeeded in creating an AR control system that makes controlling a robotic manipulator intuitive and effective. © 2020, Society for Experimental Mechanics, Inc.
469 a14831622300 Mascarenas D. p126 False Conference 19 Augmented Reality for Interactive Robot Control Robots are widely used to support mission-critical, high-risk and complex operations. Human supervision and remote robot control are often required to operate robots in unpredictable and changing scenarios. Often, robots are controlled remotely by technicians via joystick interfaces which require training and experience to operate. To improve robot usage and practicality, we propose using augmented reality (AR) to create a more intuitive, less training-intensive means of controlling robots than traditional joystick control. AR is a creative platform for developing robot control systems, because AR combines the real world (the environment around the user, the physical robot, etc.) with the digital world (holograms, digital displays, etc.); it can even interpret physical gestures, such as pinching two fingers. In this research, a Microsoft Hololens headset is used to create an AR environment to control a Yaskawa Motoman SIA5D robot. The control process begins with the user placing an interactable holographic robot in 3D space. The user can then select between two control methods: manual control and automatic control. In manual control, the user can move the end effector of the holographic robot and the physical robot will respond immediately. In automatic control, the user can move the end effector of the holographic robot to a desired location, view a holographic preview of the motion, and select execute if the motion plan is satisfactory. In this preview mode, the user is able to preview both the motion of the robot and the torques experienced by the joints of the manipulator. This gives the user additional feedback on the planned motion. In this project we succeeded in creating an AR control system that makes controlling a robotic manipulator intuitive and effective. © 2020, Society for Experimental Mechanics, Inc.
469 a14831622300 Mascarenas D. p127 False Conference 20 Visio-acoustic data fusion for structural health monitoring applications Structural health monitoring has been an expanding discipline due to its potential to decrease maintenance and downtime costs, detect failure early, extend life spans, and fulfill the increased need of safety and security. Acoustic source identification techniques’ have been used for remote structural health monitoring, but the applicability of each technique has been limited by factors ranging from achievable spatial resolution to hardware costs. This paper aims to mitigate current acoustic techniques’ limitations by exploring the possibility of fusing acoustic and video data. This paper focuses on combining microphone acoustic measurements with vibrational information recovered from video-based measurements. Among acoustic methods, acoustic arrays have been used for remotely detecting, localizing and characterizing acoustic sources. Acoustic-array based techniques are limited in their ability to discriminate multiple closely-spaced acoustic sources from far-field acoustic pressure signals. On the contrary, video-based techniques have shown the ability to recover full-field, high resolution mode shapes, and the associated frequencies and damping ratios with virtually no dependence with the distance from the target. The challenge with video methods, applied to acoustic source identification, is that acoustic sources may occur in the kilohertz range requiring a higher frame per second sampling rate than most low cost cameras. Acoustic measurements provide additional information content that is used to recover the correct frequency content of an acoustically radiating structure from temporally-aliased (sub-Nyquist) video measurements. Experiments are conducted to show how combining acoustic and video data relaxes the hardware requirements for acoustic source detection and localization applications. © 2020, The Society for Experimental Mechanics, Inc.
470 a12646372900 Harden T. p126 False Conference 19 Augmented Reality for Interactive Robot Control Robots are widely used to support mission-critical, high-risk and complex operations. Human supervision and remote robot control are often required to operate robots in unpredictable and changing scenarios. Often, robots are controlled remotely by technicians via joystick interfaces which require training and experience to operate. To improve robot usage and practicality, we propose using augmented reality (AR) to create a more intuitive, less training-intensive means of controlling robots than traditional joystick control. AR is a creative platform for developing robot control systems, because AR combines the real world (the environment around the user, the physical robot, etc.) with the digital world (holograms, digital displays, etc.); it can even interpret physical gestures, such as pinching two fingers. In this research, a Microsoft Hololens headset is used to create an AR environment to control a Yaskawa Motoman SIA5D robot. The control process begins with the user placing an interactable holographic robot in 3D space. The user can then select between two control methods: manual control and automatic control. In manual control, the user can move the end effector of the holographic robot and the physical robot will respond immediately. In automatic control, the user can move the end effector of the holographic robot to a desired location, view a holographic preview of the motion, and select execute if the motion plan is satisfactory. In this preview mode, the user is able to preview both the motion of the robot and the torques experienced by the joints of the manipulator. This gives the user additional feedback on the planned motion. In this project we succeeded in creating an AR control system that makes controlling a robotic manipulator intuitive and effective. © 2020, Society for Experimental Mechanics, Inc.
471 a55788214400 Cattaneo A. p126 False Conference 19 Augmented Reality for Interactive Robot Control Robots are widely used to support mission-critical, high-risk and complex operations. Human supervision and remote robot control are often required to operate robots in unpredictable and changing scenarios. Often, robots are controlled remotely by technicians via joystick interfaces which require training and experience to operate. To improve robot usage and practicality, we propose using augmented reality (AR) to create a more intuitive, less training-intensive means of controlling robots than traditional joystick control. AR is a creative platform for developing robot control systems, because AR combines the real world (the environment around the user, the physical robot, etc.) with the digital world (holograms, digital displays, etc.); it can even interpret physical gestures, such as pinching two fingers. In this research, a Microsoft Hololens headset is used to create an AR environment to control a Yaskawa Motoman SIA5D robot. The control process begins with the user placing an interactable holographic robot in 3D space. The user can then select between two control methods: manual control and automatic control. In manual control, the user can move the end effector of the holographic robot and the physical robot will respond immediately. In automatic control, the user can move the end effector of the holographic robot to a desired location, view a holographic preview of the motion, and select execute if the motion plan is satisfactory. In this preview mode, the user is able to preview both the motion of the robot and the torques experienced by the joints of the manipulator. This gives the user additional feedback on the planned motion. In this project we succeeded in creating an AR control system that makes controlling a robotic manipulator intuitive and effective. © 2020, Society for Experimental Mechanics, Inc.
471 a55788214400 Cattaneo A. p127 False Conference 20 Visio-acoustic data fusion for structural health monitoring applications Structural health monitoring has been an expanding discipline due to its potential to decrease maintenance and downtime costs, detect failure early, extend life spans, and fulfill the increased need of safety and security. Acoustic source identification techniques’ have been used for remote structural health monitoring, but the applicability of each technique has been limited by factors ranging from achievable spatial resolution to hardware costs. This paper aims to mitigate current acoustic techniques’ limitations by exploring the possibility of fusing acoustic and video data. This paper focuses on combining microphone acoustic measurements with vibrational information recovered from video-based measurements. Among acoustic methods, acoustic arrays have been used for remotely detecting, localizing and characterizing acoustic sources. Acoustic-array based techniques are limited in their ability to discriminate multiple closely-spaced acoustic sources from far-field acoustic pressure signals. On the contrary, video-based techniques have shown the ability to recover full-field, high resolution mode shapes, and the associated frequencies and damping ratios with virtually no dependence with the distance from the target. The challenge with video methods, applied to acoustic source identification, is that acoustic sources may occur in the kilohertz range requiring a higher frame per second sampling rate than most low cost cameras. Acoustic measurements provide additional information content that is used to recover the correct frequency content of an acoustically radiating structure from temporally-aliased (sub-Nyquist) video measurements. Experiments are conducted to show how combining acoustic and video data relaxes the hardware requirements for acoustic source detection and localization applications. © 2020, The Society for Experimental Mechanics, Inc.
472 a57219330558 Samuelson C.R. p127 True Conference 20 Visio-acoustic data fusion for structural health monitoring applications Structural health monitoring has been an expanding discipline due to its potential to decrease maintenance and downtime costs, detect failure early, extend life spans, and fulfill the increased need of safety and security. Acoustic source identification techniques’ have been used for remote structural health monitoring, but the applicability of each technique has been limited by factors ranging from achievable spatial resolution to hardware costs. This paper aims to mitigate current acoustic techniques’ limitations by exploring the possibility of fusing acoustic and video data. This paper focuses on combining microphone acoustic measurements with vibrational information recovered from video-based measurements. Among acoustic methods, acoustic arrays have been used for remotely detecting, localizing and characterizing acoustic sources. Acoustic-array based techniques are limited in their ability to discriminate multiple closely-spaced acoustic sources from far-field acoustic pressure signals. On the contrary, video-based techniques have shown the ability to recover full-field, high resolution mode shapes, and the associated frequencies and damping ratios with virtually no dependence with the distance from the target. The challenge with video methods, applied to acoustic source identification, is that acoustic sources may occur in the kilohertz range requiring a higher frame per second sampling rate than most low cost cameras. Acoustic measurements provide additional information content that is used to recover the correct frequency content of an acoustically radiating structure from temporally-aliased (sub-Nyquist) video measurements. Experiments are conducted to show how combining acoustic and video data relaxes the hardware requirements for acoustic source detection and localization applications. © 2020, The Society for Experimental Mechanics, Inc.
473 a57219332168 Duffy-Deno C.A. p127 False Conference 20 Visio-acoustic data fusion for structural health monitoring applications Structural health monitoring has been an expanding discipline due to its potential to decrease maintenance and downtime costs, detect failure early, extend life spans, and fulfill the increased need of safety and security. Acoustic source identification techniques’ have been used for remote structural health monitoring, but the applicability of each technique has been limited by factors ranging from achievable spatial resolution to hardware costs. This paper aims to mitigate current acoustic techniques’ limitations by exploring the possibility of fusing acoustic and video data. This paper focuses on combining microphone acoustic measurements with vibrational information recovered from video-based measurements. Among acoustic methods, acoustic arrays have been used for remotely detecting, localizing and characterizing acoustic sources. Acoustic-array based techniques are limited in their ability to discriminate multiple closely-spaced acoustic sources from far-field acoustic pressure signals. On the contrary, video-based techniques have shown the ability to recover full-field, high resolution mode shapes, and the associated frequencies and damping ratios with virtually no dependence with the distance from the target. The challenge with video methods, applied to acoustic source identification, is that acoustic sources may occur in the kilohertz range requiring a higher frame per second sampling rate than most low cost cameras. Acoustic measurements provide additional information content that is used to recover the correct frequency content of an acoustically radiating structure from temporally-aliased (sub-Nyquist) video measurements. Experiments are conducted to show how combining acoustic and video data relaxes the hardware requirements for acoustic source detection and localization applications. © 2020, The Society for Experimental Mechanics, Inc.
474 a57219327922 Whitworth C.B. p127 False Conference 20 Visio-acoustic data fusion for structural health monitoring applications Structural health monitoring has been an expanding discipline due to its potential to decrease maintenance and downtime costs, detect failure early, extend life spans, and fulfill the increased need of safety and security. Acoustic source identification techniques’ have been used for remote structural health monitoring, but the applicability of each technique has been limited by factors ranging from achievable spatial resolution to hardware costs. This paper aims to mitigate current acoustic techniques’ limitations by exploring the possibility of fusing acoustic and video data. This paper focuses on combining microphone acoustic measurements with vibrational information recovered from video-based measurements. Among acoustic methods, acoustic arrays have been used for remotely detecting, localizing and characterizing acoustic sources. Acoustic-array based techniques are limited in their ability to discriminate multiple closely-spaced acoustic sources from far-field acoustic pressure signals. On the contrary, video-based techniques have shown the ability to recover full-field, high resolution mode shapes, and the associated frequencies and damping ratios with virtually no dependence with the distance from the target. The challenge with video methods, applied to acoustic source identification, is that acoustic sources may occur in the kilohertz range requiring a higher frame per second sampling rate than most low cost cameras. Acoustic measurements provide additional information content that is used to recover the correct frequency content of an acoustically radiating structure from temporally-aliased (sub-Nyquist) video measurements. Experiments are conducted to show how combining acoustic and video data relaxes the hardware requirements for acoustic source detection and localization applications. © 2020, The Society for Experimental Mechanics, Inc.
475 a55220932600 Tippmann J.D. p127 False Conference 20 Visio-acoustic data fusion for structural health monitoring applications Structural health monitoring has been an expanding discipline due to its potential to decrease maintenance and downtime costs, detect failure early, extend life spans, and fulfill the increased need of safety and security. Acoustic source identification techniques’ have been used for remote structural health monitoring, but the applicability of each technique has been limited by factors ranging from achievable spatial resolution to hardware costs. This paper aims to mitigate current acoustic techniques’ limitations by exploring the possibility of fusing acoustic and video data. This paper focuses on combining microphone acoustic measurements with vibrational information recovered from video-based measurements. Among acoustic methods, acoustic arrays have been used for remotely detecting, localizing and characterizing acoustic sources. Acoustic-array based techniques are limited in their ability to discriminate multiple closely-spaced acoustic sources from far-field acoustic pressure signals. On the contrary, video-based techniques have shown the ability to recover full-field, high resolution mode shapes, and the associated frequencies and damping ratios with virtually no dependence with the distance from the target. The challenge with video methods, applied to acoustic source identification, is that acoustic sources may occur in the kilohertz range requiring a higher frame per second sampling rate than most low cost cameras. Acoustic measurements provide additional information content that is used to recover the correct frequency content of an acoustically radiating structure from temporally-aliased (sub-Nyquist) video measurements. Experiments are conducted to show how combining acoustic and video data relaxes the hardware requirements for acoustic source detection and localization applications. © 2020, The Society for Experimental Mechanics, Inc.
476 a56263319900 Qu Y. p128 True Journal 90 A Low-Profile High-Efficiency Fast Battery Charger With Unifiable Constant-Current and Constant-Voltage Regulation Present universal serial bus (USB) battery chargers often suffer from limitations to meet the increasing demand for quick charging due to compromised power efficiency and complicated hardware implementation. In this paper, we propose a charge unifiable (QU) control scheme that enables a battery charger to improve power efficiency in a low-profile hardware manner. This scheme features fully soft-switching (vis-&#x00E0;-vis hard switching) and single control scheme (vis-&#x00E0;-vis multiple) for distinct constant current (CC) and constant voltage (CV) charging modes. To the best of authors' knowledge, the proposed QU control scheme is the first to simultaneously offer fully soft-switching, innate CC-and-CV regulation, and seamless CC-to-CV transition. To verify the proposed design, we monolithically realize a low-profile high-efficiency fast battery charger based on this scheme. The prototype embodying a tiny 470-nH output inductor supports a maximum input voltage of 16V, output voltage of 2.2-4.2 V, output current of 0.1-2 A, and peak power efficiency of 96.2&#x0025;. When benchmarked against state-of-the-art counterparts, the proposed charger features at least 2.1x smaller inductor and 7.2&#x0025; higher power efficiency at both the maximum and the minimum output power charging scenarios. Further, this charger is the only design that features &#x2265; 91&#x0025; power efficiency in the whole load range. IEEE
477 a55436436900 Shu W. p128 False Journal 90 A Low-Profile High-Efficiency Fast Battery Charger With Unifiable Constant-Current and Constant-Voltage Regulation Present universal serial bus (USB) battery chargers often suffer from limitations to meet the increasing demand for quick charging due to compromised power efficiency and complicated hardware implementation. In this paper, we propose a charge unifiable (QU) control scheme that enables a battery charger to improve power efficiency in a low-profile hardware manner. This scheme features fully soft-switching (vis-&#x00E0;-vis hard switching) and single control scheme (vis-&#x00E0;-vis multiple) for distinct constant current (CC) and constant voltage (CV) charging modes. To the best of authors' knowledge, the proposed QU control scheme is the first to simultaneously offer fully soft-switching, innate CC-and-CV regulation, and seamless CC-to-CV transition. To verify the proposed design, we monolithically realize a low-profile high-efficiency fast battery charger based on this scheme. The prototype embodying a tiny 470-nH output inductor supports a maximum input voltage of 16V, output voltage of 2.2-4.2 V, output current of 0.1-2 A, and peak power efficiency of 96.2&#x0025;. When benchmarked against state-of-the-art counterparts, the proposed charger features at least 2.1x smaller inductor and 7.2&#x0025; higher power efficiency at both the maximum and the minimum output power charging scenarios. Further, this charger is the only design that features &#x2265; 91&#x0025; power efficiency in the whole load range. IEEE
478 a57218480110 Qiu L. p128 False Journal 90 A Low-Profile High-Efficiency Fast Battery Charger With Unifiable Constant-Current and Constant-Voltage Regulation Present universal serial bus (USB) battery chargers often suffer from limitations to meet the increasing demand for quick charging due to compromised power efficiency and complicated hardware implementation. In this paper, we propose a charge unifiable (QU) control scheme that enables a battery charger to improve power efficiency in a low-profile hardware manner. This scheme features fully soft-switching (vis-&#x00E0;-vis hard switching) and single control scheme (vis-&#x00E0;-vis multiple) for distinct constant current (CC) and constant voltage (CV) charging modes. To the best of authors' knowledge, the proposed QU control scheme is the first to simultaneously offer fully soft-switching, innate CC-and-CV regulation, and seamless CC-to-CV transition. To verify the proposed design, we monolithically realize a low-profile high-efficiency fast battery charger based on this scheme. The prototype embodying a tiny 470-nH output inductor supports a maximum input voltage of 16V, output voltage of 2.2-4.2 V, output current of 0.1-2 A, and peak power efficiency of 96.2&#x0025;. When benchmarked against state-of-the-art counterparts, the proposed charger features at least 2.1x smaller inductor and 7.2&#x0025; higher power efficiency at both the maximum and the minimum output power charging scenarios. Further, this charger is the only design that features &#x2265; 91&#x0025; power efficiency in the whole load range. IEEE
479 a7004688501 Kuan Y. p128 False Journal 90 A Low-Profile High-Efficiency Fast Battery Charger With Unifiable Constant-Current and Constant-Voltage Regulation Present universal serial bus (USB) battery chargers often suffer from limitations to meet the increasing demand for quick charging due to compromised power efficiency and complicated hardware implementation. In this paper, we propose a charge unifiable (QU) control scheme that enables a battery charger to improve power efficiency in a low-profile hardware manner. This scheme features fully soft-switching (vis-&#x00E0;-vis hard switching) and single control scheme (vis-&#x00E0;-vis multiple) for distinct constant current (CC) and constant voltage (CV) charging modes. To the best of authors' knowledge, the proposed QU control scheme is the first to simultaneously offer fully soft-switching, innate CC-and-CV regulation, and seamless CC-to-CV transition. To verify the proposed design, we monolithically realize a low-profile high-efficiency fast battery charger based on this scheme. The prototype embodying a tiny 470-nH output inductor supports a maximum input voltage of 16V, output voltage of 2.2-4.2 V, output current of 0.1-2 A, and peak power efficiency of 96.2&#x0025;. When benchmarked against state-of-the-art counterparts, the proposed charger features at least 2.1x smaller inductor and 7.2&#x0025; higher power efficiency at both the maximum and the minimum output power charging scenarios. Further, this charger is the only design that features &#x2265; 91&#x0025; power efficiency in the whole load range. IEEE
479 a7004688501 Kuan Y. p175 False Journal 119 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW, yielding an FoM of 37 fJ/conv.-step, the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2018 IEEE.
479 a7004688501 Kuan Y. p177 False Conference 39 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW,yielding an FoM of 37 fJ/conv.-step,the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2019 IEEE.
480 a7601550121 Chang J.S. p128 False Journal 90 A Low-Profile High-Efficiency Fast Battery Charger With Unifiable Constant-Current and Constant-Voltage Regulation Present universal serial bus (USB) battery chargers often suffer from limitations to meet the increasing demand for quick charging due to compromised power efficiency and complicated hardware implementation. In this paper, we propose a charge unifiable (QU) control scheme that enables a battery charger to improve power efficiency in a low-profile hardware manner. This scheme features fully soft-switching (vis-&#x00E0;-vis hard switching) and single control scheme (vis-&#x00E0;-vis multiple) for distinct constant current (CC) and constant voltage (CV) charging modes. To the best of authors' knowledge, the proposed QU control scheme is the first to simultaneously offer fully soft-switching, innate CC-and-CV regulation, and seamless CC-to-CV transition. To verify the proposed design, we monolithically realize a low-profile high-efficiency fast battery charger based on this scheme. The prototype embodying a tiny 470-nH output inductor supports a maximum input voltage of 16V, output voltage of 2.2-4.2 V, output current of 0.1-2 A, and peak power efficiency of 96.2&#x0025;. When benchmarked against state-of-the-art counterparts, the proposed charger features at least 2.1x smaller inductor and 7.2&#x0025; higher power efficiency at both the maximum and the minimum output power charging scenarios. Further, this charger is the only design that features &#x2265; 91&#x0025; power efficiency in the whole load range. IEEE
481 a57201735120 Bopp D.G. p129 True Conference 21 Atomic flux circuits Atomic vapors are a crucial platform for precision metrology but in their simplest implementation, a thermal vapor, the intrinsic optical resonances are broadened due to the random and isotropic thermal motion of the atoms. By structuring the container of a thermal vapor with narrow emission apertures, the velocity distribution can be modified to create a directed beam of atoms.1 These atomic beams can then interact sequentially with a series of optical fields, or interaction zones, and ultimately allow precision control over the internal state of the atom. This is useful for optical frequency standards and precision spectroscopy2, 3 and may also provide the means to build a simple flying qubit platform.4 Furthermore, atomic beams on a chip can be used as a compact, directed source to load magneto-optical traps (MOTs) while minimally increasing the ambient pressure.5 We apply microfabrication techniques to microscopically structure silicon to deterministically control the ow of Rb between connected cavities. We describe a methodology to measure the experimental parameters that govern the flux of atomic vapors in these microfabricated structures with a goal of creating an equivalent electrical circuit model. This toolkit will provide a simple platform for the creation of atomic beams on a chip with controllable pressure profiles and a thorough understanding of the influence of adsorptive effects and pseudo- ballistic trajectories on the resultant atomic beam. © 2020 SPIE.
482 a57216287696 Taylor E. p129 False Conference 21 Atomic flux circuits Atomic vapors are a crucial platform for precision metrology but in their simplest implementation, a thermal vapor, the intrinsic optical resonances are broadened due to the random and isotropic thermal motion of the atoms. By structuring the container of a thermal vapor with narrow emission apertures, the velocity distribution can be modified to create a directed beam of atoms.1 These atomic beams can then interact sequentially with a series of optical fields, or interaction zones, and ultimately allow precision control over the internal state of the atom. This is useful for optical frequency standards and precision spectroscopy2, 3 and may also provide the means to build a simple flying qubit platform.4 Furthermore, atomic beams on a chip can be used as a compact, directed source to load magneto-optical traps (MOTs) while minimally increasing the ambient pressure.5 We apply microfabrication techniques to microscopically structure silicon to deterministically control the ow of Rb between connected cavities. We describe a methodology to measure the experimental parameters that govern the flux of atomic vapors in these microfabricated structures with a goal of creating an equivalent electrical circuit model. This toolkit will provide a simple platform for the creation of atomic beams on a chip with controllable pressure profiles and a thorough understanding of the influence of adsorptive effects and pseudo- ballistic trajectories on the resultant atomic beam. © 2020 SPIE.
483 a57216287324 Le K. p129 False Conference 21 Atomic flux circuits Atomic vapors are a crucial platform for precision metrology but in their simplest implementation, a thermal vapor, the intrinsic optical resonances are broadened due to the random and isotropic thermal motion of the atoms. By structuring the container of a thermal vapor with narrow emission apertures, the velocity distribution can be modified to create a directed beam of atoms.1 These atomic beams can then interact sequentially with a series of optical fields, or interaction zones, and ultimately allow precision control over the internal state of the atom. This is useful for optical frequency standards and precision spectroscopy2, 3 and may also provide the means to build a simple flying qubit platform.4 Furthermore, atomic beams on a chip can be used as a compact, directed source to load magneto-optical traps (MOTs) while minimally increasing the ambient pressure.5 We apply microfabrication techniques to microscopically structure silicon to deterministically control the ow of Rb between connected cavities. We describe a methodology to measure the experimental parameters that govern the flux of atomic vapors in these microfabricated structures with a goal of creating an equivalent electrical circuit model. This toolkit will provide a simple platform for the creation of atomic beams on a chip with controllable pressure profiles and a thorough understanding of the influence of adsorptive effects and pseudo- ballistic trajectories on the resultant atomic beam. © 2020 SPIE.
484 a6506462706 Schima S. p129 False Conference 21 Atomic flux circuits Atomic vapors are a crucial platform for precision metrology but in their simplest implementation, a thermal vapor, the intrinsic optical resonances are broadened due to the random and isotropic thermal motion of the atoms. By structuring the container of a thermal vapor with narrow emission apertures, the velocity distribution can be modified to create a directed beam of atoms.1 These atomic beams can then interact sequentially with a series of optical fields, or interaction zones, and ultimately allow precision control over the internal state of the atom. This is useful for optical frequency standards and precision spectroscopy2, 3 and may also provide the means to build a simple flying qubit platform.4 Furthermore, atomic beams on a chip can be used as a compact, directed source to load magneto-optical traps (MOTs) while minimally increasing the ambient pressure.5 We apply microfabrication techniques to microscopically structure silicon to deterministically control the ow of Rb between connected cavities. We describe a methodology to measure the experimental parameters that govern the flux of atomic vapors in these microfabricated structures with a goal of creating an equivalent electrical circuit model. This toolkit will provide a simple platform for the creation of atomic beams on a chip with controllable pressure profiles and a thorough understanding of the influence of adsorptive effects and pseudo- ballistic trajectories on the resultant atomic beam. © 2020 SPIE.
485 a8357777200 Hummon M.T. p129 False Conference 21 Atomic flux circuits Atomic vapors are a crucial platform for precision metrology but in their simplest implementation, a thermal vapor, the intrinsic optical resonances are broadened due to the random and isotropic thermal motion of the atoms. By structuring the container of a thermal vapor with narrow emission apertures, the velocity distribution can be modified to create a directed beam of atoms.1 These atomic beams can then interact sequentially with a series of optical fields, or interaction zones, and ultimately allow precision control over the internal state of the atom. This is useful for optical frequency standards and precision spectroscopy2, 3 and may also provide the means to build a simple flying qubit platform.4 Furthermore, atomic beams on a chip can be used as a compact, directed source to load magneto-optical traps (MOTs) while minimally increasing the ambient pressure.5 We apply microfabrication techniques to microscopically structure silicon to deterministically control the ow of Rb between connected cavities. We describe a methodology to measure the experimental parameters that govern the flux of atomic vapors in these microfabricated structures with a goal of creating an equivalent electrical circuit model. This toolkit will provide a simple platform for the creation of atomic beams on a chip with controllable pressure profiles and a thorough understanding of the influence of adsorptive effects and pseudo- ballistic trajectories on the resultant atomic beam. © 2020 SPIE.
486 a7004945584 Kitching J. p129 False Conference 21 Atomic flux circuits Atomic vapors are a crucial platform for precision metrology but in their simplest implementation, a thermal vapor, the intrinsic optical resonances are broadened due to the random and isotropic thermal motion of the atoms. By structuring the container of a thermal vapor with narrow emission apertures, the velocity distribution can be modified to create a directed beam of atoms.1 These atomic beams can then interact sequentially with a series of optical fields, or interaction zones, and ultimately allow precision control over the internal state of the atom. This is useful for optical frequency standards and precision spectroscopy2, 3 and may also provide the means to build a simple flying qubit platform.4 Furthermore, atomic beams on a chip can be used as a compact, directed source to load magneto-optical traps (MOTs) while minimally increasing the ambient pressure.5 We apply microfabrication techniques to microscopically structure silicon to deterministically control the ow of Rb between connected cavities. We describe a methodology to measure the experimental parameters that govern the flux of atomic vapors in these microfabricated structures with a goal of creating an equivalent electrical circuit model. This toolkit will provide a simple platform for the creation of atomic beams on a chip with controllable pressure profiles and a thorough understanding of the influence of adsorptive effects and pseudo- ballistic trajectories on the resultant atomic beam. © 2020 SPIE.
487 a9741060000 Kaoumi D. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
488 a12143690400 Ohara Y. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
489 a57208015244 Stuber Geesey M.A. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
490 a57052262900 Xi L. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
491 a57204944822 Schoell R. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
492 a7102369425 Bryan C.R. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
493 a6603460787 Enos D.G. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
494 a6603089864 Summa D.A. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
495 a12761902000 Ulrich T.J. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
495 a12761902000 Ulrich T.J. p620 False Journal 310 Time reversal techniques Time reversal is a technique to focus wave energy to a selected point in space and time, localize and characterize a source of wave propagation, and/or communicate information between two points. This chapter will introduce the reader to the concept of time reversal and different implementations of this concept. The focus will then be directed to non-destructive evaluation applications using nonlinear elasto-dynamics together with time reversal. © Springer Nature Switzerland AG 2019.
496 a9279493200 Shayer Z. p130 False Journal 77 Detecting and imaging stress corrosion cracking in stainless steel, with application to inspecting storage canisters for spent nuclear fuel One of the primary concerns with the long-term performance of storage systems for spent nuclear fuel (SNF) is the potential for corrosion due to deliquescence of salts deposited as aerosols on the surface of the canister, which is typically made of austentic stainless steel. In regions of high residual weld stresses, this may lead to localized stress-corrosion cracking (SCC). The ability to detect and image SCC at an early stage (long before the cracks are susceptible to propagate through the thickness of the canister wall and leaks of radioactive material may occur) is essential to the performance evaluation and licensing process of the storage systems. In this paper, we explore a number of nondestructive testing techniques to detect and image SCC in austenitic stainless steel. Our attention is focused on a small rectangular sample of 1 × 2 in2 with two cracks of mm-scale sizes. The techniques explored in this paper include nonlinear resonant ultrasound spectroscopy (NRUS) for detection, Linear Elastodynamic Gradient Imaging Technique (LEGIT), ultrasonic C-scan, vibrothermography, and synchrotron X-ray diffraction for imaging. Results obtained from these techniques are compared. Cracks of mm-scale sizes can be detected and imaged with all the techniques explored in this study. © 2019
497 a57194034271 Cabas A. p131 True Conference 22 Turning Disaster into Knowledge: Geotechnical Aspects of the 2018 Mw 7.1 Anchorage Alaska Earthquake The moment magnitude (Mw) 7.1 Anchorage, Alaska, earthquake on November 30, 2018 is one of the largest earthquakes to strike near a major U.S. city since the 1994 Northridge earthquake. No fatalities were reported, but the earthquake caused widespread power outages, structural damage to residential buildings, damage to roadways and railways, and ground failures. This paper presents a summary of preliminary findings by the NSF-sponsored Geotechnical Extreme Events Reconnaissance (GEER) team. Damage was characterized using a combination of on-ground site mapping and aerial reconnaissance with state-of-art geomatics technology and photogrammetry. Recorded peak ground accelerations (PGA) at most stations range between 0.2 g and 0.3 g, with a few sites in the central and southeastern vicinities of Anchorage with PGA greater than 0.5 g. The duration of strong shaking from the M 7.1 event may not have been enough to initiate substantial movements on the majority of the historic landslides from the 1964 M 9.2 earthquake, including the slides at the Turnagain Heights and 4th Avenue. However, liquefaction appeared to have contributed to re-mobilization of the 1964 Potter Hill (Rabbit Creek) landslide. While the majority of the damage observed in Anchorage and surrounding communities appeared to be non-structural, the isolated cases of structural damage seemed to be caused by geotechnical issues, particularly settlement of the foundation and/or slope deformations. © 2020 American Society of Civil Engineers.
498 a53866135200 Beyzaei C. p131 False Conference 22 Turning Disaster into Knowledge: Geotechnical Aspects of the 2018 Mw 7.1 Anchorage Alaska Earthquake The moment magnitude (Mw) 7.1 Anchorage, Alaska, earthquake on November 30, 2018 is one of the largest earthquakes to strike near a major U.S. city since the 1994 Northridge earthquake. No fatalities were reported, but the earthquake caused widespread power outages, structural damage to residential buildings, damage to roadways and railways, and ground failures. This paper presents a summary of preliminary findings by the NSF-sponsored Geotechnical Extreme Events Reconnaissance (GEER) team. Damage was characterized using a combination of on-ground site mapping and aerial reconnaissance with state-of-art geomatics technology and photogrammetry. Recorded peak ground accelerations (PGA) at most stations range between 0.2 g and 0.3 g, with a few sites in the central and southeastern vicinities of Anchorage with PGA greater than 0.5 g. The duration of strong shaking from the M 7.1 event may not have been enough to initiate substantial movements on the majority of the historic landslides from the 1964 M 9.2 earthquake, including the slides at the Turnagain Heights and 4th Avenue. However, liquefaction appeared to have contributed to re-mobilization of the 1964 Potter Hill (Rabbit Creek) landslide. While the majority of the damage observed in Anchorage and surrounding communities appeared to be non-structural, the isolated cases of structural damage seemed to be caused by geotechnical issues, particularly settlement of the foundation and/or slope deformations. © 2020 American Society of Civil Engineers.
499 a55315026400 Franke K. p131 False Conference 22 Turning Disaster into Knowledge: Geotechnical Aspects of the 2018 Mw 7.1 Anchorage Alaska Earthquake The moment magnitude (Mw) 7.1 Anchorage, Alaska, earthquake on November 30, 2018 is one of the largest earthquakes to strike near a major U.S. city since the 1994 Northridge earthquake. No fatalities were reported, but the earthquake caused widespread power outages, structural damage to residential buildings, damage to roadways and railways, and ground failures. This paper presents a summary of preliminary findings by the NSF-sponsored Geotechnical Extreme Events Reconnaissance (GEER) team. Damage was characterized using a combination of on-ground site mapping and aerial reconnaissance with state-of-art geomatics technology and photogrammetry. Recorded peak ground accelerations (PGA) at most stations range between 0.2 g and 0.3 g, with a few sites in the central and southeastern vicinities of Anchorage with PGA greater than 0.5 g. The duration of strong shaking from the M 7.1 event may not have been enough to initiate substantial movements on the majority of the historic landslides from the 1964 M 9.2 earthquake, including the slides at the Turnagain Heights and 4th Avenue. However, liquefaction appeared to have contributed to re-mobilization of the 1964 Potter Hill (Rabbit Creek) landslide. While the majority of the damage observed in Anchorage and surrounding communities appeared to be non-structural, the isolated cases of structural damage seemed to be caused by geotechnical issues, particularly settlement of the foundation and/or slope deformations. © 2020 American Society of Civil Engineers.
499 a55315026400 Franke K. p163 True Journal 113 Observed building damage patterns and foundation performance in Mexico City following the 2017 M7.1 Puebla-Mexico City earthquake The September 19th, 2017 M7.1 Puebla-Mexico City earthquake introduced strong ground motions into the Mexico City basin, which contains very soft lacustrine soils, dense urban infrastructure, and millions of inhabitants. As a result, 38 mid-rise structures collapsed and several hundred more were damaged. This paper reports the observations related to building performance, damage patterns, and foundation performance made by the two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical aspects of the earthquake. The methodology used to perform building damage mapping following the 2017 event is described. Comparisons are made between the observed building damage patterns following the September 19th, 1985 and the 2017 earthquake, and the distinct differences in the damage pattern distribution between the two earthquakes are summarized. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized. © 2019 Elsevier Ltd
499 a55315026400 Franke K. p185 False Journal 126 The September 19, 2017 Mw 7.1 Puebla-Mexico city earthquake: Important findings from the field – Overview of Special Edition The September 19th, 2017 Mw 7.1 Puebla-Mexico City earthquake lead to strong ground shaking in the densely populated Mexico City basin, and surrounding country areas in central Mexico. As a result, 38 mid-rise buildings collapsed and several hundred more were damaged in Mexico City, and extensive damage was observed in the states of Puebla and Morelos. This special edition synthesizes observations related to structural and foundation performance, and the corresponding damage patterns, carried out by two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical earthquake engineering aspects of this event. Articles were solicited of researchers that were in the field that investigated: the characteristics of the event, the demand and damage distribution across Mexico City and surrounding regions, the seismic performance of buildings, lifelines, and other critical infrastructure, considering the site response and soil-structure interaction effects in the observed damage distribution. Special attention was paid to the impact of regional ground subsidence, in the seismic-soil structure interaction exhibited by the affected building. Advanced non-intrusive survey methods were used to map damage patterns in a regional level. Comparisons were made between the observed building damage patterns following the September 19th, 1985 Michoacan earthquake, and the 2017 Puebla-Mexico City earthquake, and the distinct differences in the damage distribution between the two earthquakes were revised. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction, which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized in each research paper include in this special issue. © 2019 Elsevier Ltd
499 a55315026400 Franke K. p210 False Journal 142 Achieving tiered model quality in 3D structure from motion models using a multi-scale view-planning algorithm for automated targeted inspection This study presents a novel multi-scale view-planning algorithm for automated targeted inspection using unmanned aircraft systems (UAS). In industrial inspection, it is important to collect the most relevant data to keep processing demands, both human and computational, to a minimum. This study investigates the viability of automated targeted multi-scale image acquisition for Structure from Motion (SfM)-based infrastructure modeling. A traditional view-planning approach for SfM is extended to a multi-scale approach, planning for targeted regions of high, medium, and low priority. The unmanned aerial vehicle (UAV) can traverse the entire aerial space and facilitates collection of an optimized set of views, both close to and far away from areas of interest. The test case for field validation is the Tibble Fork Dam in Utah. Using the targeted multi-scale flight planning, a UAV automatically flies a tiered inspection using less than 25% of the number of photos needed to model the entire dam at high-priority level. This results in approximately 75% reduced flight time and model processing load, while still maintaining high model accuracy where needed. Models display stepped improvement in visual clarity and SfM reconstruction integrity by priority level, with the higher priority regions more accurately modeling smaller and finer features. A resolution map of the final tiered model is included. While this study focuses on multi-scale view planning for optical sensors, the methods potentially extend to other remote sensors, such as aerial LiDAR. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
499 a55315026400 Franke K. p211 False Journal 143 Disaster reconnaissance using multiple small unmanned aerial vehicles" [No abstract available]
499 a55315026400 Franke K. p228 False Journal 150 Site effects in Mexico City basin: Past and present Due to the unique subsoil conditions prevailing in the Mexico City basin, seismic risk has been strongly correlated to site effects. Thus, during the Mw 8.1 09/19/1985 subduction fault earthquake, and its strong aftershock Mw 7.5 09/21/1985, extensive damage was observed in the area, along with the loss of thousands of lives, despite these events had an epicentral distance of around 430 km from Mexico City. The observed damage was mostly due to site affects originated by the high plastiCity clay deposits found in the basin, which lead to large amplifications, and duration elongation of the ground motions coming from the epicenter. In addition, a frequency content modification occurs, which in turn, leads to a double resonance effect between the incoming ground motions, soil deposits, and the damaged buildings. Exactly 32 years after this devastating event, the Mw 7.1 09/19/2017 normal fault earthquake, reminded us of the importance of accounting for site effects, and most importantly the need to carry out a proper characterization of basin geometry, soil profile configuration, hydraulic conditions, and maintenance-structure periodic assessments of the building stock in Mexico City. This is required to reduce uncertainties of seismic vulnerability studies for extreme-event seismic hazard scenarios. In this paper, the role of site response and seismic soil-structure interaction as key factors responsible of the observed damage in the City is revisited, through series of 3D finite difference models of typical structure-foundation-soil typologies found at the areas where most of the damage was observed, highlighting its clear impact in the final damage distribution observed around the City. © 2019 Elsevier Ltd
499 a55315026400 Franke K. p361 True Journal 201 Overestimation of liquefaction hazard in areas of low to moderate seismicity due to improper characterization of probabilistic seismic loading This study evaluates the impact of characterizing probabilistic ground motions for liquefaction hazard analysis (defined and quantified in this paper as liquefaction triggering and free-field post-liquefaction settlements) in areas of low to moderate seismicity. Both pseudo-probabilistic and probabilistic (i.e., performance-based) methods are assessed and compared. Results of the comparative study suggest that pseudo-probabilistic methods can significantly overestimate liquefaction hazards in areas of low seismicity. Performance-based probabilistic methods are shown to predict between 5.2 cm and 16.5 cm (approximately 36–47%) less post-liquefaction free-field settlement on average than pseudo-probabilistic methods in areas of low seismicity at a return period of 2475 years, and to predict 9 cm to 19.7cm (approximately 96%) less post-liquefaction free-field settlement on average than pseudo-probabilistic methods at a return period of 475 years. Soil site classification is shown to have substantial impact on the estimated liquefaction hazards in areas of low seismicity due to soil amplification, potentially increasing design accelerations by up to 56%. Consequences of inconsistencies regarding design ground motions in current seismic design provisions are also discussed. To avoid potential for overpredicting liquefaction hazards, engineers should apply a performance-based approach when assessing liquefaction triggering and its effects in areas of low to moderate seismicity. © 2018 The Authors
499 a55315026400 Franke K. p394 False Conference 143 Mexico City Basin Effects: Past, Present, and Future Seismic hazard in Mexico City governed by site effects. The M8.1 1985 subduction zone earthquake, which caused significant damage and loss of thousands of lives at 350 km epicentral distance, has become the quintessential example of the role that site effects can play in modifying the amplitude, frequency, and duration of ground shaking; and in aggravating the catastrophic consequences of earthquakes. We here present observations and analyses of the M7.1 September 19, 2017, event that -while triggered by an intraplate rupture at approximately half the epicentral distance of the 1985 event relative to Mexico City -caused severe structural damage to a few tens of buildings located in a relatively narrow zone between the hill and lake zones of the basin, known as the transition zone. We show that the M 7.1 mainshock exposed the vulnerabilities of the pre-1985 building code in the transition zone; but more importantly highlighted the improvement of the 1987 building code revision in terms of the performance of modern high-rise buildings that suffered catastrophic consequences during the 1985 Michoácan earthquake sequence. We next analyze several records collected at stations in the basin over the past 20 years. We highlight the importance of three-dimensional heterogeneity of the basin sediments, the coupling between hydrological setting and site response and their evolution with time, and the energy interaction between the deep basin edge and the shallow clay layers. Results presented are the collective effort of the GEER teams that were deployed to perform post-earthquake reconnaissance in the affected regions of the epicentral area and in Mexico City after the M 7.1 September 19, 2017, earthquake sequence. © 2019 American Society of Civil Engineers.
499 a55315026400 Franke K. p613 True Conference 251 Optimization of Grid Spacing Pattern for the Development of Reference Parameter Maps for Liquefaction-Induced Free-Field Settlement Performance-based earthquake engineering analysis methods are desirable in geotechnical engineering due to their ability to incorporate the various uncertainties associated with complex problems and their ability to frame responses in terms of a targeted hazard. However, such methods are difficult to implement on routine projects without the use of specialized software because the many iterative probabilistic calculations required. Prior research has introduced a simplified approach of using performance-based reference parameter maps in conjunction with correction equations that account for site-specific geotechnical and topographical conditions. This paper addresses the development of such performance-based reference parameter maps for the calculation of post-liquefaction volumetric strains and settlements in the free field. A study is performed and presented to assess the optimized grid spacing for a performance-based volumetric strain analysis and development of a strain performance-based reference parameter map. Recommended grid spacing values as correlated to USGS seismic hazard maps for PGA are provided to produce a maximum of 0.15% strain error in interpolating the reference strain for the simplified performance-based analysis approach. © 2018 American Society of Civil Engineers.
499 a55315026400 Franke K. p671 False Journal 296 Water supply damage caused by the 2016 Kumamoto Earthquake Widespread damage to lifeline systems occurred as a result from the Kumamoto Earthquakes that initiated on April 14, 2016. Interruption to the water, gas, and electric power supply affected thousands of people. Landslides and surface rupture caused significant damage to transportation systems, especially roads and bridges. This paper provides an overview of observations and information gathered by US researchers (sponsored by Geotechnical Extreme Events Reconnaissance Association), Japanese researchers, and others regarding water supply damage. Emphasis is placed on the largest water authority in the region of the earthquake, Kumamoto City, including damage metrics for various pipe materials and diameters. The greatest damage occurred at valves and other fundamental mechanisms of large diameter pipelines. Pipelines constructed of ERDIP and HDPE performed most favorably while steel and cast iron pipelines were shown to be the more vulnerable. A liquefaction-induced lateral spreading site at which pipeline damage occurred is identified for further study. © 2017 International Association of Lowland Technology. All rights reserved.
499 a55315026400 Franke K. p838 True Conference 365 Probabilistic Lateral Spread Evaluation for Long, Linear Infrastructure Using Performance-Based Reference Parameter Maps The design of long, linear infrastructure such as pipelines, levees, roads, and canals can be challenging in areas of moderate to high seismicity due to numerous seismic and geologic hazards that can be encountered along proposed alignments. One of the most challenging earthquake-related hazards in the design of large infrastructure is liquefaction-induced lateral spread displacement. This paper presents a new simplified probabilistic approach to estimate lateral spread displacements at targeted return periods across large geographic areas using performance-based lateral spread displacement reference parameter maps and (if available) site-specific geotechnical information. The approach is demonstrated on a hypothetical pipeline extending from Rock Springs, Wyoming, to West Bountiful, Utah, in the United States. Advantages and limitations of the proposed approach are discussed. The results of the demonstrative calculation show how the approach can be used to identify areas where additional geotechnical investigations might be needed, and how probabilistic lateral spread displacements can be easily predicted along numerous proposed alignments of the pipeline once geotechnical subsurface investigation and ground surveys become available. © 2017 ASCE.
499 a55315026400 Franke K. p879 True Conference 395 The use of unmanned aerial vehicles and structures from motion to measure the volume change at a deep dynamic compaction site A small unmanned aerial vehicle (sUAV) is used with structure from motion (SfM) computer vision (Marr and Nishihara 1978; Snavely et al. 2008) to measure the amount of settlement that is induced by deep dynamic compaction at a site of a new casino near Lake Havasu City, AZ. Details of the project and field operations are provided, and comparisons are made between induced settlement measurements from traditional techniques and induced settlement measurements from the new sUAV/SfM approach. Results of the study show that the sUAV/SfM approach estimates an average induced settlement of 38 cm across the site, which straddles within 2.5 cm of the average induced settlements that were measured with other traditional techniques. Additionally, the sUAV/SfM technique is shown to provide significant detail of the distribution of induced settlements across the site. This distribution of settlements could be indicative of the distribution of subsurface soils that were more affected by the DDC such as looser or cleaner sands. Implications of the findings of this study are briefly discussed. © ASCE.
500 a57216076371 Koehler R. p131 False Conference 22 Turning Disaster into Knowledge: Geotechnical Aspects of the 2018 Mw 7.1 Anchorage Alaska Earthquake The moment magnitude (Mw) 7.1 Anchorage, Alaska, earthquake on November 30, 2018 is one of the largest earthquakes to strike near a major U.S. city since the 1994 Northridge earthquake. No fatalities were reported, but the earthquake caused widespread power outages, structural damage to residential buildings, damage to roadways and railways, and ground failures. This paper presents a summary of preliminary findings by the NSF-sponsored Geotechnical Extreme Events Reconnaissance (GEER) team. Damage was characterized using a combination of on-ground site mapping and aerial reconnaissance with state-of-art geomatics technology and photogrammetry. Recorded peak ground accelerations (PGA) at most stations range between 0.2 g and 0.3 g, with a few sites in the central and southeastern vicinities of Anchorage with PGA greater than 0.5 g. The duration of strong shaking from the M 7.1 event may not have been enough to initiate substantial movements on the majority of the historic landslides from the 1964 M 9.2 earthquake, including the slides at the Turnagain Heights and 4th Avenue. However, liquefaction appeared to have contributed to re-mobilization of the 1964 Potter Hill (Rabbit Creek) landslide. While the majority of the damage observed in Anchorage and surrounding communities appeared to be non-structural, the isolated cases of structural damage seemed to be caused by geotechnical issues, particularly settlement of the foundation and/or slope deformations. © 2020 American Society of Civil Engineers.
501 a56818839700 Pierce I. p131 False Conference 22 Turning Disaster into Knowledge: Geotechnical Aspects of the 2018 Mw 7.1 Anchorage Alaska Earthquake The moment magnitude (Mw) 7.1 Anchorage, Alaska, earthquake on November 30, 2018 is one of the largest earthquakes to strike near a major U.S. city since the 1994 Northridge earthquake. No fatalities were reported, but the earthquake caused widespread power outages, structural damage to residential buildings, damage to roadways and railways, and ground failures. This paper presents a summary of preliminary findings by the NSF-sponsored Geotechnical Extreme Events Reconnaissance (GEER) team. Damage was characterized using a combination of on-ground site mapping and aerial reconnaissance with state-of-art geomatics technology and photogrammetry. Recorded peak ground accelerations (PGA) at most stations range between 0.2 g and 0.3 g, with a few sites in the central and southeastern vicinities of Anchorage with PGA greater than 0.5 g. The duration of strong shaking from the M 7.1 event may not have been enough to initiate substantial movements on the majority of the historic landslides from the 1964 M 9.2 earthquake, including the slides at the Turnagain Heights and 4th Avenue. However, liquefaction appeared to have contributed to re-mobilization of the 1964 Potter Hill (Rabbit Creek) landslide. While the majority of the damage observed in Anchorage and surrounding communities appeared to be non-structural, the isolated cases of structural damage seemed to be caused by geotechnical issues, particularly settlement of the foundation and/or slope deformations. © 2020 American Society of Civil Engineers.
502 a23570183200 Stuedlein A. p131 False Conference 22 Turning Disaster into Knowledge: Geotechnical Aspects of the 2018 Mw 7.1 Anchorage Alaska Earthquake The moment magnitude (Mw) 7.1 Anchorage, Alaska, earthquake on November 30, 2018 is one of the largest earthquakes to strike near a major U.S. city since the 1994 Northridge earthquake. No fatalities were reported, but the earthquake caused widespread power outages, structural damage to residential buildings, damage to roadways and railways, and ground failures. This paper presents a summary of preliminary findings by the NSF-sponsored Geotechnical Extreme Events Reconnaissance (GEER) team. Damage was characterized using a combination of on-ground site mapping and aerial reconnaissance with state-of-art geomatics technology and photogrammetry. Recorded peak ground accelerations (PGA) at most stations range between 0.2 g and 0.3 g, with a few sites in the central and southeastern vicinities of Anchorage with PGA greater than 0.5 g. The duration of strong shaking from the M 7.1 event may not have been enough to initiate substantial movements on the majority of the historic landslides from the 1964 M 9.2 earthquake, including the slides at the Turnagain Heights and 4th Avenue. However, liquefaction appeared to have contributed to re-mobilization of the 1964 Potter Hill (Rabbit Creek) landslide. While the majority of the damage observed in Anchorage and surrounding communities appeared to be non-structural, the isolated cases of structural damage seemed to be caused by geotechnical issues, particularly settlement of the foundation and/or slope deformations. © 2020 American Society of Civil Engineers.
503 a57215823167 Yang Z. p131 False Conference 22 Turning Disaster into Knowledge: Geotechnical Aspects of the 2018 Mw 7.1 Anchorage Alaska Earthquake The moment magnitude (Mw) 7.1 Anchorage, Alaska, earthquake on November 30, 2018 is one of the largest earthquakes to strike near a major U.S. city since the 1994 Northridge earthquake. No fatalities were reported, but the earthquake caused widespread power outages, structural damage to residential buildings, damage to roadways and railways, and ground failures. This paper presents a summary of preliminary findings by the NSF-sponsored Geotechnical Extreme Events Reconnaissance (GEER) team. Damage was characterized using a combination of on-ground site mapping and aerial reconnaissance with state-of-art geomatics technology and photogrammetry. Recorded peak ground accelerations (PGA) at most stations range between 0.2 g and 0.3 g, with a few sites in the central and southeastern vicinities of Anchorage with PGA greater than 0.5 g. The duration of strong shaking from the M 7.1 event may not have been enough to initiate substantial movements on the majority of the historic landslides from the 1964 M 9.2 earthquake, including the slides at the Turnagain Heights and 4th Avenue. However, liquefaction appeared to have contributed to re-mobilization of the 1964 Potter Hill (Rabbit Creek) landslide. While the majority of the damage observed in Anchorage and surrounding communities appeared to be non-structural, the isolated cases of structural damage seemed to be caused by geotechnical issues, particularly settlement of the foundation and/or slope deformations. © 2020 American Society of Civil Engineers.
504 a57216048774 Christie S. p131 False Conference 22 Turning Disaster into Knowledge: Geotechnical Aspects of the 2018 Mw 7.1 Anchorage Alaska Earthquake The moment magnitude (Mw) 7.1 Anchorage, Alaska, earthquake on November 30, 2018 is one of the largest earthquakes to strike near a major U.S. city since the 1994 Northridge earthquake. No fatalities were reported, but the earthquake caused widespread power outages, structural damage to residential buildings, damage to roadways and railways, and ground failures. This paper presents a summary of preliminary findings by the NSF-sponsored Geotechnical Extreme Events Reconnaissance (GEER) team. Damage was characterized using a combination of on-ground site mapping and aerial reconnaissance with state-of-art geomatics technology and photogrammetry. Recorded peak ground accelerations (PGA) at most stations range between 0.2 g and 0.3 g, with a few sites in the central and southeastern vicinities of Anchorage with PGA greater than 0.5 g. The duration of strong shaking from the M 7.1 event may not have been enough to initiate substantial movements on the majority of the historic landslides from the 1964 M 9.2 earthquake, including the slides at the Turnagain Heights and 4th Avenue. However, liquefaction appeared to have contributed to re-mobilization of the 1964 Potter Hill (Rabbit Creek) landslide. While the majority of the damage observed in Anchorage and surrounding communities appeared to be non-structural, the isolated cases of structural damage seemed to be caused by geotechnical issues, particularly settlement of the foundation and/or slope deformations. © 2020 American Society of Civil Engineers.
505 a7202049689 Tucker A.L. p132 True Journal 91 When do workarounds help or hurt patient outcomes? The moderating role of operational failures Hospital providers often use workarounds to circumvent processes so that patients can receive care. Workarounds in response to operational failures enable care to continue and therefore may be indicative of workers' commitment. On the other hand, workarounds in the absence of operational failures may signal an ineffective approach associated with lower quality of care and worse patient outcomes. Working closely with healthcare providers, we developed a survey to measure workaround behaviors and operational failures on medical/surgical units. The lead author surveyed over 4,000 nurses from 63 hospitals throughout the United States. We matched this data with audit data on the incidence of pressure injuries among over 21,000 patients on 262 nursing units in 56 survey hospitals. Hospital-acquired pressure injuries are a significant risk to patient health and hospital costs. We do not find support for our hypothesis that workarounds are associated with a higher rate of hospital-acquired pressure injuries. However, when we take into account the moderating role of operational failures on the relationship between workarounds and pressure injuries, we find significant results. When nursing units have lower levels of operational failures, workarounds are associated with higher rates of hospital-acquired pressure injuries. Our results provide evidence that workarounds may be associated with negative patient outcomes, if they stem from a process-avoiding approach. The best results can be achieved by reducing both operational failures and workarounds via instilling a process-focused approach. © 2019 Association for Supply Chain Management, Inc.
506 a57207774891 Zheng S. p132 False Journal 91 When do workarounds help or hurt patient outcomes? The moderating role of operational failures Hospital providers often use workarounds to circumvent processes so that patients can receive care. Workarounds in response to operational failures enable care to continue and therefore may be indicative of workers' commitment. On the other hand, workarounds in the absence of operational failures may signal an ineffective approach associated with lower quality of care and worse patient outcomes. Working closely with healthcare providers, we developed a survey to measure workaround behaviors and operational failures on medical/surgical units. The lead author surveyed over 4,000 nurses from 63 hospitals throughout the United States. We matched this data with audit data on the incidence of pressure injuries among over 21,000 patients on 262 nursing units in 56 survey hospitals. Hospital-acquired pressure injuries are a significant risk to patient health and hospital costs. We do not find support for our hypothesis that workarounds are associated with a higher rate of hospital-acquired pressure injuries. However, when we take into account the moderating role of operational failures on the relationship between workarounds and pressure injuries, we find significant results. When nursing units have lower levels of operational failures, workarounds are associated with higher rates of hospital-acquired pressure injuries. Our results provide evidence that workarounds may be associated with negative patient outcomes, if they stem from a process-avoiding approach. The best results can be achieved by reducing both operational failures and workarounds via instilling a process-focused approach. © 2019 Association for Supply Chain Management, Inc.
507 a7006410098 Bohn R.E. p132 False Journal 91 When do workarounds help or hurt patient outcomes? The moderating role of operational failures Hospital providers often use workarounds to circumvent processes so that patients can receive care. Workarounds in response to operational failures enable care to continue and therefore may be indicative of workers' commitment. On the other hand, workarounds in the absence of operational failures may signal an ineffective approach associated with lower quality of care and worse patient outcomes. Working closely with healthcare providers, we developed a survey to measure workaround behaviors and operational failures on medical/surgical units. The lead author surveyed over 4,000 nurses from 63 hospitals throughout the United States. We matched this data with audit data on the incidence of pressure injuries among over 21,000 patients on 262 nursing units in 56 survey hospitals. Hospital-acquired pressure injuries are a significant risk to patient health and hospital costs. We do not find support for our hypothesis that workarounds are associated with a higher rate of hospital-acquired pressure injuries. However, when we take into account the moderating role of operational failures on the relationship between workarounds and pressure injuries, we find significant results. When nursing units have lower levels of operational failures, workarounds are associated with higher rates of hospital-acquired pressure injuries. Our results provide evidence that workarounds may be associated with negative patient outcomes, if they stem from a process-avoiding approach. The best results can be achieved by reducing both operational failures and workarounds via instilling a process-focused approach. © 2019 Association for Supply Chain Management, Inc.
508 a56206655300 Sacchi C. p133 True Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
509 a55368982000 Schlegel C. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
510 a56078804700 Rossi T. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
511 a57216040137 Noble M. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
512 a7102391180 Ruggieri M. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
513 a7402406630 Cheung K.-M. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
514 a7004398165 Marchese M. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
515 a6701655006 Granelli F. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
516 a35103143500 Popescu V. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
517 a57216037206 Rice M. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
518 a7801550098 Murroni M. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
519 a14832404400 Conci N. p133 False Journal 92 Glue Technologies for Space Systems: An Introduction to a New AESS Technical Panel This article aims at introducing to the readers of the AES Magazine the recently constituted technical panel: Glue Technologies for Space Systems. A short overview of the technologies considered in the panel will be provided, along with panel vision and perspectives shared with the founder members. Some information about panel meetings and participation rules will conclude this article. © 1986-2012 IEEE.
520 a55559344500 Allen M. p134 True Journal 93 A New Boundary Harnack Principle (Equations with Right Hand Side) We introduce a new boundary Harnack principle in Lipschitz domains for equations with a right hand side. Our approach, which uses comparisons and blow-ups, will adapt to more general domains as well as other types of operators. We prove the principle for divergence form elliptic equations with lower order terms including zero order terms. The inclusion of a zero order term appears to be new even in the absence of a right hand side. © 2019, The Author(s).
521 a6701910642 Shahgholian H. p134 False Journal 93 A New Boundary Harnack Principle (Equations with Right Hand Side) We introduce a new boundary Harnack principle in Lipschitz domains for equations with a right hand side. Our approach, which uses comparisons and blow-ups, will adapt to more general domains as well as other types of operators. We prove the principle for divergence form elliptic equations with lower order terms including zero order terms. The inclusion of a zero order term appears to be new even in the absence of a right hand side. © 2019, The Author(s).
522 a56221719300 Hunt J.P. p135 True Journal 94 Streamlining the preparation of “endotoxin-free” ClearColi cell extract with autoinduction media for cell-free protein synthesis of the therapeutic protein crisantaspase An “endotoxin-free” E. coli-based cell-free protein synthesis system has been reported to produce therapeutic proteins rapidly and on-demand. However, preparation of the most complex CFPS reagent – the cell extract – remains time-consuming and labor-intensive because of the relatively slow growth kinetics of the endotoxin-free ClearColiTMBL21(DE3) strain. Here we report a streamlined procedure for preparing E. coli cell extract from ClearColi™ using auto-induction media. In this work, the term auto-induction describes cell culture media which eliminates the need for manual induction of protein expression. Culturing Clearcoli™ cells in autoinduction media significantly reduces the hands-on time required during extract preparation, and the resulting “endotoxin-free” cell extract maintained the same cell-free protein synthesis capability as extract produced with traditional induction as demonstrated by the high-yield expression of crisantaspase, an FDA approved leukemia therapeutic. It is anticipated that this work will lower the barrier for researchers to enter the field and use this technology as the method to produce endotoxin-free E. coli-based extract for CFPS. © 2019
523 a57210161259 Zhao E.L. p135 False Journal 94 Streamlining the preparation of “endotoxin-free” ClearColi cell extract with autoinduction media for cell-free protein synthesis of the therapeutic protein crisantaspase An “endotoxin-free” E. coli-based cell-free protein synthesis system has been reported to produce therapeutic proteins rapidly and on-demand. However, preparation of the most complex CFPS reagent – the cell extract – remains time-consuming and labor-intensive because of the relatively slow growth kinetics of the endotoxin-free ClearColiTMBL21(DE3) strain. Here we report a streamlined procedure for preparing E. coli cell extract from ClearColi™ using auto-induction media. In this work, the term auto-induction describes cell culture media which eliminates the need for manual induction of protein expression. Culturing Clearcoli™ cells in autoinduction media significantly reduces the hands-on time required during extract preparation, and the resulting “endotoxin-free” cell extract maintained the same cell-free protein synthesis capability as extract produced with traditional induction as demonstrated by the high-yield expression of crisantaspase, an FDA approved leukemia therapeutic. It is anticipated that this work will lower the barrier for researchers to enter the field and use this technology as the method to produce endotoxin-free E. coli-based extract for CFPS. © 2019
524 a57203181568 Soltani M. p135 False Journal 94 Streamlining the preparation of “endotoxin-free” ClearColi cell extract with autoinduction media for cell-free protein synthesis of the therapeutic protein crisantaspase An “endotoxin-free” E. coli-based cell-free protein synthesis system has been reported to produce therapeutic proteins rapidly and on-demand. However, preparation of the most complex CFPS reagent – the cell extract – remains time-consuming and labor-intensive because of the relatively slow growth kinetics of the endotoxin-free ClearColiTMBL21(DE3) strain. Here we report a streamlined procedure for preparing E. coli cell extract from ClearColi™ using auto-induction media. In this work, the term auto-induction describes cell culture media which eliminates the need for manual induction of protein expression. Culturing Clearcoli™ cells in autoinduction media significantly reduces the hands-on time required during extract preparation, and the resulting “endotoxin-free” cell extract maintained the same cell-free protein synthesis capability as extract produced with traditional induction as demonstrated by the high-yield expression of crisantaspase, an FDA approved leukemia therapeutic. It is anticipated that this work will lower the barrier for researchers to enter the field and use this technology as the method to produce endotoxin-free E. coli-based extract for CFPS. © 2019
524 a57203181568 Soltani M. p430 True Journal 238 Reengineering cell-free protein synthesis as a biosensor: Biosensing with transcription, translation, and protein-folding Biosensors highjack and reengineer biological systems for highly specific detection of diverse molecules. However, many traditional biosensor devices have slow response times and high operating costs and require specialized training and immobile lab equipment. In an effort to address these limitations, researchers have begun using cell-free protein synthesis (CFPS) systems as biosensors. CFPS-based systems provide the advantages of speed, portability, and robustness at a relatively low cost. Here, we review CFPS-based biosensors according to the three fundamental stages of CFPS: transcription, translation, and protein folding. © 2018 Elsevier B.V.
525 a57212304730 Frei M. p135 False Journal 94 Streamlining the preparation of “endotoxin-free” ClearColi cell extract with autoinduction media for cell-free protein synthesis of the therapeutic protein crisantaspase An “endotoxin-free” E. coli-based cell-free protein synthesis system has been reported to produce therapeutic proteins rapidly and on-demand. However, preparation of the most complex CFPS reagent – the cell extract – remains time-consuming and labor-intensive because of the relatively slow growth kinetics of the endotoxin-free ClearColiTMBL21(DE3) strain. Here we report a streamlined procedure for preparing E. coli cell extract from ClearColi™ using auto-induction media. In this work, the term auto-induction describes cell culture media which eliminates the need for manual induction of protein expression. Culturing Clearcoli™ cells in autoinduction media significantly reduces the hands-on time required during extract preparation, and the resulting “endotoxin-free” cell extract maintained the same cell-free protein synthesis capability as extract produced with traditional induction as demonstrated by the high-yield expression of crisantaspase, an FDA approved leukemia therapeutic. It is anticipated that this work will lower the barrier for researchers to enter the field and use this technology as the method to produce endotoxin-free E. coli-based extract for CFPS. © 2019
526 a55458271500 Nelson J.A.D. p135 False Journal 94 Streamlining the preparation of “endotoxin-free” ClearColi cell extract with autoinduction media for cell-free protein synthesis of the therapeutic protein crisantaspase An “endotoxin-free” E. coli-based cell-free protein synthesis system has been reported to produce therapeutic proteins rapidly and on-demand. However, preparation of the most complex CFPS reagent – the cell extract – remains time-consuming and labor-intensive because of the relatively slow growth kinetics of the endotoxin-free ClearColiTMBL21(DE3) strain. Here we report a streamlined procedure for preparing E. coli cell extract from ClearColi™ using auto-induction media. In this work, the term auto-induction describes cell culture media which eliminates the need for manual induction of protein expression. Culturing Clearcoli™ cells in autoinduction media significantly reduces the hands-on time required during extract preparation, and the resulting “endotoxin-free” cell extract maintained the same cell-free protein synthesis capability as extract produced with traditional induction as demonstrated by the high-yield expression of crisantaspase, an FDA approved leukemia therapeutic. It is anticipated that this work will lower the barrier for researchers to enter the field and use this technology as the method to produce endotoxin-free E. coli-based extract for CFPS. © 2019
526 a55458271500 Nelson J.A.D. p430 False Journal 238 Reengineering cell-free protein synthesis as a biosensor: Biosensing with transcription, translation, and protein-folding Biosensors highjack and reengineer biological systems for highly specific detection of diverse molecules. However, many traditional biosensor devices have slow response times and high operating costs and require specialized training and immobile lab equipment. In an effort to address these limitations, researchers have begun using cell-free protein synthesis (CFPS) systems as biosensors. CFPS-based systems provide the advantages of speed, portability, and robustness at a relatively low cost. Here, we review CFPS-based biosensors according to the three fundamental stages of CFPS: transcription, translation, and protein folding. © 2018 Elsevier B.V.
527 a56266132600 Bundy B.C. p135 False Journal 94 Streamlining the preparation of “endotoxin-free” ClearColi cell extract with autoinduction media for cell-free protein synthesis of the therapeutic protein crisantaspase An “endotoxin-free” E. coli-based cell-free protein synthesis system has been reported to produce therapeutic proteins rapidly and on-demand. However, preparation of the most complex CFPS reagent – the cell extract – remains time-consuming and labor-intensive because of the relatively slow growth kinetics of the endotoxin-free ClearColiTMBL21(DE3) strain. Here we report a streamlined procedure for preparing E. coli cell extract from ClearColi™ using auto-induction media. In this work, the term auto-induction describes cell culture media which eliminates the need for manual induction of protein expression. Culturing Clearcoli™ cells in autoinduction media significantly reduces the hands-on time required during extract preparation, and the resulting “endotoxin-free” cell extract maintained the same cell-free protein synthesis capability as extract produced with traditional induction as demonstrated by the high-yield expression of crisantaspase, an FDA approved leukemia therapeutic. It is anticipated that this work will lower the barrier for researchers to enter the field and use this technology as the method to produce endotoxin-free E. coli-based extract for CFPS. © 2019
527 a56266132600 Bundy B.C. p231 False Journal 153 Non-canonical amino acid labeling in proteomics and biotechnology Metabolic labeling of proteins with non-canonical amino acids (ncAAs) provides unique bioorthogonal chemical groups during de novo synthesis by taking advantage of both endogenous and heterologous protein synthesis machineries. Labeled proteins can then be selectively conjugated to fluorophores, affinity reagents, peptides, polymers, nanoparticles or surfaces for a wide variety of downstream applications in proteomics and biotechnology. In this review, we focus on techniques in which proteins are residue- and site-specifically labeled with ncAAs containing bioorthogonal handles. These ncAA-labeled proteins are: readily enriched from cells and tissues for identification via mass spectrometry-based proteomic analysis; selectively purified for downstream biotechnology applications; or labeled with fluorophores for in situ analysis. To facilitate the wider use of these techniques, we provide decision trees to help guide the design of future experiments. It is expected that the use of ncAA labeling will continue to expand into new application areas where spatial and temporal analysis of proteome dynamics and engineering new chemistries and new function into proteins are desired. © 2019 The Author(s).
527 a56266132600 Bundy B.C. p430 False Journal 238 Reengineering cell-free protein synthesis as a biosensor: Biosensing with transcription, translation, and protein-folding Biosensors highjack and reengineer biological systems for highly specific detection of diverse molecules. However, many traditional biosensor devices have slow response times and high operating costs and require specialized training and immobile lab equipment. In an effort to address these limitations, researchers have begun using cell-free protein synthesis (CFPS) systems as biosensors. CFPS-based systems provide the advantages of speed, portability, and robustness at a relatively low cost. Here, we review CFPS-based biosensors according to the three fundamental stages of CFPS: transcription, translation, and protein folding. © 2018 Elsevier B.V.
527 a56266132600 Bundy B.C. p439 False Journal 244 The emerging impact of cell-free chemical biosynthesis Biomanufacturing has emerged as a promising alternative to chemocatalysis for green, renewable, complex synthesis of biofuels, medicines, and fine chemicals. Cell-free chemical biosynthesis offers additional advantages over in vivo production, enabling plug-and-play assembly of separately produced enzymes into an optimal cascade, versatile reaction conditions, and direct access to the reaction environment. In order for these advantages to be realized on the larger scale of industry, strategies are needed to reduce costs of biocatalyst generation, improve biocatalyst stability, and enable economically sustainable continuous cascade operation. Here we overview the advantages and remaining challenges of applying cell-free chemical biosynthesis for commodity production, and discuss recent advances in cascade engineering, enzyme immobilization, and enzyme encapsulation which constitute important steps towards addressing these challenges. © 2017
527 a56266132600 Bundy B.C. p444 False Journal 248 Corrigendum: Efficient decellularization of whole porcine kidneys improves reseeded cell behavior (Biomedical Materials (Bristol) (2016) 11 (025003) DOI: 10.1088/1748-6041/11/2/025003) The above manuscript describes our efforts to improve the process for recellularization of porcine kidneys. We obtained what we believed to be an immortalized cell line of human renal cortical tubular epithelium (RCTE) cells from the Feinberg School of Medicine, Northwestern University to conduct our reseeding experiments. The RCTE cells that were provided to us were later discovered to actually be Madin-Darby Canine Kidney (MDCK) epithelial cells. Despite being of canine origin, MDCK cells are a distal tubule epithelial cell line that behave similarly to human RCTE cells. The conclusions regarding reseeding as reported in our paper are still sound, as described in the following. © 2018 IOP Publishing Ltd.
527 a56266132600 Bundy B.C. p537 False Journal 297 The Locational Impact of Site-Specific PEGylation: Streamlined Screening with Cell-Free Protein Expression and Coarse-Grain Simulation Although polyethylene glycol (PEG) is commonly used to improve protein stability and therapeutic efficacy, the optimal location for attaching PEG onto proteins is not well understood. Here, we present a cell-free protein synthesis-based screening platform that facilitates site-specific PEGylation and efficient evaluation of PEG attachment efficiency, thermal stability, and activity for different variants of PEGylated T4 lysozyme, including a di-PEGylated variant. We also report developing a computationally efficient coarse-grain simulation model as a potential tool to narrow experimental screening candidates. We use this simulation method as a novel tool to evaluate the locational impact of PEGylation. Using this screen, we also evaluated the predictive impact of PEGylation site solvent accessibility, conjugation site structure, PEG size, and double PEGylation. Our findings indicate that PEGylation efficiency, protein stability, and protein activity varied considerably with PEGylation site, variations that were not well predicted by common PEGylation guidelines. Overall our results suggest current guidelines are insufficiently predictive, highlighting the need for experimental and simulation screening systems such as the one presented here. © 2018 American Chemical Society.
528 a57209399454 Fanning D.T. p137 True Journal 96 Contributions of Tip Leakage and Inlet Diffusion on Inducer Backflow Inducers are used as a first stage in pumps to minimize cavitation and allow the pump to operate at lower inlet head conditions. Inlet flow recirculation or backflow in the inducer occurs at low flow conditions and can lead to instabilities and cavitation-induced head breakdown. Backflow of an inducer with a tip clearance (TC) of τ = 0.32% and with no tip clearance (NTC) is examined with a series of computational fluid dynamics simulations. Removing the TC eliminates tip leakage flow; however, backflow is still observed. In fact, the NTC case showed a 37% increase in the length of the upstream backflow penetration. Tip leakage flow does instigate a smaller secondary leading edge tip vortex that is separate from the much larger backflow structure. A comprehensive analysis of these simulations suggests that blade inlet diffusion, not tip leakage flow, is the fundamental mechanism leading to the formation of backflow. © 2019 by ASME.
529 a9245406100 Oliphant K. p137 False Journal 96 Contributions of Tip Leakage and Inlet Diffusion on Inducer Backflow Inducers are used as a first stage in pumps to minimize cavitation and allow the pump to operate at lower inlet head conditions. Inlet flow recirculation or backflow in the inducer occurs at low flow conditions and can lead to instabilities and cavitation-induced head breakdown. Backflow of an inducer with a tip clearance (TC) of τ = 0.32% and with no tip clearance (NTC) is examined with a series of computational fluid dynamics simulations. Removing the TC eliminates tip leakage flow; however, backflow is still observed. In fact, the NTC case showed a 37% increase in the length of the upstream backflow penetration. Tip leakage flow does instigate a smaller secondary leading edge tip vortex that is separate from the much larger backflow structure. A comprehensive analysis of these simulations suggests that blade inlet diffusion, not tip leakage flow, is the fundamental mechanism leading to the formation of backflow. © 2019 by ASME.
529 a9245406100 Oliphant K. p340 False Journal 96 Increasing Inducer Stability and Suction Performance With a Stability Control Device An inducer is used as the first stage of high suction performance pump. It pressurizes the fluid to delay the onset of cavitation, which can adversely affect performance in a centrifugal pump. In this paper, the performance of a water pump inducer has been explored with and without the implementation of a stability control device (SCD). This device is an inlet cover bleed system that removes high-energy fluid near the blade leading edge and reinjects it back upstream. The research was conducted by running multiphase, time-accurate computational fluid dynamic (CFD) simulations at the design flow coefficient and at low, off-design flow coefficients. The suction performance and stability for the same inducer with and without the implementation of the SCD has been explored. An improvement in stability and suction performance was observed when the SCD was implemented. Without the SCD, the inducer developed backflow at the blade tip, which led to rotating cavitation and larger rotordynamic forces. With the SCD, no significant cavitation instabilities developed, and the rotordynamic forces remained small. The lack of cavitation instabilities also allowed the inducer to operate at lower inlet pressures, increasing the suction performance of the inducer. Copyright © 2018 by ASME.
530 a57194053456 Goates C.B. p138 True Journal 97 Modeling acoustic resonators using higher-order equivalent circuits Helmholtz resonators are widely used, but classical models for the resonators, such as the lumped-element equivalent circuit, are inaccurate for most geometries. This article presents higher-order equivalent circuits for describing the resonators based on the one-dimensional wave equation. Impedance expressions are also derived. These circuits and expressions are given for various constituent resonator components, which may be combined to model resonators with curved, tapered, and straight necks. Resonance frequency predictions using this theory are demonstrated on two realistic resonators. The higher-order predictions are also applied to the theory of side branch attenuators in a duct and the theory of resonator coupling with a mode of an enclosure. © 2019 Institute of Noise Control Engineering.
531 a56968013300 Calton M.F. p138 False Journal 97 Modeling acoustic resonators using higher-order equivalent circuits Helmholtz resonators are widely used, but classical models for the resonators, such as the lumped-element equivalent circuit, are inaccurate for most geometries. This article presents higher-order equivalent circuits for describing the resonators based on the one-dimensional wave equation. Impedance expressions are also derived. These circuits and expressions are given for various constituent resonator components, which may be combined to model resonators with curved, tapered, and straight necks. Resonance frequency predictions using this theory are demonstrated on two realistic resonators. The higher-order predictions are also applied to the theory of side branch attenuators in a duct and the theory of resonator coupling with a mode of an enclosure. © 2019 Institute of Noise Control Engineering.
532 a6701723921 Copley D.C. p138 False Journal 97 Modeling acoustic resonators using higher-order equivalent circuits Helmholtz resonators are widely used, but classical models for the resonators, such as the lumped-element equivalent circuit, are inaccurate for most geometries. This article presents higher-order equivalent circuits for describing the resonators based on the one-dimensional wave equation. Impedance expressions are also derived. These circuits and expressions are given for various constituent resonator components, which may be combined to model resonators with curved, tapered, and straight necks. Resonance frequency predictions using this theory are demonstrated on two realistic resonators. The higher-order predictions are also applied to the theory of side branch attenuators in a duct and the theory of resonator coupling with a mode of an enclosure. © 2019 Institute of Noise Control Engineering.
533 a57202910211 Smith R. p139 True Conference 23 Adapting standard external clustering metrics for repetitive, noisy observations Clustering for data analysis often makes use of external metrics to evaluate how closely clustering assignments match a gold standard. In order to use external clustering metrics, explicit noise points are usually removed or treated as a single cluster. This modification reduces the relevancy of external metrics as a predictor of performance on unlabeled data, where it is not possible to identify noise points. We propose a modification of standard external metrics to explicitly handle noise points in experimental data. We illustrate the effect of this explicit treatment of noise on clustering evaluation using several examples of common noisy clustering problems as well as a real data set from mass spectrometry. We demonstrate that (external) clustering metrics that explicitly treat noise are more robust than standard (external) clustering metrics in the presence of noise. © 2019 IEEE.
534 a57196421757 Rosen J. p139 False Conference 23 Adapting standard external clustering metrics for repetitive, noisy observations Clustering for data analysis often makes use of external metrics to evaluate how closely clustering assignments match a gold standard. In order to use external clustering metrics, explicit noise points are usually removed or treated as a single cluster. This modification reduces the relevancy of external metrics as a predictor of performance on unlabeled data, where it is not possible to identify noise points. We propose a modification of standard external metrics to explicitly handle noise points in experimental data. We illustrate the effect of this explicit treatment of noise on clustering evaluation using several examples of common noisy clustering problems as well as a real data set from mass spectrometry. We demonstrate that (external) clustering metrics that explicitly treat noise are more robust than standard (external) clustering metrics in the presence of noise. © 2019 IEEE.
535 a24402340500 Ventura D. p139 False Conference 23 Adapting standard external clustering metrics for repetitive, noisy observations Clustering for data analysis often makes use of external metrics to evaluate how closely clustering assignments match a gold standard. In order to use external clustering metrics, explicit noise points are usually removed or treated as a single cluster. This modification reduces the relevancy of external metrics as a predictor of performance on unlabeled data, where it is not possible to identify noise points. We propose a modification of standard external metrics to explicitly handle noise points in experimental data. We illustrate the effect of this explicit treatment of noise on clustering evaluation using several examples of common noisy clustering problems as well as a real data set from mass spectrometry. We demonstrate that (external) clustering metrics that explicitly treat noise are more robust than standard (external) clustering metrics in the presence of noise. © 2019 IEEE.
535 a24402340500 Ventura D. p830 False Conference 358 Semantic style creation Visual style transfer involves combining the content of one image with the style of another, and recent work has produced some compelling results. This paper proposes a related task that requires additional system intelligence and autonomy-that of style creation. Rather than using the style of an existing source image, the goal is to have the system autonomously create a rendering style based on a simple (text-based) semantic description. Results demonstrate the system's ability to autonomously create interesting, semantically appropriate styles that can be applied for image rendering. © 2017, Association for the Advancement of Artificial Intelligence (www.aaai.org). All rights reserved.
536 a55645613600 Sisodia S.M. p140 True Journal 98 The effects of voids in quasi-static indentation of resin-infused reinforced polymers The focus of this study is the influence of voids on the damage behaviour in quasi-static loading of resin-infused carbon fibre-reinforced polymers. Experimental results are presented for quasi-static loading in combination with high-resolution tomographic imaging and statistical analysis (homology of pores or voids and induced cracks). Three distinct mechanisms were observed to control delamination growth in the presence of sharp and blunt voids. Delamination cracks interact with the supporting yarns, especially in combination with air pockets trapped in the resin in the form of long, sharp voids. This resulted in crack growth that coalesces with delamination cracks from neighbouring yarn-voids during increased out-of-plane load–displacement, with almost no presence of intralaminar transverse cracks. This highlights the benefits and drawbacks of the supporting yarn during out-of-plane loading. © The Author(s) 2019.
537 a55546296200 Bull D.J. p140 False Journal 98 The effects of voids in quasi-static indentation of resin-infused reinforced polymers The focus of this study is the influence of voids on the damage behaviour in quasi-static loading of resin-infused carbon fibre-reinforced polymers. Experimental results are presented for quasi-static loading in combination with high-resolution tomographic imaging and statistical analysis (homology of pores or voids and induced cracks). Three distinct mechanisms were observed to control delamination growth in the presence of sharp and blunt voids. Delamination cracks interact with the supporting yarns, especially in combination with air pockets trapped in the resin in the form of long, sharp voids. This resulted in crack growth that coalesces with delamination cracks from neighbouring yarn-voids during increased out-of-plane load–displacement, with almost no presence of intralaminar transverse cracks. This highlights the benefits and drawbacks of the supporting yarn during out-of-plane loading. © The Author(s) 2019.
538 a6603579157 Gamstedt E.K. p140 False Journal 98 The effects of voids in quasi-static indentation of resin-infused reinforced polymers The focus of this study is the influence of voids on the damage behaviour in quasi-static loading of resin-infused carbon fibre-reinforced polymers. Experimental results are presented for quasi-static loading in combination with high-resolution tomographic imaging and statistical analysis (homology of pores or voids and induced cracks). Three distinct mechanisms were observed to control delamination growth in the presence of sharp and blunt voids. Delamination cracks interact with the supporting yarns, especially in combination with air pockets trapped in the resin in the form of long, sharp voids. This resulted in crack growth that coalesces with delamination cracks from neighbouring yarn-voids during increased out-of-plane load–displacement, with almost no presence of intralaminar transverse cracks. This highlights the benefits and drawbacks of the supporting yarn during out-of-plane loading. © The Author(s) 2019.
539 a28167695400 Mavrogordato M.N. p140 False Journal 98 The effects of voids in quasi-static indentation of resin-infused reinforced polymers The focus of this study is the influence of voids on the damage behaviour in quasi-static loading of resin-infused carbon fibre-reinforced polymers. Experimental results are presented for quasi-static loading in combination with high-resolution tomographic imaging and statistical analysis (homology of pores or voids and induced cracks). Three distinct mechanisms were observed to control delamination growth in the presence of sharp and blunt voids. Delamination cracks interact with the supporting yarns, especially in combination with air pockets trapped in the resin in the form of long, sharp voids. This resulted in crack growth that coalesces with delamination cracks from neighbouring yarn-voids during increased out-of-plane load–displacement, with almost no presence of intralaminar transverse cracks. This highlights the benefits and drawbacks of the supporting yarn during out-of-plane loading. © The Author(s) 2019.
540 a57212950333 Spearing S.M. p140 False Journal 98 The effects of voids in quasi-static indentation of resin-infused reinforced polymers The focus of this study is the influence of voids on the damage behaviour in quasi-static loading of resin-infused carbon fibre-reinforced polymers. Experimental results are presented for quasi-static loading in combination with high-resolution tomographic imaging and statistical analysis (homology of pores or voids and induced cracks). Three distinct mechanisms were observed to control delamination growth in the presence of sharp and blunt voids. Delamination cracks interact with the supporting yarns, especially in combination with air pockets trapped in the resin in the form of long, sharp voids. This resulted in crack growth that coalesces with delamination cracks from neighbouring yarn-voids during increased out-of-plane load–displacement, with almost no presence of intralaminar transverse cracks. This highlights the benefits and drawbacks of the supporting yarn during out-of-plane loading. © The Author(s) 2019.
541 a55945437600 Taus M. p141 True Journal 99 Isogeometric boundary element methods and patch tests for linear elastic problems: Formulation, numerical integration, and applications An Isogeometric Boundary Element Method for solving three-dimensional boundary-value problems of classical linear elasticity theory is proposed. The method is developed as a generalization of the author's earlier work on Laplace's equation to Navier's equations. As a result the proposed method features (i) proper basis functions for approximating Dirichlet and Neumann data, (ii) high-order collocation schemes for weakly singular, singular, and hyper-singular integral operators, (iii) state-of-the-art numerical integration schemes capable of handling geometries with disparate dimensions, (iv) well-conditioned linear algebraic systems, with the condition number independent of the mesh size. Boundary Element Patch Tests, as extensions of concepts widely used for finite element methods, are also introduced. It is shown how these tests can be used to assess the veracity of boundary element formulations and numerical integration schemes, implementations, and geometric precision of Computer Aided Design models. The method is applied to two challenging case studies, representative of industrial applications. © 2019 Elsevier B.V.
542 a7004277402 Rodin G.J. p141 False Journal 99 Isogeometric boundary element methods and patch tests for linear elastic problems: Formulation, numerical integration, and applications An Isogeometric Boundary Element Method for solving three-dimensional boundary-value problems of classical linear elasticity theory is proposed. The method is developed as a generalization of the author's earlier work on Laplace's equation to Navier's equations. As a result the proposed method features (i) proper basis functions for approximating Dirichlet and Neumann data, (ii) high-order collocation schemes for weakly singular, singular, and hyper-singular integral operators, (iii) state-of-the-art numerical integration schemes capable of handling geometries with disparate dimensions, (iv) well-conditioned linear algebraic systems, with the condition number independent of the mesh size. Boundary Element Patch Tests, as extensions of concepts widely used for finite element methods, are also introduced. It is shown how these tests can be used to assess the veracity of boundary element formulations and numerical integration schemes, implementations, and geometric precision of Computer Aided Design models. The method is applied to two challenging case studies, representative of industrial applications. © 2019 Elsevier B.V.
543 a55911870000 Hughes T.J.R. p141 False Journal 99 Isogeometric boundary element methods and patch tests for linear elastic problems: Formulation, numerical integration, and applications An Isogeometric Boundary Element Method for solving three-dimensional boundary-value problems of classical linear elasticity theory is proposed. The method is developed as a generalization of the author's earlier work on Laplace's equation to Navier's equations. As a result the proposed method features (i) proper basis functions for approximating Dirichlet and Neumann data, (ii) high-order collocation schemes for weakly singular, singular, and hyper-singular integral operators, (iii) state-of-the-art numerical integration schemes capable of handling geometries with disparate dimensions, (iv) well-conditioned linear algebraic systems, with the condition number independent of the mesh size. Boundary Element Patch Tests, as extensions of concepts widely used for finite element methods, are also introduced. It is shown how these tests can be used to assess the veracity of boundary element formulations and numerical integration schemes, implementations, and geometric precision of Computer Aided Design models. The method is applied to two challenging case studies, representative of industrial applications. © 2019 Elsevier B.V.
543 a55911870000 Hughes T.J.R. p745 False Journal 360 Hierarchically refined and coarsened splines for moving interface problems, with particular application to phase-field models of prostate tumor growth Moving interface problems are ubiquitous in science and engineering. To develop an accurate and efficient methodology for this class of problems, we present algorithms for local h-adaptivity of hierarchical B-splines to be utilized in isogeometric analysis. We extend Bézier projection, an efficient quadrature-free local projection technique, to the hierarchical setting. In this case, extraction operators may not be invertible. To address this issue we develop a multi-level reconstruction operator which maintains the locality properties of the projection. We also introduce a balance parameter to control the overlap of hierarchical functions leading to improved numerical conditioning. We apply our algorithms to the simulation of localized prostate cancer growth. We model this disease using the phase-field method and a set of diffusion–reaction equations to account for the dynamics of nutrients and a key biomarker termed Prostate Specific Antigen. Our results include examples on simple 2D and 3D domains and a more compelling tissue-scale, patient-specific simulation, which is run over a prostate anatomy extracted from medical images. Our methods for local h-adaptivity efficiently capture the evolving interface between the tumor and the neighboring healthy tissue with remarkable accuracy in all cases. © 2017 Elsevier B.V.
544 a57215811083 Searle H. p142 True Conference 24 Irregular quadrature amplitude modulation for adaptive physical-layer security We propose adding an irregular quadrature amplitude modulation (QAM) constellation to a wireless transmission scheme in order to obtain greater control over the signal-to-noise ratio (SNR) required to successfully decode the signal. By altering the separation between adjacent symbols, the minimum required SNR is raised without degradation in the performance of the scheme. This allows the system to adapt to preferable channel conditions for the authorized user, making it harder for eavesdroppers to intercept and decode the transmission, thus making the communication safer. In addition, we show that by overlaying a coset code onto the QAM constellation, a new, stronger security gap metric can be further improved. Results show the effectiveness of this strategy with an interleaved coding for secrecy with a hidden key (ICSHK) scheme. © 2019 IEEE.
545 a17434035200 Gomes M.A.C. p142 False Conference 24 Irregular quadrature amplitude modulation for adaptive physical-layer security We propose adding an irregular quadrature amplitude modulation (QAM) constellation to a wireless transmission scheme in order to obtain greater control over the signal-to-noise ratio (SNR) required to successfully decode the signal. By altering the separation between adjacent symbols, the minimum required SNR is raised without degradation in the performance of the scheme. This allows the system to adapt to preferable channel conditions for the authorized user, making it harder for eavesdroppers to intercept and decode the transmission, thus making the communication safer. In addition, we show that by overlaying a coset code onto the QAM constellation, a new, stronger security gap metric can be further improved. Results show the effectiveness of this strategy with an interleaved coding for secrecy with a hidden key (ICSHK) scheme. © 2019 IEEE.
545 a17434035200 Gomes M.A.C. p186 False Journal 127 Generating a Binary Symmetric Channel for Wiretap Codes In this paper, we fill a void between information theoretic security and practical coding over the Gaussian wiretap channel using a three-stage encoder/decoder technique. Security is measured using Kullback-Leibler divergence and resolvability techniques along with a limited number of practical assumptions regarding the eavesdropper's decoder. The results specify a general coding recipe for obtaining both secure and reliable communications over the Gaussian wiretap channel, and one specific set of concatenated codes is presented as a test case for the sake of providing simulation-based evaluation of security and reliability over the network. It is shown that there exists a threshold in signal-to-noise ratio (SNR) over a Gaussian channel, such that receivers experiencing SNR below the threshold have no practical hope of receiving information about the message when the three-stage coding technique is applied. Results further indicate that the two innermost encoding stages successfully approximate a binary symmetric channel, allowing the outermost encoding stage (e.g., a wiretap code) to focus solely on secrecy coding over this approximated channel. © 2005-2012 IEEE.
545 a17434035200 Gomes M.A.C. p240 False Conference 58 Full-Duplex Jamming for Enhanced Hidden-Key Secrecy This paper presents a practical physical-layer security scheme based on coding methodologies combined with self-jamming to combat advantaged eavesdroppers, i.e., eavesdroppers that may possess an equal or even better channel than the legitimate receiver. We introduce a strengthened security gap notion, where reliability is assured by typical bit-error rate (BER) measurements, but secrecy is guaranteed by considering the entire distribution of messages upon reception, instead of average measures. Relying on this new security gap notion, we then propose a scheme that combines concatenated coding with self-jamming by the legitimate receiver for effective security and reliability even when eavesdroppers possess a channel with equal or better conditions than the legitimate receiver. © 2019 IEEE.
545 a17434035200 Gomes M.A.C. p241 False Conference 59 Adaptive Physical-Layer Security Through Punctured Coding for Secrecy We propose a coding methodology for physical layer security with adaptive characteristics, whereby adaptive we mean that the system must be tunable to different operational points/signal-to-noise ratio levels of both the legitimate receiver and the eavesdropper. Based on interleaving and scrambling as techniques that shuffle the original message before transmission, we consider puncturing over an interleaving/scrambling key and/or over the message as a mechanism to provide the required adaptability to channel conditions. The proposed techniques have shown suitable adaptability to different channel quality levels of the legitimate receiver and eavesdropper, while still guaranteeing the desired reliability for the legitimate receiver and secrecy against the eavesdropper. © 2019 IEEE.
545 a17434035200 Gomes M.A.C. p253 False Conference 60 Polar coding for physical-layer security without knowledge of the eavesdropper's channel We propose an adaptive secrecy scheme using polar codes with random frozen bits for a general wiretap channel, in which to protect the data from a potential eavesdropper, part or all of the frozen bits are randomly generated per message. To assess the secrecy level of the proposed scheme, three types of decoding strategies are evaluated: a matching decoder which knows the positions of all inserted bits inside the blocklength and tries to estimate them using the same decoding techniques, a blind decoder which treats all the frozen bits as the same value, and a random decoder which considers those dynamic bits as random at the receiver. Results are presented in terms of the system security gap, assuming an adaptive decoding strategy. It is shown that the system achieves combined secrecy and reliability. The proposed scheme does not assume knowledge of the eavesdropper's channel when defining the indices of information and frozen bits. © 2019 IEEE.
545 a17434035200 Gomes M.A.C. p470 False Conference 172 Nested QPSK Encoding for Information Theoretic Security This paper proposes a method to provide secrecy for digital communications with arbitrarily large quadrature amplitude modulation (QAM) constellations for transmission over a Gaussian fading wiretap channel. This is accomplished by breaking the constellation down into nested quadrature phase-shift keying (QPSK) symbols and randomizing the assignment between message bits and modulated symbols using channel state information (CSI). If enough random bits can be generated from CSI it becomes possible to uniquely map an arbitrary message to any symbol in the large QAM constellation. The proposed method can thereby provide perfect secrecy while maintaining high reliability by exclusively assigning minimum-distance-mapped constellations through the randomization for use by the legitimate decoder. © 2018 IEEE.
546 a24726409500 Vilela J.P. p142 False Conference 24 Irregular quadrature amplitude modulation for adaptive physical-layer security We propose adding an irregular quadrature amplitude modulation (QAM) constellation to a wireless transmission scheme in order to obtain greater control over the signal-to-noise ratio (SNR) required to successfully decode the signal. By altering the separation between adjacent symbols, the minimum required SNR is raised without degradation in the performance of the scheme. This allows the system to adapt to preferable channel conditions for the authorized user, making it harder for eavesdroppers to intercept and decode the transmission, thus making the communication safer. In addition, we show that by overlaying a coset code onto the QAM constellation, a new, stronger security gap metric can be further improved. Results show the effectiveness of this strategy with an interleaved coding for secrecy with a hidden key (ICSHK) scheme. © 2019 IEEE.
546 a24726409500 Vilela J.P. p186 False Journal 127 Generating a Binary Symmetric Channel for Wiretap Codes In this paper, we fill a void between information theoretic security and practical coding over the Gaussian wiretap channel using a three-stage encoder/decoder technique. Security is measured using Kullback-Leibler divergence and resolvability techniques along with a limited number of practical assumptions regarding the eavesdropper's decoder. The results specify a general coding recipe for obtaining both secure and reliable communications over the Gaussian wiretap channel, and one specific set of concatenated codes is presented as a test case for the sake of providing simulation-based evaluation of security and reliability over the network. It is shown that there exists a threshold in signal-to-noise ratio (SNR) over a Gaussian channel, such that receivers experiencing SNR below the threshold have no practical hope of receiving information about the message when the three-stage coding technique is applied. Results further indicate that the two innermost encoding stages successfully approximate a binary symmetric channel, allowing the outermost encoding stage (e.g., a wiretap code) to focus solely on secrecy coding over this approximated channel. © 2005-2012 IEEE.
546 a24726409500 Vilela J.P. p240 False Conference 58 Full-Duplex Jamming for Enhanced Hidden-Key Secrecy This paper presents a practical physical-layer security scheme based on coding methodologies combined with self-jamming to combat advantaged eavesdroppers, i.e., eavesdroppers that may possess an equal or even better channel than the legitimate receiver. We introduce a strengthened security gap notion, where reliability is assured by typical bit-error rate (BER) measurements, but secrecy is guaranteed by considering the entire distribution of messages upon reception, instead of average measures. Relying on this new security gap notion, we then propose a scheme that combines concatenated coding with self-jamming by the legitimate receiver for effective security and reliability even when eavesdroppers possess a channel with equal or better conditions than the legitimate receiver. © 2019 IEEE.
546 a24726409500 Vilela J.P. p241 False Conference 59 Adaptive Physical-Layer Security Through Punctured Coding for Secrecy We propose a coding methodology for physical layer security with adaptive characteristics, whereby adaptive we mean that the system must be tunable to different operational points/signal-to-noise ratio levels of both the legitimate receiver and the eavesdropper. Based on interleaving and scrambling as techniques that shuffle the original message before transmission, we consider puncturing over an interleaving/scrambling key and/or over the message as a mechanism to provide the required adaptability to channel conditions. The proposed techniques have shown suitable adaptability to different channel quality levels of the legitimate receiver and eavesdropper, while still guaranteeing the desired reliability for the legitimate receiver and secrecy against the eavesdropper. © 2019 IEEE.
546 a24726409500 Vilela J.P. p253 False Conference 60 Polar coding for physical-layer security without knowledge of the eavesdropper's channel We propose an adaptive secrecy scheme using polar codes with random frozen bits for a general wiretap channel, in which to protect the data from a potential eavesdropper, part or all of the frozen bits are randomly generated per message. To assess the secrecy level of the proposed scheme, three types of decoding strategies are evaluated: a matching decoder which knows the positions of all inserted bits inside the blocklength and tries to estimate them using the same decoding techniques, a blind decoder which treats all the frozen bits as the same value, and a random decoder which considers those dynamic bits as random at the receiver. Results are presented in terms of the system security gap, assuming an adaptive decoding strategy. It is shown that the system achieves combined secrecy and reliability. The proposed scheme does not assume knowledge of the eavesdropper's channel when defining the indices of information and frozen bits. © 2019 IEEE.
546 a24726409500 Vilela J.P. p470 False Conference 172 Nested QPSK Encoding for Information Theoretic Security This paper proposes a method to provide secrecy for digital communications with arbitrarily large quadrature amplitude modulation (QAM) constellations for transmission over a Gaussian fading wiretap channel. This is accomplished by breaking the constellation down into nested quadrature phase-shift keying (QPSK) symbols and randomizing the assignment between message bits and modulated symbols using channel state information (CSI). If enough random bits can be generated from CSI it becomes possible to uniquely map an arbitrary message to any symbol in the large QAM constellation. The proposed method can thereby provide perfect secrecy while maintaining high reliability by exclusively assigning minimum-distance-mapped constellations through the randomization for use by the legitimate decoder. © 2018 IEEE.
547 a57191862517 Nyshadham C. p143 True Journal 100 Machine-learned multi-system surrogate models for materials prediction Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys (AgCu, AlFe, AlMg, AlNi, AlTi, CoNi, CuFe, CuNi, FeV, and NbNi) with 10 different species and all possible fcc, bcc, and hcp structures up to eight atoms in the unit cell, 15,950 structures in total. We find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys is <1 meV/atom. Several state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of <2.5% for all systems. © 2019, The Author(s).
547 a57191862517 Nyshadham C. p278 False Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
548 a23091904000 Rupp M. p143 False Journal 100 Machine-learned multi-system surrogate models for materials prediction Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys (AgCu, AlFe, AlMg, AlNi, AlTi, CoNi, CuFe, CuNi, FeV, and NbNi) with 10 different species and all possible fcc, bcc, and hcp structures up to eight atoms in the unit cell, 15,950 structures in total. We find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys is <1 meV/atom. Several state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of <2.5% for all systems. © 2019, The Author(s).
549 a57208341600 Bekker B. p143 False Journal 100 Machine-learned multi-system surrogate models for materials prediction Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys (AgCu, AlFe, AlMg, AlNi, AlTi, CoNi, CuFe, CuNi, FeV, and NbNi) with 10 different species and all possible fcc, bcc, and hcp structures up to eight atoms in the unit cell, 15,950 structures in total. We find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys is <1 meV/atom. Several state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of <2.5% for all systems. © 2019, The Author(s).
550 a53878508900 Shapeev A.V. p143 False Journal 100 Machine-learned multi-system surrogate models for materials prediction Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys (AgCu, AlFe, AlMg, AlNi, AlTi, CoNi, CuFe, CuNi, FeV, and NbNi) with 10 different species and all possible fcc, bcc, and hcp structures up to eight atoms in the unit cell, 15,950 structures in total. We find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys is <1 meV/atom. Several state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of <2.5% for all systems. © 2019, The Author(s).
550 a53878508900 Shapeev A.V. p366 False Journal 204 Accelerating high-throughput searches for new alloys with active learning of interatomic potentials We propose an approach to materials prediction that uses a machine-learning interatomic potential to approximate quantum-mechanical energies and an active learning algorithm for the automatic selection of an optimal training dataset. Our approach significantly reduces the amount of density functional theory (DFT) calculations needed, resorting to DFT only to produce the training data, while structural optimization is performed using the interatomic potentials. Our approach is not limited to one (or a small number of) lattice types (as is the case for cluster expansion, for example) and can predict structures with lattice types not present in the training dataset. We demonstrate the effectiveness of our algorithm by predicting the convex hull for the following three systems: Cu-Pd, Co-Nb-V, and Al-Ni-Ti. Our method is three to four orders of magnitude faster than conventional high-throughput DFT calculations and explores a wider range of materials space. In all three systems, we found unreported stable structures compared to the AFLOW database. Because our method is much cheaper and explores much more of materials space than high-throughput methods or cluster expansion, and because our interatomic potentials have a systematically improvable accuracy compared to empirical potentials such as embedded atom model, it will have a significant impact in the discovery of new alloy phases, particularly those with three or more components. © 2018
551 a56363360200 Mueller T. p143 False Journal 100 Machine-learned multi-system surrogate models for materials prediction Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys (AgCu, AlFe, AlMg, AlNi, AlTi, CoNi, CuFe, CuNi, FeV, and NbNi) with 10 different species and all possible fcc, bcc, and hcp structures up to eight atoms in the unit cell, 15,950 structures in total. We find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys is <1 meV/atom. Several state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of <2.5% for all systems. © 2019, The Author(s).
552 a56148594700 Rosenbrock C.W. p143 False Journal 100 Machine-learned multi-system surrogate models for materials prediction Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys (AgCu, AlFe, AlMg, AlNi, AlTi, CoNi, CuFe, CuNi, FeV, and NbNi) with 10 different species and all possible fcc, bcc, and hcp structures up to eight atoms in the unit cell, 15,950 structures in total. We find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys is <1 meV/atom. Several state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of <2.5% for all systems. © 2019, The Author(s).
552 a56148594700 Rosenbrock C.W. p668 True Journal 322 Discovering the building blocks of atomic systems using machine learning: Application to grain boundaries Machine learning has proven to be a valuable tool to approximate functions in high-dimensional spaces. Unfortunately, analysis of these models to extract the relevant physics is never as easy as applying machine learning to a large data set in the first place. Here we present a description of atomic systems that generates machine learning representations with a direct path to physical interpretation. As an example, we demonstrate its usefulness as a universal descriptor of grain boundary systems. Grain boundaries in crystalline materials are a quintessential example of a complex, high-dimensional system with broad impact on many physical properties including strength, ductility, corrosion resistance, crack resistance, and conductivity. In addition to modeling such properties, the method also provides insight into the physical "building blocks" that influence them. This opens the way to discover the underlying physics behind behaviors by understanding which building blocks map to particular properties. Once the structures are understood, they can then be optimized for desirable behaviors. © 2017 The Author(s).
553 a6602577617 Csányi G. p143 False Journal 100 Machine-learned multi-system surrogate models for materials prediction Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys (AgCu, AlFe, AlMg, AlNi, AlTi, CoNi, CuFe, CuNi, FeV, and NbNi) with 10 different species and all possible fcc, bcc, and hcp structures up to eight atoms in the unit cell, 15,950 structures in total. We find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys is <1 meV/atom. Several state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of <2.5% for all systems. © 2019, The Author(s).
553 a6602577617 Csányi G. p668 False Journal 322 Discovering the building blocks of atomic systems using machine learning: Application to grain boundaries Machine learning has proven to be a valuable tool to approximate functions in high-dimensional spaces. Unfortunately, analysis of these models to extract the relevant physics is never as easy as applying machine learning to a large data set in the first place. Here we present a description of atomic systems that generates machine learning representations with a direct path to physical interpretation. As an example, we demonstrate its usefulness as a universal descriptor of grain boundary systems. Grain boundaries in crystalline materials are a quintessential example of a complex, high-dimensional system with broad impact on many physical properties including strength, ductility, corrosion resistance, crack resistance, and conductivity. In addition to modeling such properties, the method also provides insight into the physical "building blocks" that influence them. This opens the way to discover the underlying physics behind behaviors by understanding which building blocks map to particular properties. Once the structures are understood, they can then be optimized for desirable behaviors. © 2017 The Author(s).
554 a36176552000 Wingate D.W. p143 False Journal 100 Machine-learned multi-system surrogate models for materials prediction Surrogate machine-learning models are transforming computational materials science by predicting properties of materials with the accuracy of ab initio methods at a fraction of the computational cost. We demonstrate surrogate models that simultaneously interpolate energies of different materials on a dataset of 10 binary alloys (AgCu, AlFe, AlMg, AlNi, AlTi, CoNi, CuFe, CuNi, FeV, and NbNi) with 10 different species and all possible fcc, bcc, and hcp structures up to eight atoms in the unit cell, 15,950 structures in total. We find that the deviation of prediction errors when increasing the number of simultaneously modeled alloys is <1 meV/atom. Several state-of-the-art materials representations and learning algorithms were found to qualitatively agree on the prediction errors of formation enthalpy with relative errors of <2.5% for all systems. © 2019, The Author(s).
554 a36176552000 Wingate D.W. p662 False Conference 289 Deep visual gravity vector detection for unmanned aircraft attitude estimation This paper demonstrates a feasible method for using a deep neural network as a sensor to estimate the attitude of a flying vehicle using only flight video. A dataset of still images and associated gravity vectors was collected and used to perform supervised learning. The network builds on a previously trained network and was trained to be able to approximate the attitude of the camera with an average error of about 8 degrees. Flight test video was recorded and processed with a relatively simple visual odometry method. The aircraft attitude is then estimated with the visual odometry as the state propagation and network providing the attitude measurement in an extended Kalman filter. Results show that the proposed method of having the neural network provide a gravity vector attitude measurement from the flight imagery reduces the standard deviation of the attitude error by approximately 12 times compared to a baseline approach. © 2017 IEEE.
555 a57189244450 Kamminga J.W. p144 True Conference 25 Synchronization between sensors and cameras in movement data labeling frameworks Obtaining labeled data for activity recognition tasks is a tremendously time consuming, tedious, and labor-intensive task. Often, ground-truth video of the activity is recorded along with sensor-data recorded during the activity. The data must be synchronized with the recorded video to be useful. In this paper, we present and compare two labeling frameworks that each has a different approach to synchronization. Approach A uses time-stamped visual indicators positioned on the data loggers. The approach results in accurate synchronization between video and data but adds more overhead and is not practical when using multiple sensors, subjects, and cameras simultaneously. Also, synchronization needs to be redone for each recording session. Approach B uses Real-Time Clocks (RTCs) on the devices for synchronization, which is less accurate but has several advantages: multiple subjects can be recorded on various cameras, it becomes easier to collect more data, and synchronization only needs to be done once across multiple recording sessions. Therefore, it is easier to collect more data which increases the probability of capturing an unusual activity. The best way forward is likely a combination of both approaches. © 2019 Association for Computing Machinery.
556 a57211332837 Jones M. p144 False Conference 25 Synchronization between sensors and cameras in movement data labeling frameworks Obtaining labeled data for activity recognition tasks is a tremendously time consuming, tedious, and labor-intensive task. Often, ground-truth video of the activity is recorded along with sensor-data recorded during the activity. The data must be synchronized with the recorded video to be useful. In this paper, we present and compare two labeling frameworks that each has a different approach to synchronization. Approach A uses time-stamped visual indicators positioned on the data loggers. The approach results in accurate synchronization between video and data but adds more overhead and is not practical when using multiple sensors, subjects, and cameras simultaneously. Also, synchronization needs to be redone for each recording session. Approach B uses Real-Time Clocks (RTCs) on the devices for synchronization, which is less accurate but has several advantages: multiple subjects can be recorded on various cameras, it becomes easier to collect more data, and synchronization only needs to be done once across multiple recording sessions. Therefore, it is easier to collect more data which increases the probability of capturing an unusual activity. The best way forward is likely a combination of both approaches. © 2019 Association for Computing Machinery.
557 a8231832400 Seppi K. p144 False Conference 25 Synchronization between sensors and cameras in movement data labeling frameworks Obtaining labeled data for activity recognition tasks is a tremendously time consuming, tedious, and labor-intensive task. Often, ground-truth video of the activity is recorded along with sensor-data recorded during the activity. The data must be synchronized with the recorded video to be useful. In this paper, we present and compare two labeling frameworks that each has a different approach to synchronization. Approach A uses time-stamped visual indicators positioned on the data loggers. The approach results in accurate synchronization between video and data but adds more overhead and is not practical when using multiple sensors, subjects, and cameras simultaneously. Also, synchronization needs to be redone for each recording session. Approach B uses Real-Time Clocks (RTCs) on the devices for synchronization, which is less accurate but has several advantages: multiple subjects can be recorded on various cameras, it becomes easier to collect more data, and synchronization only needs to be done once across multiple recording sessions. Therefore, it is easier to collect more data which increases the probability of capturing an unusual activity. The best way forward is likely a combination of both approaches. © 2019 Association for Computing Machinery.
557 a8231832400 Seppi K. p702 False Journal 344 The human touch: How non-expert users perceive, interpret, and fix topic models Topic modeling is a common tool for understanding large bodies of text, but is typically provided as a “take it or leave it” proposition. Incorporating human knowledge in unsupervised learning is a promising approach to create high-quality topic models. Existing interactive systems and modeling algorithms support a wide range of refinement operations to express feedback. However, these systems’ interactions are primarily driven by algorithmic convenience, ignoring users who may lack expertise in topic modeling. To better understand how non-expert users understand, assess, and refine topics, we conducted two user studies—an in-person interview study and an online crowdsourced study. These studies demonstrate a disconnect between what non-expert users want and the complex, low-level operations that current interactive systems support. In particular, our findings include: (1) analysis of how non-expert users perceive topic models; (2) characterization of primary refinement operations expected by non-expert users and ordered by relative preference; (3) further evidence of the benefits of supporting users in directly refining a topic model; (4) design implications for future human-in-the-loop topic modeling interfaces. © 2017
558 a57192300416 Meratnia N. p144 False Conference 25 Synchronization between sensors and cameras in movement data labeling frameworks Obtaining labeled data for activity recognition tasks is a tremendously time consuming, tedious, and labor-intensive task. Often, ground-truth video of the activity is recorded along with sensor-data recorded during the activity. The data must be synchronized with the recorded video to be useful. In this paper, we present and compare two labeling frameworks that each has a different approach to synchronization. Approach A uses time-stamped visual indicators positioned on the data loggers. The approach results in accurate synchronization between video and data but adds more overhead and is not practical when using multiple sensors, subjects, and cameras simultaneously. Also, synchronization needs to be redone for each recording session. Approach B uses Real-Time Clocks (RTCs) on the devices for synchronization, which is less accurate but has several advantages: multiple subjects can be recorded on various cameras, it becomes easier to collect more data, and synchronization only needs to be done once across multiple recording sessions. Therefore, it is easier to collect more data which increases the probability of capturing an unusual activity. The best way forward is likely a combination of both approaches. © 2019 Association for Computing Machinery.
559 a6701454416 Havinga P.J.M. p144 False Conference 25 Synchronization between sensors and cameras in movement data labeling frameworks Obtaining labeled data for activity recognition tasks is a tremendously time consuming, tedious, and labor-intensive task. Often, ground-truth video of the activity is recorded along with sensor-data recorded during the activity. The data must be synchronized with the recorded video to be useful. In this paper, we present and compare two labeling frameworks that each has a different approach to synchronization. Approach A uses time-stamped visual indicators positioned on the data loggers. The approach results in accurate synchronization between video and data but adds more overhead and is not practical when using multiple sensors, subjects, and cameras simultaneously. Also, synchronization needs to be redone for each recording session. Approach B uses Real-Time Clocks (RTCs) on the devices for synchronization, which is less accurate but has several advantages: multiple subjects can be recorded on various cameras, it becomes easier to collect more data, and synchronization only needs to be done once across multiple recording sessions. Therefore, it is easier to collect more data which increases the probability of capturing an unusual activity. The best way forward is likely a combination of both approaches. © 2019 Association for Computing Machinery.
560 a57202064143 Johnston J.D. p146 True Journal 102 Associations between evaporative cooling and dust-mite allergens, endotoxins, and β-(1 → 3)-d-glucans in house dust: A study of low-income homes Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low-income homes. We conducted a cross-sectional study of metropolitan, low-income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust-mite allergens Der p1 and Der f1, endotoxins, and β-(1 → 3)-d-glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05-4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P '.01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P =.03). β-(1 → 3)-d-glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P '.01). Our study suggests that low-income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air-conditioned homes in dry climates, warranting studies on health implications and other exposed populations. © 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
560 a57202064143 Johnston J.D. p698 True Journal 341 Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
561 a57204597171 Cowger A.E. p146 False Journal 102 Associations between evaporative cooling and dust-mite allergens, endotoxins, and β-(1 → 3)-d-glucans in house dust: A study of low-income homes Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low-income homes. We conducted a cross-sectional study of metropolitan, low-income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust-mite allergens Der p1 and Der f1, endotoxins, and β-(1 → 3)-d-glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05-4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P '.01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P =.03). β-(1 → 3)-d-glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P '.01). Our study suggests that low-income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air-conditioned homes in dry climates, warranting studies on health implications and other exposed populations. © 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
562 a57192662939 Graul R.J. p146 False Journal 102 Associations between evaporative cooling and dust-mite allergens, endotoxins, and β-(1 → 3)-d-glucans in house dust: A study of low-income homes Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low-income homes. We conducted a cross-sectional study of metropolitan, low-income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust-mite allergens Der p1 and Der f1, endotoxins, and β-(1 → 3)-d-glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05-4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P '.01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P =.03). β-(1 → 3)-d-glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P '.01). Our study suggests that low-income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air-conditioned homes in dry climates, warranting studies on health implications and other exposed populations. © 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
562 a57192662939 Graul R.J. p698 False Journal 341 Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
563 a57210982957 Nash R. p146 False Journal 102 Associations between evaporative cooling and dust-mite allergens, endotoxins, and β-(1 → 3)-d-glucans in house dust: A study of low-income homes Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low-income homes. We conducted a cross-sectional study of metropolitan, low-income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust-mite allergens Der p1 and Der f1, endotoxins, and β-(1 → 3)-d-glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05-4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P '.01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P =.03). β-(1 → 3)-d-glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P '.01). Our study suggests that low-income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air-conditioned homes in dry climates, warranting studies on health implications and other exposed populations. © 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
564 a57204035623 Tueller J.A. p146 False Journal 102 Associations between evaporative cooling and dust-mite allergens, endotoxins, and β-(1 → 3)-d-glucans in house dust: A study of low-income homes Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low-income homes. We conducted a cross-sectional study of metropolitan, low-income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust-mite allergens Der p1 and Der f1, endotoxins, and β-(1 → 3)-d-glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05-4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P '.01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P =.03). β-(1 → 3)-d-glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P '.01). Our study suggests that low-income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air-conditioned homes in dry climates, warranting studies on health implications and other exposed populations. © 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
565 a57196952707 Hendrickson N.R. p146 False Journal 102 Associations between evaporative cooling and dust-mite allergens, endotoxins, and β-(1 → 3)-d-glucans in house dust: A study of low-income homes Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low-income homes. We conducted a cross-sectional study of metropolitan, low-income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust-mite allergens Der p1 and Der f1, endotoxins, and β-(1 → 3)-d-glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05-4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P '.01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P =.03). β-(1 → 3)-d-glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P '.01). Our study suggests that low-income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air-conditioned homes in dry climates, warranting studies on health implications and other exposed populations. © 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
566 a57196950804 Robinson D.R. p146 False Journal 102 Associations between evaporative cooling and dust-mite allergens, endotoxins, and β-(1 → 3)-d-glucans in house dust: A study of low-income homes Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low-income homes. We conducted a cross-sectional study of metropolitan, low-income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust-mite allergens Der p1 and Der f1, endotoxins, and β-(1 → 3)-d-glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05-4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P '.01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P =.03). β-(1 → 3)-d-glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P '.01). Our study suggests that low-income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air-conditioned homes in dry climates, warranting studies on health implications and other exposed populations. © 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
567 a57213874106 Beard J.D. p146 False Journal 102 Associations between evaporative cooling and dust-mite allergens, endotoxins, and β-(1 → 3)-d-glucans in house dust: A study of low-income homes Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low-income homes. We conducted a cross-sectional study of metropolitan, low-income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust-mite allergens Der p1 and Der f1, endotoxins, and β-(1 → 3)-d-glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05-4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P '.01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P =.03). β-(1 → 3)-d-glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P '.01). Our study suggests that low-income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air-conditioned homes in dry climates, warranting studies on health implications and other exposed populations. © 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
568 a7402658393 Weber K.S. p146 False Journal 102 Associations between evaporative cooling and dust-mite allergens, endotoxins, and β-(1 → 3)-d-glucans in house dust: A study of low-income homes Recent work suggests that evaporative coolers increase the level and diversity of bioaerosols, but this association remains understudied in low-income homes. We conducted a cross-sectional study of metropolitan, low-income homes in Utah with evaporative coolers (n = 20) and central air conditioners (n = 28). Dust samples (N = 147) were collected from four locations in each home and analyzed for dust-mite allergens Der p1 and Der f1, endotoxins, and β-(1 → 3)-d-glucans. In all sample locations combined, Der p1 or Der f1 was significantly higher in evaporative cooler versus central air conditioning homes (OR = 2.29, 95% CI = 1.05-4.98). Endotoxin concentration was significantly higher in evaporative cooler versus central air conditioning homes in furniture (geometric mean (GM) = 8.05 vs 2.85 EU/mg, P '.01) and all samples combined (GM = 3.60 vs 1.29 EU/mg, P =.03). β-(1 → 3)-d-glucan concentration and surface loads were significantly higher in evaporative cooler versus central air conditioning homes in all four sample locations and all samples combined (P '.01). Our study suggests that low-income, evaporative cooled homes have higher levels of immunologically important bioaerosols than central air-conditioned homes in dry climates, warranting studies on health implications and other exposed populations. © 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
568 a7402658393 Weber K.S. p698 False Journal 341 Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
569 a56680952700 Josephson C. p148 True Conference 26 Space-Time Coded ARTM CPM for Aeronautical Telemetry This paper shows that burst-based orthogonal spacetime block-coded ARTM CPM is capable of solving the two-antenna problem in aeronautical telemetry, but detection requires a prohibitively complex trellis detector. In single-input, single-output (SISO) applications, pulse truncation and state-space partitioning reduce the computational complexity of the trellis detector with only modest bit error rate (BER) performance penalties. In this paper it is shown that layering pulse truncation and state-space partition complexity-reducing techniques with a burst-based orthogonal space-time block-code does not introduce additional BER performance losses relative to the SISO case. © 2019 IEEE.
569 a56680952700 Josephson C. p435 False Conference 156 On peak-to-average power ratio optimization for coded APSK The symmetric information rate is used to define the relationship between the APSK constellation parameters, the code rate, and the average and peak Eb=N0. Minimizing the average Eb=N0 reproduces the DVB-S2 constellation parameters for 16- And 32-APSK. Minimizing the peak Eb=N0 produces DVB-S2 constellation parameters for 16- And 32-APSK that minimize the peak-to-average power ratio. The peak-to-average power ratio gains are less than 1 dB, but when used on coded systems with very steep decoded bit error probability vs. Eb=N0 curves, the gains can be significant. © 2018 IEEE.
569 a56680952700 Josephson C. p808 True Conference 343 On the design of a square-root nyquist pulse shaping filter for aeronautical telemetry Bandwidth efficient linear modulations require a pulse shape with finite support in the time domain while simultaneously achieving good spectral containment in the frequency domain. The squareroot Nyquist pulse achieves zero intersymbol interference (ISI) at its matched-filter output but does so with infinite support in the time domain. This paper investigates three different methods for generating an FIR approximation of a square-root Nyquist pulse.
569 a56680952700 Josephson C. p847 False Conference 371 Optimizing coded 16-APSK for aeronautical mobile telemetry This paper investigates the application of 16-APSK modulation to aeronautical mobile telemetry. The peak-to-average power ratio vs. code rate tradeoffis mapped to an optimization problem involving spectral efficiency and the constellation parameters. The optimization results produce a theoretically optimum solution that is 3.95 times more spectrally efficient as uncoded SOQPSKTG. When implementation losses and the available IRIG 106 LDPC code rates are factored in, the advantage drops to 3.20 times the spectral efficiency of SOQPSK-TG.
570 a7003498769 Perrins E. p148 False Conference 26 Space-Time Coded ARTM CPM for Aeronautical Telemetry This paper shows that burst-based orthogonal spacetime block-coded ARTM CPM is capable of solving the two-antenna problem in aeronautical telemetry, but detection requires a prohibitively complex trellis detector. In single-input, single-output (SISO) applications, pulse truncation and state-space partitioning reduce the computational complexity of the trellis detector with only modest bit error rate (BER) performance penalties. In this paper it is shown that layering pulse truncation and state-space partition complexity-reducing techniques with a burst-based orthogonal space-time block-code does not introduce additional BER performance losses relative to the SISO case. © 2019 IEEE.
570 a7003498769 Perrins E. p618 True Conference 255 Unification of signal models for soqpsk This paper begins by summarizing a recent advancement in the way that shaped offset quadrature phase shift keying (SOQPSK) waveforms can be viewed. This new viewpoint succeeds in eliminating the need for SOQPSK to be thought of as a “special” kind of correlated, ternary continuous phase modulation (CPM). Instead, SOQPSK can be viewed as an ordinary, binary CPM. We provide all of the details necessary to achieve a complete unification of SOQPSK models at the waveform level, at the bit sequence level, and in terms of waveform initialization. With this information, SOQPSK users can easily mix and match SOQPSK models at the transmitter and receiver in order to make use of the advantages of each model. © held by the author; distribution rights International Foundation for Telemetering.
570 a7003498769 Perrins E. p847 False Conference 371 Optimizing coded 16-APSK for aeronautical mobile telemetry This paper investigates the application of 16-APSK modulation to aeronautical mobile telemetry. The peak-to-average power ratio vs. code rate tradeoffis mapped to an optimization problem involving spectral efficiency and the constellation parameters. The optimization results produce a theoretically optimum solution that is 3.95 times more spectrally efficient as uncoded SOQPSKTG. When implementation losses and the available IRIG 106 LDPC code rates are factored in, the advantage drops to 3.20 times the spectral efficiency of SOQPSK-TG.
570 a7003498769 Perrins E. p886 False Conference 398 A summary of data-aided equalizer experiments at edwards AFB This paper summarizes the analysis of bit error rate data captured during flight tests designed to compare data-aided equalizers with SOQPSK-TG to unequalized and currently available blind, adaptive equalizers with SOQPSK-TG. The number of bit errors, on a second-by-second basis, are analyzed. The results are different for each test point. Given the uncertain behavior of the preamble detector for the data-aided equalizer and the differing channel conditions between the data-aided equalizer channel and the conventional serial streaming telemetry channel, we are unable to draw any firm comparative conclusions.
571 a55588035200 Ruoti S. p150 True Journal 105 Johnny's Journey Toward Usable Secure Email Since the publication of "Why Johnny Can't Encrypt, "10 there has been interest in creating usable, secure email that is adoptable by the general public. In this article, we summarize research from the usable-security community on this topic, identify open problems, and call for more research on usable key management. © 2003-2012 IEEE.
571 a55588035200 Ruoti S. p247 True Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
571 a55588035200 Ruoti S. p348 True Conference 120 A comparative usability study of key management in secure email We conducted a user study that compares three secure email tools that share a common user interface and differ only by key management scheme: passwords, public key directory (PKD), and identity-based encryption (IBE). Our work is the first comparative (i.e., A/B) usability evaluation of three different key management schemes and utilizes a standard quantitative metric for cross-system comparisons. We also share qualitative feedback from participants that provides valuable insights into user attitudes regarding each key management approach and secure email generally. The study serves as a model for future secure email research with A/B studies, standard metrics, and the two-person study methodology. © 2018 by The USENIX Association All Rights Reserved.
571 a55588035200 Ruoti S. p351 True Conference 122 User attitudes toward the inspection of encrypted traffic This paper reports the results of a survey of 1,976 individuals regarding their opinions on TLS inspection, a controversial technique that can be used for both benevolent and malicious purposes. Responses indicate that participants hold nuanced opinions on security and privacy trade-offs, with most recognizing legitimate uses for the practice, but also concerned about threats from hackers or government surveillance. There is strong support for notification and consent when a system is intercepting their encrypted traffic, although this support varies depending on the situation. A significant concern about malicious uses of TLS inspection is identity theft, and many would react negatively and some would change their behavior if they discovered inspection occurring without their knowledge. We also find that a small but significant number of participants are jaded by the current state of affairs and have lost any expectation of privacy. © 2016 by The USENIX Association All Rights Reserved.
571 a55588035200 Ruoti S. p352 True Conference 123 Weighing Context and Trade-offs: How suburban adults selected their online security posture Understanding how people behave when faced with complex security situations is essential to designing usable security tools. To better understand users' perceptions of their digital lives and how they managed their online security posture, we conducted a series of 23 semi-structured interviews with mostly middle-aged parents from suburban Washington state. Using a grounded theory methodology, we analyzed the interview data and found that participants chose their security posture based on the immense value the Internet provides and their belief that no combination of technology could make them perfectly safe. Within this context, users have a four-stage process for determining which security measures to adopt: learning, evaluation of risks, estimation of impact, and weighing trade-offs to various coping strategies. Our results also revealed that a majority of participants understand the basic principles of symmetric encryption. We found that participants' misconceptions related to browser-based TLS indicators lead to insecure behavior, and it is the permanence of encrypted email that causes participants to doubt that it is secure. We conclude with a discussion of possible responses to this research and avenues for future research. © 2017 by The USENIX Association. All rights reserved.
571 a55588035200 Ruoti S. p471 False Conference 173 A Tale of Two Studies: The Best and Worst of YubiKey Usability Two-factor authentication (2FA) significantly improves the security of password-based authentication. Recently, there has been increased interest in Universal 2nd Factor (U2F) security keys-small hardware devices that require users to press a button on the security key to authenticate. To examine the usability of security keys in non-enterprise usage, we conducted two user studies of the YubiKey, a popular line of U2F security keys. The first study tasked 31 participants with configuring a Windows, Google, and Facebook account to authenticate using a YubiKey. This study revealed problems with setup instructions and workflow including users locking themselves out of their operating system or thinking they had successfully enabled 2FA when they had not. In contrast, the second study had 25 participants use a YubiKey in their daily lives over a period of four weeks, revealing that participants generally enjoyed the experience. Conducting both a laboratory and longitudinal study yielded insights into the usability of security keys that would not have been evident from either study in isolation. Based on our analysis, we recommend standardizing the setup process, enabling verification of success, allowing shared accounts, integrating with operating systems, and preventing lockouts. © 2018 IEEE.
571 a55588035200 Ruoti S. p679 True Conference 292 Layering Security at Global Control Points to Secure Unmodified Software Developing secure software is inherently difficult, and is further hampered by a rush to market, the lack of cybersecurity-trained architects and developers, and the difficulty of identifying flaws and deploying mitigations. To address these problems, we advocate for an alternative paradigm-layering security onto applications from global control points, such as the browser, operating system, or network. This approach adds security to existing applications, relieving developers of this burden. The benefits of this paradigm are three-fold-(1) increased correctness in the implementation of security features, (2) coverage for all software, even non-maintained legacy software, and (3) more rapid and consistent deployment of threat mitigations and new security features. To demonstrate these benefits, we describe three concrete instantiations of this paradigm- MessageGuard, a system that layers end-to-end encryption in the browser; TrustBase, a system that layers authentication in the operating system; and software-defined perimeter, which layers access control at network middleboxes. © 2017 IEEE.
571 a55588035200 Ruoti S. p793 False Conference 330 TrustBase: An architecture to repair and strengthen certificate-based authentication The current state of certificate-based authentication is messy, with broken authentication in applications and proxies, along with serious flaws in the CA system. To solve these problems, we design TrustBase, an architecture that provides certificate-based authentication as an operating system service, with system administrator control over authentication policy. TrustBase transparently enforces best practices for certificate validation on all applications, while also providing a variety of authentication services to strengthen the CA system. We describe a research prototype of TrustBase for Linux, which uses a loadable kernel module to intercept traffic in the socket layer, then consults a userspace policy engine to evaluate certificate validity using a variety of plugins. We evaluate the security of TrustBase, including a threat analysis, application coverage, and hardening of the Linux prototype. We also describe prototypes of TrustBase for Android and Windows, illustrating the generality of our approach. We show that TrustBase has negligible overhead and universal compatibility with applications. We demonstrate its utility by describing eight authentication services that extend CA hardening to all applications. © 2017 by The USENIX Association. All Rights Reserved.
572 a6601908155 Seamons K. p150 False Journal 105 Johnny's Journey Toward Usable Secure Email Since the publication of "Why Johnny Can't Encrypt, "10 there has been interest in creating usable, secure email that is adoptable by the general public. In this article, we summarize research from the usable-security community on this topic, identify open problems, and call for more research on usable key management. © 2003-2012 IEEE.
572 a6601908155 Seamons K. p220 False Conference 52 Don't Punish all of us: Measuring User Attitudes about Two-Factor Authentication Two-factor authentication (2FA) defends against password compromise by a remote attacker. We surveyed 4,275 students, faculty, and staff at Brigham Young University to measure user sentiment about Duo 2FA one year after the university adopted it. The results were mixed. A majority of the participants felt more secure using Duo and felt it was easy to use. About half of all participants reported at least one instance of being locked out of their university account because of an inability to authenticate with Duo. We found that students and faculty generally had more negative perceptions of Duo than staff. The survey responses reveal some pain points for Duo users. In response, we offer recommendations that reduce the frequency of 2FA for users. We also suggest UI changes that draw more attention to 2FA methods that do not require WiFi, the 'Remember Me' setting, and the help utility. © 2019 IEEE.
572 a6601908155 Seamons K. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
572 a6601908155 Seamons K. p300 False Conference 82 A usability study of five two-factor authentication methods Two-factor authentication (2FA) defends against account compromise. An account secured with 2FA typically requires an individual to authenticate using something they know-typically a password-as well as something they have, such as a cell phone or hardware token. Many 2FA methods in widespread use today have not been subjected to adequate usability testing. Furthermore, previous 2FA usability research is difficult to compare due to widely-varying contexts across different studies. We conducted a two-week, between-subjects usability study of five common 2FA methods with 72 participants, collecting both quantitative and qualitative data. Participants logged into a simulated banking website nearly every day using 2FA and completed an assigned task. Participants generally gave high marks to the methods studied, and many expressed an interest in using 2FA to provide more security for their sensitive online accounts. We also conducted a within-subjects laboratory study with 30 participants to assess the general usability of the setup procedure for the five methods. While a few participants experienced difficulty setting up a hardware token and a one-time password, in general, users found the methods easy to set up. © is held by the author/owner.
572 a6601908155 Seamons K. p303 False Conference 84 Is that you, Alice? A usability study of the authentication ceremony of secure messaging applications The effective security provided by secure messaging applications depends heavily on users completing an authentication ceremony-a sequence of manual operations enabling users to verify they are indeed communicating with one another. Unfortunately, evidence to date suggests users are unable to do this. Accordingly, we study in detail how well users can locate and complete the authentication ceremony when they are aware of the need for authentication. We execute a two-phase study involving 36 pairs of participants, using three popular messaging applications with support for secure messaging functionality: WhatsApp, Viber, and Facebook Messenger. The first phase included instruction about potential threats, while the second phase also included instructions about the importance of the authentication ceremony. We find that, across the three apps, the average success rates of finding and completing the authentication ceremony increases from 14% to 79% from the first to second phase, with second-phase success rates as high as 96% for Viber. However, the time required to find and complete the ceremony is undesirably long from a usability standpoint, and our data is inconclusive on whether users make the connection between this ceremony and the security guarantees it brings. We discuss in detail the success rates, task timings, and user feedback for each application, as well as common mistakes and user grievances. We conclude by exploring user threat models, finding significant gaps in user awareness and understanding. © 2017 by The USENIX Association. All rights reserved.
572 a6601908155 Seamons K. p305 False Conference 86 Action needed! Helping users find and complete the authentication ceremony in signal The security guarantees of secure messaging applications are contingent upon users performing an authentication ceremony, which typically involves verifying the fingerprints of encryption keys. However, recent lab studies have shown that users are unable to do this without being told in advance about the ceremony and its importance. A recent study showed that even with this instruction, the time it takes users to find and complete the ceremony is excessively long-about 11 minutes. To remedy these problems, we modified Signal to include prompts for the ceremony and also simplified the ceremony itself. To gauge the effect of these changes, we conducted a between-subject user study involving 30 pairs of participants. Our study methodology includes no user training and only a small performance bonus to encourage the secure behavior. Our results show that users are able to both find and complete the ceremony more quickly in our new version of Signal. Despite these improvements, many users are still unsure or confused about the purpose of the authentication ceremony. We discuss the need for better risk communication and methods to promote trust. © 2018 by The USENIX Association All Rights Reserved.
572 a6601908155 Seamons K. p344 False Conference 117 “Something isn't secure, but I'm not sure how that translates into a problem”: Promoting autonomy by designing for understanding in Signal Security designs that presume enacting secure behaviors to be beneficial in all circumstances discount the impact of response cost on users' lives and assume that all data is equally worth protecting. However, this has the effect of reducing user autonomy by diminishing the role personal values and priorities play in the decision-making process. In this study, we demonstrate an alternative approach that emphasizes users' comprehension over compliance, with the goal of helping users to make more informed decisions regarding their own security. To this end, we conducted a three-phase redesign of the warning notifications surrounding the authentication ceremony in Signal. Our results show how improved comprehension can be achieved while still promoting favorable privacy outcomes among users. Our experience reaffirms existing arguments that users should be empowered to make personal trade-offs between perceived risk and response cost. We also find that system trust is a major factor in users' interpretation of system determinations of risk, and that properly communicating risk requires an understanding of user perceptions of the larger security ecosystem in whole. © is held by the author/owner.
572 a6601908155 Seamons K. p348 False Conference 120 A comparative usability study of key management in secure email We conducted a user study that compares three secure email tools that share a common user interface and differ only by key management scheme: passwords, public key directory (PKD), and identity-based encryption (IBE). Our work is the first comparative (i.e., A/B) usability evaluation of three different key management schemes and utilizes a standard quantitative metric for cross-system comparisons. We also share qualitative feedback from participants that provides valuable insights into user attitudes regarding each key management approach and secure email generally. The study serves as a model for future secure email research with A/B studies, standard metrics, and the two-person study methodology. © 2018 by The USENIX Association All Rights Reserved.
572 a6601908155 Seamons K. p351 False Conference 122 User attitudes toward the inspection of encrypted traffic This paper reports the results of a survey of 1,976 individuals regarding their opinions on TLS inspection, a controversial technique that can be used for both benevolent and malicious purposes. Responses indicate that participants hold nuanced opinions on security and privacy trade-offs, with most recognizing legitimate uses for the practice, but also concerned about threats from hackers or government surveillance. There is strong support for notification and consent when a system is intercepting their encrypted traffic, although this support varies depending on the situation. A significant concern about malicious uses of TLS inspection is identity theft, and many would react negatively and some would change their behavior if they discovered inspection occurring without their knowledge. We also find that a small but significant number of participants are jaded by the current state of affairs and have lost any expectation of privacy. © 2016 by The USENIX Association All Rights Reserved.
572 a6601908155 Seamons K. p352 False Conference 123 Weighing Context and Trade-offs: How suburban adults selected their online security posture Understanding how people behave when faced with complex security situations is essential to designing usable security tools. To better understand users' perceptions of their digital lives and how they managed their online security posture, we conducted a series of 23 semi-structured interviews with mostly middle-aged parents from suburban Washington state. Using a grounded theory methodology, we analyzed the interview data and found that participants chose their security posture based on the immense value the Internet provides and their belief that no combination of technology could make them perfectly safe. Within this context, users have a four-stage process for determining which security measures to adopt: learning, evaluation of risks, estimation of impact, and weighing trade-offs to various coping strategies. Our results also revealed that a majority of participants understand the basic principles of symmetric encryption. We found that participants' misconceptions related to browser-based TLS indicators lead to insecure behavior, and it is the permanence of encrypted email that causes participants to doubt that it is secure. We conclude with a discussion of possible responses to this research and avenues for future research. © 2017 by The USENIX Association. All rights reserved.
572 a6601908155 Seamons K. p471 False Conference 173 A Tale of Two Studies: The Best and Worst of YubiKey Usability Two-factor authentication (2FA) significantly improves the security of password-based authentication. Recently, there has been increased interest in Universal 2nd Factor (U2F) security keys-small hardware devices that require users to press a button on the security key to authenticate. To examine the usability of security keys in non-enterprise usage, we conducted two user studies of the YubiKey, a popular line of U2F security keys. The first study tasked 31 participants with configuring a Windows, Google, and Facebook account to authenticate using a YubiKey. This study revealed problems with setup instructions and workflow including users locking themselves out of their operating system or thinking they had successfully enabled 2FA when they had not. In contrast, the second study had 25 participants use a YubiKey in their daily lives over a period of four weeks, revealing that participants generally enjoyed the experience. Conducting both a laboratory and longitudinal study yielded insights into the usability of security keys that would not have been evident from either study in isolation. Based on our analysis, we recommend standardizing the setup process, enabling verification of success, allowing shared accounts, integrating with operating systems, and preventing lockouts. © 2018 IEEE.
572 a6601908155 Seamons K. p557 False Conference 206 The secure socket API: TLS as an operating system service SSL/TLS libraries are notoriously hard for developers to use, leaving system administrators at the mercy of buggy and vulnerable applications. We explore the use of the standard POSIX socket API as a vehicle for a simplified TLS API, while also giving administrators the ability to control applications and tailor TLS configuration to their needs. We first assess OpenSSL and its uses in open source software, recommending how this functionality should be accommodated within the POSIX API. We then propose the Secure Socket API (SSA), a minimalist TLS API built using existing network functions and find that it can be employed by existing network applications by modifications requiring as little as one line of code. We next describe a prototype SSA implementation that leverages network system calls to provide privilege separation and support for other programming languages. We end with a discussion of the benefits and limitations of the SSA and our accompanying implementation, noting avenues for future work. © 2018 Proceedings of the 27th USENIX Security Symposium. All rights reserved.
572 a6601908155 Seamons K. p679 False Conference 292 Layering Security at Global Control Points to Secure Unmodified Software Developing secure software is inherently difficult, and is further hampered by a rush to market, the lack of cybersecurity-trained architects and developers, and the difficulty of identifying flaws and deploying mitigations. To address these problems, we advocate for an alternative paradigm-layering security onto applications from global control points, such as the browser, operating system, or network. This approach adds security to existing applications, relieving developers of this burden. The benefits of this paradigm are three-fold-(1) increased correctness in the implementation of security features, (2) coverage for all software, even non-maintained legacy software, and (3) more rapid and consistent deployment of threat mitigations and new security features. To demonstrate these benefits, we describe three concrete instantiations of this paradigm- MessageGuard, a system that layers end-to-end encryption in the browser; TrustBase, a system that layers authentication in the operating system; and software-defined perimeter, which layers access control at network middleboxes. © 2017 IEEE.
572 a6601908155 Seamons K. p793 False Conference 330 TrustBase: An architecture to repair and strengthen certificate-based authentication The current state of certificate-based authentication is messy, with broken authentication in applications and proxies, along with serious flaws in the CA system. To solve these problems, we design TrustBase, an architecture that provides certificate-based authentication as an operating system service, with system administrator control over authentication policy. TrustBase transparently enforces best practices for certificate validation on all applications, while also providing a variety of authentication services to strengthen the CA system. We describe a research prototype of TrustBase for Linux, which uses a loadable kernel module to intercept traffic in the socket layer, then consults a userspace policy engine to evaluate certificate validity using a variety of plugins. We evaluate the security of TrustBase, including a threat analysis, application coverage, and hardening of the Linux prototype. We also describe prototypes of TrustBase for Android and Windows, illustrating the generality of our approach. We show that TrustBase has negligible overhead and universal compatibility with applications. We demonstrate its utility by describing eight authentication services that extend CA hardening to all applications. © 2017 by The USENIX Association. All Rights Reserved.
573 a56102505100 Paré P.E. p151 True Journal 106 Model Boundary Approximation Method as a Unifying Framework for Balanced Truncation and Singular Perturbation Approximation We show that two widely accepted model reduction techniques, balanced truncation (BT) and balanced singular perturbation approximation (BSPA), can be derived as limiting approximations of a carefully constructed parameterization of linear time invariant systems by employing the model boundary approximation method (MBAM) [1]. We also show that MBAM provides a novel way to interpolate between BT and BSPA, by exploring the set of approximations on the boundary of the 'model manifold,' which is associated with the specific choice of model parameterization and initial condition and is embedded in a sample space of measured outputs, between the elements that correspond to the two model reduction techniques. This paper suggests similar types of approximations may be obtainable in topologically similar places (i.e., on certain boundaries) on the associated model manifold of nonlinear systems if analogous parameterizations can be achieved, therefore extending these widely accepted model reduction techniques to nonlinear systems.1 © 1963-2012 IEEE.
574 a57191620725 Grimsman D. p151 False Journal 106 Model Boundary Approximation Method as a Unifying Framework for Balanced Truncation and Singular Perturbation Approximation We show that two widely accepted model reduction techniques, balanced truncation (BT) and balanced singular perturbation approximation (BSPA), can be derived as limiting approximations of a carefully constructed parameterization of linear time invariant systems by employing the model boundary approximation method (MBAM) [1]. We also show that MBAM provides a novel way to interpolate between BT and BSPA, by exploring the set of approximations on the boundary of the 'model manifold,' which is associated with the specific choice of model parameterization and initial condition and is embedded in a sample space of measured outputs, between the elements that correspond to the two model reduction techniques. This paper suggests similar types of approximations may be obtainable in topologically similar places (i.e., on certain boundaries) on the associated model manifold of nonlinear systems if analogous parameterizations can be achieved, therefore extending these widely accepted model reduction techniques to nonlinear systems.1 © 1963-2012 IEEE.
575 a56819566000 Wilson A.T. p151 False Journal 106 Model Boundary Approximation Method as a Unifying Framework for Balanced Truncation and Singular Perturbation Approximation We show that two widely accepted model reduction techniques, balanced truncation (BT) and balanced singular perturbation approximation (BSPA), can be derived as limiting approximations of a carefully constructed parameterization of linear time invariant systems by employing the model boundary approximation method (MBAM) [1]. We also show that MBAM provides a novel way to interpolate between BT and BSPA, by exploring the set of approximations on the boundary of the 'model manifold,' which is associated with the specific choice of model parameterization and initial condition and is embedded in a sample space of measured outputs, between the elements that correspond to the two model reduction techniques. This paper suggests similar types of approximations may be obtainable in topologically similar places (i.e., on certain boundaries) on the associated model manifold of nonlinear systems if analogous parameterizations can be achieved, therefore extending these widely accepted model reduction techniques to nonlinear systems.1 © 1963-2012 IEEE.
576 a16178649400 Warnick S. p151 False Journal 106 Model Boundary Approximation Method as a Unifying Framework for Balanced Truncation and Singular Perturbation Approximation We show that two widely accepted model reduction techniques, balanced truncation (BT) and balanced singular perturbation approximation (BSPA), can be derived as limiting approximations of a carefully constructed parameterization of linear time invariant systems by employing the model boundary approximation method (MBAM) [1]. We also show that MBAM provides a novel way to interpolate between BT and BSPA, by exploring the set of approximations on the boundary of the 'model manifold,' which is associated with the specific choice of model parameterization and initial condition and is embedded in a sample space of measured outputs, between the elements that correspond to the two model reduction techniques. This paper suggests similar types of approximations may be obtainable in topologically similar places (i.e., on certain boundaries) on the associated model manifold of nonlinear systems if analogous parameterizations can be achieved, therefore extending these widely accepted model reduction techniques to nonlinear systems.1 © 1963-2012 IEEE.
576 a16178649400 Warnick S. p193 False Conference 43 Abstractions and realizations of dynamic networks This paper establishes the importance of abstractions and realizations of dynamic networks in characterizing the structure and dynamics of systems. Abstractions and realizations generate dynamically equivalent representations of systems with varying degrees of structural detail. We show that dynamic networks exist that contain the same level of detail as state space models, that other dynamic networks exist that contain the same level of detail as transfer functions, and that still other dynamic networks exist that are simultaneously abstractions of state space models and realizations of transfer functions; thus containing intermediate levels of structural detail. © 2019 American Automatic Control Council.
576 a16178649400 Warnick S. p272 False Journal 179 Target control and source estimation metrics for dynamical networks This note examines metrics for target control and source estimation in dynamical networks. Specifically, the energy required to control a target node in a network from a remote input, and dually the fidelity with which a source state can be estimated from a noisy remote measurement, are studied. For both problems, spectral and graph-theoretic analyses are undertaken, and a comparison between the two metrics is also developed. The analyses highlight an essential asymmetry between target control and source estimation. © 2018 Elsevier Ltd
576 a16178649400 Warnick S. p279 False Conference 65 Necessary and Sufficient Conditions on State Transformations That Preserve the Causal Structure of LTI Dynamical Networks Linear time-invariant (LTI) dynamic networks are described by their dynamical structure function, and generally they have many possible state space realizations. This work characterizes the necessary and sufficient conditions on a state transformation that preserves the dynamical structure function, thereby generating the entire set of realizations of a given order for a specific dynamic network. © 2018 IEEE.
576 a16178649400 Warnick S. p280 False Conference 66 Dynamic Networks: Representations, Abstractions, and Well-Posedness This paper introduces notions of abstraction and realization for dynamic networks. These processes generate dynamically equivalent representations of a system, but with varying degrees of structural detail. Nuanced definitions and associated conditions for maintaining well-posedness for these multi-resolution representations of a dynamic system are then detailed, ensuring that hierarchies of network representations are sensible as multi-resolution models of dynamic networks. Although the ideas are developed precisely here for LTI networks, many of the concepts remain fundamental in the nonlinear setting. © 2018 IEEE.
576 a16178649400 Warnick S. p542 False Conference 196 On the well-posedness of LTI networks We consider networks of linear, time-invariant systems defined over matrices of rational functions in a complex variable where each element of the matrix represents a link in the network. When these rational functions are proper, but not necessarily strictly proper, we demonstrate the necessary and sufficient conditions under which such a network configuration is well-posed. We include multiple examples of network configurations and their respective well-posedness conditions, including cases where two or more ill-posed network configurations can be interconnected to form a well-posed network. © 2017 IEEE.
576 a16178649400 Warnick S. p543 False Conference 197 Necessary and sufficient conditions for identifiability of interconnected subsystems Identifiability conditions refers to the information required, beyond input-output data, to identify the structure of the system. Since there are different ways to describe a system mathematically, there are different notions of structure associated with a single system. In this work we detail the identifiability conditions of interconnected subsystems, referred to as structured linear fractional transformations. The identifiability conditions of the structured linear fractional transformation are then compared to those of the dynamical structure function, another partial system representation, whose cost for identification was detailed in previous work [1]. Both representations appear to detail the same notions of structure of a system; however, this works demonstrates that the cost of identification of the structured linear fractional transformation is always higher than that of the dynamical structure function. © 2017 IEEE.
576 a16178649400 Warnick S. p544 False Conference 198 Local control and estimation performance in dynamical networks: Structural and graph-theoretic results This work examines metrics for target reachability and source observability in dynamical networks, which are especially relevant in a network security context. Specifically, the energy required to control a target node in a network from a remote input is characterized, and dually the fidelity with which a source state can be estimated from a remote measurement is studied. The work highlights an essential asymmetry between the problems: We show that target reachability is often easy, while source observability is almost always impossible. Several spectral and graph-theoretic results are also presented, which give structural insight into how easy or hard target control and source estimation are. © 2017 IEEE.
576 a16178649400 Warnick S. p635 False Conference 270 A modeling framework for assessing cyber disruptions and attacks to the national airspace system [No abstract available]
576 a16178649400 Warnick S. p642 False Conference 274 A graph-theoretic understanding of network-wide implications of local cyber protections for mission assurance Modern Department of Defense mission systems are very complex and therefore arduous to defend, especially in the cyber domain. A major cause for this concern arises from the fact that implementation of security protections occur at a local scale, while the important operational security issues stem from a global perspective of the system, e.g., mission assurance. Being able to understand network-wide implications of local cyber protections has the potential to significantly impact the strategies we use to protect modern mission systems. In this work, we present a graph-theoretic perspective on this problem, which is based on a framework for modeling and assessing the integrated cyber-physical dynamics of complex systems. Under the framework, these dynamics (and their relationships) are modeled as a graph and then analyzed using processing techniques from graphtheory. We demonstrate the utility of this framework by conducting insider-attack threat analysis and show how the application of security protections at a local scale impact network-wide security properties from an insider perspective. As a test case, we study the problem of search and rescue (SAR) using unmanned aerial vehicle teams. Unmanned vehicle teams engaged in SAR are prototypical cyber-physical systems, in which local intrusions may cause global disruptions. Here, we describe how the insider modeling framework for cyber-physical dynamics applies to this problem and present results of a network-wide assessment of security properties of the system. We use this assessment to design a security protection for the system in which we use cryptographically secure computation techniques to limit the amount of information sharing required between system components without degrading the correct operation of the system. We show how the application of these techniques on a local scale impacts the security properties of the system on a global scale. © 2018 SPIE.
576 a16178649400 Warnick S. p682 False Conference 294 Applying a passive network reconstruction technique to Twitter data in order to identify trend setters In this work we apply a systems-theoretic approach to identifying trend setters on Twitter. A network reconstruction algorithm was applied to Twitter data to determine causal relationships among topics discussed by popular Twitter users. Causal relationships in this context means that the topics tweeted by a single user influences the topics tweeted by another user, regardless of sentiment. A user that causally influences other users, without themselves being strongly influenced is identified as a trendsetter. This work seeks to identify potential trendsetters among popular Twitter users and demonstrating that causal influence does not always directly correlate with a user's popularity in terms of followers-demonstrating that popularity alone may not be sufficient for identifying trendsetters on Twitter. © 2017 IEEE.
576 a16178649400 Warnick S. p729 False Conference 310 Cooperation induction in two player bertand markets with linear demand We present a two player gradient play differential game in a producer market with quadratic payoff as a model of behavior in a competitive environment and show that the Nash equilibrium is not efficient. An algorithm is then presented which uses side payments to induce cooperation between firms, and rules for side payment strategies are shown. The stability of the new system at a reasonable equilibrium is proved, and it is shown that all participants are at least as well off as they would be at the non-cooperative equilibrium. Numerical examples show the existence of a reasonable equilibrium and that the basin of attraction of that equilibrium appears to cover all reasonable initial conditions. © 2017 American Automatic Control Council (AACC).
576 a16178649400 Warnick S. p880 False Journal 408 Optimal Distributed Control for Platooning via Sparse Coprime Factorizations We introduce a novel distributed control architecture for heterogeneous platoons of linear time-invariant autonomous vehicles. Our approach is based on a generalization of the concept of leader-follower controllers for which we provide a Youla-like parameterization, while the sparsity constraints are imposed on the controller's left coprime factors, outlining a new concept of structural constraints in distributed control. The proposed scheme is amenable to optimal controller design via norm based costs, it guarantees string stability and eliminates the accordion effect from the behavior of the platoon. We also introduce a synchronization mechanism for the exact compensation of the time delays induced by the wireless communications. © 1963-2012 IEEE.
576 a16178649400 Warnick S. p888 False Journal 413 A minimal realization technique for the dynamical structure function of a class of LTI systems The dynamical structure function of a linear time invariant (LTI) system reveals causal dependencies among manifest variables without specifying any particular relationships among the unmeasured states of the system. As such, it is a useful representation for complex networks where a coarse description of global system structure is desired without detailing the intricacies of a full state realization. In this paper, we consider the problem of finding a minimal state realization for a given dynamical structure function. Interestingly, some dynamical structure functions require uncontrollable modes in their state realizations to deliver the desired input-output behavior while respecting a specified system structure. As a result, the minimal order necessary to realize a particular dynamical structure function may be greater than that necessary to realize its associated transfer function. Although finding a minimal realization for a given dynamical structure function is difficult in general, we present a straightforward procedure here that works for a simplified class of systems. © 2014 IEEE.
577 a35729129900 Miao X. p152 True Journal 107 Quality assessment of images with multiple distortions based on phase congruency and gradient magnitude In image communication systems, images are often contaminated by multiple types of distortions. However, most existing image quality assessment (IQA) methods mainly focused on a single type of distortions. In this paper, we proposed a no-reference (NR) IQA method for images with multiple distortions. Image distortions not only destroy the intensity of low-level image features, but also alter their distribution, to both of which the human vision system (HVS) is sensitive. Based on these observations, low-level features are represented by phase congruency (PC) which is consistent with human perception. The distribution of low-level features is extracted using local binary pattern (LBP) in PC domain at multiple scales, which can effectively characterize the impact of multiple distortions on images. Given that PC is contrast invariant while the contrast does affect perceptual image quality of the HVS, image gradient magnitude (GM) is employed as a weighting factor for LBP histogram creation. Finally a support vector regression model is trained to map the gradient-weighted LBP histograms in PC domain at multi-scale to quality scores. Experimental results on two benchmark databases demonstrate that the proposed method achieves high consistency with subjective perception and performs better than other state-of-the-art full-reference (FF) and NR IQA methods. © 2019 Elsevier B.V.
577 a35729129900 Miao X. p170 True Journal 117 Just-noticeable difference binary pattern for reduced reference image quality assessment Just-noticeable difference (JND) is defined as the smallest intensity change in an image that can be noticed by the human vision system (HVS). Any perceptible distortion level must be greater than the JND. Based on this observation, a local binary pattern (LBP) is developed for image quality assessment. First, the JND map of the image is computed. The spatial and relative intensity relationships among pixels in a local neighborhood are employed to generate the proposed LBP based on the JND map. Then, image contrast is used as a weighting factor for the LBP histogram generation to characterize the structural and contrast information of the image. Finally, the contrast and structure changes due to image distortion are measured by calculating the similarity between contrast-weighted histograms of the reference and distorted images. Support vector regression is employed to pool the similarity to predict the quality. Experimental results on benchmark databases demonstrate that the proposed LBP can effectively and accurately measure image quality, which is consistent with the HVS. The proposed method achieves high consistency with subjective perception using 18 reference values and performs better than other state-of-The-Art reduced reference image quality assessment methods. © 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).
577 a35729129900 Miao X. p179 True Journal 121 Structure descriptor based on just noticeable difference for texture image classification Local binary pattern (LBP) and its derivates have been widely used in texture classification. However, LBP-based methods are sensitive to noise, and some structure information represented by non-uniform patterns is lost due to the combination of these patterns. In this paper, a new local structure descriptor based on just noticeable difference (JND) for texture classification is proposed by exploring the spatial and relative intensity correlations among local neighborhood pixels. First, a JND map of the image is computed, and then we attempt to model the correlations among local neighborhood pixels by comparing the absolute differences in intensity between the central pixel and its neighbors with the corresponding JND threshold. A new visual pattern (JNDVP) is designed using modeled correlations to describe image structure. Next, considering that image contrast makes important contributions to structure description, contrast is employed as a weighting factor for JNDVP histogram creation to represent structural and contrast information in a single representation. Finally, the nearest neighborhood classifier is employed for texture classification. Results on two texture image databases demonstrate that the proposed structure descriptor is rotation invariant and more robust to noise than LBP. Moreover, texture classification based on JNDVP outperforms LBP-based methods. © 2019 Optical Society of America.
578 a53866006800 Chu H. p152 False Journal 107 Quality assessment of images with multiple distortions based on phase congruency and gradient magnitude In image communication systems, images are often contaminated by multiple types of distortions. However, most existing image quality assessment (IQA) methods mainly focused on a single type of distortions. In this paper, we proposed a no-reference (NR) IQA method for images with multiple distortions. Image distortions not only destroy the intensity of low-level image features, but also alter their distribution, to both of which the human vision system (HVS) is sensitive. Based on these observations, low-level features are represented by phase congruency (PC) which is consistent with human perception. The distribution of low-level features is extracted using local binary pattern (LBP) in PC domain at multiple scales, which can effectively characterize the impact of multiple distortions on images. Given that PC is contrast invariant while the contrast does affect perceptual image quality of the HVS, image gradient magnitude (GM) is employed as a weighting factor for LBP histogram creation. Finally a support vector regression model is trained to map the gradient-weighted LBP histograms in PC domain at multi-scale to quality scores. Experimental results on two benchmark databases demonstrate that the proposed method achieves high consistency with subjective perception and performs better than other state-of-the-art full-reference (FF) and NR IQA methods. © 2019 Elsevier B.V.
579 a56126031600 Liu H. p152 False Journal 107 Quality assessment of images with multiple distortions based on phase congruency and gradient magnitude In image communication systems, images are often contaminated by multiple types of distortions. However, most existing image quality assessment (IQA) methods mainly focused on a single type of distortions. In this paper, we proposed a no-reference (NR) IQA method for images with multiple distortions. Image distortions not only destroy the intensity of low-level image features, but also alter their distribution, to both of which the human vision system (HVS) is sensitive. Based on these observations, low-level features are represented by phase congruency (PC) which is consistent with human perception. The distribution of low-level features is extracted using local binary pattern (LBP) in PC domain at multiple scales, which can effectively characterize the impact of multiple distortions on images. Given that PC is contrast invariant while the contrast does affect perceptual image quality of the HVS, image gradient magnitude (GM) is employed as a weighting factor for LBP histogram creation. Finally a support vector regression model is trained to map the gradient-weighted LBP histograms in PC domain at multi-scale to quality scores. Experimental results on two benchmark databases demonstrate that the proposed method achieves high consistency with subjective perception and performs better than other state-of-the-art full-reference (FF) and NR IQA methods. © 2019 Elsevier B.V.
580 a36538565900 Yang Y. p152 False Journal 107 Quality assessment of images with multiple distortions based on phase congruency and gradient magnitude In image communication systems, images are often contaminated by multiple types of distortions. However, most existing image quality assessment (IQA) methods mainly focused on a single type of distortions. In this paper, we proposed a no-reference (NR) IQA method for images with multiple distortions. Image distortions not only destroy the intensity of low-level image features, but also alter their distribution, to both of which the human vision system (HVS) is sensitive. Based on these observations, low-level features are represented by phase congruency (PC) which is consistent with human perception. The distribution of low-level features is extracted using local binary pattern (LBP) in PC domain at multiple scales, which can effectively characterize the impact of multiple distortions on images. Given that PC is contrast invariant while the contrast does affect perceptual image quality of the HVS, image gradient magnitude (GM) is employed as a weighting factor for LBP histogram creation. Finally a support vector regression model is trained to map the gradient-weighted LBP histograms in PC domain at multi-scale to quality scores. Experimental results on two benchmark databases demonstrate that the proposed method achieves high consistency with subjective perception and performs better than other state-of-the-art full-reference (FF) and NR IQA methods. © 2019 Elsevier B.V.
581 a57210585829 Li X. p152 False Journal 107 Quality assessment of images with multiple distortions based on phase congruency and gradient magnitude In image communication systems, images are often contaminated by multiple types of distortions. However, most existing image quality assessment (IQA) methods mainly focused on a single type of distortions. In this paper, we proposed a no-reference (NR) IQA method for images with multiple distortions. Image distortions not only destroy the intensity of low-level image features, but also alter their distribution, to both of which the human vision system (HVS) is sensitive. Based on these observations, low-level features are represented by phase congruency (PC) which is consistent with human perception. The distribution of low-level features is extracted using local binary pattern (LBP) in PC domain at multiple scales, which can effectively characterize the impact of multiple distortions on images. Given that PC is contrast invariant while the contrast does affect perceptual image quality of the HVS, image gradient magnitude (GM) is employed as a weighting factor for LBP histogram creation. Finally a support vector regression model is trained to map the gradient-weighted LBP histograms in PC domain at multi-scale to quality scores. Experimental results on two benchmark databases demonstrate that the proposed method achieves high consistency with subjective perception and performs better than other state-of-the-art full-reference (FF) and NR IQA methods. © 2019 Elsevier B.V.
581 a57210585829 Li X. p179 False Journal 121 Structure descriptor based on just noticeable difference for texture image classification Local binary pattern (LBP) and its derivates have been widely used in texture classification. However, LBP-based methods are sensitive to noise, and some structure information represented by non-uniform patterns is lost due to the combination of these patterns. In this paper, a new local structure descriptor based on just noticeable difference (JND) for texture classification is proposed by exploring the spatial and relative intensity correlations among local neighborhood pixels. First, a JND map of the image is computed, and then we attempt to model the correlations among local neighborhood pixels by comparing the absolute differences in intensity between the central pixel and its neighbors with the corresponding JND threshold. A new visual pattern (JNDVP) is designed using modeled correlations to describe image structure. Next, considering that image contrast makes important contributions to structure description, contrast is employed as a weighting factor for JNDVP histogram creation to represent structural and contrast information in a single representation. Finally, the nearest neighborhood classifier is employed for texture classification. Results on two texture image databases demonstrate that the proposed structure descriptor is rotation invariant and more robust to noise than LBP. Moreover, texture classification based on JNDVP outperforms LBP-based methods. © 2019 Optical Society of America.
582 a57203978933 Sargent B. p153 True Journal 108 Heat set creases in polyethylene terephthalate (PET) sheets to enable origami-based applications Polyethylene terephthalate (PET) sheets show promise for application in origami-based engineering design. Origami-based engineering provides advantages that are not readily available in traditional engineering design methods. Several processing methods were examined to identify trends and determine the effect of processing of PET sheets on the crease properties of origami mechanisms in PET. Various annealing times, temperatures, and cooling rates were evaluated and data collected for over 1000 samples. It was determined that annealing temperature plays the largest role in crease response. An increase in the crystallinity of a PET sheet while in the folded state likely increases the force response of the crease in PET sheets. An annealing time of at least 60 min at 160 C-180 C with a quick cooling results in a high force response in the crease. The effectiveness of the processing methods was demonstrated in several origami patterns of various complexities. © 2019 IOP Publishing Ltd.
582 a57203978933 Sargent B. p454 True Conference 160 Zipper Tube Reinforcement to Mitigate Flexible Shaft Buckling The Zipper Tube Reinforcement (ZTR) is a novel support system developed to mitigate buckling in thin flexible devices used in robotic surgery. The ZTR was inspired by a construction technique called a Buckling Restrained Braced Frame (BRBF) and deployable booms for space applications. It utilizes a zipper function to allow a rolled sheet to deploy into a variable-length tube and stow in a small volume spooled on a mandrel. The tube envelops the device and allows it to support a much higher compressive load before buckling failure through the insertion stroke. The ZTR also enables the possibility of smaller, more flexible devices due to its design for continuous support and could find application in other fields. © 2018 IEEE.
582 a57203978933 Sargent B. p583 True Conference 228 Retractable anti-buckling support systems for flexible medical devices This work presents two novel support systems used to help mitigate flexible device buckling during insertion such as the insertion of medical device into the body. These systems are collapsible to accommodate the changing length of the flexible device as it is inserted. They use tension in wires or geometry to provide systems with lateral stiffness used to support the device. Through modeling, the performance of these systems can be predicted and they can be designed to a desired performance. This was validated in the geometry-based support system. They provide systems with small operating volumes and part counts. Copyright © 2018 ASME.
583 a57212415946 Brown N. p153 False Journal 108 Heat set creases in polyethylene terephthalate (PET) sheets to enable origami-based applications Polyethylene terephthalate (PET) sheets show promise for application in origami-based engineering design. Origami-based engineering provides advantages that are not readily available in traditional engineering design methods. Several processing methods were examined to identify trends and determine the effect of processing of PET sheets on the crease properties of origami mechanisms in PET. Various annealing times, temperatures, and cooling rates were evaluated and data collected for over 1000 samples. It was determined that annealing temperature plays the largest role in crease response. An increase in the crystallinity of a PET sheet while in the folded state likely increases the force response of the crease in PET sheets. An annealing time of at least 60 min at 160 C-180 C with a quick cooling results in a high force response in the crease. The effectiveness of the processing methods was demonstrated in several origami patterns of various complexities. © 2019 IOP Publishing Ltd.
583 a57212415946 Brown N. p381 False Conference 139 Rigidly foldable thick origami using designed-offset linkages We present new families of thick origami mechanisms that achieve rigid foldability and parallel stacking of panels in the flat-folded state using linkages for some or all of the hinges between panels. A degree-four vertex results in a multi-loop eight-bar spatial mechanism that can be analyzed as separate linkages. The individual linkages are designed so that they introduce offsets perpendicular to the panels that are mutually compatible around each vertex. This family of mechanisms offers the unique combination of a planar unfolded state, parallel-stacked panels in the flat folded state, and kinematic single-degree-of-freedom motion from the flat-unfolded to the flat-folded state. Copyright © 2019 ASME.
584 a57205129154 Pires dos Santos R. p154 True Journal 109 Identifying the relative importance of predictive variables in artificial neural networks based on data produced through a discrete event simulation of a manufacturing environment This research used a discrete event simulation to create data on a shipment receiving process instead of using historical records on the process. The simulation was used to create records with different inputs and operating conditions and the resulting overall elapsed time for the overall process. The resulting records were used to create a set of predictive artificial neural network models that predicted elapsed time based on the process characteristics. Then, the connection weight approach was used to determine the relative importance of the input variables. The connection weight approach was applied in three different steps: (1) on all input variables to identify predictive and non-predictive inputs, (2) on all predictive inputs, and (3) after removal of a dominating predictive input. This produced a clearer picture of the relative importance of input variables on the outcome variable than applying the connection weight approach once. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
585 a7402370024 Dean D.L. p154 False Journal 109 Identifying the relative importance of predictive variables in artificial neural networks based on data produced through a discrete event simulation of a manufacturing environment This research used a discrete event simulation to create data on a shipment receiving process instead of using historical records on the process. The simulation was used to create records with different inputs and operating conditions and the resulting overall elapsed time for the overall process. The resulting records were used to create a set of predictive artificial neural network models that predicted elapsed time based on the process characteristics. Then, the connection weight approach was used to determine the relative importance of the input variables. The connection weight approach was applied in three different steps: (1) on all input variables to identify predictive and non-predictive inputs, (2) on all predictive inputs, and (3) after removal of a dominating predictive input. This produced a clearer picture of the relative importance of input variables on the outcome variable than applying the connection weight approach once. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
586 a57203310052 Weaver J.M. p154 False Journal 109 Identifying the relative importance of predictive variables in artificial neural networks based on data produced through a discrete event simulation of a manufacturing environment This research used a discrete event simulation to create data on a shipment receiving process instead of using historical records on the process. The simulation was used to create records with different inputs and operating conditions and the resulting overall elapsed time for the overall process. The resulting records were used to create a set of predictive artificial neural network models that predicted elapsed time based on the process characteristics. Then, the connection weight approach was used to determine the relative importance of the input variables. The connection weight approach was applied in three different steps: (1) on all input variables to identify predictive and non-predictive inputs, (2) on all predictive inputs, and (3) after removal of a dominating predictive input. This produced a clearer picture of the relative importance of input variables on the outcome variable than applying the connection weight approach once. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
586 a57203310052 Weaver J.M. p257 True Journal 168 Quantifying accuracy of a concept laser metal additive machine through the NIST test artifact Purpose: The purpose of this paper is to describe the use of a test artifact proposed by NIST to quantify the dimensional accuracy of a metal additive manufacturing process. Insights from this paper are given concerning both the performance of the machine, a concept laser Mlab cusing machine, and the applicability of the NIST test artifact in characterizing accuracy. Recommendations are given for improving the artifact and standardizing a process for evaluating dimensional accuracy across the additive manufacturing industry. Design/methodology/approach: Three builds of the NIST additive manufacturing test artifact were fabricated in 316 stainless steel on a concept laser Mlab cusing machine. The paper follows the procedure described by NIST for characterizing dimensional accuracy of the additive process. Features including pins, holes and staircase flats of various sizes were measured using an optical measurement system, a touch probe and a profilometer. Findings: This paper describes the accuracy of printed features’ size and position on the test artifact, as well as surface finish on flat and inclined surfaces. Trends in variation of these dimensions are identified, along with possible root causes and remedies. This paper also describes several strengths and weaknesses in the design of the test artifact and the proposed measurement strategy, with recommendations on how to improve and standardize the process. Originality/value: This paper reviews a previously proposed design and process for measuring the capabilities of additive manufacturing processes. It also suggests improvements that can be incorporated into future designs and standardized across the industry. © 2018, Emerald Publishing Limited.
586 a57203310052 Weaver J.M. p486 True Conference 178 Transitioning a manufacturing systems engineering course to student-centered learning This evidence-based paper describes the transition of a senior-level manufacturing engineering course from a traditional lecture-focused curriculum to a more engaging curriculum based on the research in student-centered learning. Many college courses have a familiar format: students listen to lectures, read textbooks, complete assignments, and demonstrate their learning through exams. Often, the instructor will structure the course for convenience, perhaps creating highly structured PowerPoint presentations and using standardized multiple choice exams to easily grade performance. Students, on the other hand, then structure their learning practices to match - trying to determine exactly how much to come to class, read, and memorize, with the end goal of regurgitating information on the exam and getting a satisfactory grade in the course. These practices are not conducive to long-term retention and application by the students, nor to accurate assessment or facilitation of learning by the instructor. But unless both the instructor and the students in a course understand and are amenable to alternative techniques, the format is unlikely to change. There has been extensive research on techniques aimed to increase student engagement in the classroom, such as "flipping the classroom" and identifying and overcoming the "illusion of learning." This paper describes the efforts of the author over three semesters to incorporate these tools into a senior-level course on manufacturing system design and lean manufacturing to help facilitate better learning and assess proficiency more effectively. Several techniques are used, including suggestions from the recent book Make It Stick by Brown, Roediger, and McDaniel. Student feedback and instructor observations are discussed, and future recommendations for the course are given. © American Society for Engineering Education, 2018.
587 a57193627694 Ashcraft C.C. p155 True Conference 27 Moderating operator influence in human-swarm systems In human-swarm systems, human input to a robot swarm can both inhibit desirable swarm behaviors and allow the operator to properly guide the swarm to achieve mission goals. Indeed, the way that control is shared between the human operator and the inherent collective robot behaviors determines in large part the success of the human-swarm system. In this paper, we seek to understand how to design human-swarm systems that effectively moderate human influence over a robot swarm. To do this, we implement a simulated swarm system based on honeybees, and study how interacting with this swarm using various methods of moderating human influence impacts the success of the resulting human-swarm system. Our results demonstrate that moderating human influence is essential to achieving effective human-swarm systems, and highlight the need for future work in determining how to better moderate human influence in human-swarm systems. © 2019 IEEE.
588 a35175200200 Shaikh M.T. p156 True Conference 28 Intent-based robotic path-replanning: When to adapt new paths in dynamic environments For goal-based robot navigation in a dynamic environment, human intent includes expectations about what performance objectives are satisfied by a planned path in terms of objectives to be met. If the planned path drifts from the human's intent as a result of environment changes, the path needs to be replanned. This paper presents a replanning framework with three elements: (a) the integration of fast online path-planning algorithms that generate trajectories conforming to the given intent; (b) a mathematical model that says when replanning must happen; and (c) an evaluation of events that trigger replanning. An interactive graphical user interface enables a human to accept or reject replanned paths when a trigger happens. A study of 50 MTurk participants is used to assess what replanning triggers best enable a human-robot collaboration to persistently satisfy intent? © 2019 IEEE.
588 a35175200200 Shaikh M.T. p592 True Conference 235 When does a human replan? Exploring intent-based replanning in multi-objective path planning In goal-based tasks such as navigating a robot from location A to location B in a dynamic environment, human intent can mean to choose a specific trade-off between multiple competing objectives. For example, intent can mean to find a path that balances between "Go quickly" and "Go stealthily". Given human expectations about how a path balances such tradeoffs, the path should match the human's intent throughout the entire execution of the path even if the environment changes. If the path drifts from the human's intent because the environment changes, then a new robotic-path needs to be planned - referred to as path-replanning. We discuss here three system-initiated triggers (prompts) for path-replanning. The objective is to create an interactive replanning system that yields paths that consistently match human intent. The triggers are to replan (a) at regular time intervals, (b) when the current robotic path deviates from the user intent, and (c) when a better path can be obtained from a different homotopy class. Further, we consider one user-generated replanning trigger that allows the user to stop the robot anytime to put the robot onto a new route. These four trigger variants seek to answer two fundamental critical questions: When is a re-planned path acceptable to a human? and How should a planner involve a human in replanning? © 2018 SPIE.
588 a35175200200 Shaikh M.T. p765 True Conference 321 Design and Evaluation of Adverb Palette: A GUI for Selecting Tradeoffs in Multi-objective Optimization Problems An important part of expressing human intent is identifying acceptable tradeoffs among competing performance objectives. We present and evaluate a set of graphical user interfaces (GUIs), that are designed to allow a human to express intent by expressing desirable tradeoffs. The GUIs require an algorithm that identifies the set of Pareto optimal solutions to the multi-objective decision problem, which means that all the solutions are equally good in the sense that there are no other solutions better for every objective. Given the Pareto set, the GUIs provide different ways for a human to express intent by exploring tradeoffs between objectives; once a tradeoff is selected, the solution is chosen. The GUI designs are applied to interactive human-robot path-selection for a robot in an urban environment, but they can be applied to other tradeoff problems. A user study evaluates GUI designs by requiring users to select a tradeoff that satisfies a specified mission intent. Results of the user study suggest that GUIs designed to support an artist's palette-metaphor can be used to express intent without incurring unacceptable levels of human workload. © 2017 ACM.
589 a6602198438 Ogles B. p157 True Conference 29 Proving data race freedom in task parallel programs using a weaker partial order Task parallel programming models such as Habanero Java help developers write idiomatic parallel programs and avoid common errors. Data race freedom is a desirable property for task parallel programs but is difficult to prove because every possible execution of the program must be considered. A partial order over events of an observed program execution induces an equivalence class of executions that the program may also produce. The Does-not-Commute (DC) relation is an efficiently computable partial order used for data race detection. As a relatively weak partial order, the DC relation can represent relatively large equivalence classes of program executions. However, some of these executions may be infeasible, thus leading to false data race reports. The contribution of this paper is a mechanized proof that the DC relation is actually sound for commonly used task parallel programming models. Sound means that the first data race identified by the DC relation is guaranteed to be a real data race. A prototype analysis in the Java Pathfinder model checker shows that the DC relation can significantly reduce the number of explored states required to prove data race freedom in Habanero Java programs. In this application, the search for data race using the DC relation is both sound and complete. © 2019 FMCAD Inc.
590 a55948963100 Aldous P. p157 False Conference 29 Proving data race freedom in task parallel programs using a weaker partial order Task parallel programming models such as Habanero Java help developers write idiomatic parallel programs and avoid common errors. Data race freedom is a desirable property for task parallel programs but is difficult to prove because every possible execution of the program must be considered. A partial order over events of an observed program execution induces an equivalence class of executions that the program may also produce. The Does-not-Commute (DC) relation is an efficiently computable partial order used for data race detection. As a relatively weak partial order, the DC relation can represent relatively large equivalence classes of program executions. However, some of these executions may be infeasible, thus leading to false data race reports. The contribution of this paper is a mechanized proof that the DC relation is actually sound for commonly used task parallel programming models. Sound means that the first data race identified by the DC relation is guaranteed to be a real data race. A prototype analysis in the Java Pathfinder model checker shows that the DC relation can significantly reduce the number of explored states required to prove data race freedom in Habanero Java programs. In this application, the search for data race using the DC relation is both sound and complete. © 2019 FMCAD Inc.
591 a7005411524 Mercer E. p157 False Conference 29 Proving data race freedom in task parallel programs using a weaker partial order Task parallel programming models such as Habanero Java help developers write idiomatic parallel programs and avoid common errors. Data race freedom is a desirable property for task parallel programs but is difficult to prove because every possible execution of the program must be considered. A partial order over events of an observed program execution induces an equivalence class of executions that the program may also produce. The Does-not-Commute (DC) relation is an efficiently computable partial order used for data race detection. As a relatively weak partial order, the DC relation can represent relatively large equivalence classes of program executions. However, some of these executions may be infeasible, thus leading to false data race reports. The contribution of this paper is a mechanized proof that the DC relation is actually sound for commonly used task parallel programming models. Sound means that the first data race identified by the DC relation is guaranteed to be a real data race. A prototype analysis in the Java Pathfinder model checker shows that the DC relation can significantly reduce the number of explored states required to prove data race freedom in Habanero Java programs. In this application, the search for data race using the DC relation is both sound and complete. © 2019 FMCAD Inc.
591 a7005411524 Mercer E. p567 False Conference 216 GEESE: Grammatical evolution algorithm for evolution of swarm behaviors [No abstract available]
592 a36459611200 Bingham E. p158 True Journal 110 Identifying Team Selection and Alignment Factors by Delivery Method for Transportation Projects One critical antecedent to project success is team alignment. Industry professionals should focus on practices that can improve project team selection, team building, and identifying challenges to the team and project, hence improving alignment. This paper provides a summary of key findings of a national study of transportation projects, identifying current practices of industry professionals for the selection and alignment of project teams for transportation projects. Current team selection practices, the most beneficial team alignment practices, and the greatest challenges to team alignment are identified in the study. These practices are also analyzed and reported by project delivery method, and the results presented in this paper add to the body of knowledge by identifying current alignment practices, successful practices, and challenges specific to each delivery method. Among the findings are that overall project teams are selected primarily based on project experience and ability to meet schedule, regardless of the project delivery method chosen. Successful teams with good alignment were found to be characterized by having established expectations, team trust, honesty within the team, shared values, and good communication. No notable differences were found among delivery methods, demonstrating that the principles of team alignment are not dependent on the project delivery method. Challenges that cause adversarial relationships in the team include issues of constructability, schedule availability, and project complexity. The study also identified transportation-specific alignment challenges such as public involvement. The greatest challenges specific to each delivery method include team coordination for construction manager at risk (CMAR) projects, constructability procedures for design-bid-build projects, and environmental impacts for design-build projects. © 2019 American Society of Civil Engineers.
592 a36459611200 Bingham E. p501 True Journal 272 Measuring User Perceptions of Popular Transportation Project Delivery Methods Using Least Significant Difference Intervals and Multiple Range Tests One of the most critical decisions made by transportation project stakeholders is the choice of a project delivery method for their project. Delivery methods have been shown to significantly impact project cost and schedule. As the use of alternative project delivery methods increases, the perceptions of the advantages and disadvantages to using a particular method have matured. This paper reports on a national study of over 80 transportation owners and designers to measure their perceptions of the three most widely used delivery methods: design bid build (DBB), construction manager at risk (CMAR), and design build (DB). The study develops a list of factors that influence the selection of a delivery method, and then tests the most significant factors that lead to the selection of each individual method. Analyses using Fisher's least significant difference intervals and multiple range tests allow for the identification of specific correlations between the delivery method and motivating factors or project goals. The analyses show that delivery method selection is motivated primarily by project urgency, cost, and risk allocation. For the three main delivery methods of DBB, CMAR, and DB, motivation for their selection is primarily based on cost, risk allocation, and project urgency, respectively. User perceptions align with findings from literature in terms of schedule performance, but do not align in terms of cost performance. This research contributes to the body of knowledge by reporting on the most current motivating factors for the selection and use of the most popular delivery methods. © 2018 American Society of Civil Engineers.
592 a36459611200 Bingham E. p770 True Journal 377 Infrastructure Project Scope Definition Using Project Definition Rating Index Front-end planning (FEP) is a critical process for uncovering project unknowns while also developing adequate scope definition and a structured approach for the project execution process. For infrastructure projects, the FEP process assists in identifying and mitigating risks stemming from issues such as right-of-way concerns, utility adjustments, environmental hazards, logistic problems, and permitting requirements. The authors have developed a novel risk management tool, called the project definition rating index (PDRI) for infrastructure projects, which can be used to identify and address these issues systematically and in a structured manner. Input from 64 industry professionals representing over 30 organizations was used in the development of the tool. In addition to a usable definition for infrastructure in the context of the built environment, a finite and specific list of issues related to scope definition of infrastructure projects was developed with this industry input. Data from 26 completed or in-process projects are given. Results show that the PDRI assessment score is indicative of the current level of scope definition for sample projects and corresponds to project performance. Findings support the hypothesis that projects with improved early understanding of scope definition elements showed improved project outcomes; infrastructure projects with low PDRI scores (well defined) outperformed projects with high PDRI scores. This research contributes to the body of knowledge by specifically identifying those FEP elements that are critical to infrastructure projects. © 2016 American Society of Civil Engineers.
593 a7402074463 Edward Gibson G. p158 False Journal 110 Identifying Team Selection and Alignment Factors by Delivery Method for Transportation Projects One critical antecedent to project success is team alignment. Industry professionals should focus on practices that can improve project team selection, team building, and identifying challenges to the team and project, hence improving alignment. This paper provides a summary of key findings of a national study of transportation projects, identifying current practices of industry professionals for the selection and alignment of project teams for transportation projects. Current team selection practices, the most beneficial team alignment practices, and the greatest challenges to team alignment are identified in the study. These practices are also analyzed and reported by project delivery method, and the results presented in this paper add to the body of knowledge by identifying current alignment practices, successful practices, and challenges specific to each delivery method. Among the findings are that overall project teams are selected primarily based on project experience and ability to meet schedule, regardless of the project delivery method chosen. Successful teams with good alignment were found to be characterized by having established expectations, team trust, honesty within the team, shared values, and good communication. No notable differences were found among delivery methods, demonstrating that the principles of team alignment are not dependent on the project delivery method. Challenges that cause adversarial relationships in the team include issues of constructability, schedule availability, and project complexity. The study also identified transportation-specific alignment challenges such as public involvement. The greatest challenges specific to each delivery method include team coordination for construction manager at risk (CMAR) projects, constructability procedures for design-bid-build projects, and environmental impacts for design-build projects. © 2019 American Society of Civil Engineers.
593 a7402074463 Edward Gibson G. p501 False Journal 272 Measuring User Perceptions of Popular Transportation Project Delivery Methods Using Least Significant Difference Intervals and Multiple Range Tests One of the most critical decisions made by transportation project stakeholders is the choice of a project delivery method for their project. Delivery methods have been shown to significantly impact project cost and schedule. As the use of alternative project delivery methods increases, the perceptions of the advantages and disadvantages to using a particular method have matured. This paper reports on a national study of over 80 transportation owners and designers to measure their perceptions of the three most widely used delivery methods: design bid build (DBB), construction manager at risk (CMAR), and design build (DB). The study develops a list of factors that influence the selection of a delivery method, and then tests the most significant factors that lead to the selection of each individual method. Analyses using Fisher's least significant difference intervals and multiple range tests allow for the identification of specific correlations between the delivery method and motivating factors or project goals. The analyses show that delivery method selection is motivated primarily by project urgency, cost, and risk allocation. For the three main delivery methods of DBB, CMAR, and DB, motivation for their selection is primarily based on cost, risk allocation, and project urgency, respectively. User perceptions align with findings from literature in terms of schedule performance, but do not align in terms of cost performance. This research contributes to the body of knowledge by reporting on the most current motivating factors for the selection and use of the most popular delivery methods. © 2018 American Society of Civil Engineers.
593 a7402074463 Edward Gibson G. p770 False Journal 377 Infrastructure Project Scope Definition Using Project Definition Rating Index Front-end planning (FEP) is a critical process for uncovering project unknowns while also developing adequate scope definition and a structured approach for the project execution process. For infrastructure projects, the FEP process assists in identifying and mitigating risks stemming from issues such as right-of-way concerns, utility adjustments, environmental hazards, logistic problems, and permitting requirements. The authors have developed a novel risk management tool, called the project definition rating index (PDRI) for infrastructure projects, which can be used to identify and address these issues systematically and in a structured manner. Input from 64 industry professionals representing over 30 organizations was used in the development of the tool. In addition to a usable definition for infrastructure in the context of the built environment, a finite and specific list of issues related to scope definition of infrastructure projects was developed with this industry input. Data from 26 completed or in-process projects are given. Results show that the PDRI assessment score is indicative of the current level of scope definition for sample projects and corresponds to project performance. Findings support the hypothesis that projects with improved early understanding of scope definition elements showed improved project outcomes; infrastructure projects with low PDRI scores (well defined) outperformed projects with high PDRI scores. This research contributes to the body of knowledge by specifically identifying those FEP elements that are critical to infrastructure projects. © 2016 American Society of Civil Engineers.
594 a34868168700 El Asmar M. p158 False Journal 110 Identifying Team Selection and Alignment Factors by Delivery Method for Transportation Projects One critical antecedent to project success is team alignment. Industry professionals should focus on practices that can improve project team selection, team building, and identifying challenges to the team and project, hence improving alignment. This paper provides a summary of key findings of a national study of transportation projects, identifying current practices of industry professionals for the selection and alignment of project teams for transportation projects. Current team selection practices, the most beneficial team alignment practices, and the greatest challenges to team alignment are identified in the study. These practices are also analyzed and reported by project delivery method, and the results presented in this paper add to the body of knowledge by identifying current alignment practices, successful practices, and challenges specific to each delivery method. Among the findings are that overall project teams are selected primarily based on project experience and ability to meet schedule, regardless of the project delivery method chosen. Successful teams with good alignment were found to be characterized by having established expectations, team trust, honesty within the team, shared values, and good communication. No notable differences were found among delivery methods, demonstrating that the principles of team alignment are not dependent on the project delivery method. Challenges that cause adversarial relationships in the team include issues of constructability, schedule availability, and project complexity. The study also identified transportation-specific alignment challenges such as public involvement. The greatest challenges specific to each delivery method include team coordination for construction manager at risk (CMAR) projects, constructability procedures for design-bid-build projects, and environmental impacts for design-build projects. © 2019 American Society of Civil Engineers.
594 a34868168700 El Asmar M. p501 False Journal 272 Measuring User Perceptions of Popular Transportation Project Delivery Methods Using Least Significant Difference Intervals and Multiple Range Tests One of the most critical decisions made by transportation project stakeholders is the choice of a project delivery method for their project. Delivery methods have been shown to significantly impact project cost and schedule. As the use of alternative project delivery methods increases, the perceptions of the advantages and disadvantages to using a particular method have matured. This paper reports on a national study of over 80 transportation owners and designers to measure their perceptions of the three most widely used delivery methods: design bid build (DBB), construction manager at risk (CMAR), and design build (DB). The study develops a list of factors that influence the selection of a delivery method, and then tests the most significant factors that lead to the selection of each individual method. Analyses using Fisher's least significant difference intervals and multiple range tests allow for the identification of specific correlations between the delivery method and motivating factors or project goals. The analyses show that delivery method selection is motivated primarily by project urgency, cost, and risk allocation. For the three main delivery methods of DBB, CMAR, and DB, motivation for their selection is primarily based on cost, risk allocation, and project urgency, respectively. User perceptions align with findings from literature in terms of schedule performance, but do not align in terms of cost performance. This research contributes to the body of knowledge by reporting on the most current motivating factors for the selection and use of the most popular delivery methods. © 2018 American Society of Civil Engineers.
595 a57126129700 Hogstrom C. p159 False Journal 111 On Sparse Channel Estimation in Aeronautical Telemetry This paper examines the application of sparse estimation techniques for the estimation of a discrete-time equivalent multipath channel in the aeronautical telemetry context. The sensing matrix comprises samples of shaped offset QPSK-TG (a continuous phase modulation) based on the pilot bit sequence currently defined in the aeronautical telemetry standard. Representative algorithms from the three broad classes of sparse estimators were examined side by side using computer simulations to estimate the postequalizer bit error rate (BER). Ideal and nonideal frequency offset synchronization were assumed in the simulations. The results show that the performance of the matching pursuit (MP) algorithms seemed to be better suited to this application in the sense that no additional steps were required and the postequalizer BER of the best MP algorithm was slightly better than that of the other sparse estimation techniques. In the case of both ideal and nonideal frequency offset synchronization, the postequalizer BER achieved by the generalized orthogonal MP algorithm was approximately 1.5 dB better than that obtained using the nonsparse-constrained maximum likelihood channel estimate. © 1965-2011 IEEE.
595 a57126129700 Hogstrom C. p807 False Conference 342 On if-to-baseband translation and resampling in sampled-data receivers This paper summarizes the design of a discrete-time quadrature downconversion and resampling processor that operates on samples of a 70 MHz IF signal. The unique properties of discrete-time processing-aliasing due to resampling bandpass signals and polyphase filter decompositions- are applied to create a low-complexity approach that does not require any arithmetic operations at the IF sample rate. The required tasks are performed in two stages: a downsample-by-2 operation followed by a more traditional resampler based on a polyphase filterbank.
595 a57126129700 Hogstrom C. p886 False Conference 398 A summary of data-aided equalizer experiments at edwards AFB This paper summarizes the analysis of bit error rate data captured during flight tests designed to compare data-aided equalizers with SOQPSK-TG to unequalized and currently available blind, adaptive equalizers with SOQPSK-TG. The number of bit errors, on a second-by-second basis, are analyzed. The results are different for each test point. Given the uncertain behavior of the preamble detector for the data-aided equalizer and the differing channel conditions between the data-aided equalizer channel and the conventional serial streaming telemetry channel, we are unable to draw any firm comparative conclusions.
596 a57218886153 Stankovic A.M. p160 False Conference 30 Probabilistic Network Observability of a Hybrid Power System with Communication Irregularities This paper explores power system network observability while taking into account realistic communication network behavior. The overall information is obtained by combining SCADA-and phasor measurement unit-derived data, where time stamping (based on Global Positioning System or an equivalent local clock) for all measurements is assumed. Based on simulations performed in communication Network Simulator 2, empirical cumulative distribution functions can be associated with transfer times of measurement packets, which will reflect communication parameters and irregularities. This is further used to form an algorithm which maximizes the number of successful network observability checks, and thus the number of possible state estimations, in a certain time period. Application is demonstrated on the IEEE 14-bus test power system example. © 2019 IEEE.
596 a57218886153 Stankovic A.M. p284 False Conference 68 Geometrically Motivated Reparameterization for Identifiability Analysis in Power Systems Models This paper describes a geometric approach to parameter identifiability analysis in models of power systems dynamics. When a model of a power system is to be compared with measurements taken at discrete times, it can be interpreted as a mapping from parameter space into a data or prediction space. Generically, model mappings can be interpreted as manifolds with dimensionality equal to the number of structurally identifiable parameters. Empirically it is observed that model mappings often correspond to bounded manifolds. We propose a new definition of practical identifiability based the topological definition of a manifold with boundary. In many ways, our proposed definition extends the properties of structural identifiability. We construct numerical approximations to geodesics on the model manifold and use the results, combined with insights derived from the mathematical form of the equations, to identify combinations of practically identifiable and unidentifiable parameters. We give several examples of application to dynamic power systems models. © 2018 IEEE.
596 a57218886153 Stankovic A.M. p406 False Conference 152 Influence of Communication Irregularities and Co-simulation on Hybrid Power System State Estimation The paper explores the effects of sensor behavior and communication system (CS) irregularities on power system state estimation (SE). CS are modeled in Network Simulator 2 (NS-2), allowing the quantification of irregularities, including delays and dropped packets. The overall information is obtained combining SCADA measurements with phasor measurement unit (PMU) derived data, where time stamping (based on GPS or an equivalent local clock) for all measurements is assumed. To fully analyze the effects of irregularities, a detailed analysis of sensitivities to different communication system parameters is provided as well. Using the co-simulation environment PiccSIM, a SE with these irregularities is quantified for CS parameter variation, with detailed models of power and communication flows. © 2018 IEEE.
597 a57205617484 Francis B.L. p161 True Conference 31 Network Reduction in Transient Stability Models using Partial Response Matching We describe a method for simultaneously identifying and reducing dynamic power systems models in the form of differential-algebraic equations. Often, these models are large and complex, containing more parameters than can be identified from the available system measurements. We demonstrate our method on transient stability models, using the IEEE 14-bus test system. Our approach uses techniques of information geometry to remove unidentifiable parameters from the model. We examine the case of a networked system with 58 parameters using full observations throughout the network. We show that greater reduction can be achieved when only partial observations are available, Including reduction of the network itself. © 2019 IEEE.
597 a57205617484 Francis B.L. p284 False Conference 68 Geometrically Motivated Reparameterization for Identifiability Analysis in Power Systems Models This paper describes a geometric approach to parameter identifiability analysis in models of power systems dynamics. When a model of a power system is to be compared with measurements taken at discrete times, it can be interpreted as a mapping from parameter space into a data or prediction space. Generically, model mappings can be interpreted as manifolds with dimensionality equal to the number of structurally identifiable parameters. Empirically it is observed that model mappings often correspond to bounded manifolds. We propose a new definition of practical identifiability based the topological definition of a manifold with boundary. In many ways, our proposed definition extends the properties of structural identifiability. We construct numerical approximations to geodesics on the model manifold and use the results, combined with insights derived from the mathematical form of the equations, to identify combinations of practically identifiable and unidentifiable parameters. We give several examples of application to dynamic power systems models. © 2018 IEEE.
597 a57205617484 Francis B.L. p310 True Conference 90 Analysis of inertial measurement data from a model rocket payload As part of a student-educational experience in telemetry, beginning undergraduates build, program, and test small payloads flown in model rockets. These payloads, nicknamed 'femtosats,' collect and transmit real time telemetry on the rocket's performance. The femtosats measure the inertial motions of the model rocket, providing info to extract the flight path. The individually student-designed femtosat circuit board includes a simple inertial measurement sensor that collects acceleration data in the form of x, y, z acceleration vectors which are transmitted in real-time to a radio ground station. The focus of this paper is the collection and analysis of the data from the telemetered inertial measurement sensor and how it can be interpreted and applied in simple model rocket motion analysis. © 2019 International Foundation for Telemetering. All rights reserved.
597 a57205617484 Francis B.L. p403 False Conference 149 Simultaneous Global Identification of Dynamic and Network Parameters in Transient Stability Studies The paper describes a global identification procedure for dynamic power system models in the form of differential and algebraic equations. Power system models have a number of features that makes their improvement challenging - they are multi-level, multi-user and multi-physics. Not surprisingly, they are nonlinear and time varying, both in terms of states (memory variables) and parameters, and discrete structures, such as graphs, are strongly blended with continuous dynamics, resulting in network dynamics. The transient stability models are used as a prototypical example. Our method is based on information geometry, and uses advances in computational differential geometry to characterize high-dimensional manifolds in the space of measurements. In the case of network parameters, a comparison is presented with circuit-theoretic techniques. The results are illustrated on the case of IEEE 14-bus test system with 58 parameters in our realization. © 2018 IEEE.
598 a57215432728 Nuttall J.R. p161 False Conference 31 Network Reduction in Transient Stability Models using Partial Response Matching We describe a method for simultaneously identifying and reducing dynamic power systems models in the form of differential-algebraic equations. Often, these models are large and complex, containing more parameters than can be identified from the available system measurements. We demonstrate our method on transient stability models, using the IEEE 14-bus test system. Our approach uses techniques of information geometry to remove unidentifiable parameters from the model. We examine the case of a networked system with 58 parameters using full observations throughout the network. We show that greater reduction can be achieved when only partial observations are available, Including reduction of the network itself. © 2019 IEEE.
599 a56677251600 Nelson T.G. p162 True Journal 112 Origami-inspired sacrificial joints for folding compliant mechanisms Folding is a manufacturing method which can create complex 3D geometries from flat materials and can be particularly useful in cost-sensitive or planar-limited fabrication applications. This paper introduces compliant mechanisms that employ folding techniques from origami to evolve from a flat material to deployed state. We present origami-inspired sacrificial joints, joints which have mobility during assembly of the mechanism but are rigid in their final position, to create regions of high and low stiffness and the proper alignment of compliant flexures in folded mechanisms. To demonstrate the method we fold steel sheet to create some well-known and complex compliant mechanisms. © 2019 Elsevier Ltd
599 a56677251600 Nelson T.G. p201 False Journal 135 Normalized Coordinate Equations and an Energy Method for Predicting Natural Curved-Fold Configurations Of the many valid configurations that a curved fold may assume, it is of particular interest to identify natural - or lowest energy - configurations that physical models will preferentially assume. We present normalized coordinate equations - equations that relate fold surface properties to their edge of regression - to simplify curved-fold relationships. An energy method based on these normalized coordinate equations is developed to identify natural configurations of general curved folds. While it has been noted that natural configurations have nearly planar creases for curved folds, we show that nonplanar behavior near the crease ends substantially reduces the energy of a fold. © 2019 ASME.
599 a56677251600 Nelson T.G. p383 True Journal 209 Developable mechanisms on developable surfaces The trend toward smaller mechanism footprints and volumes, while maintaining the ability to perform complex tasks, presents the opportunity for exploration of hypercompact mechanical systems integrated with curved surfaces. Developable surfaces are shapes that a flat sheet can take without tearing or stretching, and they represent a wide range of manufactured surfaces. This work introduces “developable mechanisms” as devices that emerge from or conform to developable surfaces. They are made possible by aligning hinge axes with developable surface ruling lines to enable mobility. Because rigid-link motion depends on the relative orientation of hinge axes and not link geometry, links can take the shape of the corresponding developable surface. Mechanisms are classified by their associated surface type, and these relationships are defined and demonstrated by example. Developable mechanisms show promise for meeting unfilled needs using systems not previously envisioned. © 2019 The Authors, some rights reserved.
599 a56677251600 Nelson T.G. p457 True Conference 163 Implementation of Rolling Contacts for SORCE Joints The Synchronized-offset-rolling-contact element (SORCE) technique for thickness accommodation in origami-inspired mechanisms combines selected strengths of several thickness-accomadation techniques but with the tradeoff of manufacturing complexity of rolling joints. This work presents principles to facilitate the construction of rolling joints suitable for applications like the SORCE technique. These include leveraging fold-angle multipliers of origami vertices, variations of flexure assembly, sunken flexures, and form-closed rolling joints. Prototypes of origami-mechanisms using the SORCE technique are constructed demonstrating these principles. © 2018 IEEE.
599 a56677251600 Nelson T.G. p468 True Journal 258 Developable compliant-aided rolling-contact mechanisms Rolling-contact mechanisms can provide low-friction motion with unique kinematic paths. We show that developable surfaces can be used as a design tool for rolling-contact mechanisms joined with compliant bands. These mechanisms can exhibit 3D motion paths, couple rotational and translational motions into a single degree of freedom, and can be designed to exhibit various tailored kinetic responses. We set forth developable surface parametrizations well suited to the creation of rolling contacts. We highlight how the geodesic and principal curvatures of the non-ruling principal curves of a developable surface are meaningful design quantities for rolling contacts. We provide kinematic and kinetic analyses and demonstrate several developable compliant-aided rolling-contact mechanisms in physical prototypes. © 2018 Elsevier Ltd
599 a56677251600 Nelson T.G. p495 False Conference 186 Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lath Martensitic Steel The study of post-transformation microstructures and their properties can be greatly enhanced by studying their dependence on the grain boundary content of parent microstructures. Recent work has extended the crystallographic reconstruction of parent austenite in steels to include the reconstruction of special boundaries, such as annealing twins. These reconstructions present unique challenges, as twinned austenite grains share a subset of possible daughter variant orientations. This gives rise to regions of ambiguity in a reconstruction. A technique for the reconstruction of twin boundaries is presented here that is capable of reconstructing 60° <1 1 1> twins, even in the case where twin regions are comprised entirely of variants that are common between the twin and the parent. This technique is demonstrated in the reconstruction of lath martensitic steels. The reconstruction method utilizes a delayed decision-making approach, where a chosen orientation relationship is used to define all possible groupings of daughter grains into possible parents before divisive decisions are made. These overlapping, inclusive groupings (called clusters) are compared to each other individually using their calculated parent austenite orientations and the topographical nature of the overlapping region. These comparisons are used to uncover possible locations of twin boundaries present in the parent austenite. This technique can be applied to future studies on the dependence of post-transformation microstructures on the special grain boundary content of parent microstructures. © 2018 Institute of Physics Publishing. All rights reserved.
599 a56677251600 Nelson T.G. p762 False Journal 371 Thick rigidly foldable origami mechanisms based on synchronized offset rolling contact elements We present a general technique for achieving kinematic single degree of freedom (1DOF) origami-based mechanisms with thick rigid panels using synchronized offset rolling contact elements (SORCEs). We present general design analysis for planar and 3D relative motions between panels and show physically realized examples. The technique overcomes many of the limitations of previous approaches for thick rigidly foldable mechanisms. © 2017 by ASME.
599 a56677251600 Nelson T.G. p854 False Conference 378 Kinematics and discretization of curved-fold mechanisms We present several new properties of curved-fold mechanisms, those with smoothly curved surfaces joined by sharp curved folds. After describing curved folds and various relationships among their geometric properties, we show that there is an important class, uniform folds, that is particularly well suited to low-degree-of-freedom mechanisms. There is a natural discretization algorithm for uniform curved folds; we present this algorithm and show discretized example mechanisms. Copyright © 2017 ASME.
600 a57208598187 Avila A. p162 False Journal 112 Origami-inspired sacrificial joints for folding compliant mechanisms Folding is a manufacturing method which can create complex 3D geometries from flat materials and can be particularly useful in cost-sensitive or planar-limited fabrication applications. This paper introduces compliant mechanisms that employ folding techniques from origami to evolve from a flat material to deployed state. We present origami-inspired sacrificial joints, joints which have mobility during assembly of the mechanism but are rigid in their final position, to create regions of high and low stiffness and the proper alignment of compliant flexures in folded mechanisms. To demonstrate the method we fold steel sheet to create some well-known and complex compliant mechanisms. © 2019 Elsevier Ltd
600 a57208598187 Avila A. p283 True Journal 185 Origami fold states: Concept and design tool The ability of origami to alter its properties and behaviors with its shape makes it an elegant source of inspiration for many engineering designs challenges. Fold states specify the shape of the origami - its facets, creases, and fold angles. Origami research recognizes several acknowledged fold states: The unfolded, fully folded, and flat-folded states. However, these fold states are not comprehensive, excluding some of the most predominant fold states in origami-based devices. In this paper we propose a comprehensive list of fold states based on fold angles. We support the method of categorizing fold states by evaluating the functions and fold states of a large sample of origami-based devices. These correlations provide insight for selecting fold states for origami-based design. We discuss properties and behaviors of the fold states individually and provide a process for fold-state selection. © Author(s) 2019.
600 a57208598187 Avila A. p318 True Conference 98 Conceptualizing stable states in origami-based devices using an energy visualization approach In many origami-based applications a device needs to be maintained in one or more fold states. The origami stability integration method (OSIM) presented in this paper provides an approach for graphically combining various techniques to achieve stability. Techniques are divided into four groups based on whether they are intrinsic or extrinsic to the origami pattern and whether they exhibit differentiable or non-differentiable energy storage behaviors. These categorizations can help designers select appropriate techniques for their application. The paper also contains design considerations and resources for several intrinsic techniques. Finally, two case studies are presented which use the OSIM and the technique guidelines to conceptualize stability in origami-based devices. Copyright © 2019 ASME.
600 a57208598187 Avila A. p321 False Conference 101 Kirigami-based deployable transcrease hard stop models usable in origami patterns Stopping origami in arbitrary fold states can present a challenge for origami-based design. In this paper two categories of kirigami-based models are presented for stopping the fold motion of individual creases using deployable hard stops. These models are transcrease (across a crease) and deploy from a flat sheet. The first category is planar and has behavior similar to a four-bar linkage. The second category is spherical and behaves like a degree-4 origami vertex. These models are based on the zero-thickness assumption of paper and can be applied to origami patterns made from thin materials, limiting the motion of the base origami pattern through self-interference within the original facets. Model parameters are based on a desired fold or dihedral angle, as well as facet dimensions. Examples show model benefits and limitations. Copyright © 2019 ASME.
601 a7004307869 Herder J.L. p162 False Journal 112 Origami-inspired sacrificial joints for folding compliant mechanisms Folding is a manufacturing method which can create complex 3D geometries from flat materials and can be particularly useful in cost-sensitive or planar-limited fabrication applications. This paper introduces compliant mechanisms that employ folding techniques from origami to evolve from a flat material to deployed state. We present origami-inspired sacrificial joints, joints which have mobility during assembly of the mechanism but are rigid in their final position, to create regions of high and low stiffness and the proper alignment of compliant flexures in folded mechanisms. To demonstrate the method we fold steel sheet to create some well-known and complex compliant mechanisms. © 2019 Elsevier Ltd
601 a7004307869 Herder J.L. p468 False Journal 258 Developable compliant-aided rolling-contact mechanisms Rolling-contact mechanisms can provide low-friction motion with unique kinematic paths. We show that developable surfaces can be used as a design tool for rolling-contact mechanisms joined with compliant bands. These mechanisms can exhibit 3D motion paths, couple rotational and translational motions into a single degree of freedom, and can be designed to exhibit various tailored kinetic responses. We set forth developable surface parametrizations well suited to the creation of rolling contacts. We highlight how the geodesic and principal curvatures of the non-ruling principal curves of a developable surface are meaningful design quantities for rolling contacts. We provide kinematic and kinetic analyses and demonstrate several developable compliant-aided rolling-contact mechanisms in physical prototypes. © 2018 Elsevier Ltd
602 a57205257595 Machekposhti D.F. p162 False Journal 112 Origami-inspired sacrificial joints for folding compliant mechanisms Folding is a manufacturing method which can create complex 3D geometries from flat materials and can be particularly useful in cost-sensitive or planar-limited fabrication applications. This paper introduces compliant mechanisms that employ folding techniques from origami to evolve from a flat material to deployed state. We present origami-inspired sacrificial joints, joints which have mobility during assembly of the mechanism but are rigid in their final position, to create regions of high and low stiffness and the proper alignment of compliant flexures in folded mechanisms. To demonstrate the method we fold steel sheet to create some well-known and complex compliant mechanisms. © 2019 Elsevier Ltd
603 a36503632200 Candia G. p163 False Journal 113 Observed building damage patterns and foundation performance in Mexico City following the 2017 M7.1 Puebla-Mexico City earthquake The September 19th, 2017 M7.1 Puebla-Mexico City earthquake introduced strong ground motions into the Mexico City basin, which contains very soft lacustrine soils, dense urban infrastructure, and millions of inhabitants. As a result, 38 mid-rise structures collapsed and several hundred more were damaged. This paper reports the observations related to building performance, damage patterns, and foundation performance made by the two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical aspects of the earthquake. The methodology used to perform building damage mapping following the 2017 event is described. Comparisons are made between the observed building damage patterns following the September 19th, 1985 and the 2017 earthquake, and the distinct differences in the damage pattern distribution between the two earthquakes are summarized. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized. © 2019 Elsevier Ltd
604 a16481299700 Mayoral J.M. p163 False Journal 113 Observed building damage patterns and foundation performance in Mexico City following the 2017 M7.1 Puebla-Mexico City earthquake The September 19th, 2017 M7.1 Puebla-Mexico City earthquake introduced strong ground motions into the Mexico City basin, which contains very soft lacustrine soils, dense urban infrastructure, and millions of inhabitants. As a result, 38 mid-rise structures collapsed and several hundred more were damaged. This paper reports the observations related to building performance, damage patterns, and foundation performance made by the two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical aspects of the earthquake. The methodology used to perform building damage mapping following the 2017 event is described. Comparisons are made between the observed building damage patterns following the September 19th, 1985 and the 2017 earthquake, and the distinct differences in the damage pattern distribution between the two earthquakes are summarized. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized. © 2019 Elsevier Ltd
604 a16481299700 Mayoral J.M. p185 True Journal 126 The September 19, 2017 Mw 7.1 Puebla-Mexico city earthquake: Important findings from the field – Overview of Special Edition The September 19th, 2017 Mw 7.1 Puebla-Mexico City earthquake lead to strong ground shaking in the densely populated Mexico City basin, and surrounding country areas in central Mexico. As a result, 38 mid-rise buildings collapsed and several hundred more were damaged in Mexico City, and extensive damage was observed in the states of Puebla and Morelos. This special edition synthesizes observations related to structural and foundation performance, and the corresponding damage patterns, carried out by two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical earthquake engineering aspects of this event. Articles were solicited of researchers that were in the field that investigated: the characteristics of the event, the demand and damage distribution across Mexico City and surrounding regions, the seismic performance of buildings, lifelines, and other critical infrastructure, considering the site response and soil-structure interaction effects in the observed damage distribution. Special attention was paid to the impact of regional ground subsidence, in the seismic-soil structure interaction exhibited by the affected building. Advanced non-intrusive survey methods were used to map damage patterns in a regional level. Comparisons were made between the observed building damage patterns following the September 19th, 1985 Michoacan earthquake, and the 2017 Puebla-Mexico City earthquake, and the distinct differences in the damage distribution between the two earthquakes were revised. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction, which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized in each research paper include in this special issue. © 2019 Elsevier Ltd
604 a16481299700 Mayoral J.M. p228 True Journal 150 Site effects in Mexico City basin: Past and present Due to the unique subsoil conditions prevailing in the Mexico City basin, seismic risk has been strongly correlated to site effects. Thus, during the Mw 8.1 09/19/1985 subduction fault earthquake, and its strong aftershock Mw 7.5 09/21/1985, extensive damage was observed in the area, along with the loss of thousands of lives, despite these events had an epicentral distance of around 430 km from Mexico City. The observed damage was mostly due to site affects originated by the high plastiCity clay deposits found in the basin, which lead to large amplifications, and duration elongation of the ground motions coming from the epicenter. In addition, a frequency content modification occurs, which in turn, leads to a double resonance effect between the incoming ground motions, soil deposits, and the damaged buildings. Exactly 32 years after this devastating event, the Mw 7.1 09/19/2017 normal fault earthquake, reminded us of the importance of accounting for site effects, and most importantly the need to carry out a proper characterization of basin geometry, soil profile configuration, hydraulic conditions, and maintenance-structure periodic assessments of the building stock in Mexico City. This is required to reduce uncertainties of seismic vulnerability studies for extreme-event seismic hazard scenarios. In this paper, the role of site response and seismic soil-structure interaction as key factors responsible of the observed damage in the City is revisited, through series of 3D finite difference models of typical structure-foundation-soil typologies found at the areas where most of the damage was observed, highlighting its clear impact in the final damage distribution observed around the City. © 2019 Elsevier Ltd
605 a56331558100 Wood C.M. p163 False Journal 113 Observed building damage patterns and foundation performance in Mexico City following the 2017 M7.1 Puebla-Mexico City earthquake The September 19th, 2017 M7.1 Puebla-Mexico City earthquake introduced strong ground motions into the Mexico City basin, which contains very soft lacustrine soils, dense urban infrastructure, and millions of inhabitants. As a result, 38 mid-rise structures collapsed and several hundred more were damaged. This paper reports the observations related to building performance, damage patterns, and foundation performance made by the two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical aspects of the earthquake. The methodology used to perform building damage mapping following the 2017 event is described. Comparisons are made between the observed building damage patterns following the September 19th, 1985 and the 2017 earthquake, and the distinct differences in the damage pattern distribution between the two earthquakes are summarized. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized. © 2019 Elsevier Ltd
605 a56331558100 Wood C.M. p228 False Journal 150 Site effects in Mexico City basin: Past and present Due to the unique subsoil conditions prevailing in the Mexico City basin, seismic risk has been strongly correlated to site effects. Thus, during the Mw 8.1 09/19/1985 subduction fault earthquake, and its strong aftershock Mw 7.5 09/21/1985, extensive damage was observed in the area, along with the loss of thousands of lives, despite these events had an epicentral distance of around 430 km from Mexico City. The observed damage was mostly due to site affects originated by the high plastiCity clay deposits found in the basin, which lead to large amplifications, and duration elongation of the ground motions coming from the epicenter. In addition, a frequency content modification occurs, which in turn, leads to a double resonance effect between the incoming ground motions, soil deposits, and the damaged buildings. Exactly 32 years after this devastating event, the Mw 7.1 09/19/2017 normal fault earthquake, reminded us of the importance of accounting for site effects, and most importantly the need to carry out a proper characterization of basin geometry, soil profile configuration, hydraulic conditions, and maintenance-structure periodic assessments of the building stock in Mexico City. This is required to reduce uncertainties of seismic vulnerability studies for extreme-event seismic hazard scenarios. In this paper, the role of site response and seismic soil-structure interaction as key factors responsible of the observed damage in the City is revisited, through series of 3D finite difference models of typical structure-foundation-soil typologies found at the areas where most of the damage was observed, highlighting its clear impact in the final damage distribution observed around the City. © 2019 Elsevier Ltd
606 a47962305800 Montgomery J. p163 False Journal 113 Observed building damage patterns and foundation performance in Mexico City following the 2017 M7.1 Puebla-Mexico City earthquake The September 19th, 2017 M7.1 Puebla-Mexico City earthquake introduced strong ground motions into the Mexico City basin, which contains very soft lacustrine soils, dense urban infrastructure, and millions of inhabitants. As a result, 38 mid-rise structures collapsed and several hundred more were damaged. This paper reports the observations related to building performance, damage patterns, and foundation performance made by the two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical aspects of the earthquake. The methodology used to perform building damage mapping following the 2017 event is described. Comparisons are made between the observed building damage patterns following the September 19th, 1985 and the 2017 earthquake, and the distinct differences in the damage pattern distribution between the two earthquakes are summarized. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized. © 2019 Elsevier Ltd
607 a7101640734 Hutchinson T. p163 False Journal 113 Observed building damage patterns and foundation performance in Mexico City following the 2017 M7.1 Puebla-Mexico City earthquake The September 19th, 2017 M7.1 Puebla-Mexico City earthquake introduced strong ground motions into the Mexico City basin, which contains very soft lacustrine soils, dense urban infrastructure, and millions of inhabitants. As a result, 38 mid-rise structures collapsed and several hundred more were damaged. This paper reports the observations related to building performance, damage patterns, and foundation performance made by the two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical aspects of the earthquake. The methodology used to perform building damage mapping following the 2017 event is described. Comparisons are made between the observed building damage patterns following the September 19th, 1985 and the 2017 earthquake, and the distinct differences in the damage pattern distribution between the two earthquakes are summarized. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized. © 2019 Elsevier Ltd
607 a7101640734 Hutchinson T. p185 False Journal 126 The September 19, 2017 Mw 7.1 Puebla-Mexico city earthquake: Important findings from the field – Overview of Special Edition The September 19th, 2017 Mw 7.1 Puebla-Mexico City earthquake lead to strong ground shaking in the densely populated Mexico City basin, and surrounding country areas in central Mexico. As a result, 38 mid-rise buildings collapsed and several hundred more were damaged in Mexico City, and extensive damage was observed in the states of Puebla and Morelos. This special edition synthesizes observations related to structural and foundation performance, and the corresponding damage patterns, carried out by two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical earthquake engineering aspects of this event. Articles were solicited of researchers that were in the field that investigated: the characteristics of the event, the demand and damage distribution across Mexico City and surrounding regions, the seismic performance of buildings, lifelines, and other critical infrastructure, considering the site response and soil-structure interaction effects in the observed damage distribution. Special attention was paid to the impact of regional ground subsidence, in the seismic-soil structure interaction exhibited by the affected building. Advanced non-intrusive survey methods were used to map damage patterns in a regional level. Comparisons were made between the observed building damage patterns following the September 19th, 1985 Michoacan earthquake, and the 2017 Puebla-Mexico City earthquake, and the distinct differences in the damage distribution between the two earthquakes were revised. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction, which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized in each research paper include in this special issue. © 2019 Elsevier Ltd
607 a7101640734 Hutchinson T. p228 False Journal 150 Site effects in Mexico City basin: Past and present Due to the unique subsoil conditions prevailing in the Mexico City basin, seismic risk has been strongly correlated to site effects. Thus, during the Mw 8.1 09/19/1985 subduction fault earthquake, and its strong aftershock Mw 7.5 09/21/1985, extensive damage was observed in the area, along with the loss of thousands of lives, despite these events had an epicentral distance of around 430 km from Mexico City. The observed damage was mostly due to site affects originated by the high plastiCity clay deposits found in the basin, which lead to large amplifications, and duration elongation of the ground motions coming from the epicenter. In addition, a frequency content modification occurs, which in turn, leads to a double resonance effect between the incoming ground motions, soil deposits, and the damaged buildings. Exactly 32 years after this devastating event, the Mw 7.1 09/19/2017 normal fault earthquake, reminded us of the importance of accounting for site effects, and most importantly the need to carry out a proper characterization of basin geometry, soil profile configuration, hydraulic conditions, and maintenance-structure periodic assessments of the building stock in Mexico City. This is required to reduce uncertainties of seismic vulnerability studies for extreme-event seismic hazard scenarios. In this paper, the role of site response and seismic soil-structure interaction as key factors responsible of the observed damage in the City is revisited, through series of 3D finite difference models of typical structure-foundation-soil typologies found at the areas where most of the damage was observed, highlighting its clear impact in the final damage distribution observed around the City. © 2019 Elsevier Ltd
607 a7101640734 Hutchinson T. p394 False Conference 143 Mexico City Basin Effects: Past, Present, and Future Seismic hazard in Mexico City governed by site effects. The M8.1 1985 subduction zone earthquake, which caused significant damage and loss of thousands of lives at 350 km epicentral distance, has become the quintessential example of the role that site effects can play in modifying the amplitude, frequency, and duration of ground shaking; and in aggravating the catastrophic consequences of earthquakes. We here present observations and analyses of the M7.1 September 19, 2017, event that -while triggered by an intraplate rupture at approximately half the epicentral distance of the 1985 event relative to Mexico City -caused severe structural damage to a few tens of buildings located in a relatively narrow zone between the hill and lake zones of the basin, known as the transition zone. We show that the M 7.1 mainshock exposed the vulnerabilities of the pre-1985 building code in the transition zone; but more importantly highlighted the improvement of the 1987 building code revision in terms of the performance of modern high-rise buildings that suffered catastrophic consequences during the 1985 Michoácan earthquake sequence. We next analyze several records collected at stations in the basin over the past 20 years. We highlight the importance of three-dimensional heterogeneity of the basin sediments, the coupling between hydrological setting and site response and their evolution with time, and the energy interaction between the deep basin edge and the shallow clay layers. Results presented are the collective effort of the GEER teams that were deployed to perform post-earthquake reconnaissance in the affected regions of the epicentral area and in Mexico City after the M 7.1 September 19, 2017, earthquake sequence. © 2019 American Society of Civil Engineers.
608 a55916448500 Morales-Velez A.C. p163 False Journal 113 Observed building damage patterns and foundation performance in Mexico City following the 2017 M7.1 Puebla-Mexico City earthquake The September 19th, 2017 M7.1 Puebla-Mexico City earthquake introduced strong ground motions into the Mexico City basin, which contains very soft lacustrine soils, dense urban infrastructure, and millions of inhabitants. As a result, 38 mid-rise structures collapsed and several hundred more were damaged. This paper reports the observations related to building performance, damage patterns, and foundation performance made by the two UNAM-GEER engineering reconnaissance teams sent to investigate the geotechnical aspects of the earthquake. The methodology used to perform building damage mapping following the 2017 event is described. Comparisons are made between the observed building damage patterns following the September 19th, 1985 and the 2017 earthquake, and the distinct differences in the damage pattern distribution between the two earthquakes are summarized. Overall, building and foundation performance were observed to be quite good during the 2017 event, especially when compared to the 1985 event. Structures that were observed to be heavily damaged or collapsed were all built prior to 1985, and incorporated poor structural design and/or construction which resonated with the soil column on which they were constructed, and/or were built upon very soft soils that contributed to significant foundation deformations. Detailed building damage pattern maps of specific neighborhoods that were investigated are provided, and lessons learned from this event are summarized. © 2019 Elsevier Ltd
609 a57200363612 Fagergren F. p164 True Journal 114 Using non-destructive testing to predict bending modulus of carbon infiltrated-carbon nanotubes Carbon infiltrated carbon nanotubes (CI-CNT) are an important emerging material in several micro-electro-mechanical systems (MEMS) because of their unique mechanical and chemical properties. While CI-CNTs are only roughly conductive they work well in micro springs, levers, and meshes. However, fabrication of CI-CNTs can result in large mechanical property variation, and methods to characterize properties usually involve destructive testing. Destructive testing also assumes the tested specimens are representative of the entire batch which is not always true in the case of CI-CNT production. Finding a non-destructive way to test for stiffness of this material reduces the number of parts that have to be made and increases confidence in the integrity of device being used. It also simplifies testing of complex parts. The stiffness of CI-CNT beams is related to the molecular structure of the carbon material infiltrated between the carbon nanotubes (CNTs), how it interacts with the CNTs, and how much of it there is. The amount of material can be approximated with the density of the beam, and both the type of material and its interaction with the CNTs can be approximated through analysis of the Raman spectra taken at the surface. A combination of these two observations can be related to the effective material stiffness. The relationship can be fitted with a power function, with a variance of 1.41 GPa, which is about 11% of the maximum stiffness of the samples tested. © 2019 IOP Publishing Ltd.
609 a57200363612 Fagergren F. p545 False Journal 230 A comparative analysis of computer-aided design team performance with collaboration software For the past several years, the BYU CAD Lab has been developing collaborative computer-aided design (CAD) software. As this software is being developed, industry seeks to better understand the differences in performance between teams using multi-user CAD and single-user CAD to make informed decisions about implementing this new software into their engineering processes. In order to better understand the differences in performance between teams, an experimental study was conducted in which four multi-user teams and four single-user teams competed to create the best model of a hand drill. Key findings of this study were that multi-user CAD increases awareness of teammates’ activities as well as communication between team members. Performance, with respect to the metrics of quality and time for completion, could be improved with increased familiarity with the multi-user CAD software. Future research directions are suggested and discussed. © 2018 CAD Solutions, LLC.
610 a57212151348 Sypherd S. p164 False Journal 114 Using non-destructive testing to predict bending modulus of carbon infiltrated-carbon nanotubes Carbon infiltrated carbon nanotubes (CI-CNT) are an important emerging material in several micro-electro-mechanical systems (MEMS) because of their unique mechanical and chemical properties. While CI-CNTs are only roughly conductive they work well in micro springs, levers, and meshes. However, fabrication of CI-CNTs can result in large mechanical property variation, and methods to characterize properties usually involve destructive testing. Destructive testing also assumes the tested specimens are representative of the entire batch which is not always true in the case of CI-CNT production. Finding a non-destructive way to test for stiffness of this material reduces the number of parts that have to be made and increases confidence in the integrity of device being used. It also simplifies testing of complex parts. The stiffness of CI-CNT beams is related to the molecular structure of the carbon material infiltrated between the carbon nanotubes (CNTs), how it interacts with the CNTs, and how much of it there is. The amount of material can be approximated with the density of the beam, and both the type of material and its interaction with the CNTs can be approximated through analysis of the Raman spectra taken at the surface. A combination of these two observations can be related to the effective material stiffness. The relationship can be fitted with a power function, with a variance of 1.41 GPa, which is about 11% of the maximum stiffness of the samples tested. © 2019 IOP Publishing Ltd.
611 a57212147414 Snow D. p164 False Journal 114 Using non-destructive testing to predict bending modulus of carbon infiltrated-carbon nanotubes Carbon infiltrated carbon nanotubes (CI-CNT) are an important emerging material in several micro-electro-mechanical systems (MEMS) because of their unique mechanical and chemical properties. While CI-CNTs are only roughly conductive they work well in micro springs, levers, and meshes. However, fabrication of CI-CNTs can result in large mechanical property variation, and methods to characterize properties usually involve destructive testing. Destructive testing also assumes the tested specimens are representative of the entire batch which is not always true in the case of CI-CNT production. Finding a non-destructive way to test for stiffness of this material reduces the number of parts that have to be made and increases confidence in the integrity of device being used. It also simplifies testing of complex parts. The stiffness of CI-CNT beams is related to the molecular structure of the carbon material infiltrated between the carbon nanotubes (CNTs), how it interacts with the CNTs, and how much of it there is. The amount of material can be approximated with the density of the beam, and both the type of material and its interaction with the CNTs can be approximated through analysis of the Raman spectra taken at the surface. A combination of these two observations can be related to the effective material stiffness. The relationship can be fitted with a power function, with a variance of 1.41 GPa, which is about 11% of the maximum stiffness of the samples tested. © 2019 IOP Publishing Ltd.
612 a57212136375 Cunningham A. p164 False Journal 114 Using non-destructive testing to predict bending modulus of carbon infiltrated-carbon nanotubes Carbon infiltrated carbon nanotubes (CI-CNT) are an important emerging material in several micro-electro-mechanical systems (MEMS) because of their unique mechanical and chemical properties. While CI-CNTs are only roughly conductive they work well in micro springs, levers, and meshes. However, fabrication of CI-CNTs can result in large mechanical property variation, and methods to characterize properties usually involve destructive testing. Destructive testing also assumes the tested specimens are representative of the entire batch which is not always true in the case of CI-CNT production. Finding a non-destructive way to test for stiffness of this material reduces the number of parts that have to be made and increases confidence in the integrity of device being used. It also simplifies testing of complex parts. The stiffness of CI-CNT beams is related to the molecular structure of the carbon material infiltrated between the carbon nanotubes (CNTs), how it interacts with the CNTs, and how much of it there is. The amount of material can be approximated with the density of the beam, and both the type of material and its interaction with the CNTs can be approximated through analysis of the Raman spectra taken at the surface. A combination of these two observations can be related to the effective material stiffness. The relationship can be fitted with a power function, with a variance of 1.41 GPa, which is about 11% of the maximum stiffness of the samples tested. © 2019 IOP Publishing Ltd.
612 a57212136375 Cunningham A. p324 True Conference 104 Simulation of a micro-electro-mechanical system for generating electrical power from pressurized gas This paper presents a novel approach to energy scavenging for a micro-electro-mechanical system (MEMS) device to convert the energy stored in pressurized gas into electrical power. The proposed design uses input pressure to move a piston and magnet through a set of coils while pulling on another mass through non-linear springs to open and close the input air valve. The model demonstrates that the design is capable of staying in motion with continual input pressure (up to at least a time stamp of 1 second), and that an average power output of 9.47 µW over 5 ms can be achieved. We suggest that further research be done to optimize the design parameters and that the optimized design be used to the test the system. Copyright © 2019 ASME.
613 a57200529047 Neff C. p165 True Journal 115 Mechanical and temperature resilience of multi-material systems for printed electronics packaging In this work, two AM technologies were utilized to compare the effectiveness of fabricating a simple electronic device with a conductive trace and hollow cylinder representative of 'printed packaging' that would survive harsh environmental conditions. The printed packaging cylinder delineates printed potting for electronics packaging. An nScrypt direct write (DW) system was the primary manufacturing system but a developing technology - coined large area projection sintering (LAPS) - manufactured a subset of samples for comparison. The tests follow Military Standard (MIL STD) 883 K and include resiliency evaluation for die shear strength, temperature cycling, thermal shock, and high G loading by mechanical shock. Results indicate DW Master Bond epoxy devices show resilience to extreme temperatures, thermal shock, and mechanical shocks while also surpassing the die shear strength failure criteria specified by the MIL STD. LAPS sintered Nylon devices also show mechanical resilience to thermal shock and surpass the die shear strength failure criteria. However, there were some open circuits, increases in resistance, and delamination when LAPS Nylon devices were subjected to extreme temperatures and 20 000 G shock loading normal to the substrate. The thermal effects are likely due to the thermal expansion mismatch between Nylon and the conductive paste while the mechanical shock effects may be attributed to the geometry differences of the LAPS Nylon printed packaging. Further studies are required to understand these failure modes in some of the LAPS Nylon samples and refine the process to address them. © 2019 IOP Publishing Ltd.
613 a57200529047 Neff C. p229 True Journal 151 Thermal and Vapor Smoothing of Thermoplastic for Reduced Surface Roughness of Additive Manufactured RF Electronics Additive manufacturing (AM) of electronics provides a route for creating customized systems with novel geometries that are not feasible with traditional methods. Standard AM processes such as extrusion can produce substrates on which electrical traces can be deposited. However, the surface roughness of plastic extrusion reduces the effective electrical conductivity and can introduce anisotropy, especially in radio frequency (RF) devices. The roughness can be reduced using vapor smoothing (VS), but solvent absorption changes the surface composition slightly, can be environmentally hazardous, and is not feasible with all thermoplastics. A new method introduced here - coined thermal smoothing (TS) - utilizes a heat source to locally reflow the material, thus minimizing the roughness of the undulating surfaces without the drawbacks of VS. This research work compares the surface roughness impacts of both smoothing processes with profilometry and scanning electron microscope (SEM) images. Both smoothing processes significantly reduce the surface roughness of extruded components by 80% and 90% for TS and VS, respectively. This paper also examines the influence of surface smoothing on high-frequency conductivity of microdispensed conductors (CB028 paste) deposited on the substrates. The measured loss on coplanar waveguides shows an improvement of up to 40% at 7 GHz. © 2011-2012 IEEE.
613 a57200529047 Neff C. p387 True Journal 211 Adhesion testing of printed inks while varying the surface treatment of polymer substrates Additive manufacturing with conductive materials enables new approaches to printed electronics that are unachievable by standard electronics manufacturing processes. In particular, electronics can be embedded directly into structural components in nearly arbitrary 3D space. While these methods incorporate many of the same materials, the new processing methods require standard test methods to compare materials, processing conditions, and determine design limits. This work demonstrates a test method to quantitatively measure the adhesion failure of printed inks deposited on a substrate without changing the ink printing conditions. The proposed method is an adaption of single lap shear testing in which the lap joint is created by bonding the second substrate to the ink after curing. It was found that the interfacial shear strengths are independent of the adhesives used to attach cured conductive ink to the second substrate. In addition, chemical surface treatments of flame and plasma and mechanical sand-blasting increase the interfacial shear strengths by ~25% and 80%, respectively, while altering the adhesive failure mode to cohesive failure for most cases. This work also shows extruded substrates with undulated features increase adhesion strength; therefore, in addition to surface treatments, the geometric freedom of additive manufacturing (AM) could be leveraged to design surface features for enhanced adhesion. © 2019, © 2019 Taylor & Francis Group, LLC.
614 a56112492400 Nussbaum J. p165 False Journal 115 Mechanical and temperature resilience of multi-material systems for printed electronics packaging In this work, two AM technologies were utilized to compare the effectiveness of fabricating a simple electronic device with a conductive trace and hollow cylinder representative of 'printed packaging' that would survive harsh environmental conditions. The printed packaging cylinder delineates printed potting for electronics packaging. An nScrypt direct write (DW) system was the primary manufacturing system but a developing technology - coined large area projection sintering (LAPS) - manufactured a subset of samples for comparison. The tests follow Military Standard (MIL STD) 883 K and include resiliency evaluation for die shear strength, temperature cycling, thermal shock, and high G loading by mechanical shock. Results indicate DW Master Bond epoxy devices show resilience to extreme temperatures, thermal shock, and mechanical shocks while also surpassing the die shear strength failure criteria specified by the MIL STD. LAPS sintered Nylon devices also show mechanical resilience to thermal shock and surpass the die shear strength failure criteria. However, there were some open circuits, increases in resistance, and delamination when LAPS Nylon devices were subjected to extreme temperatures and 20 000 G shock loading normal to the substrate. The thermal effects are likely due to the thermal expansion mismatch between Nylon and the conductive paste while the mechanical shock effects may be attributed to the geometry differences of the LAPS Nylon printed packaging. Further studies are required to understand these failure modes in some of the LAPS Nylon samples and refine the process to address them. © 2019 IOP Publishing Ltd.
614 a56112492400 Nussbaum J. p229 False Journal 151 Thermal and Vapor Smoothing of Thermoplastic for Reduced Surface Roughness of Additive Manufactured RF Electronics Additive manufacturing (AM) of electronics provides a route for creating customized systems with novel geometries that are not feasible with traditional methods. Standard AM processes such as extrusion can produce substrates on which electrical traces can be deposited. However, the surface roughness of plastic extrusion reduces the effective electrical conductivity and can introduce anisotropy, especially in radio frequency (RF) devices. The roughness can be reduced using vapor smoothing (VS), but solvent absorption changes the surface composition slightly, can be environmentally hazardous, and is not feasible with all thermoplastics. A new method introduced here - coined thermal smoothing (TS) - utilizes a heat source to locally reflow the material, thus minimizing the roughness of the undulating surfaces without the drawbacks of VS. This research work compares the surface roughness impacts of both smoothing processes with profilometry and scanning electron microscope (SEM) images. Both smoothing processes significantly reduce the surface roughness of extruded components by 80% and 90% for TS and VS, respectively. This paper also examines the influence of surface smoothing on high-frequency conductivity of microdispensed conductors (CB028 paste) deposited on the substrates. The measured loss on coplanar waveguides shows an improvement of up to 40% at 7 GHz. © 2011-2012 IEEE.
615 a57215653879 Gardiner C. p165 False Journal 115 Mechanical and temperature resilience of multi-material systems for printed electronics packaging In this work, two AM technologies were utilized to compare the effectiveness of fabricating a simple electronic device with a conductive trace and hollow cylinder representative of 'printed packaging' that would survive harsh environmental conditions. The printed packaging cylinder delineates printed potting for electronics packaging. An nScrypt direct write (DW) system was the primary manufacturing system but a developing technology - coined large area projection sintering (LAPS) - manufactured a subset of samples for comparison. The tests follow Military Standard (MIL STD) 883 K and include resiliency evaluation for die shear strength, temperature cycling, thermal shock, and high G loading by mechanical shock. Results indicate DW Master Bond epoxy devices show resilience to extreme temperatures, thermal shock, and mechanical shocks while also surpassing the die shear strength failure criteria specified by the MIL STD. LAPS sintered Nylon devices also show mechanical resilience to thermal shock and surpass the die shear strength failure criteria. However, there were some open circuits, increases in resistance, and delamination when LAPS Nylon devices were subjected to extreme temperatures and 20 000 G shock loading normal to the substrate. The thermal effects are likely due to the thermal expansion mismatch between Nylon and the conductive paste while the mechanical shock effects may be attributed to the geometry differences of the LAPS Nylon printed packaging. Further studies are required to understand these failure modes in some of the LAPS Nylon samples and refine the process to address them. © 2019 IOP Publishing Ltd.
616 a18937960700 Zunino J.L. p165 False Journal 115 Mechanical and temperature resilience of multi-material systems for printed electronics packaging In this work, two AM technologies were utilized to compare the effectiveness of fabricating a simple electronic device with a conductive trace and hollow cylinder representative of 'printed packaging' that would survive harsh environmental conditions. The printed packaging cylinder delineates printed potting for electronics packaging. An nScrypt direct write (DW) system was the primary manufacturing system but a developing technology - coined large area projection sintering (LAPS) - manufactured a subset of samples for comparison. The tests follow Military Standard (MIL STD) 883 K and include resiliency evaluation for die shear strength, temperature cycling, thermal shock, and high G loading by mechanical shock. Results indicate DW Master Bond epoxy devices show resilience to extreme temperatures, thermal shock, and mechanical shocks while also surpassing the die shear strength failure criteria specified by the MIL STD. LAPS sintered Nylon devices also show mechanical resilience to thermal shock and surpass the die shear strength failure criteria. However, there were some open circuits, increases in resistance, and delamination when LAPS Nylon devices were subjected to extreme temperatures and 20 000 G shock loading normal to the substrate. The thermal effects are likely due to the thermal expansion mismatch between Nylon and the conductive paste while the mechanical shock effects may be attributed to the geometry differences of the LAPS Nylon printed packaging. Further studies are required to understand these failure modes in some of the LAPS Nylon samples and refine the process to address them. © 2019 IOP Publishing Ltd.
617 a57216187696 Newton M. p165 False Journal 115 Mechanical and temperature resilience of multi-material systems for printed electronics packaging In this work, two AM technologies were utilized to compare the effectiveness of fabricating a simple electronic device with a conductive trace and hollow cylinder representative of 'printed packaging' that would survive harsh environmental conditions. The printed packaging cylinder delineates printed potting for electronics packaging. An nScrypt direct write (DW) system was the primary manufacturing system but a developing technology - coined large area projection sintering (LAPS) - manufactured a subset of samples for comparison. The tests follow Military Standard (MIL STD) 883 K and include resiliency evaluation for die shear strength, temperature cycling, thermal shock, and high G loading by mechanical shock. Results indicate DW Master Bond epoxy devices show resilience to extreme temperatures, thermal shock, and mechanical shocks while also surpassing the die shear strength failure criteria specified by the MIL STD. LAPS sintered Nylon devices also show mechanical resilience to thermal shock and surpass the die shear strength failure criteria. However, there were some open circuits, increases in resistance, and delamination when LAPS Nylon devices were subjected to extreme temperatures and 20 000 G shock loading normal to the substrate. The thermal effects are likely due to the thermal expansion mismatch between Nylon and the conductive paste while the mechanical shock effects may be attributed to the geometry differences of the LAPS Nylon printed packaging. Further studies are required to understand these failure modes in some of the LAPS Nylon samples and refine the process to address them. © 2019 IOP Publishing Ltd.
618 a25627506700 Craddock T.J.A. p166 False Conference 32 Feedback regulation of immune response to maximum exercise in Gulf war illness Gulf War Illness is a disease that affects about a third of the veterans that served in the 1990-91 Persian Gulf War. The symptoms are varied, the cause is unknown, and there is no known treatment. In this paper we compare the dynamic characteristics of cytokines feedback response to exercise in n=12 veterans diagnosed with Gulf War Illness (GWI) and n=12 healthy veterans deployed to the same theatre of operations. A third-order transfer function is used to model the process dynamics of 18 cytokines projected onto principal components with a Proportional Integral Derivative (PID) controller enforcing the homeostatic regulation of these co-expression patterns. Transfer functions were fit to each subject for each principal component and the dynamic response parameters compared between the veteran control and GWI subject groups. Results of this analysis indicate that while much of the regulatory response dynamics are shared by both groups, there is a significant difference in the damping of the Th1:Th2 cytokine response to exercise in Gulf War Illness. © 2019 Association of Computing Machinery.
619 a57210477807 Fletcher M. p166 False Conference 32 Feedback regulation of immune response to maximum exercise in Gulf war illness Gulf War Illness is a disease that affects about a third of the veterans that served in the 1990-91 Persian Gulf War. The symptoms are varied, the cause is unknown, and there is no known treatment. In this paper we compare the dynamic characteristics of cytokines feedback response to exercise in n=12 veterans diagnosed with Gulf War Illness (GWI) and n=12 healthy veterans deployed to the same theatre of operations. A third-order transfer function is used to model the process dynamics of 18 cytokines projected onto principal components with a Proportional Integral Derivative (PID) controller enforcing the homeostatic regulation of these co-expression patterns. Transfer functions were fit to each subject for each principal component and the dynamic response parameters compared between the veteran control and GWI subject groups. Results of this analysis indicate that while much of the regulatory response dynamics are shared by both groups, there is a significant difference in the damping of the Th1:Th2 cytokine response to exercise in Gulf War Illness. © 2019 Association of Computing Machinery.
620 a7005345401 Klimas N.G. p166 False Conference 32 Feedback regulation of immune response to maximum exercise in Gulf war illness Gulf War Illness is a disease that affects about a third of the veterans that served in the 1990-91 Persian Gulf War. The symptoms are varied, the cause is unknown, and there is no known treatment. In this paper we compare the dynamic characteristics of cytokines feedback response to exercise in n=12 veterans diagnosed with Gulf War Illness (GWI) and n=12 healthy veterans deployed to the same theatre of operations. A third-order transfer function is used to model the process dynamics of 18 cytokines projected onto principal components with a Proportional Integral Derivative (PID) controller enforcing the homeostatic regulation of these co-expression patterns. Transfer functions were fit to each subject for each principal component and the dynamic response parameters compared between the veteran control and GWI subject groups. Results of this analysis indicate that while much of the regulatory response dynamics are shared by both groups, there is a significant difference in the damping of the Th1:Th2 cytokine response to exercise in Gulf War Illness. © 2019 Association of Computing Machinery.
621 a7005976828 Broderick G. p166 False Conference 32 Feedback regulation of immune response to maximum exercise in Gulf war illness Gulf War Illness is a disease that affects about a third of the veterans that served in the 1990-91 Persian Gulf War. The symptoms are varied, the cause is unknown, and there is no known treatment. In this paper we compare the dynamic characteristics of cytokines feedback response to exercise in n=12 veterans diagnosed with Gulf War Illness (GWI) and n=12 healthy veterans deployed to the same theatre of operations. A third-order transfer function is used to model the process dynamics of 18 cytokines projected onto principal components with a Proportional Integral Derivative (PID) controller enforcing the homeostatic regulation of these co-expression patterns. Transfer functions were fit to each subject for each principal component and the dynamic response parameters compared between the veteran control and GWI subject groups. Results of this analysis indicate that while much of the regulatory response dynamics are shared by both groups, there is a significant difference in the damping of the Th1:Th2 cytokine response to exercise in Gulf War Illness. © 2019 Association of Computing Machinery.
622 a57192067288 Johnson C.L. p167 False Conference 33 Examining Nonlinear Terahertz Photonic and Phononic Excitation with Two-Dimensional Spectroscopy We use high-field, broadband terahertz (THz) pulses to nonlinearly excite a set of Raman active modes in centrosymmetric crystals. Using two-dimensional (2D) THz spectroscopy we can investigate photonic and phononic excitation and isolate the dominant and secondary nonlinear excitation pathways. We present a general framework for 2D THz vibrational spectroscopy in solid systems that provides important clarification for the growing new field of nonlinear phononics. © 2019 IEEE.
623 a57202855772 Moss C.D. p167 False Conference 33 Examining Nonlinear Terahertz Photonic and Phononic Excitation with Two-Dimensional Spectroscopy We use high-field, broadband terahertz (THz) pulses to nonlinearly excite a set of Raman active modes in centrosymmetric crystals. Using two-dimensional (2D) THz spectroscopy we can investigate photonic and phononic excitation and isolate the dominant and secondary nonlinear excitation pathways. We present a general framework for 2D THz vibrational spectroscopy in solid systems that provides important clarification for the growing new field of nonlinear phononics. © 2019 IEEE.
624 a57212089454 Amin M.N. p171 True Conference 35 Free Space Excitation in Optofluidic Devices for Single Particle Detection Free space top-down illumination of liquid-core waveguides in an optofluidic chip is implemented by milling slits into a metal layer covering the waveguide channel. Detection of single microbeads with excellent signal-to-noise ratio is demonstrated for different milling depths. © 2019 IEEE.
625 a57202116348 Hamblin M. p171 False Conference 35 Free Space Excitation in Optofluidic Devices for Single Particle Detection Free space top-down illumination of liquid-core waveguides in an optofluidic chip is implemented by milling slits into a metal layer covering the waveguide channel. Detection of single microbeads with excellent signal-to-noise ratio is demonstrated for different milling depths. © 2019 IEEE.
625 a57202116348 Hamblin M. p359 True Journal 200 Broadband antireflective light-blocking layer using nanoparticle suspension in photoresist with high-resolution patterning Background: Many MEMS and optical sensor devices can benefit from layers that block transmission and suppress reflection of light across the visible spectrum. Because these devices can include complicated topography, many existing methods for depositing antireflective layers are difficult, impractical, or unusable. Aim: To create a light-blocking antireflective layer that works well with complicated MEMS and sensor devices, a layer should be made that is cheap, simple, and can be deposited and patterned with high resolution at low temperatures. Approach: Light blocking is achieved using an aluminum layer. Suppressing reflection is achieved by mixing aluminum oxide nanoparticles in photoresist to create a layer that partially absorbs and partially scatters light. Results: The combination of a layer of metal and a layer of nanoparticles and photoresist completely blocks transmission of light and significantly reduces reflections across the visible spectrum, particularly for shorter wavelengths. The layer is also patternable to sizes as small as a few microns with high resolution. Conclusion: By combining a metal layer and a layer of nanoparticles in photoresist, a simple, cheap, and effective light-blocking antireflective layer can be created that is compatible with planar devices with complex topography. © 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).
625 a57202116348 Hamblin M. p522 True Journal 262 Antireflective light-blocking layers using a liquid top matte coating Methods exist for the creation of antireflective thin film layers; however, many of these methods depend on the use of high temperatures, harsh chemical etches, or are made with difficult pattern materials, rendering them unusable for many applications. In addition, most methods of light blocking are specifically designed to increase light coupling and absorption in the substrate, making them incompatible with some applications that also require blocking transmission of light. A method of forming a simple, patternable light-blocking layer that drastically reduces both transmission and reflection of light without dependence on processes that could damage underlying structures using a light scattering matte coating over a partially antireflective thin film light-blocking layer is presented. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
626 a56709476900 Meena G.G. p171 False Conference 35 Free Space Excitation in Optofluidic Devices for Single Particle Detection Free space top-down illumination of liquid-core waveguides in an optofluidic chip is implemented by milling slits into a metal layer covering the waveguide channel. Detection of single microbeads with excellent signal-to-noise ratio is demonstrated for different milling depths. © 2019 IEEE.
626 a56709476900 Meena G.G. p172 True Conference 36 Multiplexed Detection of Single Antibiotic Drug-Resistant Plasmids using Multimode Interference Waveguide Based Optofluidic Chip A single multimode interference waveguide is used to create distinct spectral spot patterns on two liquid-core waveguides on an optofluidic chip. This device is used for multiplexed detection of antibiotic-resistant plasmids with single nucleic acid sensitivity. © 2019 IEEE.
626 a56709476900 Meena G.G. p235 False Conference 56 Single Particle Detection Enhancement with Wavelet-based Signal Processing Technique Chip-based single molecule detection requires ultra-sensitive devices and robust signal processing methods. A new wavelet-based signal processing method is introduced that improves detection and error rates on an optofluidic platform by 2x and 3x, respectively. © 2019 The Author(s) 2019 OSA.
626 a56709476900 Meena G.G. p239 False Conference 57 Optofluidic Platform with Integrated Optical Waveguides and Sample Preparation for Digitized Detection of Nucleic Acid Targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s) 2019 OSA.
626 a56709476900 Meena G.G. p347 False Conference 119 Single particle detection enhancement with wavelet-based signal processing technique Chip-based single molecule detection requires ultra-sensitive devices and robust signal processing methods. A new wavelet-based signal processing method is introduced that improves detection and error rates on an optofluidic platform by 2x and 3x, respectively. © 2019 The Author(s)
626 a56709476900 Meena G.G. p378 False Conference 137 Optofluidic platform with integrated optical waveguides and sample preparation for digitized detection of nucleic acid targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s)
626 a56709476900 Meena G.G. p407 True Journal 217 Integration of sample preparation and analysis into an optofluidic chip for multi-target disease detection Detection of molecular biomarkers with high specificity and sensitivity from biological samples requires both sophisticated sample preparation and subsequent analysis. These tasks are often carried out on separate platforms which increases required sample volumes and the risk of errors, sample loss, and contamination. Here, we present an optofluidic platform which combines an optical detection section with single nucleic acid strand sensitivity, and a sample processing unit capable of on-chip, specific extraction and labeling of nucleic acid and protein targets in complex biological matrices. First, on-chip labeling and detection of individual lambda DNA molecules down to concentrations of 8 fM is demonstrated. Subsequently, we demonstrate the simultaneous capture, fluorescence tagging and detection of both Zika specific nucleic acid and NS-1 protein targets in both buffer and human serum. We show that the dual DNA and protein assay allows for successful differentiation and diagnosis of Zika against cross-reacting species like dengue. © The Royal Society of Chemistry 2018.
626 a56709476900 Meena G.G. p459 False Journal 256 Buried Rib SiO2 Multimode Interference Waveguides for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used to create wavelength-dependent spot patterns which enables simultaneous analyte detection on a single optofluidic chip, useful for disease diagnostics. The fidelity of such multi-spot patterns is important for high sensitivity and accurate target identification. Buried rib structures have been incorporated into these SiO2-based waveguides to improve environmental stability. Through experiments and simulation, this letter explores design parameters for a buried MMI rib waveguide based on anti-resonant reflecting optical waveguides in order to produce high-fidelity spot patterns. Optimal rib heights and widths are reported in the context of available microfabrication etch technology and performance for an optimized biosensor is shown. © 1989-2012 IEEE.
626 a56709476900 Meena G.G. p706 False Journal 347 Optofluidic lab-on-a-chip fluorescence sensor using integrated buried ARROW (bARROW) waveguides Optofluidic, lab-on-a-chip fluorescence sensors were fabricated using buried anti-resonant reflecting optical waveguides (bARROWs). The bARROWs are impervious to the negative water absorption effects that typically occur in waveguides made using hygroscopic, plasma-enhanced chemical vapor deposition (PECVD) oxides. These sensors were used to detect fluorescent microbeads and had an average signal-to-noise ratio (SNR) that was 81.3% higher than that of single-oxide ARROW fluorescence sensors. While the single-oxide ARROW sensors were annealed at 300 ◦ C to drive moisture out of the waveguides, the bARROW sensors required no annealing process to obtain a high SNR. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.
626 a56709476900 Meena G.G. p786 True Conference 323 MMI waveguide based multispectral detection of nucleic acids for analysis of drug-resistant bacteria A multi-mode interference waveguide is used for creating distinct temporal fluorescence patterns at multiple excitation wavelengths. This allows for identification of bacterial nucleic acids labeled with molecular beacons in two colors. © 2016 IEEE.
627 a57205025235 Brown O. p172 False Conference 36 Multiplexed Detection of Single Antibiotic Drug-Resistant Plasmids using Multimode Interference Waveguide Based Optofluidic Chip A single multimode interference waveguide is used to create distinct spectral spot patterns on two liquid-core waveguides on an optofluidic chip. This device is used for multiplexed detection of antibiotic-resistant plasmids with single nucleic acid sensitivity. © 2019 IEEE.
628 a57202256915 Hanson R. p172 False Conference 36 Multiplexed Detection of Single Antibiotic Drug-Resistant Plasmids using Multimode Interference Waveguide Based Optofluidic Chip A single multimode interference waveguide is used to create distinct spectral spot patterns on two liquid-core waveguides on an optofluidic chip. This device is used for multiplexed detection of antibiotic-resistant plasmids with single nucleic acid sensitivity. © 2019 IEEE.
629 a57193755486 Wood R.L. p172 False Conference 36 Multiplexed Detection of Single Antibiotic Drug-Resistant Plasmids using Multimode Interference Waveguide Based Optofluidic Chip A single multimode interference waveguide is used to create distinct spectral spot patterns on two liquid-core waveguides on an optofluidic chip. This device is used for multiplexed detection of antibiotic-resistant plasmids with single nucleic acid sensitivity. © 2019 IEEE.
630 a57002749600 Robison R. p172 False Conference 36 Multiplexed Detection of Single Antibiotic Drug-Resistant Plasmids using Multimode Interference Waveguide Based Optofluidic Chip A single multimode interference waveguide is used to create distinct spectral spot patterns on two liquid-core waveguides on an optofluidic chip. This device is used for multiplexed detection of antibiotic-resistant plasmids with single nucleic acid sensitivity. © 2019 IEEE.
630 a57002749600 Robison R. p786 False Conference 323 MMI waveguide based multispectral detection of nucleic acids for analysis of drug-resistant bacteria A multi-mode interference waveguide is used for creating distinct temporal fluorescence patterns at multiple excitation wavelengths. This allows for identification of bacterial nucleic acids labeled with molecular beacons in two colors. © 2016 IEEE.
631 a57208584595 Roundtree K.A. p174 True Journal 118 Transparency: Transitioning From Human–Machine Systems to Human-Swarm Systems Swarm robotic systems are gaining in interest with the prospect of their use for various applications, including monitoring, tracking, infrastructure support, and protection. Prior human-swarm system research investigated transparency for these systems, but assumed perfect communication scenarios. Real-world human-swarm systems will not have perfect communication due to human processing limitations caused by a large number of individual entities, emergent behavior due to varying environments, and bandwidth issues. Factors that affect transparency or are influenced by transparency were identified from various human–machine system domains; however, understanding the relationship between factors can help designers identify what criteria can be implemented to achieve transparency for swarms. Challenges that may arise based on transparency criteria from human–machine systems are examined to identify improvements for spatial swarm systems. © 2019, Human Factors and Ergonomics Society.
632 a35546747200 Adams J.A. p174 False Journal 118 Transparency: Transitioning From Human–Machine Systems to Human-Swarm Systems Swarm robotic systems are gaining in interest with the prospect of their use for various applications, including monitoring, tracking, infrastructure support, and protection. Prior human-swarm system research investigated transparency for these systems, but assumed perfect communication scenarios. Real-world human-swarm systems will not have perfect communication due to human processing limitations caused by a large number of individual entities, emergent behavior due to varying environments, and bandwidth issues. Factors that affect transparency or are influenced by transparency were identified from various human–machine system domains; however, understanding the relationship between factors can help designers identify what criteria can be implemented to achieve transparency for swarms. Challenges that may arise based on transparency criteria from human–machine systems are examined to identify improvements for spatial swarm systems. © 2019, Human Factors and Ergonomics Society.
632 a35546747200 Adams J.A. p534 True Conference 193 Swarm Transparency A key element of system transparency is allowing humans to calibrate their trust in a system, given the implicit inherent uncertainty, emergent behaviors, etc. As robotic swarms progress towards real-world missions, such transparency becomes increasingly necessary in order to reduce the disuse, misuse and errors humans make when influencing and directing the swarm. However,achieving this objective requires addressing the complex challenges associated with providing transparency. Two swarm transparency challenge categories, with exemplar challenges, are provided. © 2018 Authors.
633 a57003496300 Swindlehurst E. p175 True Journal 119 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW, yielding an FoM of 37 fJ/conv.-step, the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2018 IEEE.
633 a57003496300 Swindlehurst E. p177 True Conference 39 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW,yielding an FoM of 37 fJ/conv.-step,the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2019 IEEE.
633 a57003496300 Swindlehurst E. p277 False Journal 182 A 9-Bit 10-MHz 28-μW SAR ADC Using Tapered Bit Periods and a Partially Interdigitated DAC A successive-approximation-register (SAR) analogto- digital converter (ADC) incorporates "tapered bit periods" to reduce power consumption by minimizing the digital-to-analog converter (DAC) timing overhead. Utilizing a variable delay line and the standard SAR logic, the proposed technique reduces power by downsizing the DAC drivers and digital logic without decreasing the sampling rate. A detailed analysis derives, for the first time, a closed-form solution of the capacitive DAC settling time accounting for parasitics, and determines the time savings of the proposed design. In addition, this brief proposes a "partially interdigitated" DAC layout to reduce the bottom-plate parasitic capacitance to minimize the DAC power. A 9-bit prototype fabricated in 180-nm technology achieves a signal-to-noise-distortion ratio (SNDR) of 55.5 dB at a 10-MHz sampling rate while consuming 28 μW, yielding a figure-of-merit of 5.7 fJ/conversionstep, the lowest among published ADCs at similar speeds and resolutions. © 2004-2012 IEEE.
633 a57003496300 Swindlehurst E. p676 False Journal 327 High-Precision, Mixed-Signal Mismatch Measurement of Metal-Oxide-Metal Capacitors This brief presents a high-precision, mixed-signal mismatch measurement technique for metal-oxide-metal capacitors. The proposed technique incorporates a switched-capacitor op amp within the measurement circuit to significantly improve the measurement precision while relaxing the resolution requirement on the backend analog-to-digital converter (ADC). The proposed technique is also robust against multiple types of errors. A detailed analysis is presented to quantify the sensitivity improvement of the proposed technique over the conventional one. In addition, this brief proposes a multiplexing technique to measure a large number of capacitors in a single chip and a new layout to improve matching. A prototype fabricated in 180 nm technology demonstrates the ability to sense capacitor mismatch standard deviation as low as 0.045% with excellent repeatability, all without the need of a high-resolution ADC. © 2004-2012 IEEE.
634 a57212110613 Jensen H. p175 False Journal 119 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW, yielding an FoM of 37 fJ/conv.-step, the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2018 IEEE.
634 a57212110613 Jensen H. p177 False Conference 39 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW,yielding an FoM of 37 fJ/conv.-step,the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2019 IEEE.
635 a57216244800 Chang M.-C.F. p175 False Journal 119 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW, yielding an FoM of 37 fJ/conv.-step, the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2018 IEEE.
636 a7409253428 Wu J.-T. p175 False Journal 119 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW, yielding an FoM of 37 fJ/conv.-step, the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2018 IEEE.
636 a7409253428 Wu J.-T. p177 False Conference 39 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW,yielding an FoM of 37 fJ/conv.-step,the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2019 IEEE.
637 a7404504014 Chang M.-C.F. p177 False Conference 39 An 8-bit 10-GHz 21-mW Time-Interleaved SAR ADC with Grouped DAC Capacitors and Dual-Path Bootstrapped Switch An 8-bit 10-GHz 8× time-interleaved SAR ADC in 28-nm CMOS incorporates an aggressively scaled DAC with grouped capacitors in a symmetrical comb structure to afford a threefold reduction in the bottom-plate parasitic capacitance. A dual-path bootstrapped switch decouples critical signal from nonlinear capacitance to boost the sampling SFDR by more than 5 dB. The ADC demonstrates an SNDR of 36.9 dB at Nyquist while consuming 21 mW,yielding an FoM of 37 fJ/conv.-step,the lowest among the reported ADCs with similar speeds and resolutions and more than 2× improvement from the state-of-the-art. © 2019 IEEE.
638 a57144864700 Chen Y.-F. p178 True Journal 120 Design of a Clinical Decision Support System for Predicting Erectile Dysfunction in Men Using NHIRD Dataset Erectile dysfunction (ED) affects millions of men worldwide. Men with ED generally complain failure to attain or maintain an adequate erection during sexual activity. The prevalence of ED is strongly correlated with age, affecting about 40% of men at age 40 and nearly 70% at age 70. A variety of chronic diseases, including diabetes, ischemic heart disease, congestive heart failure, hypertension, depression, chronic renal failure, obstructive sleep apnea, prostate disease, gout, and sleep disorder, were reported to be associated with ED. In this study, data retrieved from a subset of the National Health Insurance Research Database of Taiwan were used for designing the clinical decision support system (CDSS) for predicting ED incidences in men. The positive cases were male patients aged 20-65 who were diagnosed with ED between January 2000 and December 2010 confirmed by at least three outpatient visits or at least one inpatient visit, while the negative cases were randomly selected from the database without a history of ED and were frequency (1:1), age, and index year matched with the ED patients. Data of a total of 2832 ED patients and 2832 non-ED patients, each consisting of 41 features including index age, 10 comorbidities, and 30 other comorbidity-related variables, were retrieved for designing the predictive models. Integrated genetic algorithm and support vector machine was adopted to design the CDSSs with two experiments of independent training and testing (ITT) conducted to verify their effectiveness. In the 1st ITT experiment, data extracted from January 2000 till December 2005 (61.51%, 1742 positive cases and 1742 negative cases) were used for training and validating and the data retrieved from January 2006 till December 2010 were used for testing (38.49%), whereas in the 2nd ITT experiment, data in the training set (77.78%) were extracted from January 2000 till Deceber 2007 and those in the testing set (22.22%) were retrieved afterward. Tenfold cross validation and three different objective functions were adopted for obtaining the optimal models with best predictive performance in the training phase. The testing results show that the CDSSs achieved a predictive performance with accuracy, sensitivity, specificity, g-mean, and area under ROC curve of 74.72%-76.65%, 72.33%-83.76%, 69.54%-77.10%, 0.7468-0.7632, and 0.766-0.817, respectively. In conclusion, the CDSSs designed based on cost-sensitive objective functions as well as salient comorbidity-related features achieve satisfactory predictive performance for predicting ED incidences. © 2013 IEEE.
639 a57194205673 Lin C.-S. p178 False Journal 120 Design of a Clinical Decision Support System for Predicting Erectile Dysfunction in Men Using NHIRD Dataset Erectile dysfunction (ED) affects millions of men worldwide. Men with ED generally complain failure to attain or maintain an adequate erection during sexual activity. The prevalence of ED is strongly correlated with age, affecting about 40% of men at age 40 and nearly 70% at age 70. A variety of chronic diseases, including diabetes, ischemic heart disease, congestive heart failure, hypertension, depression, chronic renal failure, obstructive sleep apnea, prostate disease, gout, and sleep disorder, were reported to be associated with ED. In this study, data retrieved from a subset of the National Health Insurance Research Database of Taiwan were used for designing the clinical decision support system (CDSS) for predicting ED incidences in men. The positive cases were male patients aged 20-65 who were diagnosed with ED between January 2000 and December 2010 confirmed by at least three outpatient visits or at least one inpatient visit, while the negative cases were randomly selected from the database without a history of ED and were frequency (1:1), age, and index year matched with the ED patients. Data of a total of 2832 ED patients and 2832 non-ED patients, each consisting of 41 features including index age, 10 comorbidities, and 30 other comorbidity-related variables, were retrieved for designing the predictive models. Integrated genetic algorithm and support vector machine was adopted to design the CDSSs with two experiments of independent training and testing (ITT) conducted to verify their effectiveness. In the 1st ITT experiment, data extracted from January 2000 till December 2005 (61.51%, 1742 positive cases and 1742 negative cases) were used for training and validating and the data retrieved from January 2006 till December 2010 were used for testing (38.49%), whereas in the 2nd ITT experiment, data in the training set (77.78%) were extracted from January 2000 till Deceber 2007 and those in the testing set (22.22%) were retrieved afterward. Tenfold cross validation and three different objective functions were adopted for obtaining the optimal models with best predictive performance in the training phase. The testing results show that the CDSSs achieved a predictive performance with accuracy, sensitivity, specificity, g-mean, and area under ROC curve of 74.72%-76.65%, 72.33%-83.76%, 69.54%-77.10%, 0.7468-0.7632, and 0.766-0.817, respectively. In conclusion, the CDSSs designed based on cost-sensitive objective functions as well as salient comorbidity-related features achieve satisfactory predictive performance for predicting ED incidences. © 2013 IEEE.
639 a57194205673 Lin C.-S. p657 False Journal 316 Design of a clinical decision support system for fracture prediction using imbalanced dataset More than 1 billion people suffer from chronic respiratory diseases worldwide, accounting for more than 4 million deaths annually. Inhaled corticosteroid is a popular medication for treating chronic respiratory diseases. Its side effects include decreased bone mineral density and osteoporosis. The aims of this study are to investigate the association of inhaled corticosteroids and fracture and to design a clinical support system for fracture prediction. The data of patients aged 20 years and older, who had visited healthcare centers and been prescribed with inhaled corticosteroids within 2002-2010, were retrieved from the National Health Insurance Research Database (NHIRD). After excluding patients diagnosed with hip fracture or vertebrate fractures before using inhaled corticosteroid, a total of 11645 patients receiving inhaled corticosteroid therapy were included for this study. Among them, 1134 (9.7%) were diagnosed with hip fracture or vertebrate fracture. The statistical results showed that demographic information, chronic respiratory diseases and comorbidities, and corticosteroid-related variables (cumulative dose, mean exposed daily dose, follow-up duration, and exposed duration) were significantly different between fracture and nonfracture patients. The clinical decision support systems (CDSSs) were designed with integrated genetic algorithm (GA) and support vector machine (SVM) by training and validating the models with balanced training sets obtained by random and cluster-based undersampling methods and testing with the imbalanced NHIRD dataset. Two different objective functions were adopted for obtaining optimal models with best predictive performance. The predictive performance of the CDSSs exhibits a sensitivity of 69.84-77.00% and an AUC of 0.7495-0.7590. It was concluded that long-term use of inhaled corticosteroids may induce osteoporosis and exhibit higher incidence of hip or vertebrate fractures. The accumulated dose of ICS and OCS therapies should be continuously monitored, especially for patients with older age and women after menopause, to prevent from exceeding the maximum dosage. © 2018 Yung-Fu Chen et al.
640 a35078644900 Hong C.-F. p178 False Journal 120 Design of a Clinical Decision Support System for Predicting Erectile Dysfunction in Men Using NHIRD Dataset Erectile dysfunction (ED) affects millions of men worldwide. Men with ED generally complain failure to attain or maintain an adequate erection during sexual activity. The prevalence of ED is strongly correlated with age, affecting about 40% of men at age 40 and nearly 70% at age 70. A variety of chronic diseases, including diabetes, ischemic heart disease, congestive heart failure, hypertension, depression, chronic renal failure, obstructive sleep apnea, prostate disease, gout, and sleep disorder, were reported to be associated with ED. In this study, data retrieved from a subset of the National Health Insurance Research Database of Taiwan were used for designing the clinical decision support system (CDSS) for predicting ED incidences in men. The positive cases were male patients aged 20-65 who were diagnosed with ED between January 2000 and December 2010 confirmed by at least three outpatient visits or at least one inpatient visit, while the negative cases were randomly selected from the database without a history of ED and were frequency (1:1), age, and index year matched with the ED patients. Data of a total of 2832 ED patients and 2832 non-ED patients, each consisting of 41 features including index age, 10 comorbidities, and 30 other comorbidity-related variables, were retrieved for designing the predictive models. Integrated genetic algorithm and support vector machine was adopted to design the CDSSs with two experiments of independent training and testing (ITT) conducted to verify their effectiveness. In the 1st ITT experiment, data extracted from January 2000 till December 2005 (61.51%, 1742 positive cases and 1742 negative cases) were used for training and validating and the data retrieved from January 2006 till December 2010 were used for testing (38.49%), whereas in the 2nd ITT experiment, data in the training set (77.78%) were extracted from January 2000 till Deceber 2007 and those in the testing set (22.22%) were retrieved afterward. Tenfold cross validation and three different objective functions were adopted for obtaining the optimal models with best predictive performance in the training phase. The testing results show that the CDSSs achieved a predictive performance with accuracy, sensitivity, specificity, g-mean, and area under ROC curve of 74.72%-76.65%, 72.33%-83.76%, 69.54%-77.10%, 0.7468-0.7632, and 0.766-0.817, respectively. In conclusion, the CDSSs designed based on cost-sensitive objective functions as well as salient comorbidity-related features achieve satisfactory predictive performance for predicting ED incidences. © 2013 IEEE.
641 a57204475222 Sun C. p178 False Journal 120 Design of a Clinical Decision Support System for Predicting Erectile Dysfunction in Men Using NHIRD Dataset Erectile dysfunction (ED) affects millions of men worldwide. Men with ED generally complain failure to attain or maintain an adequate erection during sexual activity. The prevalence of ED is strongly correlated with age, affecting about 40% of men at age 40 and nearly 70% at age 70. A variety of chronic diseases, including diabetes, ischemic heart disease, congestive heart failure, hypertension, depression, chronic renal failure, obstructive sleep apnea, prostate disease, gout, and sleep disorder, were reported to be associated with ED. In this study, data retrieved from a subset of the National Health Insurance Research Database of Taiwan were used for designing the clinical decision support system (CDSS) for predicting ED incidences in men. The positive cases were male patients aged 20-65 who were diagnosed with ED between January 2000 and December 2010 confirmed by at least three outpatient visits or at least one inpatient visit, while the negative cases were randomly selected from the database without a history of ED and were frequency (1:1), age, and index year matched with the ED patients. Data of a total of 2832 ED patients and 2832 non-ED patients, each consisting of 41 features including index age, 10 comorbidities, and 30 other comorbidity-related variables, were retrieved for designing the predictive models. Integrated genetic algorithm and support vector machine was adopted to design the CDSSs with two experiments of independent training and testing (ITT) conducted to verify their effectiveness. In the 1st ITT experiment, data extracted from January 2000 till December 2005 (61.51%, 1742 positive cases and 1742 negative cases) were used for training and validating and the data retrieved from January 2006 till December 2010 were used for testing (38.49%), whereas in the 2nd ITT experiment, data in the training set (77.78%) were extracted from January 2000 till Deceber 2007 and those in the testing set (22.22%) were retrieved afterward. Tenfold cross validation and three different objective functions were adopted for obtaining the optimal models with best predictive performance in the training phase. The testing results show that the CDSSs achieved a predictive performance with accuracy, sensitivity, specificity, g-mean, and area under ROC curve of 74.72%-76.65%, 72.33%-83.76%, 69.54%-77.10%, 0.7468-0.7632, and 0.766-0.817, respectively. In conclusion, the CDSSs designed based on cost-sensitive objective functions as well as salient comorbidity-related features achieve satisfactory predictive performance for predicting ED incidences. © 2013 IEEE.
642 a8208317300 Lin H.-H. p178 False Journal 120 Design of a Clinical Decision Support System for Predicting Erectile Dysfunction in Men Using NHIRD Dataset Erectile dysfunction (ED) affects millions of men worldwide. Men with ED generally complain failure to attain or maintain an adequate erection during sexual activity. The prevalence of ED is strongly correlated with age, affecting about 40% of men at age 40 and nearly 70% at age 70. A variety of chronic diseases, including diabetes, ischemic heart disease, congestive heart failure, hypertension, depression, chronic renal failure, obstructive sleep apnea, prostate disease, gout, and sleep disorder, were reported to be associated with ED. In this study, data retrieved from a subset of the National Health Insurance Research Database of Taiwan were used for designing the clinical decision support system (CDSS) for predicting ED incidences in men. The positive cases were male patients aged 20-65 who were diagnosed with ED between January 2000 and December 2010 confirmed by at least three outpatient visits or at least one inpatient visit, while the negative cases were randomly selected from the database without a history of ED and were frequency (1:1), age, and index year matched with the ED patients. Data of a total of 2832 ED patients and 2832 non-ED patients, each consisting of 41 features including index age, 10 comorbidities, and 30 other comorbidity-related variables, were retrieved for designing the predictive models. Integrated genetic algorithm and support vector machine was adopted to design the CDSSs with two experiments of independent training and testing (ITT) conducted to verify their effectiveness. In the 1st ITT experiment, data extracted from January 2000 till December 2005 (61.51%, 1742 positive cases and 1742 negative cases) were used for training and validating and the data retrieved from January 2006 till December 2010 were used for testing (38.49%), whereas in the 2nd ITT experiment, data in the training set (77.78%) were extracted from January 2000 till Deceber 2007 and those in the testing set (22.22%) were retrieved afterward. Tenfold cross validation and three different objective functions were adopted for obtaining the optimal models with best predictive performance in the training phase. The testing results show that the CDSSs achieved a predictive performance with accuracy, sensitivity, specificity, g-mean, and area under ROC curve of 74.72%-76.65%, 72.33%-83.76%, 69.54%-77.10%, 0.7468-0.7632, and 0.766-0.817, respectively. In conclusion, the CDSSs designed based on cost-sensitive objective functions as well as salient comorbidity-related features achieve satisfactory predictive performance for predicting ED incidences. © 2013 IEEE.
642 a8208317300 Lin H.-H. p657 False Journal 316 Design of a clinical decision support system for fracture prediction using imbalanced dataset More than 1 billion people suffer from chronic respiratory diseases worldwide, accounting for more than 4 million deaths annually. Inhaled corticosteroid is a popular medication for treating chronic respiratory diseases. Its side effects include decreased bone mineral density and osteoporosis. The aims of this study are to investigate the association of inhaled corticosteroids and fracture and to design a clinical support system for fracture prediction. The data of patients aged 20 years and older, who had visited healthcare centers and been prescribed with inhaled corticosteroids within 2002-2010, were retrieved from the National Health Insurance Research Database (NHIRD). After excluding patients diagnosed with hip fracture or vertebrate fractures before using inhaled corticosteroid, a total of 11645 patients receiving inhaled corticosteroid therapy were included for this study. Among them, 1134 (9.7%) were diagnosed with hip fracture or vertebrate fracture. The statistical results showed that demographic information, chronic respiratory diseases and comorbidities, and corticosteroid-related variables (cumulative dose, mean exposed daily dose, follow-up duration, and exposed duration) were significantly different between fracture and nonfracture patients. The clinical decision support systems (CDSSs) were designed with integrated genetic algorithm (GA) and support vector machine (SVM) by training and validating the models with balanced training sets obtained by random and cluster-based undersampling methods and testing with the imbalanced NHIRD dataset. Two different objective functions were adopted for obtaining optimal models with best predictive performance. The predictive performance of the CDSSs exhibits a sensitivity of 69.84-77.00% and an AUC of 0.7495-0.7590. It was concluded that long-term use of inhaled corticosteroids may induce osteoporosis and exhibit higher incidence of hip or vertebrate fractures. The accumulated dose of ICS and OCS therapies should be continuously monitored, especially for patients with older age and women after menopause, to prevent from exceeding the maximum dosage. © 2018 Yung-Fu Chen et al.
643 a55797091700 Zhao W. p179 False Journal 121 Structure descriptor based on just noticeable difference for texture image classification Local binary pattern (LBP) and its derivates have been widely used in texture classification. However, LBP-based methods are sensitive to noise, and some structure information represented by non-uniform patterns is lost due to the combination of these patterns. In this paper, a new local structure descriptor based on just noticeable difference (JND) for texture classification is proposed by exploring the spatial and relative intensity correlations among local neighborhood pixels. First, a JND map of the image is computed, and then we attempt to model the correlations among local neighborhood pixels by comparing the absolute differences in intensity between the central pixel and its neighbors with the corresponding JND threshold. A new visual pattern (JNDVP) is designed using modeled correlations to describe image structure. Next, considering that image contrast makes important contributions to structure description, contrast is employed as a weighting factor for JNDVP histogram creation to represent structural and contrast information in a single representation. Finally, the nearest neighborhood classifier is employed for texture classification. Results on two texture image databases demonstrate that the proposed structure descriptor is rotation invariant and more robust to noise than LBP. Moreover, texture classification based on JNDVP outperforms LBP-based methods. © 2019 Optical Society of America.
644 a57204783601 Yang X. p179 False Journal 121 Structure descriptor based on just noticeable difference for texture image classification Local binary pattern (LBP) and its derivates have been widely used in texture classification. However, LBP-based methods are sensitive to noise, and some structure information represented by non-uniform patterns is lost due to the combination of these patterns. In this paper, a new local structure descriptor based on just noticeable difference (JND) for texture classification is proposed by exploring the spatial and relative intensity correlations among local neighborhood pixels. First, a JND map of the image is computed, and then we attempt to model the correlations among local neighborhood pixels by comparing the absolute differences in intensity between the central pixel and its neighbors with the corresponding JND threshold. A new visual pattern (JNDVP) is designed using modeled correlations to describe image structure. Next, considering that image contrast makes important contributions to structure description, contrast is employed as a weighting factor for JNDVP histogram creation to represent structural and contrast information in a single representation. Finally, the nearest neighborhood classifier is employed for texture classification. Results on two texture image databases demonstrate that the proposed structure descriptor is rotation invariant and more robust to noise than LBP. Moreover, texture classification based on JNDVP outperforms LBP-based methods. © 2019 Optical Society of America.
645 a57192945685 Hu R. p180 True Journal 122 3D hydrodynamic flow focusing-based micromixer enables high-resolution imaging for studying the early folding kinetics of G-quadruplex Hydrodynamic flow focusing-based micromixers (laminar micromixers) have been widely applied to the investigation of the folding kinetics of biomacromolecules, due to their capability to resolve the folding events in a microsecond time scale. Although most existing laminar micromixers attempted to reduce mixing time, our work focused on developing a system that can generate high-resolution images under a more stable flow, which results in more accurate kinetic analysis. Specifically, we developed a simple three-dimensional (3D) laminar micromixer, which distributes the sample stream to a 3D profile to address flow-instability issues caused by Dean vortices in a two-dimensional mixer. In the 3D mixer, the sample stream was successfully focused to a one-pixel width at the resolution of ˜200 nm/pixel, which approached the resolving power of an optical microscope and represented the highest imaging resolution ever achieved using a 3D mixer. Furthermore, we used the device to investigate the early folding kinetics of G-quadruplex under various sodium cation concentrations. Interestingly, a lag phase was found before the exponential phase during the folding process. Moreover, we obtained the G-quadruplex's observed kinetics of (1.51 ± 0.02) ×104 s−1, (1.68 ± 0.04) ×104 s−1 and (2.01 ± 0.02) ×104 s−1 at 50-, 100- and 200 mM NaCl, respectively. © 2019 Elsevier B.V.
646 a56939117000 Liu C. p180 False Journal 122 3D hydrodynamic flow focusing-based micromixer enables high-resolution imaging for studying the early folding kinetics of G-quadruplex Hydrodynamic flow focusing-based micromixers (laminar micromixers) have been widely applied to the investigation of the folding kinetics of biomacromolecules, due to their capability to resolve the folding events in a microsecond time scale. Although most existing laminar micromixers attempted to reduce mixing time, our work focused on developing a system that can generate high-resolution images under a more stable flow, which results in more accurate kinetic analysis. Specifically, we developed a simple three-dimensional (3D) laminar micromixer, which distributes the sample stream to a 3D profile to address flow-instability issues caused by Dean vortices in a two-dimensional mixer. In the 3D mixer, the sample stream was successfully focused to a one-pixel width at the resolution of ˜200 nm/pixel, which approached the resolving power of an optical microscope and represented the highest imaging resolution ever achieved using a 3D mixer. Furthermore, we used the device to investigate the early folding kinetics of G-quadruplex under various sodium cation concentrations. Interestingly, a lag phase was found before the exponential phase during the folding process. Moreover, we obtained the G-quadruplex's observed kinetics of (1.51 ± 0.02) ×104 s−1, (1.68 ± 0.04) ×104 s−1 and (2.01 ± 0.02) ×104 s−1 at 50-, 100- and 200 mM NaCl, respectively. © 2019 Elsevier B.V.
647 a56585491000 Xuan J. p180 False Journal 122 3D hydrodynamic flow focusing-based micromixer enables high-resolution imaging for studying the early folding kinetics of G-quadruplex Hydrodynamic flow focusing-based micromixers (laminar micromixers) have been widely applied to the investigation of the folding kinetics of biomacromolecules, due to their capability to resolve the folding events in a microsecond time scale. Although most existing laminar micromixers attempted to reduce mixing time, our work focused on developing a system that can generate high-resolution images under a more stable flow, which results in more accurate kinetic analysis. Specifically, we developed a simple three-dimensional (3D) laminar micromixer, which distributes the sample stream to a 3D profile to address flow-instability issues caused by Dean vortices in a two-dimensional mixer. In the 3D mixer, the sample stream was successfully focused to a one-pixel width at the resolution of ˜200 nm/pixel, which approached the resolving power of an optical microscope and represented the highest imaging resolution ever achieved using a 3D mixer. Furthermore, we used the device to investigate the early folding kinetics of G-quadruplex under various sodium cation concentrations. Interestingly, a lag phase was found before the exponential phase during the folding process. Moreover, we obtained the G-quadruplex's observed kinetics of (1.51 ± 0.02) ×104 s−1, (1.68 ± 0.04) ×104 s−1 and (2.01 ± 0.02) ×104 s−1 at 50-, 100- and 200 mM NaCl, respectively. © 2019 Elsevier B.V.
648 a16308483700 Xu Y. p180 False Journal 122 3D hydrodynamic flow focusing-based micromixer enables high-resolution imaging for studying the early folding kinetics of G-quadruplex Hydrodynamic flow focusing-based micromixers (laminar micromixers) have been widely applied to the investigation of the folding kinetics of biomacromolecules, due to their capability to resolve the folding events in a microsecond time scale. Although most existing laminar micromixers attempted to reduce mixing time, our work focused on developing a system that can generate high-resolution images under a more stable flow, which results in more accurate kinetic analysis. Specifically, we developed a simple three-dimensional (3D) laminar micromixer, which distributes the sample stream to a 3D profile to address flow-instability issues caused by Dean vortices in a two-dimensional mixer. In the 3D mixer, the sample stream was successfully focused to a one-pixel width at the resolution of ˜200 nm/pixel, which approached the resolving power of an optical microscope and represented the highest imaging resolution ever achieved using a 3D mixer. Furthermore, we used the device to investigate the early folding kinetics of G-quadruplex under various sodium cation concentrations. Interestingly, a lag phase was found before the exponential phase during the folding process. Moreover, we obtained the G-quadruplex's observed kinetics of (1.51 ± 0.02) ×104 s−1, (1.68 ± 0.04) ×104 s−1 and (2.01 ± 0.02) ×104 s−1 at 50-, 100- and 200 mM NaCl, respectively. © 2019 Elsevier B.V.
649 a57200214703 Li T. p180 False Journal 122 3D hydrodynamic flow focusing-based micromixer enables high-resolution imaging for studying the early folding kinetics of G-quadruplex Hydrodynamic flow focusing-based micromixers (laminar micromixers) have been widely applied to the investigation of the folding kinetics of biomacromolecules, due to their capability to resolve the folding events in a microsecond time scale. Although most existing laminar micromixers attempted to reduce mixing time, our work focused on developing a system that can generate high-resolution images under a more stable flow, which results in more accurate kinetic analysis. Specifically, we developed a simple three-dimensional (3D) laminar micromixer, which distributes the sample stream to a 3D profile to address flow-instability issues caused by Dean vortices in a two-dimensional mixer. In the 3D mixer, the sample stream was successfully focused to a one-pixel width at the resolution of ˜200 nm/pixel, which approached the resolving power of an optical microscope and represented the highest imaging resolution ever achieved using a 3D mixer. Furthermore, we used the device to investigate the early folding kinetics of G-quadruplex under various sodium cation concentrations. Interestingly, a lag phase was found before the exponential phase during the folding process. Moreover, we obtained the G-quadruplex's observed kinetics of (1.51 ± 0.02) ×104 s−1, (1.68 ± 0.04) ×104 s−1 and (2.01 ± 0.02) ×104 s−1 at 50-, 100- and 200 mM NaCl, respectively. © 2019 Elsevier B.V.
650 a35311157900 Liu B.-F. p180 False Journal 122 3D hydrodynamic flow focusing-based micromixer enables high-resolution imaging for studying the early folding kinetics of G-quadruplex Hydrodynamic flow focusing-based micromixers (laminar micromixers) have been widely applied to the investigation of the folding kinetics of biomacromolecules, due to their capability to resolve the folding events in a microsecond time scale. Although most existing laminar micromixers attempted to reduce mixing time, our work focused on developing a system that can generate high-resolution images under a more stable flow, which results in more accurate kinetic analysis. Specifically, we developed a simple three-dimensional (3D) laminar micromixer, which distributes the sample stream to a 3D profile to address flow-instability issues caused by Dean vortices in a two-dimensional mixer. In the 3D mixer, the sample stream was successfully focused to a one-pixel width at the resolution of ˜200 nm/pixel, which approached the resolving power of an optical microscope and represented the highest imaging resolution ever achieved using a 3D mixer. Furthermore, we used the device to investigate the early folding kinetics of G-quadruplex under various sodium cation concentrations. Interestingly, a lag phase was found before the exponential phase during the folding process. Moreover, we obtained the G-quadruplex's observed kinetics of (1.51 ± 0.02) ×104 s−1, (1.68 ± 0.04) ×104 s−1 and (2.01 ± 0.02) ×104 s−1 at 50-, 100- and 200 mM NaCl, respectively. © 2019 Elsevier B.V.
651 a55972769000 Li Y. p180 False Journal 122 3D hydrodynamic flow focusing-based micromixer enables high-resolution imaging for studying the early folding kinetics of G-quadruplex Hydrodynamic flow focusing-based micromixers (laminar micromixers) have been widely applied to the investigation of the folding kinetics of biomacromolecules, due to their capability to resolve the folding events in a microsecond time scale. Although most existing laminar micromixers attempted to reduce mixing time, our work focused on developing a system that can generate high-resolution images under a more stable flow, which results in more accurate kinetic analysis. Specifically, we developed a simple three-dimensional (3D) laminar micromixer, which distributes the sample stream to a 3D profile to address flow-instability issues caused by Dean vortices in a two-dimensional mixer. In the 3D mixer, the sample stream was successfully focused to a one-pixel width at the resolution of ˜200 nm/pixel, which approached the resolving power of an optical microscope and represented the highest imaging resolution ever achieved using a 3D mixer. Furthermore, we used the device to investigate the early folding kinetics of G-quadruplex under various sodium cation concentrations. Interestingly, a lag phase was found before the exponential phase during the folding process. Moreover, we obtained the G-quadruplex's observed kinetics of (1.51 ± 0.02) ×104 s−1, (1.68 ± 0.04) ×104 s−1 and (2.01 ± 0.02) ×104 s−1 at 50-, 100- and 200 mM NaCl, respectively. © 2019 Elsevier B.V.
652 a36483856300 Yang Y. p180 False Journal 122 3D hydrodynamic flow focusing-based micromixer enables high-resolution imaging for studying the early folding kinetics of G-quadruplex Hydrodynamic flow focusing-based micromixers (laminar micromixers) have been widely applied to the investigation of the folding kinetics of biomacromolecules, due to their capability to resolve the folding events in a microsecond time scale. Although most existing laminar micromixers attempted to reduce mixing time, our work focused on developing a system that can generate high-resolution images under a more stable flow, which results in more accurate kinetic analysis. Specifically, we developed a simple three-dimensional (3D) laminar micromixer, which distributes the sample stream to a 3D profile to address flow-instability issues caused by Dean vortices in a two-dimensional mixer. In the 3D mixer, the sample stream was successfully focused to a one-pixel width at the resolution of ˜200 nm/pixel, which approached the resolving power of an optical microscope and represented the highest imaging resolution ever achieved using a 3D mixer. Furthermore, we used the device to investigate the early folding kinetics of G-quadruplex under various sodium cation concentrations. Interestingly, a lag phase was found before the exponential phase during the folding process. Moreover, we obtained the G-quadruplex's observed kinetics of (1.51 ± 0.02) ×104 s−1, (1.68 ± 0.04) ×104 s−1 and (2.01 ± 0.02) ×104 s−1 at 50-, 100- and 200 mM NaCl, respectively. © 2019 Elsevier B.V.
653 a57194027885 Zhang Y. p181 True Journal 123 Thermal and hydrothermal stability of pure and silica-doped mesoporous aluminas Thermal and hydrothermal stabilities of solvent deficient derived pure alumina (PA) as well as silica-doped aluminas (SDA) with three different dopant concentrations (5, 15, 27% by weight) have been investigated for changes in phase and pore structure after calcination at high temperatures under air and steam/air atmospheres. For all aluminas, heat treatment results in decreased surface area and increased pore diameter. Starting at 700 °C, metastable to stable phase transformation occurs, causing a substantial change in the pore structure of all aluminas. By 1100 (PA), 1200 (15 SDA) and 1200 °C (27 SDA), the transition to α-Al2O3 was complete, respectively. No α-Al2O3 is observed for 5 wt % silica doped alumina (5SDA) under thermal calcination. Calcination in steam and air, instead of in air only, results in enlarged pore size and depressed temperature of alpha phase transformation for all aluminas. Results show that the silica dopant modifies the pores of the alumina, stabilizes the oxygen lattice of γ-Al2O3, and retards α-Al2O3 formation. This study of the thermal and hydrothermal stability not only suggests the applicability of 5SDA for catalytic reactions occurring at high temperature in the presence of steam, but also contributes to a better understanding of the structural features responsible for the improved thermal stability of these aluminas. © 2019 Elsevier Inc.
654 a55345299700 Huang B. p181 False Journal 123 Thermal and hydrothermal stability of pure and silica-doped mesoporous aluminas Thermal and hydrothermal stabilities of solvent deficient derived pure alumina (PA) as well as silica-doped aluminas (SDA) with three different dopant concentrations (5, 15, 27% by weight) have been investigated for changes in phase and pore structure after calcination at high temperatures under air and steam/air atmospheres. For all aluminas, heat treatment results in decreased surface area and increased pore diameter. Starting at 700 °C, metastable to stable phase transformation occurs, causing a substantial change in the pore structure of all aluminas. By 1100 (PA), 1200 (15 SDA) and 1200 °C (27 SDA), the transition to α-Al2O3 was complete, respectively. No α-Al2O3 is observed for 5 wt % silica doped alumina (5SDA) under thermal calcination. Calcination in steam and air, instead of in air only, results in enlarged pore size and depressed temperature of alpha phase transformation for all aluminas. Results show that the silica dopant modifies the pores of the alumina, stabilizes the oxygen lattice of γ-Al2O3, and retards α-Al2O3 formation. This study of the thermal and hydrothermal stability not only suggests the applicability of 5SDA for catalytic reactions occurring at high temperature in the presence of steam, but also contributes to a better understanding of the structural features responsible for the improved thermal stability of these aluminas. © 2019 Elsevier Inc.
655 a56110251000 Mardkhe M.K. p181 False Journal 123 Thermal and hydrothermal stability of pure and silica-doped mesoporous aluminas Thermal and hydrothermal stabilities of solvent deficient derived pure alumina (PA) as well as silica-doped aluminas (SDA) with three different dopant concentrations (5, 15, 27% by weight) have been investigated for changes in phase and pore structure after calcination at high temperatures under air and steam/air atmospheres. For all aluminas, heat treatment results in decreased surface area and increased pore diameter. Starting at 700 °C, metastable to stable phase transformation occurs, causing a substantial change in the pore structure of all aluminas. By 1100 (PA), 1200 (15 SDA) and 1200 °C (27 SDA), the transition to α-Al2O3 was complete, respectively. No α-Al2O3 is observed for 5 wt % silica doped alumina (5SDA) under thermal calcination. Calcination in steam and air, instead of in air only, results in enlarged pore size and depressed temperature of alpha phase transformation for all aluminas. Results show that the silica dopant modifies the pores of the alumina, stabilizes the oxygen lattice of γ-Al2O3, and retards α-Al2O3 formation. This study of the thermal and hydrothermal stability not only suggests the applicability of 5SDA for catalytic reactions occurring at high temperature in the presence of steam, but also contributes to a better understanding of the structural features responsible for the improved thermal stability of these aluminas. © 2019 Elsevier Inc.
656 a57208682307 Corie T.H. p183 True Journal 125 Simulated Tremor Propagation in the Upper Limb: From Muscle Activity to Joint Displacement Although tremor is the most common movement disorder, there are few noninvasive treatment options. Creating effective tremor suppression devices requires a knowledge of where tremor originates mechanically (which muscles) and how it propagates through the limb (to which degrees-of-freedom (DOF)). To simulate tremor propagation, we created a simple model of the upper limb, with tremorogenic activity in the 15 major superficial muscles as inputs and tremulous joint displacement in the seven major DOF as outputs. The model approximated the muscle excitation-contraction dynamics, musculoskeletal geometry, and mechanical impedance of the limb. From our simulations, we determined fundamental principles for tremor propagation: (1) The distribution of tremor depends strongly on musculoskeletal dynamics. (2) The spreading of tremor is due to inertial coupling (primarily) and musculoskeletal geometry (secondarily). (3) Tremorogenic activity in a given muscle causes significant tremor in only a small subset of DOF, though these affected DOF may be distant from the muscle. (4) Assuming uniform distribution of tremorogenic activity among muscles, tremor increases proximal-distally, and the contribution from muscles increases proximal-distally. (5) Although adding inertia (e.g., with weighted utensils) is often used to suppress tremor, it is possible to increase tremor by adding inertia to the wrong DOF. (6) Similarly, adding viscoelasticity to the wrong DOF can increase tremor. Based solely on the musculoskeletal system, these principles indicate that tremor treatments targeting muscles should focus first on the distal muscles, and devices targeting DOF should focus first on the distal DOF. © 2019 by ASME.
657 a57201589125 Raven L.A. p184 False Journal 104 Hardware friendly robust synthetic basis feature descriptor Finding corresponding image features between two images is often the first step for many computer vision algorithms. This paper introduces an improved synthetic basis feature descriptor algorithm that describes and compares image features in an efficient and discrete manner with rotation and scale invariance. It works by performing a number of similarity tests between the feature region surrounding the feature point and a predetermined number of synthetic basis images to generate a feature descriptor that uniquely describes the feature region. Features in two images are matched by comparing their descriptors. By only storing the similarity of the feature region to each synthetic basis image, the overall storage size is greatly reduced. In short, this new binary feature descriptor is designed to provide high feature matching accuracy with computational simplicity, relatively low resource usage, and a hardware friendly design for real-time vision applications. Experimental results show that our algorithm produces higher precision rates and larger number of correct matches than the original version and other mainstream algorithms and is a good alternative for common computer vision applications. Two applications that often have to cope with scaling and rotation variations are included in this work to demonstrate its performance. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
658 a24779209500 Fernandes T. p186 False Journal 127 Generating a Binary Symmetric Channel for Wiretap Codes In this paper, we fill a void between information theoretic security and practical coding over the Gaussian wiretap channel using a three-stage encoder/decoder technique. Security is measured using Kullback-Leibler divergence and resolvability techniques along with a limited number of practical assumptions regarding the eavesdropper's decoder. The results specify a general coding recipe for obtaining both secure and reliable communications over the Gaussian wiretap channel, and one specific set of concatenated codes is presented as a test case for the sake of providing simulation-based evaluation of security and reliability over the network. It is shown that there exists a threshold in signal-to-noise ratio (SNR) over a Gaussian channel, such that receivers experiencing SNR below the threshold have no practical hope of receiving information about the message when the three-stage coding technique is applied. Results further indicate that the two innermost encoding stages successfully approximate a binary symmetric channel, allowing the outermost encoding stage (e.g., a wiretap code) to focus solely on secrecy coding over this approximated channel. © 2005-2012 IEEE.
659 a56012631600 Wang T. p187 True Journal 128 Evaluation of intermetallic compound layer at aluminum/steel interface joined by friction stir scribe technology Heat input and high strain rate deformation during friction stir welding of aluminum and steel resulted in the diffusion-based formation of a Fe x Al y intermetallic compound (IMC) layer. Compared with conventional friction stir welding tools, a friction stir scribe tool can reduce heat input significantly limiting the IMC layer thickness (~100–750 nm). Friction stir scribe joined lap joints fractured either through the welded interface or within the base aluminum alloy on the loading side, depending on IMC layer thickness during tensile lap shear testing. In addition, a modified effective heat of formation model predicted that Al 13 Fe 4 formed first at aluminum/steel interface and, during welding process, was substituted by Al 5 Fe 2 with local silicon enrichment, which was verified via microstructural characterization. © 2019 The Authors
660 a56487893500 Sidhar H. p187 False Journal 128 Evaluation of intermetallic compound layer at aluminum/steel interface joined by friction stir scribe technology Heat input and high strain rate deformation during friction stir welding of aluminum and steel resulted in the diffusion-based formation of a Fe x Al y intermetallic compound (IMC) layer. Compared with conventional friction stir welding tools, a friction stir scribe tool can reduce heat input significantly limiting the IMC layer thickness (~100–750 nm). Friction stir scribe joined lap joints fractured either through the welded interface or within the base aluminum alloy on the loading side, depending on IMC layer thickness during tensile lap shear testing. In addition, a modified effective heat of formation model predicted that Al 13 Fe 4 formed first at aluminum/steel interface and, during welding process, was substituted by Al 5 Fe 2 with local silicon enrichment, which was verified via microstructural characterization. © 2019 The Authors
661 a7402648240 Mishra R.S. p187 False Journal 128 Evaluation of intermetallic compound layer at aluminum/steel interface joined by friction stir scribe technology Heat input and high strain rate deformation during friction stir welding of aluminum and steel resulted in the diffusion-based formation of a Fe x Al y intermetallic compound (IMC) layer. Compared with conventional friction stir welding tools, a friction stir scribe tool can reduce heat input significantly limiting the IMC layer thickness (~100–750 nm). Friction stir scribe joined lap joints fractured either through the welded interface or within the base aluminum alloy on the loading side, depending on IMC layer thickness during tensile lap shear testing. In addition, a modified effective heat of formation model predicted that Al 13 Fe 4 formed first at aluminum/steel interface and, during welding process, was substituted by Al 5 Fe 2 with local silicon enrichment, which was verified via microstructural characterization. © 2019 The Authors
661 a7402648240 Mishra R.S. p396 False Journal 214 Preface [No abstract available]
661 a7402648240 Mishra R.S. p885 False Journal 411 Preface [No abstract available]
662 a57200884469 Upadhyay P. p187 False Journal 128 Evaluation of intermetallic compound layer at aluminum/steel interface joined by friction stir scribe technology Heat input and high strain rate deformation during friction stir welding of aluminum and steel resulted in the diffusion-based formation of a Fe x Al y intermetallic compound (IMC) layer. Compared with conventional friction stir welding tools, a friction stir scribe tool can reduce heat input significantly limiting the IMC layer thickness (~100–750 nm). Friction stir scribe joined lap joints fractured either through the welded interface or within the base aluminum alloy on the loading side, depending on IMC layer thickness during tensile lap shear testing. In addition, a modified effective heat of formation model predicted that Al 13 Fe 4 formed first at aluminum/steel interface and, during welding process, was substituted by Al 5 Fe 2 with local silicon enrichment, which was verified via microstructural characterization. © 2019 The Authors
662 a57200884469 Upadhyay P. p396 False Journal 214 Preface [No abstract available]
662 a57200884469 Upadhyay P. p637 False Conference 271 Local texture evolution and mechanical performance of ultra-high-speed friction stir weld of AA 6111-T4 sheets Friction stir welding has gained wide interest in industry and drawn large research attention due to its high level of automation and superior joint performance. In this study we further expand the welding parameters to be of magnitudes higher than those previously reported to lower the cost and enable high volume joint production. Sound butt-joints were produced with aluminum alloy 6111-T4 blanks with welding speeds up to 6000, mm/min. Tensile tests of the joint pieces show >97% joint efficiency in terms of ultimate tensile strength. The T4 natural aging and grain refinement is found to contribute to the superior joint properties. Electron backscatter diffraction (EBSD) analysis is used to qualitatively study the local shear texture inside the nugget zones of the welds. The shear texture result is a good indicator of the material flow directions in the nugget zones. The flow directions behind the rotation tool are found to be flattened towards the top surface of the workpiece when the welding speed is increased, suggesting intense material mixing and transportation along the longitudinal welding direction (WD). © The Minerals, Metals & Materials Society 2018.
662 a57200884469 Upadhyay P. p638 False Journal 227 High-Speed Friction Stir Welding of AA7075-T6 Sheet: Microstructure, Mechanical Properties, Micro-texture, and Thermal History Friction stir welding (FSW) is a cost-effective and high-quality joining process for aluminum alloys (especially heat-treatable alloys) that is historically operated at lower joining speeds (up to hundreds of millimeters per minute). In this study, we present a microstructural analysis of friction stir welded AA7075-T6 blanks with high welding speeds up to 3 M/min. Textures, microstructures, mechanical properties, and weld quality are analyzed using TEM, EBSD, metallographic imaging, and Vickers hardness. The higher welding speed results in narrower, stronger heat-affected zones (HAZs) and also higher hardness in the nugget zones. The material flow direction in the nugget zone is found to be leaning towards the welding direction as the welding speed increases. Results are coupled with welding parameters and thermal history to aid in the understanding of the complex material flow and texture gradients within the welds in an effort to optimize welding parameters for high-speed processing. © 2017, The Minerals, Metals & Materials Society and ASM International.
662 a57200884469 Upadhyay P. p746 False Journal 361 Enabling Dissimilar Material Joining Using Friction Stir Scribe Technology One challenge in adapting welding processes to dissimilar material joining is the diversity of melting temperatures of the different materials. Although the use of mechanical fasteners and adhesives have mostly paved the way for near-term implementation of dissimilar material systems, these processes only accentuate the need for low-cost welding processes capable of impartially joining dissimilar material components regardless of alloy, properties, or melting temperature. Friction stir scribe technology was developed to overcome the challenges of joining dissimilar material components where melting temperatures vary greatly, and properties and/or chemistry are not compatible with more traditional welding processes. Although the friction stir scribe process is capable of joining dissimilar metals and metal/polymer systems, a more detailed evaluation of several aluminum/steel joints is presented herein to demonstrate the ability to both chemically and mechanically join dissimilar materials. © 2017, The Minerals, Metals & Materials Society.
662 a57200884469 Upadhyay P. p872 False Journal 404 Predicting Lap Shear Strength for Friction Stir Scribe Joining of Dissimilar Materials Friction stir scribe technology has been developed to join materials with vastly different properties, most importantly different melting regimes. Specifically lighter, lower temperature materials such as aluminum or magnesium can be joined to higher temperature materials such as steel and titanium. The scribe portion of the modified friction stir welding pin tool creates in situ mechanical interlocks at the material interface. This mechanical interlocking, or hook-like interface morphology, has shown promising joint strength. However, this morphology can vary along a weld length and is sensitive to joining and tooling parameters. The current work seeks to determine the sensitivity of joint strength to the morphology of the hook interface and predict joint strength based on key morphology parameters. Key morphology features of the hooks extracted from joined samples are varied to quantify their impact on simulated lap shear strength. Predictable joint strength is key to wide spread use of this technique. © 2017, The Minerals, Metals & Materials Society.
662 a57200884469 Upadhyay P. p873 False Journal 405 High-Speed FSW Aluminum Alloy 7075 Microstructure and Corrosion Properties High-speed friction stir welding provides an opportunity to enable high-volume aluminum joining, thus lowering the expense of the process. To better understand this important industrial process the properties of the welds must be fully characterized. In this study we examined the microstructures of AA7075 butt welds with welding speeds of 1, 2 and 3 m/min. The welds were also tested for their corrosion resistance in a diluted EXCO solution at room temperature. The welds with higher speeds had a smaller corrosion sensitive area along with smaller HAZs, but the nugget zone became more corrosion susceptible. Their microstructure features were used to explain the non-uniform corrosion behavior across the weld. Both constituent particles and precipitate distribution were altered by the friction stir process and resulted in an overall sensitized weld affected region compared to the base material. © 2017, The Minerals, Metals & Materials Society.
662 a57200884469 Upadhyay P. p885 False Journal 411 Preface [No abstract available]
662 a57200884469 Upadhyay P. p887 True Journal 412 Joining Dissimilar Material Using Friction Stir Scribe Technique The ability to effectively join materials with vastly different melting points, like aluminum to steel, and polymer composites to metals, has been one of the roadblocks to realizing multi-material components for lightweighting efforts. The friction stir scribe (FSS) technique is a promising method that produces continuous overlap joints between materials with vastly different melting regimes and high-temperature flow characteristics. FSS uses an offset cutting tool at the tip of the friction stir welding pin to create an in situ mechanical interlock between material interfaces. With investments from the U.S. Department of Energy Vehicle Technologies Office and several automotive manufacturers and suppliers, Pacific Northwest National Laboratory is developing the FSS process and has demonstrated the viability of joining several material combinations. Details of welding trials, unique challenges, and mitigation strategies in different material combinations will be discussed. Joint characterization, including mechanical tests and joint performance, will also be presented. © 2017, The Minerals, Metals & Materials Society.
663 a57203221999 Carlson B. p187 False Journal 128 Evaluation of intermetallic compound layer at aluminum/steel interface joined by friction stir scribe technology Heat input and high strain rate deformation during friction stir welding of aluminum and steel resulted in the diffusion-based formation of a Fe x Al y intermetallic compound (IMC) layer. Compared with conventional friction stir welding tools, a friction stir scribe tool can reduce heat input significantly limiting the IMC layer thickness (~100–750 nm). Friction stir scribe joined lap joints fractured either through the welded interface or within the base aluminum alloy on the loading side, depending on IMC layer thickness during tensile lap shear testing. In addition, a modified effective heat of formation model predicted that Al 13 Fe 4 formed first at aluminum/steel interface and, during welding process, was substituted by Al 5 Fe 2 with local silicon enrichment, which was verified via microstructural characterization. © 2019 The Authors
663 a57203221999 Carlson B. p615 False Conference 253 Initial Comparisons of Friction Stir Spot Welding and Self Piercing Riveting of Ultra-Thin Steel Sheet Due to the limitations on resistance spot welding of ultra-thin steel sheet (thicknesses below 0.5 mm) in high-volume automotive manufacturing, a comparison of friction stir spot welding and self-piercing riveting was performed to determine which process may be more amenable to enabling assembly of ultra-thin steel sheet. Statistical comparisons between mechanical properties of lap-shear tensile and T-peel were made in sheet thickness below 0.5 mm and for dissimilar thickness combinations. An evaluation of energy to fracture, fracture mechanisms, and joint consistency is presented. © 2018 SAE International; Ford Motor Company; General Motors LLC.
663 a57203221999 Carlson B. p746 False Journal 361 Enabling Dissimilar Material Joining Using Friction Stir Scribe Technology One challenge in adapting welding processes to dissimilar material joining is the diversity of melting temperatures of the different materials. Although the use of mechanical fasteners and adhesives have mostly paved the way for near-term implementation of dissimilar material systems, these processes only accentuate the need for low-cost welding processes capable of impartially joining dissimilar material components regardless of alloy, properties, or melting temperature. Friction stir scribe technology was developed to overcome the challenges of joining dissimilar material components where melting temperatures vary greatly, and properties and/or chemistry are not compatible with more traditional welding processes. Although the friction stir scribe process is capable of joining dissimilar metals and metal/polymer systems, a more detailed evaluation of several aluminum/steel joints is presented herein to demonstrate the ability to both chemically and mechanically join dissimilar materials. © 2017, The Minerals, Metals & Materials Society.
663 a57203221999 Carlson B. p887 False Journal 412 Joining Dissimilar Material Using Friction Stir Scribe Technique The ability to effectively join materials with vastly different melting points, like aluminum to steel, and polymer composites to metals, has been one of the roadblocks to realizing multi-material components for lightweighting efforts. The friction stir scribe (FSS) technique is a promising method that produces continuous overlap joints between materials with vastly different melting regimes and high-temperature flow characteristics. FSS uses an offset cutting tool at the tip of the friction stir welding pin to create an in situ mechanical interlock between material interfaces. With investments from the U.S. Department of Energy Vehicle Technologies Office and several automotive manufacturers and suppliers, Pacific Northwest National Laboratory is developing the FSS process and has demonstrated the viability of joining several material combinations. Details of welding trials, unique challenges, and mitigation strategies in different material combinations will be discussed. Joint characterization, including mechanical tests and joint performance, will also be presented. © 2017, The Minerals, Metals & Materials Society.
664 a6603570606 Shoemaker G. p188 False Journal 129 Soft body armor time-dependent back face deformation (BFD) with ballistics gel backing This paper presents a method for obtaining time dependent back face deformation (BFD) data for body armor during ballistic impact using a clear ballistics gelatin backing and high-speed cameras to capture the deformation profile. Using this method, baseline fabric characterization data was obtained for samples comprised of varying layers of 467 g/m 2 Kevlar K29 fabric impacted with 8.24 g steel ball projectile and backed with NATO standard 20% clear ballistics gelatin. For these tests, deformation depths were seen to increase with increasing impact energy and decreasing total areal density. A limited study of the various test parameters was performed by testing one additional fabric, projectile, and ballistics gelatin. From these comparisons, it was observed that 122 g/m 2 Kevlar KM2+ fabric performs better per weight than 467 g/m 2 Kevlar K29 fabric in terms of BFD, 9 mm FMJ projectiles produce deeper BFDs than 12.7 mm steel ball projectiles, and backing a sample with FBI standard 10% ballistics gel increases the BFD considerably over NATO standard 20% ballistics gel. © 2019
664 a6603570606 Shoemaker G. p645 False Conference 277 In-situ measurements of strain in soft body armor with FBG sensors during ballistic impacts The strain on a single FBG sensor, integrated into a single layer of Kevlar mounted behind a Kevlar soft body armor coupon, is measured throughout a ballistic impact event. The strain is collected through high-speed, full-spectral interrogation of the FBG during the event. The use of the wavelength shift and spectral distortion of the FBG provides a description of the strain profile and interaction between the optical fiber and Kevlar fabric. The measurements are correlated to high-speed camera images taken from the rear and side of the armor coupon. In future testing, this information can be applied to identify the sequence of energy dissipation mechanisms enacted within the armor to resist the ballistic impact. © OSA 2018 © 2018 The Author(s)
665 a57203028829 Schultz S. p188 False Journal 129 Soft body armor time-dependent back face deformation (BFD) with ballistics gel backing This paper presents a method for obtaining time dependent back face deformation (BFD) data for body armor during ballistic impact using a clear ballistics gelatin backing and high-speed cameras to capture the deformation profile. Using this method, baseline fabric characterization data was obtained for samples comprised of varying layers of 467 g/m 2 Kevlar K29 fabric impacted with 8.24 g steel ball projectile and backed with NATO standard 20% clear ballistics gelatin. For these tests, deformation depths were seen to increase with increasing impact energy and decreasing total areal density. A limited study of the various test parameters was performed by testing one additional fabric, projectile, and ballistics gelatin. From these comparisons, it was observed that 122 g/m 2 Kevlar KM2+ fabric performs better per weight than 467 g/m 2 Kevlar K29 fabric in terms of BFD, 9 mm FMJ projectiles produce deeper BFDs than 12.7 mm steel ball projectiles, and backing a sample with FBI standard 10% ballistics gel increases the BFD considerably over NATO standard 20% ballistics gel. © 2019
665 a57203028829 Schultz S. p511 False Journal 280 Noise reduction techniques in fiber optic sensors Test and evaluation needs are becoming more and more demanding on the sensors being used. Fiber optic sensors are known for their ability to survive in harsh environments such as high pressure and temperature like those within oil/gas wells, or high vibration like those with electromagnetic railguns. As these sensors become commercially available, one challenge is overcoming multiple noise sources simultaneously in the sensor and its network imposed from the harsh environment. Optical amplifiers are typically used in fiber optic sensors to improve the signal-to-noise ratio (SNR). This method is suitable for boosting the signal above the floor caused by electrical noise. However, certain noise sources in fiber optic sensors directly modulate the optical signal. This can be due to other measurands being induced on the system. For example, while a slab coupled optical sensor (SCOS) is sensitive to electric field, it is also inherently sensitive to strain; therefore, any strain noise imposed on the sensor would overwhelm the electric field measurement and be considered noise. In this chapter, optical phase induced interference noise (PIIN) in a sensor network is reduced by using optical phase modulation in both a SCOS and a fiber Bragg grating (FBG). Strain induced noise on the optical fiber sensor is reduced using a differential sensor setup called a push-pull SCOS. Phase modulation and differentiation are then combined to allow for simultaneous noise reduction from different noise sources and allow for optical sensing of electric fields in harsh environments. These principles are applicable to other types of fiber optic sensors and sensors in general. © 2018 Nova Science Publishers, Inc.
665 a57203028829 Schultz S. p645 False Conference 277 In-situ measurements of strain in soft body armor with FBG sensors during ballistic impacts The strain on a single FBG sensor, integrated into a single layer of Kevlar mounted behind a Kevlar soft body armor coupon, is measured throughout a ballistic impact event. The strain is collected through high-speed, full-spectral interrogation of the FBG during the event. The use of the wavelength shift and spectral distortion of the FBG provides a description of the strain profile and interaction between the optical fiber and Kevlar fabric. The measurements are correlated to high-speed camera images taken from the rear and side of the armor coupon. In future testing, this information can be applied to identify the sequence of energy dissipation mechanisms enacted within the armor to resist the ballistic impact. © OSA 2018 © 2018 The Author(s)
665 a57203028829 Schultz S. p678 False Conference 291 High-Speed Interrogation of Multiplexed Fiber Bragg Gratings with Spectral Distortion Fiber Bragg grating (FBG) sensors can be multiplexed in large numbers to monitor the performance of large structures. This paper addresses the collection of FBG reflection spectra from wavelength division multiplexed sensors at fast acquisition rates. The spectral and temporal resolution is first derived as a function of the tunable filter and measurement system properties. The method is applied to impact loading investigations of a stiffened composite skin panel. The reflected spectrum of each FBG in an array, embedded in the panel, is collected at 100 kHz during the impact events with a spectral resolution down to 40 pm. Visualization of the FBG responses to these impact events, including the presence of spectral distortion in some FBG spectra, is presented. Future analyses based on the full-spectral data sets can enable the assessment of the localized progression of internal damage in such structures. © 2001-2012 IEEE.
665 a57203028829 Schultz S. p705 False Journal 346 Non-perturbing voltage measurement in a coaxial cable with slab-coupled optical sensors Voltage in a coaxial cable is measured by an electric-field optical fiber sensor exploiting the proportionality of voltage and electric field in a fixed structure. The sensor is inserted in a hole drilled through the dielectric of the RG-218 coaxial cable and sealed with epoxy to displace all air and prevent the adverse effects of charge buildup during high-voltage measurements. It is shown that the presence of the sensor in the coaxial cable does not significantly increase electrical reflections in the cable. A slab-coupled optical fiber sensor (SCOS) is used for its compact size and dielectric make. The dynamic range of 50 dB is shown experimentally with detection of signals as low as 1 V and up to 157 kV. A low corner of 0.3 Hz is demonstrated and the SCOS is shown to be able to measure 90 ns rise time. © 2017 Optical Society of America.
665 a57203028829 Schultz S. p736 False Conference 317 Project-based learning curriculum for the junior year based on building a laser tag system [No abstract available]
665 a57203028829 Schultz S. p740 False Journal 346 Optical electric field sensor sensitivity direction rerouting and enhancement using a passive integrated dipole antenna This work introduces a passive dipole antenna integrated into the packaging of a slab-coupled optical sensor to enhance the directional sensitivity of electro-optic electric field measurements parallel to the fiber axis. Using the passive integrated dipole antenna described in this work, a sensor that can typically only sense fields transverse to the fiber direction is able to sense a 1.25 kV/m field along the fiber direction with a gain of 17.5. This is verified through simulation and experiment. © 2017 Optical Society of America.
666 a56824897200 Nielsen J. p190 True Conference 40 Relative moving target tracking and circumnavigation This paper develops observers and controllers for relative estimation and circumnavigation of a moving ground target using bearing-only measurements or range with bearing measurements. A bearing-only observer, range with bearing observer, a general circumnavigation velocity command for an arbitrary aircraft, and nonlinear velocity-based multirotor controller are developed. The observers are designed in the body-fixed reference frame, while the velocity command and multirotor controller are developed in the body-level frame, independent of aircraft heading. This enables target circumnavigation in GPS-denied environments when only a camera-IMU estimator is used for state estimation and ensures observable conditions for the estimator. Simulation results demonstrate the effectiveness of the observers, velocity command, and multirotor controller under various target motions. © 2019 American Automatic Control Council.
666 a56824897200 Nielsen J. p215 False Conference 50 Error-state LQR control of a multirotor UAV We propose an implementation of an LQR controller for the full-state tracking of a time-dependent trajectory with a multirotor UAV. The proposed LQR formulation is based in Lie theory and linearized at each time step according to the multirotor's current state. We show experiments in both simulation and hardware that demonstrate the proposed control scheme's ability to accurately reach and track a given trajectory. The implementation is shown to run onboard at the full rate of a UAV's estimated state. © 2019 IEEE.
666 a56824897200 Nielsen J. p794 True Conference 331 Relative target estimation using a cascade of extended Kalman filters This paper presents a method of tracking multiple ground targets from an unmanned aerial vehicle (UAV) in a 3D reference frame. The tracking method uses a monocular camera and makes no assumptions on the shape of the terrain or the target motion. The UAV runs two cascaded estimators. The first is an Extended Kalman Filter (EKF), which is responsible for tracking the UAV's state, such as position and velocity relative to a fixed frame. The second estimator is an EKF that is responsible for estimating a fixed number of landmarks within the camera's field of view. Landmarks are parameterized by a quaternion associated with bearing from the camera's optical axis and an inverse distance parameter. The bearing quaternion allows for a minimal representation of each landmark's direction and distance, a filter with no singularities, and a fast update rate due to few trigonometric functions. Three methods for estimating the ground target positions are demonstrated: the first uses the landmark estimator directly on the targets, the second computes the target depth with a weighted average of converged landmark depths, and the third extends the target's measured bearing vector to intersect a ground plane approximated from the landmark estimates. Simulation results show that the third target estimation method yields the most accurate results. © 2017, Institute of Navigation.
667 a57210916608 Wynn J.S. p191 True Conference 41 Visual servoing with feed-forward for precision shipboard landing of an autonomous multirotor In this paper the problem of performing a precision landing of an autonomous multirotor on a small barge at sea is studied. An image-based visual servoing approach, which was initially developed for landing on stationary targets, is extended to suit the shipboard landing case. The approach includes visual servoing for aligning the multirotor with a target on the vessel, and a velocity feed-forward term which is estimated online by fusing vision and GPS velocity measurements. Special considerations are made to account for the presence of wind, and the approach is validated through full-scale outdoor hardware flight tests. The hardware system is composed entirely from off-the-shelf components that are commonly used in industry. © 2019 American Automatic Control Council.
667 a57210916608 Wynn J.S. p216 True Conference 51 Visual servoing for multirotor precision landing in daylight and after-dark conditions The problem of precision landing for autonomous multirotor UAVs operating during the day and at night is studied. A vision-based approach is proposed and consists of varying-degree-of-freedom image-based visual servoing (VDOF IBVS), and a specialized landing marker. The proposed approach is validated through extensive flight testing outdoors in both daylight and after-dark conditions, and is done using a standard off-the-shelf autopilot system. © 2019 IEEE.
668 a57210911049 Bidstrup C.C. p192 True Conference 42 Tracking multiple vehicles constrained to a road network from a uav with sparse visual measurements Many multiple target tracking algorithms operate in the local frame of the sensor and have difficulty with track reallocation when targets move in and out of the sensor field of view. This poses a problem when an unmanned aerial vehicle (UAV) is tracking multiple ground targets on a road network larger than its field of view. We propose a Rao-Blackwellized Particle Filter (RBPF) to maintain individual target tracks and to perform probabilistic data association when the targets are constrained to a road network. This is particularly useful when a target leaves then re-enters the UAV's field of view. The RBPF is structured as a particle filter of particle filters. The top level filter handles data association and each of its particles maintains a bank of particle filters to handle target tracking. The tracking particle filters incorporate both positive and negative information when a measurement is received. We then implement a receding horizon controller to improve the filter certainty of multiple target locations. The controller prioritizes searching for targets based on the entropy of each target's estimate. © 2019 American Automatic Control Council.
668 a57210911049 Bidstrup C.C. p215 False Conference 50 Error-state LQR control of a multirotor UAV We propose an implementation of an LQR controller for the full-state tracking of a time-dependent trajectory with a multirotor UAV. The proposed LQR formulation is based in Lie theory and linearized at each time step according to the multirotor's current state. We show experiments in both simulation and hardware that demonstrate the proposed control scheme's ability to accurately reach and track a given trajectory. The implementation is shown to run onboard at the full rate of a UAV's estimated state. © 2019 IEEE.
669 a57207008616 Moore J.J. p192 False Conference 42 Tracking multiple vehicles constrained to a road network from a uav with sparse visual measurements Many multiple target tracking algorithms operate in the local frame of the sensor and have difficulty with track reallocation when targets move in and out of the sensor field of view. This poses a problem when an unmanned aerial vehicle (UAV) is tracking multiple ground targets on a road network larger than its field of view. We propose a Rao-Blackwellized Particle Filter (RBPF) to maintain individual target tracks and to perform probabilistic data association when the targets are constrained to a road network. This is particularly useful when a target leaves then re-enters the UAV's field of view. The RBPF is structured as a particle filter of particle filters. The top level filter handles data association and each of its particles maintains a bank of particle filters to handle target tracking. The tracking particle filters incorporate both positive and negative information when a measurement is received. We then implement a receding horizon controller to improve the filter certainty of multiple target locations. The controller prioritizes searching for targets based on the entropy of each target's estimate. © 2019 American Automatic Control Council.
670 a56315330500 Woodbury N. p193 True Conference 43 Abstractions and realizations of dynamic networks This paper establishes the importance of abstractions and realizations of dynamic networks in characterizing the structure and dynamics of systems. Abstractions and realizations generate dynamically equivalent representations of systems with varying degrees of structural detail. We show that dynamic networks exist that contain the same level of detail as state space models, that other dynamic networks exist that contain the same level of detail as transfer functions, and that still other dynamic networks exist that are simultaneously abstractions of state space models and realizations of transfer functions; thus containing intermediate levels of structural detail. © 2019 American Automatic Control Council.
670 a56315330500 Woodbury N. p280 True Conference 66 Dynamic Networks: Representations, Abstractions, and Well-Posedness This paper introduces notions of abstraction and realization for dynamic networks. These processes generate dynamically equivalent representations of a system, but with varying degrees of structural detail. Nuanced definitions and associated conditions for maintaining well-posedness for these multi-resolution representations of a dynamic system are then detailed, ensuring that hierarchies of network representations are sensible as multi-resolution models of dynamic networks. Although the ideas are developed precisely here for LTI networks, many of the concepts remain fundamental in the nonlinear setting. © 2018 IEEE.
670 a56315330500 Woodbury N. p542 True Conference 196 On the well-posedness of LTI networks We consider networks of linear, time-invariant systems defined over matrices of rational functions in a complex variable where each element of the matrix represents a link in the network. When these rational functions are proper, but not necessarily strictly proper, we demonstrate the necessary and sufficient conditions under which such a network configuration is well-posed. We include multiple examples of network configurations and their respective well-posedness conditions, including cases where two or more ill-posed network configurations can be interconnected to form a well-posed network. © 2017 IEEE.
670 a56315330500 Woodbury N. p682 False Conference 294 Applying a passive network reconstruction technique to Twitter data in order to identify trend setters In this work we apply a systems-theoretic approach to identifying trend setters on Twitter. A network reconstruction algorithm was applied to Twitter data to determine causal relationships among topics discussed by popular Twitter users. Causal relationships in this context means that the topics tweeted by a single user influences the topics tweeted by another user, regardless of sentiment. A user that causally influences other users, without themselves being strongly influenced is identified as a trendsetter. This work seeks to identify potential trendsetters among popular Twitter users and demonstrating that causal influence does not always directly correlate with a user's popularity in terms of followers-demonstrating that popularity alone may not be sufficient for identifying trendsetters on Twitter. © 2017 IEEE.
671 a55858031100 Wood A.E. p194 True Journal 131 Quantifying the effects of various factors on the utility of design ethnography in the developing world Ethnography, a tool traditionally used by social scientists, has been adopted by product design engineers as a tool to build empathy, understand customers and their contexts, and learn about needs for a product. This tool is particularly valuable for designers from the developed world working on products for customers in developing communities as differences in culture, language, and life experience make the designer’s intuition less reliable in these communities. This paper reports the use of design ethnography under a variety of conditions in the developing world. The data analyzed here come from field studies completed in four different developing communities on four different continents. Researchers had varying degrees of cultural familiarity, language fluency, and community partner participation in each location. Other factors were also included in the study such as the effects of gender and age of the respondents, the ethnographic activity used, and others. Some of the results are intuitive and some are surprising, but all are quantified through rigorous statistical analysis. The results of this study can help design teams of all types including NGOs, student teams, industrial teams, and any other team with an interest in product design in developing communities. These results can help teams plan their own ethnographic activities to increase the likelihood of collecting information that is useful for making product design decisions based on the conditions of their particular project. © 2019, Springer-Verlag London Ltd., part of Springer Nature.
671 a55858031100 Wood A.E. p743 False Journal 358 Village Drill: A Case Study in Engineering for Global Development with Five Years of Data Post Market-Introduction This paper presents a case study in engineering for global development. It introduces the Village Drill, which is an engineered product that has - 5 years after its introduction to the market - enabled hundreds of thousands of people across 15 countries and three continents to have access to clean water. The Village Drill creates a 15 cm (6 in) borehole as deep as 76 m (250 ft) to reach groundwater suitable for drinking. The case study presents facts for the actual development and sustaining and are unaltered for the purpose of publication. This approach provides the reader with a realistic view of the development time, testing conditions, fundraising, and the work needed to sustain the drill through 5 years of sales and distribution. The purpose of the case study is to provide sufficient and frank data about a real project so as to promote discussion, critique, and other evaluations that will lead to new developments that inspire and inform successful engineering for global development. As part of the case, the paper describes six fundamental items: the product, the customer, the impact, the manufacturing, the delivery, and the revenue model of the drill. Copyright © 2017 by ASME.
672 a57211493546 Wilson A.E. p196 True Conference 45 Neutron radiation testing of fault tolerant risc-v soft processor on xilinx SRAM-based FPGAs Many space applications are considering the use of commercial SRAM-based FPGAs over radiation hardened devices. When using SRAM-based FPGAs, soft processors may be required to fulfill application requirements, but the FPGA designs must overcome radiation-induced soft errors to provide a reliable system. TMR is one solution in designing a fault tolerant soft processor to mitigate the failures caused by SEUs. This paper compares the neutron soft-error reliability of an unmitigated and TMR version of a Taiga RISC-V soft processor on a Xilinx SRAM-based FPGA. The TMR RISC-V processor showed a 33× reduction in the neutron cross section and a 27% decrease in operational frequency, resulting in a 24× improvement of the mean work to failure with a cost of around 5.6× resource utilization. © 2019 IEEE.
673 a57205881788 Baker M.J. p197 True Conference 46 Extended Abstract: Comparison of Peer and Instructor Qualitative Feedback on Presentations New presentation-feedback technologies enable peers and instructors to provide real-time qualitative feedback on oral presentations. Previous research suggests that summative quantitative ratings of peers and instructors tend to be moderately reliable, but no research exists on how substantive qualitative ratings compare. Analyzing the substantive qualitative feedback from 10 students and 10 instructors on two professional presentations, this study analyzes differences in the message- and messenger-related comments of peers and instructors. Findings suggest that instructors provide proportionally more messenger-related feedback. © 2019 IEEE.
673 a57205881788 Baker M.J. p222 False Journal 145 Using case-method pedagogy to facilitate audience awareness Introduction: Technical and professional communication (TPC) instructors value audience awareness, using peer-and client-based projects to facilitate it. We explore how students' audience awareness is facilitated by the case method, which presents students with a professional communication task within a workplace scenario. Situating the case: Case-method research suggests including a detailed audience and situation, multiple genres, and multimedia. Few studies have explored how case materials facilitate students' audience awareness. About the case: A 12-week case that was consistent with case-method research asked students to respond to an engineering firm's internal problem with a proposal and report. How the case was studied: Students from two sections of a genre-based course completed reflections about their audience awareness after the proposal and report. We qualitatively analyzed 51 reflections. Results/discussion: Students stated they could understand the facts about their primary audience but couldn't identify secondary and tertiary audiences. Students stated they could identify audience needs, but they disagreed about the amount of detail to understand those needs. Also, students stated they could respond to the audience using appropriate evidence and writing style. Conclusions: When using the case method, instructors should know that students may need varying levels of detail to interpret their audience's needs. Also, including data and conflicting needs gives students opportunities to make strategic decisions about content. © 1988-2012 IEEE.
674 a57214032187 Baker W.H. p197 False Conference 46 Extended Abstract: Comparison of Peer and Instructor Qualitative Feedback on Presentations New presentation-feedback technologies enable peers and instructors to provide real-time qualitative feedback on oral presentations. Previous research suggests that summative quantitative ratings of peers and instructors tend to be moderately reliable, but no research exists on how substantive qualitative ratings compare. Analyzing the substantive qualitative feedback from 10 students and 10 instructors on two professional presentations, this study analyzes differences in the message- and messenger-related comments of peers and instructors. Findings suggest that instructors provide proportionally more messenger-related feedback. © 2019 IEEE.
675 a57208524360 Hanks K.N. p198 True Journal 132 Experimental Performance of Block-Out Connections at the Base of Steel Moment Frames In a block-out connection, a steel column is connected to a footing through an opening (block-out) in a slab-on-grade that is later filled with unreinforced concrete. In design, engineers generally neglect any beneficial effects of the block-out concrete. The objective of this study is to experimentally quantify the effect of block-out concrete on the lower-bound flexural strength and stiffness of block-out connections at the base of steel moment frames. Eight specimens were tested with varying column shape, block-out depth, and baseplate/anchor rod designs. The block-out concrete increased the connection flexural strengths by 69%-91% for block-out depths that were 1.2-1.5 times the column depth. A strength model proposed in previous work was found to reasonably predict the flexural strength, accounting for the effects of block-out concrete. With regard to stiffness, specimens with block-out concrete depths at least 1.15 times the column depth could be accurately modeled as fixed at the top-of-footing elevation. © 2019 American Society of Civil Engineers.
676 a26634229600 Richards P.W. p198 False Journal 132 Experimental Performance of Block-Out Connections at the Base of Steel Moment Frames In a block-out connection, a steel column is connected to a footing through an opening (block-out) in a slab-on-grade that is later filled with unreinforced concrete. In design, engineers generally neglect any beneficial effects of the block-out concrete. The objective of this study is to experimentally quantify the effect of block-out concrete on the lower-bound flexural strength and stiffness of block-out connections at the base of steel moment frames. Eight specimens were tested with varying column shape, block-out depth, and baseplate/anchor rod designs. The block-out concrete increased the connection flexural strengths by 69%-91% for block-out depths that were 1.2-1.5 times the column depth. A strength model proposed in previous work was found to reasonably predict the flexural strength, accounting for the effects of block-out concrete. With regard to stiffness, specimens with block-out concrete depths at least 1.15 times the column depth could be accurately modeled as fixed at the top-of-footing elevation. © 2019 American Society of Civil Engineers.
676 a26634229600 Richards P.W. p425 False Journal 235 Column axial load effects on the performance of skewed SMF RBS connections The selection of an appropriate seismic steel system (braced frame, moment frame, shear wall, etc.) is often influenced by architectural considerations. Moment frame configurations offer the most architectural flexibility, but are somewhat limited by a lack of guidance in the AISC seismic provisions regarding the use of non-orthogonal (skewed) beam-column connections. A recent study investigating laterally skewed moment frame connections indicates adequate seismic performance; however, it was observed that skewed connections increase the potential for column twist and column flange yielding. It is unclear how larger column axial loads present in medium-to-high-rise structures will affect the performance of skewed special moment frame connections. This study investigates the effects of column axial loads on skewed special moment frame connections containing reduced beam sections (RBSs). Detailed finite element analyses are used for all investigations, and several beam-column connection configurations are considered, representing: 3 beam-column geometries (shallow, medium and deep columns); 4 levels of skew at the beam-to-column connection; and 4 levels of applied column axial load. Results indicate that for axial loads less than 50% of the column axial capacity, there is little effect on connection rotation capacity. Beam-skew angle is the main contributor to resulting column twist. With the exception of the deep column geometries that experienced local flange buckling at 50% ΦPn axial load, increased column axial loads have little effect on resulting column flange yielding in skewed RBS moment connections. © 2018 Elsevier Ltd
676 a26634229600 Richards P.W. p432 True Journal 240 Flexural strength and stiffness of block-out connections for steel columns In many steel buildings, the columns are attached to the foundation through a block-out in the slab-on-grade that is later filled with unreinforced concrete. Engineers typically neglect the block-out concrete in design, effectively treating block-out connections as exposed connections with pinned behavior. Quantifying the flexural strength and stiffness of block-out connections is helpful for determining moment demands on foundations and may lead to more economical connections at the base of steel moment frames. Eight experimental specimens (two-thirds scale) were subjected to lateral loads to investigate the effects of column size, block-out thickness, and load orientation on connection flexural strength and stiffness. The observed flexural strengths were 1.4–2.7 times greater than those calculated neglecting the block-out concrete, because the block-out concrete effectively thickened and expanded the column base plate. A simple method was developed that predicted the flexural strength of the block-out connections to within 10 percent. The effective flexural stiffness at the base of the columns that were tested could be reasonably estimated using a model that combines the theory of beams on elastic foundations with a base rotational spring. © 2018
677 a7005934389 Randall G.C. p199 True Journal 133 Lower-bound dislocation density mapping in microcoined tantalum using high-resolution electron backscatter diffraction High-resolution electron backscatter diffraction (HR-EBSD) is used to map the geometrically necessary dislocation (GND) density in the cross-sections of annealed, rolled, and microcoined tantalum foils that are typical targets used in modern laser-induced compression materials science studies. The microcoined samples are characteristic of microforming, where the deformation length scale is on the order of the grain size (~50 μm). In particular, inhomogeneities in dislocation density maps across 0.1–1 mm regions of interest are compared with expectations from slip line field approximations. The average HR-EBSD GND dislocation density measurements in various annealed and cold worked tantalum samples are compared with corresponding dislocation density approximations from microhardness measurements. GND densities in the range 1013 − 1015 m−2 are typical. © 2019 Elsevier Inc.
678 a57208823236 Hansen K.R. p199 False Journal 133 Lower-bound dislocation density mapping in microcoined tantalum using high-resolution electron backscatter diffraction High-resolution electron backscatter diffraction (HR-EBSD) is used to map the geometrically necessary dislocation (GND) density in the cross-sections of annealed, rolled, and microcoined tantalum foils that are typical targets used in modern laser-induced compression materials science studies. The microcoined samples are characteristic of microforming, where the deformation length scale is on the order of the grain size (~50 μm). In particular, inhomogeneities in dislocation density maps across 0.1–1 mm regions of interest are compared with expectations from slip line field approximations. The average HR-EBSD GND dislocation density measurements in various annealed and cold worked tantalum samples are compared with corresponding dislocation density approximations from microhardness measurements. GND densities in the range 1013 − 1015 m−2 are typical. © 2019 Elsevier Inc.
678 a57208823236 Hansen K.R. p442 True Journal 247 Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
678 a57208823236 Hansen K.R. p757 False Journal 369 Tuning Ferritin's band gap through mixed metal oxide nanoparticle formation This study uses the formation of a mixed metal oxide inside ferritin to tune the band gap energy of the ferritin mineral. The mixed metal oxide is composed of both Co and Mn, and is formed by reacting aqueous Co2+ with MnO4in the presence of apoferritin. Altering the ratio between the two reactants allowed for controlled tuning of the band gap energies. All minerals formed were indirect band gap materials, with indirect band gap energies ranging from 0.52 to 1.30 eV. The direct transitions were also measured, with energy values ranging from 2.71 to 3.11 eV. Tuning the band gap energies of these samples changes the wavelengths absorbed by each mineral, increasing ferritin's potential in solar-energy harvesting. Additionally, the success of using MnO4 in ferritin mineral formation opens the possibility for new mixed metal oxide cores inside ferritin. © 2017 IOP Publishing Ltd.
678 a57208823236 Hansen K.R. p758 False Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
679 a57190605478 Jackson B. p199 False Journal 133 Lower-bound dislocation density mapping in microcoined tantalum using high-resolution electron backscatter diffraction High-resolution electron backscatter diffraction (HR-EBSD) is used to map the geometrically necessary dislocation (GND) density in the cross-sections of annealed, rolled, and microcoined tantalum foils that are typical targets used in modern laser-induced compression materials science studies. The microcoined samples are characteristic of microforming, where the deformation length scale is on the order of the grain size (~50 μm). In particular, inhomogeneities in dislocation density maps across 0.1–1 mm regions of interest are compared with expectations from slip line field approximations. The average HR-EBSD GND dislocation density measurements in various annealed and cold worked tantalum samples are compared with corresponding dislocation density approximations from microhardness measurements. GND densities in the range 1013 − 1015 m−2 are typical. © 2019 Elsevier Inc.
680 a35508257500 Long D.G. p200 True Journal 134 Enhanced-Resolution SMAP Brightness Temperature Image Products The NASA-sponsored Calibrated Passive Micro- wave Daily Equal-Area Scalable Earth Grid 2.0 Brightness Temperature (CETB) Earth System Data Record Project team has generated a multisensor, multidecadal time series of high-resolution radiometer products designed to support climate studies. This project uses image reconstruction techniques to generate conventional and enhanced-resolution daily brightness temperature images on a standard set of map projections. Sensors included in CETB are the Aqua Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E), Scanning Multichannel Microwave Radiometer, and all Special Sensor Microwave/Imager and Special Sensor Microwave Imager/Sounder radiometers. These span frequencies between 6 and 89 GHz. This paper considers the issues of adding the L-band (1.6 GHz) Soil Moisture Active Passive (SMAP) radiometer measurements to the CETB climate record, with emphasis on optimizing the reconstruction to provide the highest possible spatial resolution at the lowest noise level. SMAP radiometer reconstruction on SMAP-standard grids is also considered. Simulation is used to optimize the reconstruction, and the results confirmed using actual data. A comparison of the performance of the Backus-Gilbert approach and the radiometer form of the Scatterometer Image Reconstruction algorithm is provided. These are compared to the conventional drop-in-the-bucket gridded imaging. © 1980-2012 IEEE.
680 a35508257500 Long D.G. p218 False Journal 134 Improved Ultrahigh-Resolution Wind Retrieval for RapidScat This paper introduces RapidScat 2.5-km ultrahigh-resolution (UHR) wind estimation and validates it in near-coastal regions. RapidScat UHR wind estimation provides finer resolution ocean wind vector fields than conventional 12.5-km level 2B (L2B) wind products at a cost of higher noise. In addition, this paper applies direction interval retrieval techniques and develops other wind processing improvements to enhance the performance of RapidScat UHR wind estimation. The new algorithm is validated with L2B wind estimates, numerical weather prediction wind products, and buoy measurements. The wind processing improvements produce more spatially consistent UHR winds that compare well with the wind products mentioned above. © 2018 IEEE.
680 a35508257500 Long D.G. p219 True Journal 134 Scatterometer Backscatter Imaging Using Backus-Gilbert Inversion Wind scatterometer measurements are collected over an irregular grid, and processing is required to generate backscatter images on an Earth-centered grid. The most common algorithms used for this are "drop in the bucket" (DIB) and variations of the scatterometer image reconstruction (SIR) algorithm. These algorithms are also used for radiometer brightness temperature imaging. The Backus-Gilbert (BG) algorithm has been used for radiometer imaging but has not been applied to scatterometer backscatter imaging. In this paper, the application of BG to scatterometer backscatter imaging is explored and its performance is compared to DIB and SIR. Like SIR, optimally tuned BG is capable of producing higher resolution images than DIB, though its noise performance is slightly inferior to SIR's. While BG and SIR produce similar results for radiometer data, the higher relative noise level of scatterometer data increases the differences between the SIR and BG algorithm performance, and limits the performance of BG relative to SIR in scatterometer imaging. Comparison of the SIR and BG algorithms in scatterometer imaging offers important insights into the inversion/reconstruction problem. © 2018 IEEE.
680 a35508257500 Long D.G. p397 False Journal 215 The winds and currents mission concept The Winds and Currents Mission (WaCM) is a proposed approach to meet the need identified by the NRC Decadal Survey for the simultaneous measurements of ocean vector winds and currents. WaCM features a Ka-band pencil-beam Doppler scatterometer able to map ocean winds and currents globally. We review the principles behind the WaCM measurement and the requirements driving the mission. We then present an overview of the WaCM observatory and tie its capabilities to other OceanObs reviews and measurement approaches. © 2019 Rodríguez, Bourassa, Chelton, Farrar, Long, Perkovic-Martin and Samelson.
680 a35508257500 Long D.G. p576 False Conference 221 Femtosats: Elegant flight telemetry payloads for model rockets An elegant telemetry payload, which transmits IMU, atmospheric, or light data during flight and deployment from a small model rocket, is presented. Data is received by a custom, mobile, hand-pointed ground station. The payload is patterned after a thumb-sized satellite, called a femtosat. Its design is optimized for ease of implementation. The femtosat system resulted from a grassroots, student peer-mentoring program developed at Brigham Young University. © held by the author; distribution rights International Foundation for Telemetering.
680 a35508257500 Long D.G. p590 False Conference 233 Architectures for Earth-observing CubeSat scatterometers Earth-observing satellite scatterometers are important instruments capable of measuring a variety of geophysical properties. Historically, the scatterometer design space has revolved around two main architectures: the fan beam and the scanning pencil beam. Since the implementation of these architectures, developments in satellite- relevant technology, spacecraft standards, and engineering practice have expanded the potential design space for Earth-observing scatterometer systems. This expanded design space is investigated and example designs are presented that utilize the expanded design space to improve performance and reduce cost. © 2018 SPIE.
680 a35508257500 Long D.G. p628 False Journal 311 Guest Editorial Special Issue on Marine and Maritime Radar Remote Sensing [No abstract available]
680 a35508257500 Long D.G. p767 False Journal 374 Ground-based 3D radar imaging of trees using a 2D synthetic aperture Motivated by the desire to gain insight into the details of conventional airborne synthetic aperture radar (SAR) imaging of trees, a ground-based SAR system designed for short-range three-dimensional (3D) radar imaging is developed using a two-dimensional (2D) synthetic aperture. The heart of the system is a compact linear frequency modulation-continuous wave (LFM-CW) radar, a custom two-dimensional scan mechanism, and a three-dimensional time-domain backprojection algorithm that generates three-dimensional backscatter images at an over-sampled resolution of 10 cm by 10 cm by 10 cm. The backprojection algorithm is formulated directly in spatial coordinates. A new method for estimating and compensating for signal attenuation within the canopy is used that exploits the backprojection image formation approach. Several three-dimensional C-band backscatter images of different individual trees of multiple species are generated from data collected for trees both in isolation and near buildings. The trees imaged in this study are about 10 m in height. The transformation of the three-dimensional images to airborne SAR images is described and a sample result provided. © 2017 by the authors; licensee MDPI, Basel, Switzerland.
680 a35508257500 Long D.G. p800 False Journal 390 Extension of the QuikSCAT Sea Ice Extent Data Set with OSCAT Data The Ku-band Oceansat-2 Scatterometer (OSCAT) is very similar to the Quick Scatterometer (QuikSCAT), which operated from 1999 to 2009. OSCAT continues the Ku-band scatterometer data record through 2014 with an overlap of 19 days with QuikSCAT's mission in 2009. This letter discusses a particular climate application of the time series for sea ice extent observation. In this letter, a QuikSCAT sea ice extent algorithm is modified for OSCAT. Gaps in OSCAT data are accounted for and filled in to support sea ice extent mapping. The OSCAT sea ice extent data are validated with QuikSCAT and Special Sensor Microwave/Imager sea ice extent data. © 2004-2012 IEEE.
681 a8321530600 Brodzik M.J. p200 False Journal 134 Enhanced-Resolution SMAP Brightness Temperature Image Products The NASA-sponsored Calibrated Passive Micro- wave Daily Equal-Area Scalable Earth Grid 2.0 Brightness Temperature (CETB) Earth System Data Record Project team has generated a multisensor, multidecadal time series of high-resolution radiometer products designed to support climate studies. This project uses image reconstruction techniques to generate conventional and enhanced-resolution daily brightness temperature images on a standard set of map projections. Sensors included in CETB are the Aqua Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E), Scanning Multichannel Microwave Radiometer, and all Special Sensor Microwave/Imager and Special Sensor Microwave Imager/Sounder radiometers. These span frequencies between 6 and 89 GHz. This paper considers the issues of adding the L-band (1.6 GHz) Soil Moisture Active Passive (SMAP) radiometer measurements to the CETB climate record, with emphasis on optimizing the reconstruction to provide the highest possible spatial resolution at the lowest noise level. SMAP radiometer reconstruction on SMAP-standard grids is also considered. Simulation is used to optimize the reconstruction, and the results confirmed using actual data. A comparison of the performance of the Backus-Gilbert approach and the radiometer form of the Scatterometer Image Reconstruction algorithm is provided. These are compared to the conventional drop-in-the-bucket gridded imaging. © 1980-2012 IEEE.
682 a7005709969 Hardman M.A. p200 False Journal 134 Enhanced-Resolution SMAP Brightness Temperature Image Products The NASA-sponsored Calibrated Passive Micro- wave Daily Equal-Area Scalable Earth Grid 2.0 Brightness Temperature (CETB) Earth System Data Record Project team has generated a multisensor, multidecadal time series of high-resolution radiometer products designed to support climate studies. This project uses image reconstruction techniques to generate conventional and enhanced-resolution daily brightness temperature images on a standard set of map projections. Sensors included in CETB are the Aqua Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E), Scanning Multichannel Microwave Radiometer, and all Special Sensor Microwave/Imager and Special Sensor Microwave Imager/Sounder radiometers. These span frequencies between 6 and 89 GHz. This paper considers the issues of adding the L-band (1.6 GHz) Soil Moisture Active Passive (SMAP) radiometer measurements to the CETB climate record, with emphasis on optimizing the reconstruction to provide the highest possible spatial resolution at the lowest noise level. SMAP radiometer reconstruction on SMAP-standard grids is also considered. Simulation is used to optimize the reconstruction, and the results confirmed using actual data. A comparison of the performance of the Backus-Gilbert approach and the radiometer form of the Scatterometer Image Reconstruction algorithm is provided. These are compared to the conventional drop-in-the-bucket gridded imaging. © 1980-2012 IEEE.
683 a57208255032 Badger J.C. p201 True Journal 135 Normalized Coordinate Equations and an Energy Method for Predicting Natural Curved-Fold Configurations Of the many valid configurations that a curved fold may assume, it is of particular interest to identify natural - or lowest energy - configurations that physical models will preferentially assume. We present normalized coordinate equations - equations that relate fold surface properties to their edge of regression - to simplify curved-fold relationships. An energy method based on these normalized coordinate equations is developed to identify natural configurations of general curved folds. While it has been noted that natural configurations have nearly planar creases for curved folds, we show that nonplanar behavior near the crease ends substantially reduces the energy of a fold. © 2019 ASME.
684 a15848771600 Lang R.J. p201 False Journal 135 Normalized Coordinate Equations and an Energy Method for Predicting Natural Curved-Fold Configurations Of the many valid configurations that a curved fold may assume, it is of particular interest to identify natural - or lowest energy - configurations that physical models will preferentially assume. We present normalized coordinate equations - equations that relate fold surface properties to their edge of regression - to simplify curved-fold relationships. An energy method based on these normalized coordinate equations is developed to identify natural configurations of general curved folds. While it has been noted that natural configurations have nearly planar creases for curved folds, we show that nonplanar behavior near the crease ends substantially reduces the energy of a fold. © 2019 ASME.
684 a15848771600 Lang R.J. p283 False Journal 185 Origami fold states: Concept and design tool The ability of origami to alter its properties and behaviors with its shape makes it an elegant source of inspiration for many engineering designs challenges. Fold states specify the shape of the origami - its facets, creases, and fold angles. Origami research recognizes several acknowledged fold states: The unfolded, fully folded, and flat-folded states. However, these fold states are not comprehensive, excluding some of the most predominant fold states in origami-based devices. In this paper we propose a comprehensive list of fold states based on fold angles. We support the method of categorizing fold states by evaluating the functions and fold states of a large sample of origami-based devices. These correlations provide insight for selecting fold states for origami-based design. We discuss properties and behaviors of the fold states individually and provide a process for fold-state selection. © Author(s) 2019.
684 a15848771600 Lang R.J. p381 True Conference 139 Rigidly foldable thick origami using designed-offset linkages We present new families of thick origami mechanisms that achieve rigid foldability and parallel stacking of panels in the flat-folded state using linkages for some or all of the hinges between panels. A degree-four vertex results in a multi-loop eight-bar spatial mechanism that can be analyzed as separate linkages. The individual linkages are designed so that they introduce offsets perpendicular to the panels that are mutually compatible around each vertex. This family of mechanisms offers the unique combination of a planar unfolded state, parallel-stacked panels in the flat folded state, and kinematic single-degree-of-freedom motion from the flat-unfolded to the flat-folded state. Copyright © 2019 ASME.
684 a15848771600 Lang R.J. p383 False Journal 209 Developable mechanisms on developable surfaces The trend toward smaller mechanism footprints and volumes, while maintaining the ability to perform complex tasks, presents the opportunity for exploration of hypercompact mechanical systems integrated with curved surfaces. Developable surfaces are shapes that a flat sheet can take without tearing or stretching, and they represent a wide range of manufactured surfaces. This work introduces “developable mechanisms” as devices that emerge from or conform to developable surfaces. They are made possible by aligning hinge axes with developable surface ruling lines to enable mobility. Because rigid-link motion depends on the relative orientation of hinge axes and not link geometry, links can take the shape of the corresponding developable surface. Mechanisms are classified by their associated surface type, and these relationships are defined and demonstrated by example. Developable mechanisms show promise for meeting unfilled needs using systems not previously envisioned. © 2019 The Authors, some rights reserved.
684 a15848771600 Lang R.J. p412 False Journal 222 A model for multi-input mechanical advantage in origami-based mechanisms Mechanical advantage is traditionally defined for single-input and single-output rigidbody mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origamibased mechanisms are capable of offering unique solutions to engineering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi-input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. © 2018 by ASME.
684 a15848771600 Lang R.J. p457 False Conference 163 Implementation of Rolling Contacts for SORCE Joints The Synchronized-offset-rolling-contact element (SORCE) technique for thickness accommodation in origami-inspired mechanisms combines selected strengths of several thickness-accomadation techniques but with the tradeoff of manufacturing complexity of rolling joints. This work presents principles to facilitate the construction of rolling joints suitable for applications like the SORCE technique. These include leveraging fold-angle multipliers of origami vertices, variations of flexure assembly, sunken flexures, and form-closed rolling joints. Prototypes of origami-mechanisms using the SORCE technique are constructed demonstrating these principles. © 2018 IEEE.
684 a15848771600 Lang R.J. p524 True Journal 222 Rigidly foldable quadrilateral meshes from angle arrays We present a design technique for generating rigidly foldable quadrilateral meshes (RFQMs), taking as input four arrays of direction angles and fold angles for horizontal and vertical folds. By starting with angles, rather than vertex coordinates, and enforcing the fold-angle multiplier condition at each vertex, it is possible to achieve arbitrarily large and complex panel arrays that flex from unfolded to flatly folded with a single degree-of-freedom (DOF). Furthermore, the design technique is computationally simple, reducing for some cases to a simple linear-programming problem. The resulting mechanisms have applications in architectural facades, furniture design, and more. © 2018 by ASME.
684 a15848771600 Lang R.J. p598 True Journal 306 A Review of Thickness-Accommodation Techniques in Origami-Inspired Engineering Origami has served as the inspiration for a number of engineered systems. In most cases, they require nonpaper materials where material thickness is non-negligible. Foldable mechanisms based on origami-like forms present special challenges for preserving kinematics and assuring non-self-intersection when the thickness of the panels must be accommodated. Several design approaches for constructing thick origami mechanisms by beginning with a zero-thickness origami pattern and transforming it into a rigidly foldable mechanism with thick panels are reviewed. The review includes existing approaches and introduces new hybrid approaches. The approaches are compared and contrasted and their manufacturability analyzed. © 2018 by ASME.
684 a15848771600 Lang R.J. p599 True Journal 306 Closure to "discussion of 'a review of thickness-accommodation techniques in origami-inspired engineering'" (Lang, R. J., Tolman, K. A., Crampton, E. B., Magleby, S. P., and Howell, L. L., 2018, ASME Appl. Mech. Rev., 70(1), p. 010805) [No abstract available]
684 a15848771600 Lang R.J. p762 True Journal 371 Thick rigidly foldable origami mechanisms based on synchronized offset rolling contact elements We present a general technique for achieving kinematic single degree of freedom (1DOF) origami-based mechanisms with thick rigid panels using synchronized offset rolling contact elements (SORCEs). We present general design analysis for planar and 3D relative motions between panels and show physically realized examples. The technique overcomes many of the limitations of previous approaches for thick rigidly foldable mechanisms. © 2017 by ASME.
684 a15848771600 Lang R.J. p854 True Conference 378 Kinematics and discretization of curved-fold mechanisms We present several new properties of curved-fold mechanisms, those with smoothly curved surfaces joined by sharp curved folds. After describing curved folds and various relationships among their geometric properties, we show that there is an important class, uniform folds, that is particularly well suited to low-degree-of-freedom mechanisms. There is a natural discretization algorithm for uniform curved folds; we present this algorithm and show discretized example mechanisms. Copyright © 2017 ASME.
684 a15848771600 Lang R.J. p855 False Conference 379 Split-vertex technique for thickness-accommodation in origami-based mechanisms A novel thickness-accommodation technique for origami based mechanisms is introduced. This technique modifies a zerothickness pattern by splitting each vertex along the minor folds into a system of two vertices. The modified fold pattern then has thickness applied to it and the resulting mechanism is kinematically equivalent to the modified fold pattern. Origami patterns that are rigid-foldable and only have two panels that stack between folds are utilized in the technique. The technique produces thick origami mechanisms where all panels lie in a plane in the unfolded state without any holes or protrusions and maintain a single degree of freedom. Steps for synthesizing split-vertex mechanisms are presented and examples of split-vertex mechanisms are shown. Advantages and potential applications of the technique are discussed. Copyright © 2017 ASME.
684 a15848771600 Lang R.J. p856 True Conference 380 Rigidly foldable quadrilateral meshes from angle arrays We present a design technique for generating rigidly fold-able quadrilateral meshes, taking as input four arrays of direction angles and fold angles for horizontal and vertical folds. By starting with angles, rather than vertex coordinates, and enforcing the fold-angle-multiplier condition at each vertex, it is possible to achieve arbitrarily large and complex panel arrays that flex from unfolded to flatly folded with a single degree of freedom. Furthermore, the design technique is computationally simple, reducing for some cases to a simple linear programming problem. The resulting mechanisms have applications in architectural facades, furniture design, and more. Copyright © 2017 ASME.
685 a57199980412 Guo C. p202 True Journal 136 Heat transfer to bouncing droplets on superhydrophobic surfaces This study experimentally and theoretically investigates the dynamics and heat transfer to impinging water droplets on superhydrophobic surfaces heated below the boiling temperature. Different from impingement on hydrophilic substrates, the droplets rebound from the surface after the spreading and retraction stages. Experiments are performed using simultaneous high speed video and infrared (IR) imaging to capture droplet dynamics and temperature variation during the transient event. Thermal images allow estimation of bulk droplet temperature change during contact such that the cooling effectiveness for an individual droplet can be estimated. A similarity solution is utilized to yield a model for the transient heat flux at the droplet-wall interface, where convection inside the droplet is accounted for. The experimental and theoretical results for the cooling effectiveness show good agreement. It is revealed that the cooling effectiveness increases with Weber number but decreases with droplet diameter and surface cavity fraction (the ratio of cavity area to total surface area). © 2019 Elsevier Ltd
686 a55475654800 Zhao D. p202 False Journal 136 Heat transfer to bouncing droplets on superhydrophobic surfaces This study experimentally and theoretically investigates the dynamics and heat transfer to impinging water droplets on superhydrophobic surfaces heated below the boiling temperature. Different from impingement on hydrophilic substrates, the droplets rebound from the surface after the spreading and retraction stages. Experiments are performed using simultaneous high speed video and infrared (IR) imaging to capture droplet dynamics and temperature variation during the transient event. Thermal images allow estimation of bulk droplet temperature change during contact such that the cooling effectiveness for an individual droplet can be estimated. A similarity solution is utilized to yield a model for the transient heat flux at the droplet-wall interface, where convection inside the droplet is accounted for. The experimental and theoretical results for the cooling effectiveness show good agreement. It is revealed that the cooling effectiveness increases with Weber number but decreases with droplet diameter and surface cavity fraction (the ratio of cavity area to total surface area). © 2019 Elsevier Ltd
687 a43961414900 Ridge S.T. p203 True Journal 137 Relationships between footwear, foot structure, and foot muscle strength [No abstract available]
688 a9041055700 Remund K. p204 False Journal 137 Running shoe optimal stiffness and speed [No abstract available]
689 a57191156976 Hammond A.M. p205 True Journal 138 Accelerating silicon photonic parameter extraction using artificial neural networks We present a novel silicon photonic parameter extraction tool that uses artificial neural networks. While other parameter extraction methods are restricted to relatively simple devices whose responses are easily modeled by analytic transfer functions, this method is capable of extracting parameters for any device with a discrete number of design parameters. To validate the method, we design and fabricate integrated chirped Bragg gratings. We then estimate the actual device parameters by iteratively fitting the simultaneously measured group delay and reflection profiles to the artificial neural network output. The method is fast, accurate, and capable of modeling the complicated chirping and index contrast. © 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.
689 a57191156976 Hammond A.M. p424 True Journal 234 Error correction in structured optical receivers Quantum green machines using integrated optics may enable better communication in photon-starved environments, but fabrication inconsistencies induce unpredictable internal phase errors, making them difficult to construct. We describe and experimentally demonstrate a new method to compensate for arbitrary phase errors by deriving a convex error space and implementing an algorithm to learn a unique codebook of codewords corresponding to each matrix. © 1995-2012 IEEE.
689 a57191156976 Hammond A.M. p561 True Conference 210 Open source computational photonics toolbox We present an open source and collaborative integrated photonics simulation environment capable of accurately modeling individual components using traditional vectorial methods and large circuits using linear system theory and deep learning. © 2018 The Author(s).
689 a57191156976 Hammond A.M. p740 False Journal 346 Optical electric field sensor sensitivity direction rerouting and enhancement using a passive integrated dipole antenna This work introduces a passive dipole antenna integrated into the packaging of a slab-coupled optical sensor to enhance the directional sensitivity of electro-optic electric field measurements parallel to the fiber axis. Using the passive integrated dipole antenna described in this work, a sensor that can typically only sense fields transverse to the fiber direction is able to sense a 1.25 kV/m field along the fiber direction with a gain of 17.5. This is verified through simulation and experiment. © 2017 Optical Society of America.
690 a57209978209 Potokar E. p205 False Journal 138 Accelerating silicon photonic parameter extraction using artificial neural networks We present a novel silicon photonic parameter extraction tool that uses artificial neural networks. While other parameter extraction methods are restricted to relatively simple devices whose responses are easily modeled by analytic transfer functions, this method is capable of extracting parameters for any device with a discrete number of design parameters. To validate the method, we design and fabricate integrated chirped Bragg gratings. We then estimate the actual device parameters by iteratively fitting the simultaneously measured group delay and reflection profiles to the artificial neural network output. The method is fast, accurate, and capable of modeling the complicated chirping and index contrast. © 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.
691 a57118455800 Liu F.C. p206 True Journal 139 Effect of Post-weld Heat Treatment on Microstructure and Mechanical Properties of Dissimilar Metal Weld Used in Power Plants High base metal dilution (50 pct) dissimilar metal weld between A508 low-alloy steel and 309L clad layer was fabricated to investigate the effect of extended post-weld heat treatment (PWHT) on microstructure and mechanical properties. Extended PWHT at 607 °C caused significant carbon migration and microstructural change across the fusion boundary. Following PWHT at 607 °C for 20 hours, the carbon-enriched zone exhibited little to no reduction in hardness although 20 pct hardness reduction occurred in the remainder of the first butter layer. This is because tempering of the martensite in the carbon-enriched zone was entirely offset by the formation of a high density of chromium carbides. In contrast, following PWHT at 607 °C for 20 hours the average hardness of the carbon-depleted zone decreased from 241 HV to 169 HV due to the elimination of martensite, ferrite grain coarsening and carbon depletion. In addition, the extended PWHT significantly enhanced the mismatch in mechanical properties between the carbon-enriched zone (351 HV) and the adjacent carbon-depleted zone (169 HV). The formation of chromium carbides (less than 200 nm in size) in the carbon-enriched zone reduced the carbon concentration in the matrix, generating a continued driving force for carbon migration from A508 steel to the weld metal during PWHT. © 2019, The Minerals, Metals & Materials Society and ASM International.
691 a57118455800 Liu F.C. p252 False Journal 165 Predicting recrystallized grain size in friction stir processed 304L stainless steel A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone (HAZ). Friction stir processing (FSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304L stainless steel. A numerical simulation of the FSP process in 304L was developed to predict temperatures and recrystallized grain size in the stir zone. The model employed an Eulerian finite element approach, where flow stresses for a large range of strain rates and temperatures inherent in FSP were used as input. Temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. The predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. The maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%. © 2019
691 a57118455800 Liu F.C. p499 True Journal 270 Twining and dynamic recrystallization in austenitic Alloy 718 during friction welding Quantitative boundary misorientation analysis verified that discontinuous dynamic recrystallization (DDRX) was the primary grain refinement mechanism in friction welding of Alloy 718. Two models were developed to explain the formation mechanism of intragranular twins and intergranular twins, respectively. Intragranular twins were caused by grain boundary growth incidents. After twin initiation, the twin boundary migrated toward the plastic-deformed grain interior to reduce the stored energy. Additionally, intergranular twin boundaries were ascribed to boundary growth stagnation. When boundary growth stagnation occurred, twin boundaries could form and altered the orientation of the boundary migration front, so that boundary migration could progress, leaving a single twin boundary behind. © 2018 Elsevier Inc.
691 a57118455800 Liu F.C. p547 True Journal 301 Grain structure evolution, grain boundary sliding and material flow resistance in friction welding of Alloy 718 Alloy 718 tubes were subjected to rotary friction welding to understand to the process fundamental and grain structure evolution during welding. The distribution of grain size, low-angle grain boundaries (LAGBs), and twin boundaries throughout the joints were quantitatively analyzed. The weld power, axial load, and weld temperature were monitored. The grain structure evolution during friction welding was clarified. The grain structure in the recrystallization zone (RXZ) of the weld was a result of competition between dynamic recrystallization and grain boundary sliding (GBS), which is controlled by the local deformation condition. The axial force during welding decreased with reducing the rotation rate from 1000 rpm to 500 rpm. This anomalistic phenomenon can be ascribed that a decrease in rotation rate resulted in finer grain size in the RXZ of the weld, which required lower applied force to enable GBS. © 2017 Elsevier B.V.
691 a57118455800 Liu F.C. p572 True Journal 303 A review of friction stir welding of steels: Tool, material flow, microstructure, and properties Considerable progress has been achieved in friction stir welding (FSW) of steels in every aspect of tool fabrication, microstructure control and properties evaluation in the past two decades. With the development of reliable welding tools and precise control systems, FSW of steels has reached a new level of technical maturity. High-quality, long welds can be produced in many engineering steels. Compared to traditional fusion welding, FSW exhibits unique advantages producing joints with better properties. As a result of active control of the welding temperature and/or cooling rate, FSW has the capability of fabricating steel joints with excellent toughness and strength. For example, unfavorable phase transformations that usually occur during traditional welding can be avoided and favorable phase fractions in advanced steels can be maintained in the weld zone thus avoiding the typical property degradations associated with fusion welding. If phase transformations do occur during FSW of thick steels, optimization of microstructure and properties can be attained by controlling the heat input and post-weld cooling rate. © 2017
691 a57118455800 Liu F.C. p573 False Journal 303 Solid state crack repair by friction stir processing in 304L stainless steel Friction stir processing (FSP) was investigated as a method of repairing cracks in 12 mm thick 304L stainless steel plate. Healing feasibility was demonstrated by processing a tapered crack using a PCBN/W-Re tool with a 25 mm diameter shoulder and a pin length of 6.4 mm. The experiment showed that it was possible to heal a crack that begins narrow and then progressively grows up to a width of 2 mm. Bead on plate experiments were used to find the best parameters for creating a consolidated stir zone with the least amount of hardness difference compared to the base metal. Grain refinement in some specimens resulted in much higher stir zone hardness, compared to base metal. A plot of grain size versus microhardness showed a very strong inverse correlation between grain size and hardness, as expected from the Hall-Petch relationship. Corrosion testing was carried out in order to evaluate the effect of FSP on potential sensitization of the stir zone. After 1000 h of intermittent immersion in 3.5% saline solution at room temperature it was found that no corrosion products formed on the base material controls or on any of the friction stir processed specimens. © 2017
691 a57118455800 Liu F.C. p778 True Journal 385 In-situ grain structure and texture evolution during friction stir welding of austenite stainless steel The in-situ grain structure and texture evolution during the whole process of friction stir welding (FSW) are clarified. As the base material approached the probe, grains were compressed, forming compression zone (CPZ). The grains evolved to fine equiaxed grains mainly through discontinue dynamic recrystallization (DDRX) and twining as it approached the tool. As material in MFZ rotated around the probe, the fraction of low-angle grain boundaries (LAGBs) was reduced, the ratio of twin boundaries increased, and the grain size distribution became wider, while the average grain size was fairly constant despite the increase in strain. After the material was deposited behind the probe, the grains began to grow. Deformation caused by tool shoulder disrupted the twin boundaries and generated some segments of LAGBs. In the post-weld zone, some LAGBs disappeared and new twin boundaries developed as a result of elevated temperatures. The B component {112} 〈110〉 was developed and was sustained in the MFZ with its shear direction being consisted with the local probe rotation. The shear plan of B component maintained approximately 30 deg. away from the probe surface. In the weld zone behind the probe, the B component was weakened and evolved to a C component {001}〈110〉. © 2016 Elsevier Ltd
692 a7401431037 Nelson T.W. p206 False Journal 139 Effect of Post-weld Heat Treatment on Microstructure and Mechanical Properties of Dissimilar Metal Weld Used in Power Plants High base metal dilution (50 pct) dissimilar metal weld between A508 low-alloy steel and 309L clad layer was fabricated to investigate the effect of extended post-weld heat treatment (PWHT) on microstructure and mechanical properties. Extended PWHT at 607 °C caused significant carbon migration and microstructural change across the fusion boundary. Following PWHT at 607 °C for 20 hours, the carbon-enriched zone exhibited little to no reduction in hardness although 20 pct hardness reduction occurred in the remainder of the first butter layer. This is because tempering of the martensite in the carbon-enriched zone was entirely offset by the formation of a high density of chromium carbides. In contrast, following PWHT at 607 °C for 20 hours the average hardness of the carbon-depleted zone decreased from 241 HV to 169 HV due to the elimination of martensite, ferrite grain coarsening and carbon depletion. In addition, the extended PWHT significantly enhanced the mismatch in mechanical properties between the carbon-enriched zone (351 HV) and the adjacent carbon-depleted zone (169 HV). The formation of chromium carbides (less than 200 nm in size) in the carbon-enriched zone reduced the carbon concentration in the matrix, generating a continued driving force for carbon migration from A508 steel to the weld metal during PWHT. © 2019, The Minerals, Metals & Materials Society and ASM International.
692 a7401431037 Nelson T.W. p252 False Journal 165 Predicting recrystallized grain size in friction stir processed 304L stainless steel A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone (HAZ). Friction stir processing (FSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304L stainless steel. A numerical simulation of the FSP process in 304L was developed to predict temperatures and recrystallized grain size in the stir zone. The model employed an Eulerian finite element approach, where flow stresses for a large range of strain rates and temperatures inherent in FSP were used as input. Temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. The predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. The maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%. © 2019
692 a7401431037 Nelson T.W. p261 False Journal 171 Microstructural evaluation of hydrogen embrittlement and successive recovery in advanced high strength steel Advanced high strength steels (AHSS) have high susceptibility to hydrogen embrittlement, and are often exposed to hydrogen environments in processing. In order to study the embrittlement and recovery of steel, tensile tests were conducted on two different types of AHSS over time after hydrogen charging. Concentration measurements and hydrogen microprinting were carried out at the same time steps to visualize the hydrogen behavior during recovery. The diffusible hydrogen concentration was found to decay exponentially, and empirical relations were found for both types of steel. Hydrogen concentration decay rates were determined to be -0.355 /hr in TBF-980, and -0.225 /hr in DP-980. Hydrogen concentration thresholds for embrittlement were found to be 1.04 mL/100 g for TBF, and 0.87 mL/100 g for DP steel. TBF steel is predicted to recover from embrittlement within 4.2 h, compared to 7.2 h in DP steel. A two-factor method of evaluating recovery from embrittlement, requiring hydrogen concentration threshold and decay rate, is explained for use in predicting recovery after exposure to hydrogen. Anisotropic hydrogen diffusion rates were also observed on the surface of both steels for a short time after charging, as hydrogen left the surface through <001> and <101> grains faster than grains with <111> orientations. This could be explained by differences in surface energies between the different orientations. © 2018 Elsevier B.V.
692 a7401431037 Nelson T.W. p499 False Journal 270 Twining and dynamic recrystallization in austenitic Alloy 718 during friction welding Quantitative boundary misorientation analysis verified that discontinuous dynamic recrystallization (DDRX) was the primary grain refinement mechanism in friction welding of Alloy 718. Two models were developed to explain the formation mechanism of intragranular twins and intergranular twins, respectively. Intragranular twins were caused by grain boundary growth incidents. After twin initiation, the twin boundary migrated toward the plastic-deformed grain interior to reduce the stored energy. Additionally, intergranular twin boundaries were ascribed to boundary growth stagnation. When boundary growth stagnation occurred, twin boundaries could form and altered the orientation of the boundary migration front, so that boundary migration could progress, leaving a single twin boundary behind. © 2018 Elsevier Inc.
692 a7401431037 Nelson T.W. p514 False Journal 283 Non-dimensional modeling of the effects of weld parameters on peak temperature and cooling rate in friction stir welding Experimental data from friction stir welded Al 7075 and HSLA-65 were used to create dimensionless, empirical models relating critical weld parameters to the peak temperature rise and cooling rate of the weld heat-affected zone. Five different backing plate materials and a wide range of travel speeds and weld powers were used in the experimental design to ensure the models are relevant to a broad range of welding parameters. The resulting models have R-squared values of 0.997 and 0.995 for the dimensionless peak temperature rise and cooling rate correlations, respectively. Demonstrations of the models’ practical applications are provided. Herein is shown how the models can identify welding parameter (i.e. travel speed or power) levels needed to produce a desired weld peak temperature rise or cooling rate. Also demonstrated is how the models can be used to explore the relative effects of travel speed and backing plate thermal diffusivity on weld peak temperature rise and cooling rate. © 2017 Elsevier B.V.
692 a7401431037 Nelson T.W. p547 False Journal 301 Grain structure evolution, grain boundary sliding and material flow resistance in friction welding of Alloy 718 Alloy 718 tubes were subjected to rotary friction welding to understand to the process fundamental and grain structure evolution during welding. The distribution of grain size, low-angle grain boundaries (LAGBs), and twin boundaries throughout the joints were quantitatively analyzed. The weld power, axial load, and weld temperature were monitored. The grain structure evolution during friction welding was clarified. The grain structure in the recrystallization zone (RXZ) of the weld was a result of competition between dynamic recrystallization and grain boundary sliding (GBS), which is controlled by the local deformation condition. The axial force during welding decreased with reducing the rotation rate from 1000 rpm to 500 rpm. This anomalistic phenomenon can be ascribed that a decrease in rotation rate resulted in finer grain size in the RXZ of the weld, which required lower applied force to enable GBS. © 2017 Elsevier B.V.
692 a7401431037 Nelson T.W. p572 False Journal 303 A review of friction stir welding of steels: Tool, material flow, microstructure, and properties Considerable progress has been achieved in friction stir welding (FSW) of steels in every aspect of tool fabrication, microstructure control and properties evaluation in the past two decades. With the development of reliable welding tools and precise control systems, FSW of steels has reached a new level of technical maturity. High-quality, long welds can be produced in many engineering steels. Compared to traditional fusion welding, FSW exhibits unique advantages producing joints with better properties. As a result of active control of the welding temperature and/or cooling rate, FSW has the capability of fabricating steel joints with excellent toughness and strength. For example, unfavorable phase transformations that usually occur during traditional welding can be avoided and favorable phase fractions in advanced steels can be maintained in the weld zone thus avoiding the typical property degradations associated with fusion welding. If phase transformations do occur during FSW of thick steels, optimization of microstructure and properties can be attained by controlling the heat input and post-weld cooling rate. © 2017
692 a7401431037 Nelson T.W. p573 False Journal 303 Solid state crack repair by friction stir processing in 304L stainless steel Friction stir processing (FSP) was investigated as a method of repairing cracks in 12 mm thick 304L stainless steel plate. Healing feasibility was demonstrated by processing a tapered crack using a PCBN/W-Re tool with a 25 mm diameter shoulder and a pin length of 6.4 mm. The experiment showed that it was possible to heal a crack that begins narrow and then progressively grows up to a width of 2 mm. Bead on plate experiments were used to find the best parameters for creating a consolidated stir zone with the least amount of hardness difference compared to the base metal. Grain refinement in some specimens resulted in much higher stir zone hardness, compared to base metal. A plot of grain size versus microhardness showed a very strong inverse correlation between grain size and hardness, as expected from the Hall-Petch relationship. Corrosion testing was carried out in order to evaluate the effect of FSP on potential sensitization of the stir zone. After 1000 h of intermittent immersion in 3.5% saline solution at room temperature it was found that no corrosion products formed on the base material controls or on any of the friction stir processed specimens. © 2017
692 a7401431037 Nelson T.W. p778 False Journal 385 In-situ grain structure and texture evolution during friction stir welding of austenite stainless steel The in-situ grain structure and texture evolution during the whole process of friction stir welding (FSW) are clarified. As the base material approached the probe, grains were compressed, forming compression zone (CPZ). The grains evolved to fine equiaxed grains mainly through discontinue dynamic recrystallization (DDRX) and twining as it approached the tool. As material in MFZ rotated around the probe, the fraction of low-angle grain boundaries (LAGBs) was reduced, the ratio of twin boundaries increased, and the grain size distribution became wider, while the average grain size was fairly constant despite the increase in strain. After the material was deposited behind the probe, the grains began to grow. Deformation caused by tool shoulder disrupted the twin boundaries and generated some segments of LAGBs. In the post-weld zone, some LAGBs disappeared and new twin boundaries developed as a result of elevated temperatures. The B component {112} 〈110〉 was developed and was sustained in the MFZ with its shear direction being consisted with the local probe rotation. The shear plan of B component maintained approximately 30 deg. away from the probe surface. In the weld zone behind the probe, the B component was weakened and evolved to a C component {001}〈110〉. © 2016 Elsevier Ltd
693 a24401574900 McCracken S.L. p206 False Journal 139 Effect of Post-weld Heat Treatment on Microstructure and Mechanical Properties of Dissimilar Metal Weld Used in Power Plants High base metal dilution (50 pct) dissimilar metal weld between A508 low-alloy steel and 309L clad layer was fabricated to investigate the effect of extended post-weld heat treatment (PWHT) on microstructure and mechanical properties. Extended PWHT at 607 °C caused significant carbon migration and microstructural change across the fusion boundary. Following PWHT at 607 °C for 20 hours, the carbon-enriched zone exhibited little to no reduction in hardness although 20 pct hardness reduction occurred in the remainder of the first butter layer. This is because tempering of the martensite in the carbon-enriched zone was entirely offset by the formation of a high density of chromium carbides. In contrast, following PWHT at 607 °C for 20 hours the average hardness of the carbon-depleted zone decreased from 241 HV to 169 HV due to the elimination of martensite, ferrite grain coarsening and carbon depletion. In addition, the extended PWHT significantly enhanced the mismatch in mechanical properties between the carbon-enriched zone (351 HV) and the adjacent carbon-depleted zone (169 HV). The formation of chromium carbides (less than 200 nm in size) in the carbon-enriched zone reduced the carbon concentration in the matrix, generating a continued driving force for carbon migration from A508 steel to the weld metal during PWHT. © 2019, The Minerals, Metals & Materials Society and ASM International.
694 a57201432287 Li X. p207 True Journal 140 S-splines: A simple surface solution for IGA and CAD This paper introduces S-spline curves and surfaces. Local refinement of S-spline surfaces is much simpler to understand and to implement than T-spline refinement. Furthermore, no unwanted control points arise in S-spline refinement, unlike T-spline refinement. The refinement algorithm assures linear independence of blending functions. Thus, for isogeometric analysis, S-spline surfaces provide optimal degrees of freedom during adaptive local refinement. S-splines are compatible with NURBS and T-splines, and can easily be added to existing T-spline implementations. © 2019 Elsevier B.V.
695 a7003498548 Sederberg T.W. p207 False Journal 140 S-splines: A simple surface solution for IGA and CAD This paper introduces S-spline curves and surfaces. Local refinement of S-spline surfaces is much simpler to understand and to implement than T-spline refinement. Furthermore, no unwanted control points arise in S-spline refinement, unlike T-spline refinement. The refinement algorithm assures linear independence of blending functions. Thus, for isogeometric analysis, S-spline surfaces provide optimal degrees of freedom during adaptive local refinement. S-splines are compatible with NURBS and T-splines, and can easily be added to existing T-spline implementations. © 2019 Elsevier B.V.
696 a57207334294 Adams D.W. p208 True Journal 141 Atomistic survey of grain boundary-dislocation interactions in FCC nickel It is well known that grain boundaries (GBs) have a strong influence on mechanical properties of polycrystalline materials. Not as well-known is how different GBs interact with dislocations to influence dislocation movement. This work presents a molecular dynamics study of 33 different FCC Ni bicrystals, each subjected to four different loading conditions to induce incident dislocation-GB interactions in 132 unique configurations. The resulting simulations produce 189 dislocation-GB interactions. Each interaction is analyzed to determine properties that affect the likelihood of transmission, reflection, or absorption of the dislocation at the GB of interest. The results confirm the ability to predict the slip system of a transmitted dislocation using common geometric criteria. Furthermore, machine learning reveals that geometric properties, such as the minimum residual Burgers vector (RBV) and the disorientation angle between the two grains, are strong indicators of whether or not a dislocation will transmit through a GB. © 2019 Elsevier B.V.
696 a57207334294 Adams D.W. p227 False Journal 149 Modeling of trans-grain twin transmission in AZ31 via a neighborhood-based viscoplastic self-consistent model The impact of twin transmission between neighboring grains as a contributor to overall twin activity is considered via a neighborhood viscoplastic self-consistent (NVPSC) model. The NVPSC model is an extension of a stochastic model for twin nucleation developed by Niezgoda et al. and a dislocation density based hardening law model developed by Knezevic et al. Beyond the baseline combined framework, the new model tracks sets of neighboring grains and allows twin transmission between them under certain conditions. The influence of grain boundary (GB) character is included in the stochastic models of twin nucleation and transmission. The starting texture from a rolled magnesium alloy AZ31B sheet was obtained using electron backscatter diffraction (EBSD) for initial input into the NVPSC. The sample was further deformed by uniaxial compression to encourage twin formation and the corresponding texture information was collected using EBSD. The accuracy of simulated twin activity was determined by comparing it with the twin activity seen in the deformed sample. The total number of predicted twins and the number of transmission twins is found to agree favorably with those observed via the EBSD scans. This validation demonstrates the significance of incorporating twin transmission as a twin formation mode in predictive models for this material. © 2018 Elsevier Ltd.
697 a26641352100 Saftner D.A. p209 True Conference 47 Lowman's model goes back to the movies Lowman's Two Dimensional Model of Effective College Teaching identifies traits of successful teachers and presents these traits in a functional framework useful as a tool for improvement. While the model is effective at outlining a mechanism to move towards status as a “Complete Exemplar,” the categories of the model are broad, subjective, and can be difficult to precisely identify. Through development of a rubric, this paper seeks to improve educators' understanding of Lowman's model by sharing a series of examples. Teachers in contemporary movies and television are identified to represent several of the nine cells within the two-dimensional model. A previous paper provided an initial assessment of several famous actors portraying teachers. However, the examples in this previous paper are becoming dated and an updated paper with more contemporary examples may be useful for faculty attempting to better understand and apply Lowman's model. The contents of this paper first introduces the reader to the Lowman Teaching Model and provides support of the model through discussion of related literature. Development of the rubric is explained and the plot thickens as a series of characters are assessed with the rubric. As the curtain falls, a summary of the assessment and recommendations for use of the rubric are shared. © American Society for Engineering Education, 2019
697 a26641352100 Saftner D.A. p492 False Conference 184 Lowman's model goes back to the movies Lowman's Two Dimensional Model of Effective College Teaching identifies traits of successful teachers and presents these traits in a functional framework useful as a tool for improvement. While the model is effective at outlining a mechanism to move towards status as a "Complete Exemplar," the categories of the model are broad, subjective, and can be difficult to precisely identify. Through development of a rubric, this paper seeks to improve educators' understanding of Lowman's model by sharing a series of examples. Teachers in contemporary movies and television are identified to represent several of the nine cells within the two-dimensional model. A previous paper provided an initial assessment of several famous actors portraying teachers. However, the examples in this previous paper are becoming dated and an updated paper with more contemporary examples may be useful for faculty attempting to better understand and apply Lowman's model. The contents of this paper first introduces the reader to the Lowman Teaching Model and provides support of the model through discussion of related literature. Development of the rubric is explained and the plot thickens as a series of characters are assessed with the rubric. As the curtain falls, a summary of the assessment and recommendations for use of the rubric are shared. © American Society for Engineering Education, 2018.
698 a23569552400 Farnsworth C.B. p209 False Conference 47 Lowman's model goes back to the movies Lowman's Two Dimensional Model of Effective College Teaching identifies traits of successful teachers and presents these traits in a functional framework useful as a tool for improvement. While the model is effective at outlining a mechanism to move towards status as a “Complete Exemplar,” the categories of the model are broad, subjective, and can be difficult to precisely identify. Through development of a rubric, this paper seeks to improve educators' understanding of Lowman's model by sharing a series of examples. Teachers in contemporary movies and television are identified to represent several of the nine cells within the two-dimensional model. A previous paper provided an initial assessment of several famous actors portraying teachers. However, the examples in this previous paper are becoming dated and an updated paper with more contemporary examples may be useful for faculty attempting to better understand and apply Lowman's model. The contents of this paper first introduces the reader to the Lowman Teaching Model and provides support of the model through discussion of related literature. Development of the rubric is explained and the plot thickens as a series of characters are assessed with the rubric. As the curtain falls, a summary of the assessment and recommendations for use of the rubric are shared. © American Society for Engineering Education, 2019
698 a23569552400 Farnsworth C.B. p492 True Conference 184 Lowman's model goes back to the movies Lowman's Two Dimensional Model of Effective College Teaching identifies traits of successful teachers and presents these traits in a functional framework useful as a tool for improvement. While the model is effective at outlining a mechanism to move towards status as a "Complete Exemplar," the categories of the model are broad, subjective, and can be difficult to precisely identify. Through development of a rubric, this paper seeks to improve educators' understanding of Lowman's model by sharing a series of examples. Teachers in contemporary movies and television are identified to represent several of the nine cells within the two-dimensional model. A previous paper provided an initial assessment of several famous actors portraying teachers. However, the examples in this previous paper are becoming dated and an updated paper with more contemporary examples may be useful for faculty attempting to better understand and apply Lowman's model. The contents of this paper first introduces the reader to the Lowman Teaching Model and provides support of the model through discussion of related literature. Development of the rubric is explained and the plot thickens as a series of characters are assessed with the rubric. As the curtain falls, a summary of the assessment and recommendations for use of the rubric are shared. © American Society for Engineering Education, 2018.
698 a23569552400 Farnsworth C.B. p552 True Conference 202 Evaluation of curve fitting techniques for estimating time of surcharge release in embankment construction over soft soils Constructing embankments over soft soils can be problematic due to the magnitude and time associated with subsurface compression. Determining the end of primary consolidation is greatly exacerbated for layered soils that compress at varying rates. This paper discusses the use of magnet extensometer instrumentation to isolate compression within specific subsurface layers and associated techniques for estimating the time of construction induced settlement. Field data is used during construction to estimate the end of construction induced subsurface compression, which greatly affects the project schedule. This case study briefly summarizes instrumentation installation, data gathering, and the challenges associated with projecting the time of construction settlement. Two different curve fitting techniques were evaluated in this research: using standard primary consolidation equations and finite difference equations for estimating the end of primary consolidation settlement. For the site investigated, the curve fitting techniques proved to be somewhat problematic because the soil layers had small magnitudes of settlement and the transition between primary and secondary settlement was not readily apparent during the evaluation of real time field data. Using the finite difference equations also proved somewhat problematic trying to fit the full record of field data based on all of the different stages of loading. Additional lessons learned include the need for effective project communication between contractors, designers, and owners and a corresponding open discussion regarding practical settlement risk. © 2018 American Society of Civil Engineers (ASCE). All rights reserved.
698 a23569552400 Farnsworth C.B. p684 False Journal 330 Use of Personality Profile Assessments in the U.S. Commercial Construction Industry Employee turnover is a continuing challenge in the construction industry with negative effects on construction companies. Other industries have begun using personality profile assessments as a tool for reducing employee turnover, and more specifically in their hiring, promoting, team building, and leadership development processes. However, it was unknown if this trend was effecting the construction industry. The purpose of this research was to determine if and how U.S. commercial construction companies utilize personality profiles in their employee retention processes. A survey was randomly sent to 235 of the top 400 commercial construction companies in the United States to determine if these companies were using assessments, and if it had any effect on the turnover within these companies. Interviews were conducted over the phone with human resources representatives from these companies, and responses were sorted into similar themes and ideas using qualitative pattern coding techniques. Of the 78 responding companies, one-third were using employee personality profiles within their business practices. This article reports the experiences and general attitudes for both the companies that do and do not utilize personality profiles. The results of this research provides strong evidence that using personality profile assessments can help construction companies reduce employee turnover. © 2017 Associated Schools of Construction.
698 a23569552400 Farnsworth C.B. p726 False Journal 355 Strategies employed and lessons learned by commercial construction companies during economic recession and recovery The purpose of this research was to identify strategies used and lessons learned by western U.S. commercial construction companies during the great recession (2007-2009). The experience gained by companies who weather an economic downturn must be absorbed into the corporate structure in a meaningful way if that knowledge is to be accessible for future recessions. This study focused on identifying and better understanding the specific approaches that commercial construction companies employed to weather the great recession and the corresponding lessons learned. A stratified purposeful sampling survey was conducted across 15 different commercial construction companies and included 57 participants in various management roles. This paper provides a comprehensive list of 124 different strategies or lessons learned across six principal categories: (1) contracting, (2) risk management, (3) cost-control, (4) human resources, (5) financial, and (6) investment related responses. This paper also provides recommendations for commercial construction companies to consider during various economic cycles on the basis of the lessons learned during this recession and recovery. © 2017 American Society of Civil Engineers.
698 a23569552400 Farnsworth C.B. p732 False Conference 313 Experiential learning: Using small-scale projects to teach project complexities and relationship roles in construction Experiential learning opportunities give students the ability to understand the implications of principles and theories learned in the classroom through lived experiences. This article examines the use of a construction project simulation activity to teach project management principles in an undergraduate construction management course. After a description of the experiential learning theory and relevant literature examining experiential learning simulations in education, it provides an overview of the methods used to create the experience of small-scale design-bidbuild project simulation in a project management course. Around 240 undergraduates students at the junior or senior level participated as designated contractual players in the project and went through the project from inception to completion over the course of 5 weeks. Finally, it offers a brief discussion of the implications of the findings for construction management and engineering education. Specifically, it discusses that simulated projects possess the potential to provide unique learning opportunities particularly, designed experiences triggering different emotions within the structures of the traditional classroom. © American Society for Engineering Education, 2017.
698 a23569552400 Farnsworth C.B. p737 True Conference 318 A model workshop for helping new faculty engage students in the STEM Classroom In May 2016 a workshop entitled "Engaging Students in the STEM Classroom" was presented to faculty at Southern Utah University. Although not exclusive to new faculty, the target audience and predominant attendees, were new faculty from the science, technology, engineering, and math (STEM) disciplines on campus. The three-day workshop focused on basic principles of effective learning and teaching, aligning learning outcomes to assessments and teaching activities, methods for active learning, and strategies for effective classroom presentation. The workshop curriculum was centered around the following goals: 1) promoting broader awareness of alternative teaching strategies for STEM classrooms, 2) increasing faculty comfort level in using alternative teaching strategies, 3) increasing adoption of active learning and other evidence-based pedagogies, 4) building a campus community dedicated to improving teaching, and 5) increasing multi-disciplinary collaborations amongst faculty attendees. The purpose of this paper is to provide an example of a model workshop designed to help new faculty engage students in STEM disciplines, and includes the planning, implementation, and assessment of this workshop. The paper begins by introducing the development of the workshop, including the logic model and assessment plan, the curriculum outline, and preparation processes. The paper also explores the implementation lessons learned. Finally, this paper includes the assessment results of the effectiveness of the workshop in meeting the workshop goals. This includes a preand post-workshop comparison of the participant's attitudes regarding evidence based pedagogies and their perceived competency in using them. This paper is useful for engineering educators in developing teaching expertise, researchers interested in faculty attitudes and perceived competency in using alternate teaching strategies, and faculty and administrators planning to create professional development opportunities to help faculty of all levels become more proficient in evidence-based pedagogies. This paper also serves as an example of a model workshop to develop interdisciplinary communities of educational practice, as well as strengthen the abilities of a new faculty in establishing an engaging and effective classroom. © American Society for Engineering Education, 2017.
699 a36769181100 Retherford J. p209 False Conference 47 Lowman's model goes back to the movies Lowman's Two Dimensional Model of Effective College Teaching identifies traits of successful teachers and presents these traits in a functional framework useful as a tool for improvement. While the model is effective at outlining a mechanism to move towards status as a “Complete Exemplar,” the categories of the model are broad, subjective, and can be difficult to precisely identify. Through development of a rubric, this paper seeks to improve educators' understanding of Lowman's model by sharing a series of examples. Teachers in contemporary movies and television are identified to represent several of the nine cells within the two-dimensional model. A previous paper provided an initial assessment of several famous actors portraying teachers. However, the examples in this previous paper are becoming dated and an updated paper with more contemporary examples may be useful for faculty attempting to better understand and apply Lowman's model. The contents of this paper first introduces the reader to the Lowman Teaching Model and provides support of the model through discussion of related literature. Development of the rubric is explained and the plot thickens as a series of characters are assessed with the rubric. As the curtain falls, a summary of the assessment and recommendations for use of the rubric are shared. © American Society for Engineering Education, 2019
699 a36769181100 Retherford J. p492 False Conference 184 Lowman's model goes back to the movies Lowman's Two Dimensional Model of Effective College Teaching identifies traits of successful teachers and presents these traits in a functional framework useful as a tool for improvement. While the model is effective at outlining a mechanism to move towards status as a "Complete Exemplar," the categories of the model are broad, subjective, and can be difficult to precisely identify. Through development of a rubric, this paper seeks to improve educators' understanding of Lowman's model by sharing a series of examples. Teachers in contemporary movies and television are identified to represent several of the nine cells within the two-dimensional model. A previous paper provided an initial assessment of several famous actors portraying teachers. However, the examples in this previous paper are becoming dated and an updated paper with more contemporary examples may be useful for faculty attempting to better understand and apply Lowman's model. The contents of this paper first introduces the reader to the Lowman Teaching Model and provides support of the model through discussion of related literature. Development of the rubric is explained and the plot thickens as a series of characters are assessed with the rubric. As the curtain falls, a summary of the assessment and recommendations for use of the rubric are shared. © American Society for Engineering Education, 2018.
700 a56976354400 Okeson T.J. p210 True Journal 142 Achieving tiered model quality in 3D structure from motion models using a multi-scale view-planning algorithm for automated targeted inspection This study presents a novel multi-scale view-planning algorithm for automated targeted inspection using unmanned aircraft systems (UAS). In industrial inspection, it is important to collect the most relevant data to keep processing demands, both human and computational, to a minimum. This study investigates the viability of automated targeted multi-scale image acquisition for Structure from Motion (SfM)-based infrastructure modeling. A traditional view-planning approach for SfM is extended to a multi-scale approach, planning for targeted regions of high, medium, and low priority. The unmanned aerial vehicle (UAV) can traverse the entire aerial space and facilitates collection of an optimized set of views, both close to and far away from areas of interest. The test case for field validation is the Tibble Fork Dam in Utah. Using the targeted multi-scale flight planning, a UAV automatically flies a tiered inspection using less than 25% of the number of photos needed to model the entire dam at high-priority level. This results in approximately 75% reduced flight time and model processing load, while still maintaining high model accuracy where needed. Models display stepped improvement in visual clarity and SfM reconstruction integrity by priority level, with the higher priority regions more accurately modeling smaller and finer features. A resolution map of the final tiered model is included. While this study focuses on multi-scale view planning for optical sensors, the methods potentially extend to other remote sensors, such as aerial LiDAR. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
701 a57209659294 Barrett B.J. p210 False Journal 142 Achieving tiered model quality in 3D structure from motion models using a multi-scale view-planning algorithm for automated targeted inspection This study presents a novel multi-scale view-planning algorithm for automated targeted inspection using unmanned aircraft systems (UAS). In industrial inspection, it is important to collect the most relevant data to keep processing demands, both human and computational, to a minimum. This study investigates the viability of automated targeted multi-scale image acquisition for Structure from Motion (SfM)-based infrastructure modeling. A traditional view-planning approach for SfM is extended to a multi-scale approach, planning for targeted regions of high, medium, and low priority. The unmanned aerial vehicle (UAV) can traverse the entire aerial space and facilitates collection of an optimized set of views, both close to and far away from areas of interest. The test case for field validation is the Tibble Fork Dam in Utah. Using the targeted multi-scale flight planning, a UAV automatically flies a tiered inspection using less than 25% of the number of photos needed to model the entire dam at high-priority level. This results in approximately 75% reduced flight time and model processing load, while still maintaining high model accuracy where needed. Models display stepped improvement in visual clarity and SfM reconstruction integrity by priority level, with the higher priority regions more accurately modeling smaller and finer features. A resolution map of the final tiered model is included. While this study focuses on multi-scale view planning for optical sensors, the methods potentially extend to other remote sensors, such as aerial LiDAR. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
702 a57209655847 Arce S. p210 False Journal 142 Achieving tiered model quality in 3D structure from motion models using a multi-scale view-planning algorithm for automated targeted inspection This study presents a novel multi-scale view-planning algorithm for automated targeted inspection using unmanned aircraft systems (UAS). In industrial inspection, it is important to collect the most relevant data to keep processing demands, both human and computational, to a minimum. This study investigates the viability of automated targeted multi-scale image acquisition for Structure from Motion (SfM)-based infrastructure modeling. A traditional view-planning approach for SfM is extended to a multi-scale approach, planning for targeted regions of high, medium, and low priority. The unmanned aerial vehicle (UAV) can traverse the entire aerial space and facilitates collection of an optimized set of views, both close to and far away from areas of interest. The test case for field validation is the Tibble Fork Dam in Utah. Using the targeted multi-scale flight planning, a UAV automatically flies a tiered inspection using less than 25% of the number of photos needed to model the entire dam at high-priority level. This results in approximately 75% reduced flight time and model processing load, while still maintaining high model accuracy where needed. Models display stepped improvement in visual clarity and SfM reconstruction integrity by priority level, with the higher priority regions more accurately modeling smaller and finer features. A resolution map of the final tiered model is included. While this study focuses on multi-scale view planning for optical sensors, the methods potentially extend to other remote sensors, such as aerial LiDAR. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
703 a57204570329 Vernon C.A. p210 False Journal 142 Achieving tiered model quality in 3D structure from motion models using a multi-scale view-planning algorithm for automated targeted inspection This study presents a novel multi-scale view-planning algorithm for automated targeted inspection using unmanned aircraft systems (UAS). In industrial inspection, it is important to collect the most relevant data to keep processing demands, both human and computational, to a minimum. This study investigates the viability of automated targeted multi-scale image acquisition for Structure from Motion (SfM)-based infrastructure modeling. A traditional view-planning approach for SfM is extended to a multi-scale approach, planning for targeted regions of high, medium, and low priority. The unmanned aerial vehicle (UAV) can traverse the entire aerial space and facilitates collection of an optimized set of views, both close to and far away from areas of interest. The test case for field validation is the Tibble Fork Dam in Utah. Using the targeted multi-scale flight planning, a UAV automatically flies a tiered inspection using less than 25% of the number of photos needed to model the entire dam at high-priority level. This results in approximately 75% reduced flight time and model processing load, while still maintaining high model accuracy where needed. Models display stepped improvement in visual clarity and SfM reconstruction integrity by priority level, with the higher priority regions more accurately modeling smaller and finer features. A resolution map of the final tiered model is included. While this study focuses on multi-scale view planning for optical sensors, the methods potentially extend to other remote sensors, such as aerial LiDAR. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
704 a57210191104 Derricott J. p211 False Journal 143 Disaster reconnaissance using multiple small unmanned aerial vehicles" [No abstract available]
705 a57214009254 Peterson C. p211 False Journal 143 Disaster reconnaissance using multiple small unmanned aerial vehicles" [No abstract available]
706 a57217482839 Allen B.C. p212 True Journal 144 EFFECT OF GYROSCOPE PARAMETERS ON GYROSCOPIC TREMOR SUPPRESSION IN A SINGLE DEGREE OF FREEDOM Although tremor is one of the most common movement disorders, there are few effective tremor-suppressing options available to patients. Gyrostabilization is a potential option, but we do not currently know how to optimize gyrostabilization for tremor suppression. To address this gap, we present a systematic investigation of how gyrostabilizer parameters affect tremor suppression in a single degree of freedom (DOF). A simple model with a single DOF at the wrist and a gyroscope mounted on the back of the hand was used to focus on the most basic effects. We simulated the frequency response of the system (hand + gyroscope) to a tremorogenic input torque at the wrist. Varying system parameters one at a time, we determined the effect of individual parameters on the system's frequency response. To minimize the bandwidth without adding significant inertia, the inertia and spin speed of the flywheel should be as high as design constraints allow, whereas the distance from the wrist joint axis to the gyroscope and the precession stiffness and damping should be kept as low as possible. The results demonstrate the potential of gyroscopic tremor suppression and can serve as foundation for further investigations of gyroscopic tremor suppression in the upper limb. © 2019 World Scientific Publishing Company.
706 a57217482839 Allen B.C. p707 False Conference 299 Toward quantitative characterization of essential tremor for future tremor suppression Tremor is the most common movement deficit and manifests in a variety of disorders, including Essential Tremor, Parkinson's Disease, Dystonia, and Cerebellar Ataxia. Although medication and surgical interventions have significantly reduced patient suffering, they are only partially effective and can carry undesired side effects, leaving many patients without satisfactory treatment options. Wearable tremor-suppressing devices could provide an alternative to medication and surgery. Multiple research groups have developed orthotic prototypes to low-pass filter tremor, but these devices have not yet been optimized for in-vivo use. Optimizing non-invasive tremor suppression requires an understanding of where the tremor originates mechanically (which muscles) and how it propagates to the hand (where it matters most). Here we present on the beginnings of our multi-pronged work to determine the origin, propagation, and distribution of Essential Tremor, and we provide preliminary results. © 2017 IEEE.
707 a57209640119 Ellingson J. p213 True Conference 48 Deep RC: Enabling remote control through deep learning Human remote-control (RC) pilots have the ability to perceive the position and orientation of an aircraft using only third-person-perspective visual sensing. While novice pilots often struggle when learning to control RC aircraft, they can sense the orientation of the aircraft with relative ease. In this paper, we hypothesize and demonstrate that deep learning methods can be used to mimic the human ability to perceive the orientation of an aircraft from monocular imagery. This work uses a neural network to directly sense the aircraft attitude. The network is combined with more conventional image processing methods for visual tracking of the aircraft. The aircraft track and attitude measurements from the convolutional neural network (CNN) are combined in a particle filter that provides a complete state estimate of the aircraft. The network topology, training, and testing results are presented as well as filter development and results. The proposed method was tested in simulation and hardware flight demonstrations. © 2019 IEEE.
707 a57209640119 Ellingson J. p291 False Conference 73 Identifying mode shapes of turbo-machinery blades using principal component analysis and support vector machines Manually identifying mode shapes generated from finite element solvers images is an expensive task. This paper proposes an automated process to identify mode shapes from gray-scale images of compressor blades within a jetengine. This work introduces mode shape identification using principal component analysis (PCA), similar to approaches in facial and other recognition tasks in computer vision. This technique calculates the projected values of potentially linearly correlated values onto P-linearly orthogonal axes, where P is the number of principal axes that define a subset space. Classification was done using support vector machines (SVM). Using the PCA and SVM algorithm, approximately 5300 training images representative of 16 different modes were used to create a classifier. The classifier achieved on average 98% accuracy when tested using a test set of approximately 2000 images given P D 70. The results suggest that using digital images to perform mode shape identification can be achieved with high accuracy. Potential generalization of this method could be applied to other engineering design and analysis applications. © The Society for Experimental Mechanics, Inc. 2019.
708 a57210919648 Jain P. p214 True Conference 49 Encirclement of moving targets using relative range and bearing measurements This paper presents a controller that uses relative range and bearing measurements to steer unmanned aerial vehicles (UAVs) to circular trajectories around a constant velocity target. Estimates of the range rate and angular rate to the target are used to improve the error in the range and bearing. For moving targets, their velocity is also estimated and used in the control law. Theoretical proofs using Lyapunov theory for stationary targets and feedback linearization for moving targets are provided. Numerical simulations show vehicles converging to circular formations around both stationary and moving targets. © 2019 IEEE.
709 a57210912098 Farrell M. p215 True Conference 50 Error-state LQR control of a multirotor UAV We propose an implementation of an LQR controller for the full-state tracking of a time-dependent trajectory with a multirotor UAV. The proposed LQR formulation is based in Lie theory and linearized at each time step according to the multirotor's current state. We show experiments in both simulation and hardware that demonstrate the proposed control scheme's ability to accurately reach and track a given trajectory. The implementation is shown to run onboard at the full rate of a UAV's estimated state. © 2019 IEEE.
710 a57206968876 Jackson J. p215 False Conference 50 Error-state LQR control of a multirotor UAV We propose an implementation of an LQR controller for the full-state tracking of a time-dependent trajectory with a multirotor UAV. The proposed LQR formulation is based in Lie theory and linearized at each time step according to the multirotor's current state. We show experiments in both simulation and hardware that demonstrate the proposed control scheme's ability to accurately reach and track a given trajectory. The implementation is shown to run onboard at the full rate of a UAV's estimated state. © 2019 IEEE.
710 a57206968876 Jackson J. p254 True Journal 166 Direct Relative Edge Optimization, A Robust Alternative for Pose Graph Optimization Pose graph optimization is a common problem in robotics and associated fields. Most commonly, pose graph optimization is performed by finding the set of pose estimates which are the most likely for a given set of measurements. In some situations, arbitrarily large errors in pose graph initialization are unavoidable and can cause these pose-based methods to diverge or fail especially in cases where global inputs become available after some time after initialization. This letter details the parameterization of the classic pose graph problem in a relative context, optimizing directly over relative edge constraints between vertices in the pose graph and not on the poses themselves. Unlike previous literature on relative optimization, this letter details relative optimization over an entire pose graph, instead of a subset of edges, resulting in greater robustness to arbitrarily large errors than the classic pose-based or prior relative edge-based methods. Several small-scale simulation comparison studies, along with single and multi-agent hardware experiments, are presented. Results point to relative edge optimization as a strong candidate for solving real-world pose graph optimization problems that contain large heading propagation or initialization errors. © 2016 IEEE.
710 a57206968876 Jackson J. p466 False Journal 257 Relative Navigation: A Keyframe-Based Approach for Observable GPS-Degraded Navigation As relevant technologies become smaller and less expensive, micro air vehicles (MAVs) are transitioning from predominantly military and hobbyist applications to mainstream use. Exciting new applications include the delivery of medical supplies to remote areas, infrastructure inspection, environmental change detection, precision agriculture, survelliance of visible satellites. These issues are particularly prevalent when flying near the ground, where safety and reliability are especially important. © 1991-2012 IEEE.
711 a57205198823 Hutchings N. p218 True Journal 134 Improved Ultrahigh-Resolution Wind Retrieval for RapidScat This paper introduces RapidScat 2.5-km ultrahigh-resolution (UHR) wind estimation and validates it in near-coastal regions. RapidScat UHR wind estimation provides finer resolution ocean wind vector fields than conventional 12.5-km level 2B (L2B) wind products at a cost of higher noise. In addition, this paper applies direction interval retrieval techniques and develops other wind processing improvements to enhance the performance of RapidScat UHR wind estimation. The new algorithm is validated with L2B wind estimates, numerical weather prediction wind products, and buoy measurements. The wind processing improvements produce more spatially consistent UHR winds that compare well with the wind products mentioned above. © 2018 IEEE.
712 a57210927548 Dutson J. p220 True Conference 52 Don't Punish all of us: Measuring User Attitudes about Two-Factor Authentication Two-factor authentication (2FA) defends against password compromise by a remote attacker. We surveyed 4,275 students, faculty, and staff at Brigham Young University to measure user sentiment about Duo 2FA one year after the university adopted it. The results were mixed. A majority of the participants felt more secure using Duo and felt it was easy to use. About half of all participants reported at least one instance of being locked out of their university account because of an inability to authenticate with Duo. We found that students and faculty generally had more negative perceptions of Duo than staff. The survey responses reveal some pain points for Duo users. In response, we offer recommendations that reduce the frequency of 2FA for users. We also suggest UI changes that draw more attention to 2FA methods that do not require WiFi, the 'Remember Me' setting, and the help utility. © 2019 IEEE.
712 a57210927548 Dutson J. p300 False Conference 82 A usability study of five two-factor authentication methods Two-factor authentication (2FA) defends against account compromise. An account secured with 2FA typically requires an individual to authenticate using something they know-typically a password-as well as something they have, such as a cell phone or hardware token. Many 2FA methods in widespread use today have not been subjected to adequate usability testing. Furthermore, previous 2FA usability research is difficult to compare due to widely-varying contexts across different studies. We conducted a two-week, between-subjects usability study of five common 2FA methods with 72 participants, collecting both quantitative and qualitative data. Participants logged into a simulated banking website nearly every day using 2FA and completed an assigned task. Participants generally gave high marks to the methods studied, and many expressed an interest in using 2FA to provide more security for their sensitive online accounts. We also conducted a within-subjects laboratory study with 30 participants to assess the general usability of the setup procedure for the five methods. While a few participants experienced difficulty setting up a hardware token and a one-time password, in general, users found the methods easy to set up. © is held by the author/owner.
713 a57210928665 Allen D. p220 False Conference 52 Don't Punish all of us: Measuring User Attitudes about Two-Factor Authentication Two-factor authentication (2FA) defends against password compromise by a remote attacker. We surveyed 4,275 students, faculty, and staff at Brigham Young University to measure user sentiment about Duo 2FA one year after the university adopted it. The results were mixed. A majority of the participants felt more secure using Duo and felt it was easy to use. About half of all participants reported at least one instance of being locked out of their university account because of an inability to authenticate with Duo. We found that students and faculty generally had more negative perceptions of Duo than staff. The survey responses reveal some pain points for Duo users. In response, we offer recommendations that reduce the frequency of 2FA for users. We also suggest UI changes that draw more attention to 2FA methods that do not require WiFi, the 'Remember Me' setting, and the help utility. © 2019 IEEE.
714 a6602572190 Eggett D. p220 False Conference 52 Don't Punish all of us: Measuring User Attitudes about Two-Factor Authentication Two-factor authentication (2FA) defends against password compromise by a remote attacker. We surveyed 4,275 students, faculty, and staff at Brigham Young University to measure user sentiment about Duo 2FA one year after the university adopted it. The results were mixed. A majority of the participants felt more secure using Duo and felt it was easy to use. About half of all participants reported at least one instance of being locked out of their university account because of an inability to authenticate with Duo. We found that students and faculty generally had more negative perceptions of Duo than staff. The survey responses reveal some pain points for Duo users. In response, we offer recommendations that reduce the frequency of 2FA for users. We also suggest UI changes that draw more attention to 2FA methods that do not require WiFi, the 'Remember Me' setting, and the help utility. © 2019 IEEE.
714 a6602572190 Eggett D. p245 False Journal 160 Informatics analysis of capillary electropherograms of autologously doped and undoped blood An ‘Autologous Blood Transfusion' (ABT) is the reinjection of blood previously taken from an athlete to increase its oxygen transport capabilities. Despite the World Anti-Doping Agency's ban on such practices, ABT abuse continues. Autologous blood doping (ABD) is challenging to detect because of the similarities between an individual's doped and undoped blood. Recently, Harrison et al. reported that high-speed capillary electrophoresis may identify ABD. In their work, first order derivatives of the electropherograms were used to identify doping. However, this method suffered from false negatives due to the subjective nature of the analysis. Here, we provide an informatics analysis of the data from this study, contrasting the results of traditional statistical methods and less traditional mathematical techniques. First, three well-known multivariate statistical tools: cluster analysis, principal component analysis (PCA), and partial least squares (PLS) are applied to develop calibrations and/or group electropherograms of undoped (0%) and doped (5% and 10%) blood samples. (These doping levels were chosen due to the low physiological effect of doping below 5%, with 10% corresponding to the approximate ‘gain' derived from the transfusion of a single unit of blood into an adult.) Different preprocessing and variable selection methods were considered. Due to variation in the electropherograms and the limited sample size, these methods were inadequate. We next considered four less commonly used mathematical/informatics tools: pattern recognition entropy (PRE), the Euclidean distance between vectors, a peak fitting/integration method, and the second moment (SM). Each of these techniques showed some ability to differentiate between the 0, 5, and 10% doped samples. We then evaluated the prediction capabilities of inverse least squares (ILS) models based on these summary statistics. An ILS calibration based on PRE, the Euclidean distance, and peak fitting/integration proved more successful than the PLS model at predicting levels of blood doping from the corresponding electropherograms; the ILS model distinguished between doped (5% and 10%) and undoped (0%) blood. This methodology may be applicable to other challenging informatics problems like determining risk factors for genetically linked diseases, robust pattern finding in peak-like data such as ChIP-seq, or other genomic sequencing for understanding the 3D genome. © The Royal Society of Chemistry.
714 a6602572190 Eggett D. p408 False Journal 218 Evaluating Safety Impacts of Access Management Alternatives with the Surrogate Safety Assessment Model In a traditional safety impact analysis, it is necessary to have crash data on existing roadway conditions and a few years must pass before accumulating additional crash data to evaluate the safety impact of an improvement. This is a time-consuming approach and there remains uncertainty in the crash data integrity. The surrogate safety assessment model (SSAM) was developed for resolving these issues. With SSAM, a conflict analysis is performed in a simulated environment. A planned improvement alternative is modeled and no physical installation of the alternative is needed. This study evaluated if SSAM can be used to assess the safety of a highway segment in terms of the number and type of conflicts and to compare the safety effects of multiple access management alternatives. An evaluation of the effect of converting a two-way left-turn lane (TWLTL) into a raised median on a section of an urban street was performed using SSAM working on VISSIM simulation’s trajectory files. The analysis showed that a raised median would be much safer than a TWLTL median for the same level of traffic volume, with approximately 32 to 50 percent reduction in the number of crossing conflicts. The analysis showed that about 34,000 to 38,000 veh/day would be the demand level where the median conversion is recommended for the four-lane study section. The study concluded that the combination of a simulation software program with SSAM could be a viable surrogate analysis approach for evaluating and comparing the safety effects of multiple access management alternatives. © National Academy of Sciences: Transportation Research Board 2018.
714 a6602572190 Eggett D. p687 False Journal 333 Use of Hi-resolution data for evaluating accuracy of traffic volume counts collected by microwave sensors Over the past few years, the Utah Department of Transportation has developed the signal performance metrics (SPMs) system to evaluate the performance of signalized intersections dynamically. This system currently provides data summaries for several performance measures, one of them being turning movement counts collected by microwave sensors. As this system became public, there was a need to evaluate the accuracy of the data placed on the SPMs. A large-scale data collection was carried out to meet this need. Vehicles in the Hi-resolution data from microwave sensors were matched with the vehicles by ground-truth volume count data. Matching vehicles from the microwave sensor data and the ground-truth data manually collected required significant effort. A spreadsheet-based data analysis procedure was developed to carry out the task. A mixed model analysis of variance was used to analyze the effects of the factors considered on turning volume count accuracy. The analysis found that approach volume level and number of approach lanes would have significant effect on the accuracy of turning volume counts but the location of the sensors did not significantly affect the accuracy of turning volume counts. In addition, it was found that the location of lanes in relation to the sensor did not significantly affect the accuracy of lane-by-lane volume counts. This indicated that accuracy analysis could be performed by using total approach volumes without comparing specific turning counts, that is, left-turn, through and right-turn movements. In general, the accuracy of approach volume counts collected by microwave sensors were within the margin of error that traffic engineers could accept. The procedure taken to perform the analysis and a summary of accuracy of volume counts for the factor combinations considered are presented in this paper. © 2017 The Authors
715 a57210914089 Akagi J. p221 True Conference 53 Gesture commands for controlling high-level UAV behavior In this paper, an accelerometer and gyroscope are used to sense gesture commands, which are then classified using a logistic regression model. Seven gestures were chosen and mapped to specific behaviors that a fixed wing unmanned air vehicle could accomplish. These behaviors specified various searching, following, and tracking patterns that could be used in a dynamic environment. The system was trained to recognize the seven gestures and then tested in a hardware-in-the-loop simulation. The system was able to identify all gestures with an overall accuracy of 90% and with five of the seven gestures being accurately identified at least 94% of the time. Each of the behaviors associated with the gestures was tested in simulation and the ability to dynamically switch between behaviors was proven. The results show that the system can be used as a natural interface to assist an operator in directing an unmanned air vehicle's behaviors. © 2019 IEEE.
716 a57203981655 Moon B. p221 False Conference 53 Gesture commands for controlling high-level UAV behavior In this paper, an accelerometer and gyroscope are used to sense gesture commands, which are then classified using a logistic regression model. Seven gestures were chosen and mapped to specific behaviors that a fixed wing unmanned air vehicle could accomplish. These behaviors specified various searching, following, and tracking patterns that could be used in a dynamic environment. The system was trained to recognize the seven gestures and then tested in a hardware-in-the-loop simulation. The system was able to identify all gestures with an overall accuracy of 90% and with five of the seven gestures being accurately identified at least 94% of the time. Each of the behaviors associated with the gestures was tested in simulation and the ability to dynamically switch between behaviors was proven. The results show that the system can be used as a natural interface to assist an operator in directing an unmanned air vehicle's behaviors. © 2019 IEEE.
716 a57203981655 Moon B. p453 True Conference 159 Learned Search Parameters for Cooperating Vehicles using Gaussian Process Regressions Unmanned vehicles are capable of working as teams to accomplish a wide variety of mission objectives, such as searching for and tracking targets. In this paper, vehicle search paths are dictated by a joint cost function which maximizes the reward earned from partitioned sections across the search area. In previous work, these rewards were assigned based on the elapsed time since the section had last been searched. This approach is effective in rewarding vehicles to search out areas which haven't been visited in a long time, yet it lacks the ability to weight grid cells differently based on the probability that targets will be in that section. This paper proposes a method of using accumulated knowledge of the average density of targets within an area, along with a Gaussian process regression to assign rewards. Vehicles then choose paths that are more likely to find targets rather than seeking areas which have not been searched recently. Through numerical simulations we show that this method increases the number of targets seen by cooperating UAVs and provides an accurate estimate of target density within a search area. © 2018 IEEE.
717 a57210920448 Chen X. p221 False Conference 53 Gesture commands for controlling high-level UAV behavior In this paper, an accelerometer and gyroscope are used to sense gesture commands, which are then classified using a logistic regression model. Seven gestures were chosen and mapped to specific behaviors that a fixed wing unmanned air vehicle could accomplish. These behaviors specified various searching, following, and tracking patterns that could be used in a dynamic environment. The system was trained to recognize the seven gestures and then tested in a hardware-in-the-loop simulation. The system was able to identify all gestures with an overall accuracy of 90% and with five of the seven gestures being accurately identified at least 94% of the time. Each of the behaviors associated with the gestures was tested in simulation and the ability to dynamically switch between behaviors was proven. The results show that the system can be used as a natural interface to assist an operator in directing an unmanned air vehicle's behaviors. © 2019 IEEE.
718 a57202433366 Robles V.D. p222 True Journal 145 Using case-method pedagogy to facilitate audience awareness Introduction: Technical and professional communication (TPC) instructors value audience awareness, using peer-and client-based projects to facilitate it. We explore how students' audience awareness is facilitated by the case method, which presents students with a professional communication task within a workplace scenario. Situating the case: Case-method research suggests including a detailed audience and situation, multiple genres, and multimedia. Few studies have explored how case materials facilitate students' audience awareness. About the case: A 12-week case that was consistent with case-method research asked students to respond to an engineering firm's internal problem with a proposal and report. How the case was studied: Students from two sections of a genre-based course completed reflections about their audience awareness after the proposal and report. We qualitatively analyzed 51 reflections. Results/discussion: Students stated they could understand the facts about their primary audience but couldn't identify secondary and tertiary audiences. Students stated they could identify audience needs, but they disagreed about the amount of detail to understand those needs. Also, students stated they could respond to the audience using appropriate evidence and writing style. Conclusions: When using the case method, instructors should know that students may need varying levels of detail to interpret their audience's needs. Also, including data and conflicting needs gives students opportunities to make strategic decisions about content. © 1988-2012 IEEE.
719 a56724258600 Khajah T. p223 True Journal 146 Highly accurate acoustic scattering: Isogeometric Analysis coupled with local high order Farfield Expansion ABC This work is concerned with a unique combination of high order local absorbing boundary conditions (ABC) with a general curvilinear Finite Element Method (FEM) and its implementation in Isogeometric Analysis (IGA) for time-harmonic acoustic waves. The ABC employed were recently devised by Villamizar et al. (2017). They are derived from exact Farfield Expansions representations of the outgoing waves in the exterior of the regions enclosed by the artificial boundary. As a consequence, the error due to the ABC on the artificial boundary can be reduced conveniently such that the dominant error comes from the volume discretization method used in the interior of the computational domain. Reciprocally, the error in the interior can be made as small as the error at the artificial boundary by appropriate implementation of p- and h-refinement. We apply this novel method to cylindrical, spherical and arbitrary shape scatterers including a prototype submarine. Our numerical results exhibit spectral-like approximation and high order convergence rate. Additionally, they show that the proposed method can reduce both the pollution and artificial boundary errors to negligible levels even in very low- and high-frequency regimes with rather coarse discretization densities in the IGA. As a result, we have developed a highly accurate computational platform to numerically solve time-harmonic acoustic wave scattering in two- and three-dimensions. © 2019 Elsevier B.V.
720 a7801676127 Villamizar V. p223 False Journal 146 Highly accurate acoustic scattering: Isogeometric Analysis coupled with local high order Farfield Expansion ABC This work is concerned with a unique combination of high order local absorbing boundary conditions (ABC) with a general curvilinear Finite Element Method (FEM) and its implementation in Isogeometric Analysis (IGA) for time-harmonic acoustic waves. The ABC employed were recently devised by Villamizar et al. (2017). They are derived from exact Farfield Expansions representations of the outgoing waves in the exterior of the regions enclosed by the artificial boundary. As a consequence, the error due to the ABC on the artificial boundary can be reduced conveniently such that the dominant error comes from the volume discretization method used in the interior of the computational domain. Reciprocally, the error in the interior can be made as small as the error at the artificial boundary by appropriate implementation of p- and h-refinement. We apply this novel method to cylindrical, spherical and arbitrary shape scatterers including a prototype submarine. Our numerical results exhibit spectral-like approximation and high order convergence rate. Additionally, they show that the proposed method can reduce both the pollution and artificial boundary errors to negligible levels even in very low- and high-frequency regimes with rather coarse discretization densities in the IGA. As a result, we have developed a highly accurate computational platform to numerically solve time-harmonic acoustic wave scattering in two- and three-dimensions. © 2019 Elsevier B.V.
721 a57194391871 Blackburn L. p224 True Journal 147 Dynamic optimization of a district energy system with storage using a novel mixed-integer quadratic programming algorithm As more renewable energy is integrated into the power grid, it is increasingly important to exploit variable electricity pricing structures to minimize commercial utility costs and enable more intermittent renewables on the grid through proactive management of energy storage. Using data from a large campus district energy system, equipped with centralized chilled water plants and a thermal energy storage tank, a novel technique is proposed to optimize this system in real-time, formulated as a mixed-integer quadratic programming problem. This method, titled Quadratic Programming Hybrid with Augmented Constraints, is sufficiently fast to be computed in real-time for a district chiller system. This method is compared to both Branch and Bound and a simple logical decision algorithm in both speed and optimality. The proposed method for solving this mixed-integer quadratic programming problem proves very successful at achieving a near-optimal solution when compared to a standard Branch and Bound (BnB) algorithm. Although suboptimal, the proposed algorithm takes 99.96–99.99% less computational time than the standard BnB and computes an answer to within 29.9% of the BnB objective function. When compared to a simple logical decision algorithm, which represents an operator manually controlling the plant, the proposed method is estimated to yield 8.10–33.7% in savings on chiller energy costs. The Quadratic Programming Hybrid with Augmented Constraints algorithm shows potential for use in a real-time optimization application to exploit variable electricity pricing and significantly reduce the costs of running a chiller plant with thermal energy storage. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
722 a57189491950 Young A. p224 False Journal 147 Dynamic optimization of a district energy system with storage using a novel mixed-integer quadratic programming algorithm As more renewable energy is integrated into the power grid, it is increasingly important to exploit variable electricity pricing structures to minimize commercial utility costs and enable more intermittent renewables on the grid through proactive management of energy storage. Using data from a large campus district energy system, equipped with centralized chilled water plants and a thermal energy storage tank, a novel technique is proposed to optimize this system in real-time, formulated as a mixed-integer quadratic programming problem. This method, titled Quadratic Programming Hybrid with Augmented Constraints, is sufficiently fast to be computed in real-time for a district chiller system. This method is compared to both Branch and Bound and a simple logical decision algorithm in both speed and optimality. The proposed method for solving this mixed-integer quadratic programming problem proves very successful at achieving a near-optimal solution when compared to a standard Branch and Bound (BnB) algorithm. Although suboptimal, the proposed algorithm takes 99.96–99.99% less computational time than the standard BnB and computes an answer to within 29.9% of the BnB objective function. When compared to a simple logical decision algorithm, which represents an operator manually controlling the plant, the proposed method is estimated to yield 8.10–33.7% in savings on chiller energy costs. The Quadratic Programming Hybrid with Augmented Constraints algorithm shows potential for use in a real-time optimization application to exploit variable electricity pricing and significantly reduce the costs of running a chiller plant with thermal energy storage. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
723 a57205348362 Rogers P. p224 False Journal 147 Dynamic optimization of a district energy system with storage using a novel mixed-integer quadratic programming algorithm As more renewable energy is integrated into the power grid, it is increasingly important to exploit variable electricity pricing structures to minimize commercial utility costs and enable more intermittent renewables on the grid through proactive management of energy storage. Using data from a large campus district energy system, equipped with centralized chilled water plants and a thermal energy storage tank, a novel technique is proposed to optimize this system in real-time, formulated as a mixed-integer quadratic programming problem. This method, titled Quadratic Programming Hybrid with Augmented Constraints, is sufficiently fast to be computed in real-time for a district chiller system. This method is compared to both Branch and Bound and a simple logical decision algorithm in both speed and optimality. The proposed method for solving this mixed-integer quadratic programming problem proves very successful at achieving a near-optimal solution when compared to a standard Branch and Bound (BnB) algorithm. Although suboptimal, the proposed algorithm takes 99.96–99.99% less computational time than the standard BnB and computes an answer to within 29.9% of the BnB objective function. When compared to a simple logical decision algorithm, which represents an operator manually controlling the plant, the proposed method is estimated to yield 8.10–33.7% in savings on chiller energy costs. The Quadratic Programming Hybrid with Augmented Constraints algorithm shows potential for use in a real-time optimization application to exploit variable electricity pricing and significantly reduce the costs of running a chiller plant with thermal energy storage. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
724 a51461952600 Powell K. p224 False Journal 147 Dynamic optimization of a district energy system with storage using a novel mixed-integer quadratic programming algorithm As more renewable energy is integrated into the power grid, it is increasingly important to exploit variable electricity pricing structures to minimize commercial utility costs and enable more intermittent renewables on the grid through proactive management of energy storage. Using data from a large campus district energy system, equipped with centralized chilled water plants and a thermal energy storage tank, a novel technique is proposed to optimize this system in real-time, formulated as a mixed-integer quadratic programming problem. This method, titled Quadratic Programming Hybrid with Augmented Constraints, is sufficiently fast to be computed in real-time for a district chiller system. This method is compared to both Branch and Bound and a simple logical decision algorithm in both speed and optimality. The proposed method for solving this mixed-integer quadratic programming problem proves very successful at achieving a near-optimal solution when compared to a standard Branch and Bound (BnB) algorithm. Although suboptimal, the proposed algorithm takes 99.96–99.99% less computational time than the standard BnB and computes an answer to within 29.9% of the BnB objective function. When compared to a simple logical decision algorithm, which represents an operator manually controlling the plant, the proposed method is estimated to yield 8.10–33.7% in savings on chiller energy costs. The Quadratic Programming Hybrid with Augmented Constraints algorithm shows potential for use in a real-time optimization application to exploit variable electricity pricing and significantly reduce the costs of running a chiller plant with thermal energy storage. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.
724 a51461952600 Powell K. p431 False Journal 239 Performance comparison of low temperature and chemical absorption carbon capture processes in response to dynamic electricity demand and price profiles Current projections to the year 2050 reveal that fossil fuels will remain the main source of energy generation. To achieve the target limits of carbon dioxide emission, set by national and international policies, carbon capture will play a key role. Modeling and optimization of various carbon capture technologies such as pre-combustion, oxy-fuel, and post-combustion, when integrated with coal-fired power plants, have been researched extensively in literature. Research on the integration of power generation with capture technologies regarding comparisons between the different schemes in response to dynamic inputs is lacking. This work provides a comparison between a low temperature carbon capture and a chemical absorption process in response to a dynamic electricity demand and price profile and in the presence of an intermittent wind power supply. The objective in this work is to meet the overall electricity demand of residential users and the carbon capture process while the total operating cost associated with the integrated system of power generation and carbon capture is minimized. This comparison includes scenarios with and without energy storage associated with each capture technology. It is observed that in both integrated systems, with and without energy storage, the overall electricity demanded by the capture process and residential users is supplied by a combination of coal and wind power. For the case without energy storage, the total operating cost and energy demand of the low temperature carbon capture, based on a similar amount of captured carbon dioxide, are 4.3% and 20.5% less than that of chemical absorption, respectively. For the scenario with energy storage, the low temperature carbon capture requires 32.34% less energy to capture similar amounts of carbon dioxide while incurring 9.09% less overall operational cost. © 2018 Elsevier Ltd
724 a51461952600 Powell K. p844 False Journal 398 Optimal combined long-term facility design and short-term operational strategy for CHP capacity investments This work presents a detailed case study for the optimization of the expansion of a district energy system evaluating the investment decision timing, type of capacity expansion, and fine-scale operational modes. The study develops an optimization framework to find the investment schedule over 30 years with options of investing in traditional heating sources (boilers) or a next-generation combined heat and power (CHP) plant that provides heat and electricity. In district energy systems, the selected capacity and type of system is dependent on demand-side requirements, energy prices, and environmental costs. This work formulates capacity planning over a time horizon as a dynamic optimal control problem considering both operational modes and capital investment decisions. The initial plant is modified by the dynamic optimization throughout the 30 years to maximize profitability. The combined optimal controller and capital investment planner solves a large scale mixed integer nonlinear programming problem to provide the timing and size of the capacity investment (30 year outlook) and also guidance on the mode of operation (1 h time intervals). The optimizer meets optimal economic, environmental, and regulatory constraints with the suggested design and operational guidance with daily cyclical load following of heat and electricity demand. © 2016 Elsevier Ltd
725 a57216491948 Hershman R. p226 False Journal 148 Fabrication of demineralized bone matrix/polycaprolactone composites using large area projection sintering (LAPS) Cadaveric decellularized bone tissue is utilized as an allograft in many musculoskeletal surgical procedures. Typically, the allograft acts as a scaffold to guide tissue regeneration with superior biocompatibility relative to synthetic scaffolds. Traditionally these scaffolds are machined into the required dimensions and shapes. However, the geometrical simplicity and, in some cases, limited dimensions of the donated tissue restrict the use of allograft scaffolds. This could be overcome by additive manufacturing using granulated bone that is both decellularized and demineralized. In this study, the large area projection sintering (LAPS) method is evaluated as a fabrication method to build porous structures composed of granulated cortical bone bound by polycaprolactone (PCL). This additive manufacturing method utilizes visible light to selectively cure the deposited material layer-by-layer to create 3D geometry. First, the spreading behavior of the composite mixtures is evaluated and the conditions to attain improved powder bed density to fabricate the test specimens are determined. The tensile strength of the LAPS fabricated samples in both dry and hydrated states are determined and compared to the demineralized cancellous bone allograft and the heat treated demineralized-bone/PCL mixture in mold. The results indicated that the projection sintered composites of 45–55 wt %. Demineralized bone matrix (DBM) particulates produced strength comparable to processed and demineralized cancellous bone. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
726 a57191587072 Chelladurai I. p227 True Journal 149 Modeling of trans-grain twin transmission in AZ31 via a neighborhood-based viscoplastic self-consistent model The impact of twin transmission between neighboring grains as a contributor to overall twin activity is considered via a neighborhood viscoplastic self-consistent (NVPSC) model. The NVPSC model is an extension of a stochastic model for twin nucleation developed by Niezgoda et al. and a dislocation density based hardening law model developed by Knezevic et al. Beyond the baseline combined framework, the new model tracks sets of neighboring grains and allows twin transmission between them under certain conditions. The influence of grain boundary (GB) character is included in the stochastic models of twin nucleation and transmission. The starting texture from a rolled magnesium alloy AZ31B sheet was obtained using electron backscatter diffraction (EBSD) for initial input into the NVPSC. The sample was further deformed by uniaxial compression to encourage twin formation and the corresponding texture information was collected using EBSD. The accuracy of simulated twin activity was determined by comparing it with the twin activity seen in the deformed sample. The total number of predicted twins and the number of transmission twins is found to agree favorably with those observed via the EBSD scans. This validation demonstrates the significance of incorporating twin transmission as a twin formation mode in predictive models for this material. © 2018 Elsevier Ltd.
726 a57191587072 Chelladurai I. p756 True Journal 361 Microstructure Correlation with Formability for Biaxial Stretching of Magnesium Alloy AZ31B at Mildly Elevated Temperatures Magnesium AZ31B sheets of 2 mm thickness were stretch formed with a 101.6-mm-diameter punch at temperatures from 25°C to 150°C, in 25°C increments. Surface strains were measured with a digital image correlation method. The punch height versus load curve was found to be the same for temperatures of 25°C and for 50°C, whereas at 75°C and above, the load for a given punch height started to decrease, indicating a potential change in deformation mechanism. Electron backscatter diffraction was used to quantify features of the microstructure in the tested specimens. In particular, the gradual decrease in twinning activity as a result of easier thermally activated slip with increasing temperatures is quantified across this range. Moreover, twin activity was found to predominantly involve the formation of {10 1 ¯ 1 } compression twins that rapidly transform to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
726 a57191587072 Chelladurai I. p884 True Conference 397 Formability of magnesium alloy AZ31B from room temperature to 125, °C under biaxial tension Magnesium AZ31B sheets of 2, mm thickness were stretch formed using a 101.6, mm diameter punch at room temperature and subsequent increments from 25 to 125, °C. Surface strains were measured using a digital image correlation method in order to ensure that biaxial stretching was achieved. The punch height versus load curve was found to be the same for temperatures of 25 and for 50, °C, while at 75, °C the load for a given punch height was less. This difference seems to indicate a change in deformation mechanism between 50 and 75, °C. Electron Backscatter Diffraction (EBSD) was used to quantify features of the microstructure in the as-received and the strained specimens. Rather than a sudden transition from twinning to slip at low temperatures, it appears that twinning gradually decreases and slip activity increases as temperatures rise across the range from 25 to 125, °C. This confirms recent predictions found in the literature. The twin activity predominantly involves the formation of compression twins which rapidly transform further to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
727 a24295291100 Miles M.P. p227 False Journal 149 Modeling of trans-grain twin transmission in AZ31 via a neighborhood-based viscoplastic self-consistent model The impact of twin transmission between neighboring grains as a contributor to overall twin activity is considered via a neighborhood viscoplastic self-consistent (NVPSC) model. The NVPSC model is an extension of a stochastic model for twin nucleation developed by Niezgoda et al. and a dislocation density based hardening law model developed by Knezevic et al. Beyond the baseline combined framework, the new model tracks sets of neighboring grains and allows twin transmission between them under certain conditions. The influence of grain boundary (GB) character is included in the stochastic models of twin nucleation and transmission. The starting texture from a rolled magnesium alloy AZ31B sheet was obtained using electron backscatter diffraction (EBSD) for initial input into the NVPSC. The sample was further deformed by uniaxial compression to encourage twin formation and the corresponding texture information was collected using EBSD. The accuracy of simulated twin activity was determined by comparing it with the twin activity seen in the deformed sample. The total number of predicted twins and the number of transmission twins is found to agree favorably with those observed via the EBSD scans. This validation demonstrates the significance of incorporating twin transmission as a twin formation mode in predictive models for this material. © 2018 Elsevier Ltd.
727 a24295291100 Miles M.P. p252 True Journal 165 Predicting recrystallized grain size in friction stir processed 304L stainless steel A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone (HAZ). Friction stir processing (FSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304L stainless steel. A numerical simulation of the FSP process in 304L was developed to predict temperatures and recrystallized grain size in the stir zone. The model employed an Eulerian finite element approach, where flow stresses for a large range of strain rates and temperatures inherent in FSP were used as input. Temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. The predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. The maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%. © 2019
727 a24295291100 Miles M.P. p257 False Journal 168 Quantifying accuracy of a concept laser metal additive machine through the NIST test artifact Purpose: The purpose of this paper is to describe the use of a test artifact proposed by NIST to quantify the dimensional accuracy of a metal additive manufacturing process. Insights from this paper are given concerning both the performance of the machine, a concept laser Mlab cusing machine, and the applicability of the NIST test artifact in characterizing accuracy. Recommendations are given for improving the artifact and standardizing a process for evaluating dimensional accuracy across the additive manufacturing industry. Design/methodology/approach: Three builds of the NIST additive manufacturing test artifact were fabricated in 316 stainless steel on a concept laser Mlab cusing machine. The paper follows the procedure described by NIST for characterizing dimensional accuracy of the additive process. Features including pins, holes and staircase flats of various sizes were measured using an optical measurement system, a touch probe and a profilometer. Findings: This paper describes the accuracy of printed features’ size and position on the test artifact, as well as surface finish on flat and inclined surfaces. Trends in variation of these dimensions are identified, along with possible root causes and remedies. This paper also describes several strengths and weaknesses in the design of the test artifact and the proposed measurement strategy, with recommendations on how to improve and standardize the process. Originality/value: This paper reviews a previously proposed design and process for measuring the capabilities of additive manufacturing processes. It also suggests improvements that can be incorporated into future designs and standardized across the industry. © 2018, Emerald Publishing Limited.
727 a24295291100 Miles M.P. p445 False Journal 249 Effect of strain path on forming limits and retained austenite transformation in Q&P 1180 steel Forming limits and retained austenite (RA) transformation in Q&P 1180 steel are quantified as a function of plastic strain levels for three different strain paths. In-plane uniaxial tension testing was performed in a standard test frame, while limiting dome height tooling was employed for out-of-plane biaxial and plane strain tension experiments. Sheet specimens were tested incrementally for each strain path, and the RA content at each level of strain was measured using electron backscatter diffraction (EBSD). The biaxial tension strain path resulted in the greatest effective strain prior to necking at 0.355, compared to 0.123 for plane strain and 0.142 for uniaxial tension. EBSD measurements for various levels of plastic strain reveal a clear dependence of RA rate of transformation on strain path for the three linear strain paths that were employed in this work. Thinning strains appear to provide a slightly better correlation to RA transformation than effective strain levels, where biaxial tension achieved the greatest level just prior to necking, followed by plane-strain tension, and then uniaxial tension. © 2018 Elsevier B.V.
727 a24295291100 Miles M.P. p572 False Journal 303 A review of friction stir welding of steels: Tool, material flow, microstructure, and properties Considerable progress has been achieved in friction stir welding (FSW) of steels in every aspect of tool fabrication, microstructure control and properties evaluation in the past two decades. With the development of reliable welding tools and precise control systems, FSW of steels has reached a new level of technical maturity. High-quality, long welds can be produced in many engineering steels. Compared to traditional fusion welding, FSW exhibits unique advantages producing joints with better properties. As a result of active control of the welding temperature and/or cooling rate, FSW has the capability of fabricating steel joints with excellent toughness and strength. For example, unfavorable phase transformations that usually occur during traditional welding can be avoided and favorable phase fractions in advanced steels can be maintained in the weld zone thus avoiding the typical property degradations associated with fusion welding. If phase transformations do occur during FSW of thick steels, optimization of microstructure and properties can be attained by controlling the heat input and post-weld cooling rate. © 2017
727 a24295291100 Miles M.P. p573 False Journal 303 Solid state crack repair by friction stir processing in 304L stainless steel Friction stir processing (FSP) was investigated as a method of repairing cracks in 12 mm thick 304L stainless steel plate. Healing feasibility was demonstrated by processing a tapered crack using a PCBN/W-Re tool with a 25 mm diameter shoulder and a pin length of 6.4 mm. The experiment showed that it was possible to heal a crack that begins narrow and then progressively grows up to a width of 2 mm. Bead on plate experiments were used to find the best parameters for creating a consolidated stir zone with the least amount of hardness difference compared to the base metal. Grain refinement in some specimens resulted in much higher stir zone hardness, compared to base metal. A plot of grain size versus microhardness showed a very strong inverse correlation between grain size and hardness, as expected from the Hall-Petch relationship. Corrosion testing was carried out in order to evaluate the effect of FSP on potential sensitization of the stir zone. After 1000 h of intermittent immersion in 3.5% saline solution at room temperature it was found that no corrosion products formed on the base material controls or on any of the friction stir processed specimens. © 2017
727 a24295291100 Miles M.P. p713 False Journal 351 Process responses and resultant joint properties of friction stir welding of dissimilar 5083 and 6061aluminum alloys The effects of combinations of dissimilar aluminum alloys during Friction stir welding (FSW) on the process response and resultant joint properties are experimentally investigated using two dissimilar automotive structural aluminum alloys. Depending on the materials on the advancing and retreating sides of the tool travel direction during FSW, four different material combinations are considered. FSW joints without macroscopic defects are successfully fabricated for the four different material combinations. The optical microscopy results show that the macroscopic material mixing behaviors of the two dissimilar material combinations during FSW are somewhat different from each other, even though the process responses during joining are not much different. The results of the quasi-static tensile tests and EBSD analysis demonstrate that the mechanical behaviors and orientation changes of the joint during tensile deformation are affected by the material locations with respect to the tool travel direction during FSW. © 2017, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany.
727 a24295291100 Miles M.P. p756 False Journal 361 Microstructure Correlation with Formability for Biaxial Stretching of Magnesium Alloy AZ31B at Mildly Elevated Temperatures Magnesium AZ31B sheets of 2 mm thickness were stretch formed with a 101.6-mm-diameter punch at temperatures from 25°C to 150°C, in 25°C increments. Surface strains were measured with a digital image correlation method. The punch height versus load curve was found to be the same for temperatures of 25°C and for 50°C, whereas at 75°C and above, the load for a given punch height started to decrease, indicating a potential change in deformation mechanism. Electron backscatter diffraction was used to quantify features of the microstructure in the tested specimens. In particular, the gradual decrease in twinning activity as a result of easier thermally activated slip with increasing temperatures is quantified across this range. Moreover, twin activity was found to predominantly involve the formation of {10 1 ¯ 1 } compression twins that rapidly transform to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
727 a24295291100 Miles M.P. p772 False Journal 379 Effect of tool geometry and process parameters on mechanical properties of friction stir spot welded dissimilar aluminum alloys The effects of tool geometry and process parameters on the mechanical properties of friction stir spot welded (FSSW) dissimilar aluminum alloys are experimentally investigated. Two tools with different shoulder profiles, concave and convex, were considered. Two typical automotive aluminum alloys were selected for FSSW, thus resulting in two different material combinations for each shoulder profile. The experimental results showed that the two shoulder profiles caused significant differences in the axial force, the mixing of materials, and the mechanical properties of the joint. The sensitivity of joint strength to the variation of the tool rotation speed and the plunge speed was also quite dependent on the shoulder profile. The experimental result shows that the change of joint strength can be quite significant. © 2017, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.
727 a24295291100 Miles M.P. p884 False Conference 397 Formability of magnesium alloy AZ31B from room temperature to 125, °C under biaxial tension Magnesium AZ31B sheets of 2, mm thickness were stretch formed using a 101.6, mm diameter punch at room temperature and subsequent increments from 25 to 125, °C. Surface strains were measured using a digital image correlation method in order to ensure that biaxial stretching was achieved. The punch height versus load curve was found to be the same for temperatures of 25 and for 50, °C, while at 75, °C the load for a given punch height was less. This difference seems to indicate a change in deformation mechanism between 50 and 75, °C. Electron Backscatter Diffraction (EBSD) was used to quantify features of the microstructure in the as-received and the strained specimens. Rather than a sudden transition from twinning to slip at low temperatures, it appears that twinning gradually decreases and slip activity increases as temperatures rise across the range from 25 to 125, °C. This confirms recent predictions found in the literature. The twin activity predominantly involves the formation of compression twins which rapidly transform further to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
728 a23052031200 Niezgoda S. p227 False Journal 149 Modeling of trans-grain twin transmission in AZ31 via a neighborhood-based viscoplastic self-consistent model The impact of twin transmission between neighboring grains as a contributor to overall twin activity is considered via a neighborhood viscoplastic self-consistent (NVPSC) model. The NVPSC model is an extension of a stochastic model for twin nucleation developed by Niezgoda et al. and a dislocation density based hardening law model developed by Knezevic et al. Beyond the baseline combined framework, the new model tracks sets of neighboring grains and allows twin transmission between them under certain conditions. The influence of grain boundary (GB) character is included in the stochastic models of twin nucleation and transmission. The starting texture from a rolled magnesium alloy AZ31B sheet was obtained using electron backscatter diffraction (EBSD) for initial input into the NVPSC. The sample was further deformed by uniaxial compression to encourage twin formation and the corresponding texture information was collected using EBSD. The accuracy of simulated twin activity was determined by comparing it with the twin activity seen in the deformed sample. The total number of predicted twins and the number of transmission twins is found to agree favorably with those observed via the EBSD scans. This validation demonstrates the significance of incorporating twin transmission as a twin formation mode in predictive models for this material. © 2018 Elsevier Ltd.
729 a7004495126 Beyerlein I.J. p227 False Journal 149 Modeling of trans-grain twin transmission in AZ31 via a neighborhood-based viscoplastic self-consistent model The impact of twin transmission between neighboring grains as a contributor to overall twin activity is considered via a neighborhood viscoplastic self-consistent (NVPSC) model. The NVPSC model is an extension of a stochastic model for twin nucleation developed by Niezgoda et al. and a dislocation density based hardening law model developed by Knezevic et al. Beyond the baseline combined framework, the new model tracks sets of neighboring grains and allows twin transmission between them under certain conditions. The influence of grain boundary (GB) character is included in the stochastic models of twin nucleation and transmission. The starting texture from a rolled magnesium alloy AZ31B sheet was obtained using electron backscatter diffraction (EBSD) for initial input into the NVPSC. The sample was further deformed by uniaxial compression to encourage twin formation and the corresponding texture information was collected using EBSD. The accuracy of simulated twin activity was determined by comparing it with the twin activity seen in the deformed sample. The total number of predicted twins and the number of transmission twins is found to agree favorably with those observed via the EBSD scans. This validation demonstrates the significance of incorporating twin transmission as a twin formation mode in predictive models for this material. © 2018 Elsevier Ltd.
729 a7004495126 Beyerlein I.J. p756 False Journal 361 Microstructure Correlation with Formability for Biaxial Stretching of Magnesium Alloy AZ31B at Mildly Elevated Temperatures Magnesium AZ31B sheets of 2 mm thickness were stretch formed with a 101.6-mm-diameter punch at temperatures from 25°C to 150°C, in 25°C increments. Surface strains were measured with a digital image correlation method. The punch height versus load curve was found to be the same for temperatures of 25°C and for 50°C, whereas at 75°C and above, the load for a given punch height started to decrease, indicating a potential change in deformation mechanism. Electron backscatter diffraction was used to quantify features of the microstructure in the tested specimens. In particular, the gradual decrease in twinning activity as a result of easier thermally activated slip with increasing temperatures is quantified across this range. Moreover, twin activity was found to predominantly involve the formation of {10 1 ¯ 1 } compression twins that rapidly transform to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
729 a7004495126 Beyerlein I.J. p884 False Conference 397 Formability of magnesium alloy AZ31B from room temperature to 125, °C under biaxial tension Magnesium AZ31B sheets of 2, mm thickness were stretch formed using a 101.6, mm diameter punch at room temperature and subsequent increments from 25 to 125, °C. Surface strains were measured using a digital image correlation method in order to ensure that biaxial stretching was achieved. The punch height versus load curve was found to be the same for temperatures of 25 and for 50, °C, while at 75, °C the load for a given punch height was less. This difference seems to indicate a change in deformation mechanism between 50 and 75, °C. Electron Backscatter Diffraction (EBSD) was used to quantify features of the microstructure in the as-received and the strained specimens. Rather than a sudden transition from twinning to slip at low temperatures, it appears that twinning gradually decreases and slip activity increases as temperatures rise across the range from 25 to 125, °C. This confirms recent predictions found in the literature. The twin activity predominantly involves the formation of compression twins which rapidly transform further to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
730 a12778890800 Knezevic M. p227 False Journal 149 Modeling of trans-grain twin transmission in AZ31 via a neighborhood-based viscoplastic self-consistent model The impact of twin transmission between neighboring grains as a contributor to overall twin activity is considered via a neighborhood viscoplastic self-consistent (NVPSC) model. The NVPSC model is an extension of a stochastic model for twin nucleation developed by Niezgoda et al. and a dislocation density based hardening law model developed by Knezevic et al. Beyond the baseline combined framework, the new model tracks sets of neighboring grains and allows twin transmission between them under certain conditions. The influence of grain boundary (GB) character is included in the stochastic models of twin nucleation and transmission. The starting texture from a rolled magnesium alloy AZ31B sheet was obtained using electron backscatter diffraction (EBSD) for initial input into the NVPSC. The sample was further deformed by uniaxial compression to encourage twin formation and the corresponding texture information was collected using EBSD. The accuracy of simulated twin activity was determined by comparing it with the twin activity seen in the deformed sample. The total number of predicted twins and the number of transmission twins is found to agree favorably with those observed via the EBSD scans. This validation demonstrates the significance of incorporating twin transmission as a twin formation mode in predictive models for this material. © 2018 Elsevier Ltd.
730 a12778890800 Knezevic M. p756 False Journal 361 Microstructure Correlation with Formability for Biaxial Stretching of Magnesium Alloy AZ31B at Mildly Elevated Temperatures Magnesium AZ31B sheets of 2 mm thickness were stretch formed with a 101.6-mm-diameter punch at temperatures from 25°C to 150°C, in 25°C increments. Surface strains were measured with a digital image correlation method. The punch height versus load curve was found to be the same for temperatures of 25°C and for 50°C, whereas at 75°C and above, the load for a given punch height started to decrease, indicating a potential change in deformation mechanism. Electron backscatter diffraction was used to quantify features of the microstructure in the tested specimens. In particular, the gradual decrease in twinning activity as a result of easier thermally activated slip with increasing temperatures is quantified across this range. Moreover, twin activity was found to predominantly involve the formation of {10 1 ¯ 1 } compression twins that rapidly transform to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
730 a12778890800 Knezevic M. p884 False Conference 397 Formability of magnesium alloy AZ31B from room temperature to 125, °C under biaxial tension Magnesium AZ31B sheets of 2, mm thickness were stretch formed using a 101.6, mm diameter punch at room temperature and subsequent increments from 25 to 125, °C. Surface strains were measured using a digital image correlation method in order to ensure that biaxial stretching was achieved. The punch height versus load curve was found to be the same for temperatures of 25 and for 50, °C, while at 75, °C the load for a given punch height was less. This difference seems to indicate a change in deformation mechanism between 50 and 75, °C. Electron Backscatter Diffraction (EBSD) was used to quantify features of the microstructure in the as-received and the strained specimens. Rather than a sudden transition from twinning to slip at low temperatures, it appears that twinning gradually decreases and slip activity increases as temperatures rise across the range from 25 to 125, °C. This confirms recent predictions found in the literature. The twin activity predominantly involves the formation of compression twins which rapidly transform further to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
731 a57194703295 Asimaki D. p228 False Journal 150 Site effects in Mexico City basin: Past and present Due to the unique subsoil conditions prevailing in the Mexico City basin, seismic risk has been strongly correlated to site effects. Thus, during the Mw 8.1 09/19/1985 subduction fault earthquake, and its strong aftershock Mw 7.5 09/21/1985, extensive damage was observed in the area, along with the loss of thousands of lives, despite these events had an epicentral distance of around 430 km from Mexico City. The observed damage was mostly due to site affects originated by the high plastiCity clay deposits found in the basin, which lead to large amplifications, and duration elongation of the ground motions coming from the epicenter. In addition, a frequency content modification occurs, which in turn, leads to a double resonance effect between the incoming ground motions, soil deposits, and the damaged buildings. Exactly 32 years after this devastating event, the Mw 7.1 09/19/2017 normal fault earthquake, reminded us of the importance of accounting for site effects, and most importantly the need to carry out a proper characterization of basin geometry, soil profile configuration, hydraulic conditions, and maintenance-structure periodic assessments of the building stock in Mexico City. This is required to reduce uncertainties of seismic vulnerability studies for extreme-event seismic hazard scenarios. In this paper, the role of site response and seismic soil-structure interaction as key factors responsible of the observed damage in the City is revisited, through series of 3D finite difference models of typical structure-foundation-soil typologies found at the areas where most of the damage was observed, highlighting its clear impact in the final damage distribution observed around the City. © 2019 Elsevier Ltd
731 a57194703295 Asimaki D. p394 True Conference 143 Mexico City Basin Effects: Past, Present, and Future Seismic hazard in Mexico City governed by site effects. The M8.1 1985 subduction zone earthquake, which caused significant damage and loss of thousands of lives at 350 km epicentral distance, has become the quintessential example of the role that site effects can play in modifying the amplitude, frequency, and duration of ground shaking; and in aggravating the catastrophic consequences of earthquakes. We here present observations and analyses of the M7.1 September 19, 2017, event that -while triggered by an intraplate rupture at approximately half the epicentral distance of the 1985 event relative to Mexico City -caused severe structural damage to a few tens of buildings located in a relatively narrow zone between the hill and lake zones of the basin, known as the transition zone. We show that the M 7.1 mainshock exposed the vulnerabilities of the pre-1985 building code in the transition zone; but more importantly highlighted the improvement of the 1987 building code revision in terms of the performance of modern high-rise buildings that suffered catastrophic consequences during the 1985 Michoácan earthquake sequence. We next analyze several records collected at stations in the basin over the past 20 years. We highlight the importance of three-dimensional heterogeneity of the basin sediments, the coupling between hydrological setting and site response and their evolution with time, and the energy interaction between the deep basin edge and the shallow clay layers. Results presented are the collective effort of the GEER teams that were deployed to perform post-earthquake reconnaissance in the affected regions of the epicentral area and in Mexico City after the M 7.1 September 19, 2017, earthquake sequence. © 2019 American Society of Civil Engineers.
732 a57144565100 Tepalcapa S. p228 False Journal 150 Site effects in Mexico City basin: Past and present Due to the unique subsoil conditions prevailing in the Mexico City basin, seismic risk has been strongly correlated to site effects. Thus, during the Mw 8.1 09/19/1985 subduction fault earthquake, and its strong aftershock Mw 7.5 09/21/1985, extensive damage was observed in the area, along with the loss of thousands of lives, despite these events had an epicentral distance of around 430 km from Mexico City. The observed damage was mostly due to site affects originated by the high plastiCity clay deposits found in the basin, which lead to large amplifications, and duration elongation of the ground motions coming from the epicenter. In addition, a frequency content modification occurs, which in turn, leads to a double resonance effect between the incoming ground motions, soil deposits, and the damaged buildings. Exactly 32 years after this devastating event, the Mw 7.1 09/19/2017 normal fault earthquake, reminded us of the importance of accounting for site effects, and most importantly the need to carry out a proper characterization of basin geometry, soil profile configuration, hydraulic conditions, and maintenance-structure periodic assessments of the building stock in Mexico City. This is required to reduce uncertainties of seismic vulnerability studies for extreme-event seismic hazard scenarios. In this paper, the role of site response and seismic soil-structure interaction as key factors responsible of the observed damage in the City is revisited, through series of 3D finite difference models of typical structure-foundation-soil typologies found at the areas where most of the damage was observed, highlighting its clear impact in the final damage distribution observed around the City. © 2019 Elsevier Ltd
733 a57189458176 Roman-de la Sancha A. p228 False Journal 150 Site effects in Mexico City basin: Past and present Due to the unique subsoil conditions prevailing in the Mexico City basin, seismic risk has been strongly correlated to site effects. Thus, during the Mw 8.1 09/19/1985 subduction fault earthquake, and its strong aftershock Mw 7.5 09/21/1985, extensive damage was observed in the area, along with the loss of thousands of lives, despite these events had an epicentral distance of around 430 km from Mexico City. The observed damage was mostly due to site affects originated by the high plastiCity clay deposits found in the basin, which lead to large amplifications, and duration elongation of the ground motions coming from the epicenter. In addition, a frequency content modification occurs, which in turn, leads to a double resonance effect between the incoming ground motions, soil deposits, and the damaged buildings. Exactly 32 years after this devastating event, the Mw 7.1 09/19/2017 normal fault earthquake, reminded us of the importance of accounting for site effects, and most importantly the need to carry out a proper characterization of basin geometry, soil profile configuration, hydraulic conditions, and maintenance-structure periodic assessments of the building stock in Mexico City. This is required to reduce uncertainties of seismic vulnerability studies for extreme-event seismic hazard scenarios. In this paper, the role of site response and seismic soil-structure interaction as key factors responsible of the observed damage in the City is revisited, through series of 3D finite difference models of typical structure-foundation-soil typologies found at the areas where most of the damage was observed, highlighting its clear impact in the final damage distribution observed around the City. © 2019 Elsevier Ltd
734 a24080990600 Montalva G. p228 False Journal 150 Site effects in Mexico City basin: Past and present Due to the unique subsoil conditions prevailing in the Mexico City basin, seismic risk has been strongly correlated to site effects. Thus, during the Mw 8.1 09/19/1985 subduction fault earthquake, and its strong aftershock Mw 7.5 09/21/1985, extensive damage was observed in the area, along with the loss of thousands of lives, despite these events had an epicentral distance of around 430 km from Mexico City. The observed damage was mostly due to site affects originated by the high plastiCity clay deposits found in the basin, which lead to large amplifications, and duration elongation of the ground motions coming from the epicenter. In addition, a frequency content modification occurs, which in turn, leads to a double resonance effect between the incoming ground motions, soil deposits, and the damaged buildings. Exactly 32 years after this devastating event, the Mw 7.1 09/19/2017 normal fault earthquake, reminded us of the importance of accounting for site effects, and most importantly the need to carry out a proper characterization of basin geometry, soil profile configuration, hydraulic conditions, and maintenance-structure periodic assessments of the building stock in Mexico City. This is required to reduce uncertainties of seismic vulnerability studies for extreme-event seismic hazard scenarios. In this paper, the role of site response and seismic soil-structure interaction as key factors responsible of the observed damage in the City is revisited, through series of 3D finite difference models of typical structure-foundation-soil typologies found at the areas where most of the damage was observed, highlighting its clear impact in the final damage distribution observed around the City. © 2019 Elsevier Ltd
735 a56323465700 Rojas-Nastrucci E.A. p229 False Journal 151 Thermal and Vapor Smoothing of Thermoplastic for Reduced Surface Roughness of Additive Manufactured RF Electronics Additive manufacturing (AM) of electronics provides a route for creating customized systems with novel geometries that are not feasible with traditional methods. Standard AM processes such as extrusion can produce substrates on which electrical traces can be deposited. However, the surface roughness of plastic extrusion reduces the effective electrical conductivity and can introduce anisotropy, especially in radio frequency (RF) devices. The roughness can be reduced using vapor smoothing (VS), but solvent absorption changes the surface composition slightly, can be environmentally hazardous, and is not feasible with all thermoplastics. A new method introduced here - coined thermal smoothing (TS) - utilizes a heat source to locally reflow the material, thus minimizing the roughness of the undulating surfaces without the drawbacks of VS. This research work compares the surface roughness impacts of both smoothing processes with profilometry and scanning electron microscope (SEM) images. Both smoothing processes significantly reduce the surface roughness of extruded components by 80% and 90% for TS and VS, respectively. This paper also examines the influence of surface smoothing on high-frequency conductivity of microdispensed conductors (CB028 paste) deposited on the substrates. The measured loss on coplanar waveguides shows an improvement of up to 40% at 7 GHz. © 2011-2012 IEEE.
736 a57209274795 Griffin D. p229 False Journal 151 Thermal and Vapor Smoothing of Thermoplastic for Reduced Surface Roughness of Additive Manufactured RF Electronics Additive manufacturing (AM) of electronics provides a route for creating customized systems with novel geometries that are not feasible with traditional methods. Standard AM processes such as extrusion can produce substrates on which electrical traces can be deposited. However, the surface roughness of plastic extrusion reduces the effective electrical conductivity and can introduce anisotropy, especially in radio frequency (RF) devices. The roughness can be reduced using vapor smoothing (VS), but solvent absorption changes the surface composition slightly, can be environmentally hazardous, and is not feasible with all thermoplastics. A new method introduced here - coined thermal smoothing (TS) - utilizes a heat source to locally reflow the material, thus minimizing the roughness of the undulating surfaces without the drawbacks of VS. This research work compares the surface roughness impacts of both smoothing processes with profilometry and scanning electron microscope (SEM) images. Both smoothing processes significantly reduce the surface roughness of extruded components by 80% and 90% for TS and VS, respectively. This paper also examines the influence of surface smoothing on high-frequency conductivity of microdispensed conductors (CB028 paste) deposited on the substrates. The measured loss on coplanar waveguides shows an improvement of up to 40% at 7 GHz. © 2011-2012 IEEE.
737 a7102483892 Weller T.M. p229 False Journal 151 Thermal and Vapor Smoothing of Thermoplastic for Reduced Surface Roughness of Additive Manufactured RF Electronics Additive manufacturing (AM) of electronics provides a route for creating customized systems with novel geometries that are not feasible with traditional methods. Standard AM processes such as extrusion can produce substrates on which electrical traces can be deposited. However, the surface roughness of plastic extrusion reduces the effective electrical conductivity and can introduce anisotropy, especially in radio frequency (RF) devices. The roughness can be reduced using vapor smoothing (VS), but solvent absorption changes the surface composition slightly, can be environmentally hazardous, and is not feasible with all thermoplastics. A new method introduced here - coined thermal smoothing (TS) - utilizes a heat source to locally reflow the material, thus minimizing the roughness of the undulating surfaces without the drawbacks of VS. This research work compares the surface roughness impacts of both smoothing processes with profilometry and scanning electron microscope (SEM) images. Both smoothing processes significantly reduce the surface roughness of extruded components by 80% and 90% for TS and VS, respectively. This paper also examines the influence of surface smoothing on high-frequency conductivity of microdispensed conductors (CB028 paste) deposited on the substrates. The measured loss on coplanar waveguides shows an improvement of up to 40% at 7 GHz. © 2011-2012 IEEE.
738 a57200208018 May D. p230 True Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
739 a36701008900 Aktas A. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
740 a7201687754 Advani S.G. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
741 a7202401225 Berg D.C. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
742 a12805837100 Endruweit A. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
743 a56257805000 Fauster E. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
744 a7005067917 Lomov S.V. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
745 a7202417224 Long A. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
746 a55927295500 Mitschang P. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
747 a6508257901 Abaimov S. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
748 a55931847400 Abliz D. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
749 a7004092560 Akhatov I. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
750 a56955794500 Ali M.A. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
751 a55778257800 Allen T.D. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
752 a6701664914 Bickerton S. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
753 a24504209800 Bodaghi M. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
754 a55247112800 Caglar B. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
755 a57207841000 Caglar H. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
756 a12780700500 Chiminelli A. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
757 a7006236094 Correia N. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
758 a16303239800 Cosson B. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
759 a55315191100 Danzi M. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
760 a57194063754 Dittmann J. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
761 a6701501207 Ermanni P. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
762 a24072733200 Francucci G. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
763 a57192140261 Grishaev V. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
764 a57207843958 Hancioglu M. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
765 a57207841443 Kabachi M.A. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
766 a57207846799 Kind K. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
767 a56473665600 Deléglise-Lagardère M. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
768 a23977815400 Laspalas M. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
769 a56308354900 Lebedev O.V. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
770 a36859700200 Lizaranzu M. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
771 a26221155700 Liotier P.-J. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
772 a24385613600 Middendorf P. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
773 a15081415200 Morán J. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
774 a7408416878 Park C.-H. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
775 a11042527300 Pipes R.B. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
776 a56185388600 Pucci M.F. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
777 a57207844500 Raynal J. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
778 a57189577432 Rodriguez E.S. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
779 a6602943081 Schledjewski R. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
780 a57207842677 Schubnel R. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
781 a39062078800 Sharp N. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
782 a7101608513 Sims G. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
783 a6602499334 Sozer E.M. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
784 a57202152216 Sousa P. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
785 a57213372150 Thomas J. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
786 a8555191500 Umer R. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
787 a57195579636 Wijaya W. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
788 a57207842193 Willenbacher B. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
789 a57203836326 Yong A. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
790 a55639502500 Zaremba S. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
791 a6602168494 Ziegmann G. p230 False Journal 152 In-plane permeability characterization of engineering textiles based on radial flow experiments: A benchmark exercise Although good progress was made by two international benchmark exercises on in-plane permeability, existing methods have not yet been standardized. This paper presents the results of a third benchmark exercise using in-plane permeability measurement, based on systems applying the radial unsaturated injection method. 19 participants using 20 systems characterized a non-crimp and a woven fabric at three different fiber volume contents, using a commercially available silicone oil as impregnating fluid. They followed a detailed characterization procedure and also completed a questionnaire on their set-up and analysis methods. Excluding outliers (2 of 20), the average coefficient of variation (c v ) between the participant's results was 32% and 44% (non-crimp and woven fabric), while the average c v for individual participants was 8% and 12%, respectively. This indicates statistically significant variations between the measurement systems. Cavity deformation was identified as a major influence, besides fluid pressure/viscosity measurement, textile variations, and data analysis. © 2019 Elsevier Ltd
792 a57209284973 Saleh A.M. p231 True Journal 153 Non-canonical amino acid labeling in proteomics and biotechnology Metabolic labeling of proteins with non-canonical amino acids (ncAAs) provides unique bioorthogonal chemical groups during de novo synthesis by taking advantage of both endogenous and heterologous protein synthesis machineries. Labeled proteins can then be selectively conjugated to fluorophores, affinity reagents, peptides, polymers, nanoparticles or surfaces for a wide variety of downstream applications in proteomics and biotechnology. In this review, we focus on techniques in which proteins are residue- and site-specifically labeled with ncAAs containing bioorthogonal handles. These ncAA-labeled proteins are: readily enriched from cells and tissues for identification via mass spectrometry-based proteomic analysis; selectively purified for downstream biotechnology applications; or labeled with fluorophores for in situ analysis. To facilitate the wider use of these techniques, we provide decision trees to help guide the design of future experiments. It is expected that the use of ncAA labeling will continue to expand into new application areas where spatial and temporal analysis of proteome dynamics and engineering new chemistries and new function into proteins are desired. © 2019 The Author(s).
793 a56221901100 Wilding K.M. p231 False Journal 153 Non-canonical amino acid labeling in proteomics and biotechnology Metabolic labeling of proteins with non-canonical amino acids (ncAAs) provides unique bioorthogonal chemical groups during de novo synthesis by taking advantage of both endogenous and heterologous protein synthesis machineries. Labeled proteins can then be selectively conjugated to fluorophores, affinity reagents, peptides, polymers, nanoparticles or surfaces for a wide variety of downstream applications in proteomics and biotechnology. In this review, we focus on techniques in which proteins are residue- and site-specifically labeled with ncAAs containing bioorthogonal handles. These ncAA-labeled proteins are: readily enriched from cells and tissues for identification via mass spectrometry-based proteomic analysis; selectively purified for downstream biotechnology applications; or labeled with fluorophores for in situ analysis. To facilitate the wider use of these techniques, we provide decision trees to help guide the design of future experiments. It is expected that the use of ncAA labeling will continue to expand into new application areas where spatial and temporal analysis of proteome dynamics and engineering new chemistries and new function into proteins are desired. © 2019 The Author(s).
793 a56221901100 Wilding K.M. p439 True Journal 244 The emerging impact of cell-free chemical biosynthesis Biomanufacturing has emerged as a promising alternative to chemocatalysis for green, renewable, complex synthesis of biofuels, medicines, and fine chemicals. Cell-free chemical biosynthesis offers additional advantages over in vivo production, enabling plug-and-play assembly of separately produced enzymes into an optimal cascade, versatile reaction conditions, and direct access to the reaction environment. In order for these advantages to be realized on the larger scale of industry, strategies are needed to reduce costs of biocatalyst generation, improve biocatalyst stability, and enable economically sustainable continuous cascade operation. Here we overview the advantages and remaining challenges of applying cell-free chemical biosynthesis for commodity production, and discuss recent advances in cascade engineering, enzyme immobilization, and enzyme encapsulation which constitute important steps towards addressing these challenges. © 2017
793 a56221901100 Wilding K.M. p537 True Journal 297 The Locational Impact of Site-Specific PEGylation: Streamlined Screening with Cell-Free Protein Expression and Coarse-Grain Simulation Although polyethylene glycol (PEG) is commonly used to improve protein stability and therapeutic efficacy, the optimal location for attaching PEG onto proteins is not well understood. Here, we present a cell-free protein synthesis-based screening platform that facilitates site-specific PEGylation and efficient evaluation of PEG attachment efficiency, thermal stability, and activity for different variants of PEGylated T4 lysozyme, including a di-PEGylated variant. We also report developing a computationally efficient coarse-grain simulation model as a potential tool to narrow experimental screening candidates. We use this simulation method as a novel tool to evaluate the locational impact of PEGylation. Using this screen, we also evaluated the predictive impact of PEGylation site solvent accessibility, conjugation site structure, PEG size, and double PEGylation. Our findings indicate that PEGylation efficiency, protein stability, and protein activity varied considerably with PEGylation site, variations that were not well predicted by common PEGylation guidelines. Overall our results suggest current guidelines are insufficiently predictive, highlighting the need for experimental and simulation screening systems such as the one presented here. © 2018 American Chemical Society.
794 a6507753128 Calve S. p231 False Journal 153 Non-canonical amino acid labeling in proteomics and biotechnology Metabolic labeling of proteins with non-canonical amino acids (ncAAs) provides unique bioorthogonal chemical groups during de novo synthesis by taking advantage of both endogenous and heterologous protein synthesis machineries. Labeled proteins can then be selectively conjugated to fluorophores, affinity reagents, peptides, polymers, nanoparticles or surfaces for a wide variety of downstream applications in proteomics and biotechnology. In this review, we focus on techniques in which proteins are residue- and site-specifically labeled with ncAAs containing bioorthogonal handles. These ncAA-labeled proteins are: readily enriched from cells and tissues for identification via mass spectrometry-based proteomic analysis; selectively purified for downstream biotechnology applications; or labeled with fluorophores for in situ analysis. To facilitate the wider use of these techniques, we provide decision trees to help guide the design of future experiments. It is expected that the use of ncAA labeling will continue to expand into new application areas where spatial and temporal analysis of proteome dynamics and engineering new chemistries and new function into proteins are desired. © 2019 The Author(s).
795 a6504734319 Kinzer-Ursem T.L. p231 False Journal 153 Non-canonical amino acid labeling in proteomics and biotechnology Metabolic labeling of proteins with non-canonical amino acids (ncAAs) provides unique bioorthogonal chemical groups during de novo synthesis by taking advantage of both endogenous and heterologous protein synthesis machineries. Labeled proteins can then be selectively conjugated to fluorophores, affinity reagents, peptides, polymers, nanoparticles or surfaces for a wide variety of downstream applications in proteomics and biotechnology. In this review, we focus on techniques in which proteins are residue- and site-specifically labeled with ncAAs containing bioorthogonal handles. These ncAA-labeled proteins are: readily enriched from cells and tissues for identification via mass spectrometry-based proteomic analysis; selectively purified for downstream biotechnology applications; or labeled with fluorophores for in situ analysis. To facilitate the wider use of these techniques, we provide decision trees to help guide the design of future experiments. It is expected that the use of ncAA labeling will continue to expand into new application areas where spatial and temporal analysis of proteome dynamics and engineering new chemistries and new function into proteins are desired. © 2019 The Author(s).
796 a24759275600 McDonald J.K. p234 True Journal 154 The design critique and the moral goods of studio pedagogy In this paper we inquire into the moral goods that are significant for design studio instructors, by examining how they talk about the way critiques fit into the studio as a social practice. We studied this issue using in-depth interviews with six studio instructors. Through these interviews, we found that critiques are how they structure the studio so they can pursue three types of moral goods: a) for student development; b) for their own self-cultivation; and c) for other stakeholders. Along with presenting these goods, we discuss what instructors say about multiple goods exerting influence on them at the same time. Finally, we discuss implications these findings have for understanding the studio environment, and why critiques matter within this environment. © 2019 Elsevier Ltd
797 a57207312334 Michela E. p234 False Journal 154 The design critique and the moral goods of studio pedagogy In this paper we inquire into the moral goods that are significant for design studio instructors, by examining how they talk about the way critiques fit into the studio as a social practice. We studied this issue using in-depth interviews with six studio instructors. Through these interviews, we found that critiques are how they structure the studio so they can pursue three types of moral goods: a) for student development; b) for their own self-cultivation; and c) for other stakeholders. Along with presenting these goods, we discuss what instructors say about multiple goods exerting influence on them at the same time. Finally, we discuss implications these findings have for understanding the studio environment, and why critiques matter within this environment. © 2019 Elsevier Ltd
798 a56709364700 Stott M.A. p235 False Conference 56 Single Particle Detection Enhancement with Wavelet-based Signal Processing Technique Chip-based single molecule detection requires ultra-sensitive devices and robust signal processing methods. A new wavelet-based signal processing method is introduced that improves detection and error rates on an optofluidic platform by 2x and 3x, respectively. © 2019 The Author(s) 2019 OSA.
798 a56709364700 Stott M.A. p347 False Conference 119 Single particle detection enhancement with wavelet-based signal processing technique Chip-based single molecule detection requires ultra-sensitive devices and robust signal processing methods. A new wavelet-based signal processing method is introduced that improves detection and error rates on an optofluidic platform by 2x and 3x, respectively. © 2019 The Author(s)
798 a56709364700 Stott M.A. p459 True Journal 256 Buried Rib SiO2 Multimode Interference Waveguides for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used to create wavelength-dependent spot patterns which enables simultaneous analyte detection on a single optofluidic chip, useful for disease diagnostics. The fidelity of such multi-spot patterns is important for high sensitivity and accurate target identification. Buried rib structures have been incorporated into these SiO2-based waveguides to improve environmental stability. Through experiments and simulation, this letter explores design parameters for a buried MMI rib waveguide based on anti-resonant reflecting optical waveguides in order to produce high-fidelity spot patterns. Optimal rib heights and widths are reported in the context of available microfabrication etch technology and performance for an optimized biosensor is shown. © 1989-2012 IEEE.
798 a56709364700 Stott M.A. p502 True Journal 273 Optimized ARROW-Based MMI Waveguides for High Fidelity Excitation Patterns for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used for multiplexing and de-multiplexing optical signals. High fidelity, wavelength dependent multi-spot patterns from MMI waveguides are useful for sensitive and simultaneous identification of multiple targets in multiplexed fluorescence optofluidic biosensors. Through experiments and simulation, this paper explores design parameters for an MMI rib anti-resonant reflecting optical waveguide in order to produce high fidelity spot patterns at the liquid core biomarker excitation region. Width and etch depth of the single excitation rib waveguide used to excite the MMI waveguide are especially critical because they determine the size of the input optical mode which is imaged at the MMI waveguide's output. To increase optical throughput into the MMI waveguide when light is coupled in from an optical fiber, tapers in the waveguide width can be used for better mode matching. © 2012 IEEE.
798 a56709364700 Stott M.A. p607 True Conference 245 High fidelity MMI excitation patterns for optofluidic multiplexing High fidelity interference patterns from multimode interference waveguides are needed for multiplexed optofluidic biosensors. Spot pattern fidelity can be optimized by careful design of the single-mode waveguides used to excite the multimode waveguides. © OSA 2018.
798 a56709364700 Stott M.A. p608 False Conference 246 3D hydrodynamic focusing for optofluidics using a stacked channel design We present a 3D hydrodynamic focusing design suitable for optofluidic devices allowing planar fabrication and velocity independent particle focusing. Simulations are presented and fabrication outlined with evidence that stacked SU8 layers are suitable building blocks. © OSA 2018.
798 a56709364700 Stott M.A. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
798 a56709364700 Stott M.A. p786 False Conference 323 MMI waveguide based multispectral detection of nucleic acids for analysis of drug-resistant bacteria A multi-mode interference waveguide is used for creating distinct temporal fluorescence patterns at multiple excitation wavelengths. This allows for identification of bacterial nucleic acids labeled with molecular beacons in two colors. © 2016 IEEE.
798 a56709364700 Stott M.A. p787 False Conference 324 Design and characterization of integrated 2D ABEL trap Design and characterization of a chip-based electro-optic single-particle trap with feedback-based confinement in two dimensions is demonstrated. Improvements over 1D confinement and integration of nanopores for gated delivery of individual nanoparticles are discussed. © 2016 IEEE.
798 a56709364700 Stott M.A. p840 False Conference 367 Multimodal multiplexing of single-virus detection using multi-mode interference waveguides Multi-mode interference waveguides are used to implement simultaneous spectral and spatial multiplex fluorescence analysis in liquid-core waveguide channels. A six-times multiplex identification of single influenza viruses is demonstrated with two excitation colors and threechannels. © 2017 OSA.
798 a56709364700 Stott M.A. p841 False Conference 368 Single particle fluorescence analysis on demand on electro-optofluidic chip with gated particle delivery Electronic feedback enables introduction of single microbeads and DNA molecules into a liquid-core waveguide through a micro/nanopore. Subsequent fluorescence detection from a controlled number of individual particles is demonstrated, enabling single particle analysis on demand. © 2017 OSA.
799 a57192981384 Davis H.C. p236 True Journal 155 Sagittal plane walking biomechanics in individuals with knee osteoarthritis after quadriceps strengthening Objective: To compare sagittal walking gait biomechanics between participants with knee osteoarthritis (KOA) who increased quadriceps strength following a lower-extremity strengthening intervention (responders) and those who did not increase strength following the same strengthening protocol (non-responders) both at baseline and following the lower extremity strengthening protocol. Design: Fifty-three participants with radiographic KOA (47% female, 62.3 ± 7.1 years, BMI = 28.5 ± 3.9 kg/m 2 ) were enrolled in 10 sessions of lower extremity strengthening over a 28-day period. Maximum isometric quadriceps strength and walking gait biomechanics were collected on the involved limb at baseline and 4-weeks following the strengthening intervention. Responders were classified as individuals who increased quadriceps strength greater than the upper limit of the 95% confidence interval (CI) for the minimal detectable change (MDC) in quadriceps strength (29 Nm) determined in a previous study. 2 × 2 functional analyses of variance were used to evaluate the effects of group (responders and non-responders) and time (baseline and 4-weeks) on time-normalized waveforms for knee flexion angle (KFA), vertical ground reaction force (vGRF), and internal knee extension moment (KEM). Results: A significant group x time interaction for KFA demonstrated greater KFA in the first half of stance at baseline and greater knee extension in the second half of stance at 4-weeks in responders compared to non-responders. There was no significant group x time interaction for vGRF or internal KEM. Conclusions: Quadriceps strengthening may be used to stimulate small changes in KFA in individuals with KOA. © 2019 Osteoarthritis Research Society International
800 a57190258899 Luc-Harkey B.A. p236 False Journal 155 Sagittal plane walking biomechanics in individuals with knee osteoarthritis after quadriceps strengthening Objective: To compare sagittal walking gait biomechanics between participants with knee osteoarthritis (KOA) who increased quadriceps strength following a lower-extremity strengthening intervention (responders) and those who did not increase strength following the same strengthening protocol (non-responders) both at baseline and following the lower extremity strengthening protocol. Design: Fifty-three participants with radiographic KOA (47% female, 62.3 ± 7.1 years, BMI = 28.5 ± 3.9 kg/m 2 ) were enrolled in 10 sessions of lower extremity strengthening over a 28-day period. Maximum isometric quadriceps strength and walking gait biomechanics were collected on the involved limb at baseline and 4-weeks following the strengthening intervention. Responders were classified as individuals who increased quadriceps strength greater than the upper limit of the 95% confidence interval (CI) for the minimal detectable change (MDC) in quadriceps strength (29 Nm) determined in a previous study. 2 × 2 functional analyses of variance were used to evaluate the effects of group (responders and non-responders) and time (baseline and 4-weeks) on time-normalized waveforms for knee flexion angle (KFA), vertical ground reaction force (vGRF), and internal knee extension moment (KEM). Results: A significant group x time interaction for KFA demonstrated greater KFA in the first half of stance at baseline and greater knee extension in the second half of stance at 4-weeks in responders compared to non-responders. There was no significant group x time interaction for vGRF or internal KEM. Conclusions: Quadriceps strengthening may be used to stimulate small changes in KFA in individuals with KOA. © 2019 Osteoarthritis Research Society International
801 a24333330300 Seeley M.K. p236 False Journal 155 Sagittal plane walking biomechanics in individuals with knee osteoarthritis after quadriceps strengthening Objective: To compare sagittal walking gait biomechanics between participants with knee osteoarthritis (KOA) who increased quadriceps strength following a lower-extremity strengthening intervention (responders) and those who did not increase strength following the same strengthening protocol (non-responders) both at baseline and following the lower extremity strengthening protocol. Design: Fifty-three participants with radiographic KOA (47% female, 62.3 ± 7.1 years, BMI = 28.5 ± 3.9 kg/m 2 ) were enrolled in 10 sessions of lower extremity strengthening over a 28-day period. Maximum isometric quadriceps strength and walking gait biomechanics were collected on the involved limb at baseline and 4-weeks following the strengthening intervention. Responders were classified as individuals who increased quadriceps strength greater than the upper limit of the 95% confidence interval (CI) for the minimal detectable change (MDC) in quadriceps strength (29 Nm) determined in a previous study. 2 × 2 functional analyses of variance were used to evaluate the effects of group (responders and non-responders) and time (baseline and 4-weeks) on time-normalized waveforms for knee flexion angle (KFA), vertical ground reaction force (vGRF), and internal knee extension moment (KEM). Results: A significant group x time interaction for KFA demonstrated greater KFA in the first half of stance at baseline and greater knee extension in the second half of stance at 4-weeks in responders compared to non-responders. There was no significant group x time interaction for vGRF or internal KEM. Conclusions: Quadriceps strengthening may be used to stimulate small changes in KFA in individuals with KOA. © 2019 Osteoarthritis Research Society International
801 a24333330300 Seeley M.K. p517 False Journal 286 Effect of environmental and material factors on the response of nanocomposite foam impact sensors Nanocomposite foam (NCF) is a multifunctional material that can be used to measure impact. Interactions between the flexible polymer matrix and conductive particles dispersed throughout it produce a voltage signal under dynamic strain, which correlates to the magnitude of impact. Though promising in applications requiring both impact sensing and energy absorption, NCF's voltage response has been observed to suffer from significant signal drift. This paper investigates several causes of variance in the response of NCF sensors to consistent impacts. These effects can be classified into three general types: recoverable transient effects (such as those relating to viscoelasticity or capacitive charging), environmental drift (due to humidity and temperature), and permanent signal decay from material degradation. The motivation for the study arises from various potential repeat-impact applications where periodic recalibration of the sensor would be difficult (such as a gait-tracking insole in use for a marathon event). A cyclic drop testing machine was used to apply consistent impacts to NCF, and drift resulting from each factor (in ranges typical of an insole environment) was experimentally isolated. Models representing each factor's contribution to signal drift are presented. Of the factors investigated, humidity and temperature caused the most significant drift, with permanent material degradation accounting for only minor decay in voltage response. Transient effects were also observed, with a characteristic 'warm-up' (or 'charging') time required for the NCF to achieve steady-state; this phenomenon, and the related 'recovery' time for the material to return to its original state, were determined. The resultant data can be leveraged to implement a correction algorithm or other drift-compensating method to retain an NCF sensor's accuracy in both long and short data collection scenarios. © 2018 IOP Publishing Ltd.
801 a24333330300 Seeley M.K. p546 False Journal 300 Materials selection of flexible open-cell foams in energy absorption applications Foam must be engineered to absorb a particular range of energy in various impact-related applications. Since energy absorption is dependent upon the unique stress-strain response of each foam specimen, it is difficult to quantify analytically; thus, energy absorption cannot be easily compared across materials. Current methods accomplish this using an experimental approach, individually testing foam materials, densities, and geometries to quantify how each influences energy absorption. Such methods require large amounts of time and money to characterize a narrow range of foams. This paper facilitates foam selection by deriving generalized energy absorption material indices. Assuming Euler buckling of columns in the open-cell foam structure, this paper applies equations derived by Maiti et al. to a typical impact scenario wherein the indices are extracted. Using existing Ashby charts, these indices allow polymers to be ranked by the mass and cost each would require as a foamed structure to satisfy specific energy absorption constraints. The presented method allows the energy absorption of a wide range of flexible foams to be compared and relieves the need for extensive factor-specific testing. This method is applied to football helmet foam selection; however, it can be used for many applications where energy absorption is of interest. © 2017 Elsevier Ltd
801 a24333330300 Seeley M.K. p666 False Journal 320 Nano-Composite Foam Sensor System in Football Helmets American football has both the highest rate of concussion incidences as well as the highest number of concussions of all contact sports due to both the number of athletes and nature of the sport. Recent research has linked concussions with long term health complications such as chronic traumatic encephalopathy and early onset Alzheimer’s. Understanding the mechanical characteristics of concussive impacts is critical to help protect athletes from these debilitating diseases and is now possible using helmet-based sensor systems. To date, real time on-field measurement of head impacts has been almost exclusively measured by devices that rely on accelerometers or gyroscopes attached to the player’s helmet, or embedded in a mouth guard. These systems monitor motion of the head or helmet, but do not directly measure impact energy. This paper evaluates the accuracy of a novel, multifunctional foam-based sensor that replaces a portion of the helmet foam to measure impact. All modified helmets were tested using a National Operating Committee Standards for Athletic Equipment-style drop tower with a total of 24 drop tests (4 locations with 6 impact energies). The impacts were evaluated using a headform, instrumented with a tri-axial accelerometer, mounted to a Hybrid III neck assembly. The resultant accelerations were evaluated for both the peak acceleration and the severity indices. These data were then compared to the voltage response from multiple Nano Composite Foam sensors located throughout the helmet. The foam sensor system proved to be accurate in measuring both the HIC and Gadd severity index, as well as peak acceleration while also providing additional details that were previously difficult to obtain, such as impact energy. © 2017, Biomedical Engineering Society.
801 a24333330300 Seeley M.K. p694 False Journal 320 Estimation of 3D Ground Reaction Force Using Nanocomposite Piezo-Responsive Foam Sensors During Walking This paper describes a method for the estimation of the 3D ground reaction force (GRF) during human walking using novel nanocomposite piezo-responsive foam (NCPF) sensors. Nine subjects (5 male, 4 female) walked on a force-instrumented treadmill at 1.34 m/s for 120 s each while wearing a shoe that was instrumented with four NCPF sensors. GRF data, measured via the treadmill, and sensor data, measured via the NCPF inserts, were used in a tenfold cross validation process to calibrate a separate model for each individual. The calibration model estimated average anterior–posterior, mediolateral and vertical GRF with mean average errors (MAE) of 6.52 N (2.14%), 4.79 N (6.34%), and 15.4 N (2.15%), respectively. Two additional models were created using the sensor data from all subjects and subject demographics. A tenfold cross validation process for this combined data set resulted in models that estimated average anterior–posterior, mediolateral and vertical GRF with less than 8.16 N (2.41%), 6.63 N (7.37%), and 19.4 N (2.31%) errors, respectively. Intra-subject estimates based on the model had a higher accuracy than inter-subject estimates, likely due to the relatively small subject cohort used in creating the model. The novel NCPF sensors demonstrate the ability to accurately estimate 3D GRF during human movement outside of the traditional biomechanics laboratory setting. © 2017, Biomedical Engineering Society.
802 a57189382200 Troy Blackburn J. p236 False Journal 155 Sagittal plane walking biomechanics in individuals with knee osteoarthritis after quadriceps strengthening Objective: To compare sagittal walking gait biomechanics between participants with knee osteoarthritis (KOA) who increased quadriceps strength following a lower-extremity strengthening intervention (responders) and those who did not increase strength following the same strengthening protocol (non-responders) both at baseline and following the lower extremity strengthening protocol. Design: Fifty-three participants with radiographic KOA (47% female, 62.3 ± 7.1 years, BMI = 28.5 ± 3.9 kg/m 2 ) were enrolled in 10 sessions of lower extremity strengthening over a 28-day period. Maximum isometric quadriceps strength and walking gait biomechanics were collected on the involved limb at baseline and 4-weeks following the strengthening intervention. Responders were classified as individuals who increased quadriceps strength greater than the upper limit of the 95% confidence interval (CI) for the minimal detectable change (MDC) in quadriceps strength (29 Nm) determined in a previous study. 2 × 2 functional analyses of variance were used to evaluate the effects of group (responders and non-responders) and time (baseline and 4-weeks) on time-normalized waveforms for knee flexion angle (KFA), vertical ground reaction force (vGRF), and internal knee extension moment (KEM). Results: A significant group x time interaction for KFA demonstrated greater KFA in the first half of stance at baseline and greater knee extension in the second half of stance at 4-weeks in responders compared to non-responders. There was no significant group x time interaction for vGRF or internal KEM. Conclusions: Quadriceps strengthening may be used to stimulate small changes in KFA in individuals with KOA. © 2019 Osteoarthritis Research Society International
803 a57203250533 Pietrosimone B. p236 False Journal 155 Sagittal plane walking biomechanics in individuals with knee osteoarthritis after quadriceps strengthening Objective: To compare sagittal walking gait biomechanics between participants with knee osteoarthritis (KOA) who increased quadriceps strength following a lower-extremity strengthening intervention (responders) and those who did not increase strength following the same strengthening protocol (non-responders) both at baseline and following the lower extremity strengthening protocol. Design: Fifty-three participants with radiographic KOA (47% female, 62.3 ± 7.1 years, BMI = 28.5 ± 3.9 kg/m 2 ) were enrolled in 10 sessions of lower extremity strengthening over a 28-day period. Maximum isometric quadriceps strength and walking gait biomechanics were collected on the involved limb at baseline and 4-weeks following the strengthening intervention. Responders were classified as individuals who increased quadriceps strength greater than the upper limit of the 95% confidence interval (CI) for the minimal detectable change (MDC) in quadriceps strength (29 Nm) determined in a previous study. 2 × 2 functional analyses of variance were used to evaluate the effects of group (responders and non-responders) and time (baseline and 4-weeks) on time-normalized waveforms for knee flexion angle (KFA), vertical ground reaction force (vGRF), and internal knee extension moment (KEM). Results: A significant group x time interaction for KFA demonstrated greater KFA in the first half of stance at baseline and greater knee extension in the second half of stance at 4-weeks in responders compared to non-responders. There was no significant group x time interaction for vGRF or internal KEM. Conclusions: Quadriceps strengthening may be used to stimulate small changes in KFA in individuals with KOA. © 2019 Osteoarthritis Research Society International
804 a57203957449 Teng J. p237 True Journal 156 Recognition of Chinese food using convolutional neural network Food recognition is the first step for dietary assessment. Computer vision technology is being viewed as an effective tool for automatic food recognition for monitoring nutrition intake. Of the many food recognition algorithms in the literature, Bag-of-Features model is a proven approach that has shown impressive recognition accuracy. In this paper, we propose a small and efficient convolutional neural network architecture for Chinese food recognition, which is more applicable for resources limited platforms. Our network architecture is designed to model and perform a pipeline of processing similar to the Bag-of-Features approach. The main advantage of the proposed architecture, like other convolutional neural networks, is its ability to unifiedly optimize the entire network through back propagation, which is critical to recognition accuracy. We further compare and correlate our architecture with the traditional Bag-of-Features model in an attempt to investigate the similarities between them and identify factors that influence the recognition accuracy. The proposed architecture with a 5-layer deep convolutional neural network achieves the top-1 accuracy of 97.12% and the top-5 accuracy of 99.86% on a newly created Chinese food image dataset that is composed of 8734 images of 25 food categories. Our experimental result demonstrates the feasibility of applying the proposed compact CNN architecture to a challenging problem and achieve real-time performance. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.
805 a55247719300 Jain A. p239 True Conference 57 Optofluidic Platform with Integrated Optical Waveguides and Sample Preparation for Digitized Detection of Nucleic Acid Targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s) 2019 OSA.
805 a55247719300 Jain A. p378 True Conference 137 Optofluidic platform with integrated optical waveguides and sample preparation for digitized detection of nucleic acid targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s)
805 a55247719300 Jain A. p407 False Journal 217 Integration of sample preparation and analysis into an optofluidic chip for multi-target disease detection Detection of molecular biomarkers with high specificity and sensitivity from biological samples requires both sophisticated sample preparation and subsequent analysis. These tasks are often carried out on separate platforms which increases required sample volumes and the risk of errors, sample loss, and contamination. Here, we present an optofluidic platform which combines an optical detection section with single nucleic acid strand sensitivity, and a sample processing unit capable of on-chip, specific extraction and labeling of nucleic acid and protein targets in complex biological matrices. First, on-chip labeling and detection of individual lambda DNA molecules down to concentrations of 8 fM is demonstrated. Subsequently, we demonstrate the simultaneous capture, fluorescence tagging and detection of both Zika specific nucleic acid and NS-1 protein targets in both buffer and human serum. We show that the dual DNA and protein assay allows for successful differentiation and diagnosis of Zika against cross-reacting species like dengue. © The Royal Society of Chemistry 2018.
805 a55247719300 Jain A. p840 False Conference 367 Multimodal multiplexing of single-virus detection using multi-mode interference waveguides Multi-mode interference waveguides are used to implement simultaneous spectral and spatial multiplex fluorescence analysis in liquid-core waveguide channels. A six-times multiplex identification of single influenza viruses is demonstrated with two excitation colors and threechannels. © 2017 OSA.
806 a56871132500 Stambaugh A. p239 False Conference 57 Optofluidic Platform with Integrated Optical Waveguides and Sample Preparation for Digitized Detection of Nucleic Acid Targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s) 2019 OSA.
806 a56871132500 Stambaugh A. p378 False Conference 137 Optofluidic platform with integrated optical waveguides and sample preparation for digitized detection of nucleic acid targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s)
806 a56871132500 Stambaugh A. p407 False Journal 217 Integration of sample preparation and analysis into an optofluidic chip for multi-target disease detection Detection of molecular biomarkers with high specificity and sensitivity from biological samples requires both sophisticated sample preparation and subsequent analysis. These tasks are often carried out on separate platforms which increases required sample volumes and the risk of errors, sample loss, and contamination. Here, we present an optofluidic platform which combines an optical detection section with single nucleic acid strand sensitivity, and a sample processing unit capable of on-chip, specific extraction and labeling of nucleic acid and protein targets in complex biological matrices. First, on-chip labeling and detection of individual lambda DNA molecules down to concentrations of 8 fM is demonstrated. Subsequently, we demonstrate the simultaneous capture, fluorescence tagging and detection of both Zika specific nucleic acid and NS-1 protein targets in both buffer and human serum. We show that the dual DNA and protein assay allows for successful differentiation and diagnosis of Zika against cross-reacting species like dengue. © The Royal Society of Chemistry 2018.
807 a7402407628 Patterson J.L. p239 False Conference 57 Optofluidic Platform with Integrated Optical Waveguides and Sample Preparation for Digitized Detection of Nucleic Acid Targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s) 2019 OSA.
807 a7402407628 Patterson J.L. p378 False Conference 137 Optofluidic platform with integrated optical waveguides and sample preparation for digitized detection of nucleic acid targets An architecture of sensitive solid-core and liquid-core optical waveguides are integrated with a pneumatic valve array on a single optofluidic platform to enable specific capture, labeling and detection of single nucleic acid strands using barcode fluorescence reporters. © 2019 The Author(s)
807 a7402407628 Patterson J.L. p407 False Journal 217 Integration of sample preparation and analysis into an optofluidic chip for multi-target disease detection Detection of molecular biomarkers with high specificity and sensitivity from biological samples requires both sophisticated sample preparation and subsequent analysis. These tasks are often carried out on separate platforms which increases required sample volumes and the risk of errors, sample loss, and contamination. Here, we present an optofluidic platform which combines an optical detection section with single nucleic acid strand sensitivity, and a sample processing unit capable of on-chip, specific extraction and labeling of nucleic acid and protein targets in complex biological matrices. First, on-chip labeling and detection of individual lambda DNA molecules down to concentrations of 8 fM is demonstrated. Subsequently, we demonstrate the simultaneous capture, fluorescence tagging and detection of both Zika specific nucleic acid and NS-1 protein targets in both buffer and human serum. We show that the dual DNA and protein assay allows for successful differentiation and diagnosis of Zika against cross-reacting species like dengue. © The Royal Society of Chemistry 2018.
807 a7402407628 Patterson J.L. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
808 a57210286057 Dryer Z. p240 True Conference 58 Full-Duplex Jamming for Enhanced Hidden-Key Secrecy This paper presents a practical physical-layer security scheme based on coding methodologies combined with self-jamming to combat advantaged eavesdroppers, i.e., eavesdroppers that may possess an equal or even better channel than the legitimate receiver. We introduce a strengthened security gap notion, where reliability is assured by typical bit-error rate (BER) measurements, but secrecy is guaranteed by considering the entire distribution of messages upon reception, instead of average measures. Relying on this new security gap notion, we then propose a scheme that combines concatenated coding with self-jamming by the legitimate receiver for effective security and reliability even when eavesdroppers possess a channel with equal or better conditions than the legitimate receiver. © 2019 IEEE.
809 a57210287346 Nickerl A. p240 False Conference 58 Full-Duplex Jamming for Enhanced Hidden-Key Secrecy This paper presents a practical physical-layer security scheme based on coding methodologies combined with self-jamming to combat advantaged eavesdroppers, i.e., eavesdroppers that may possess an equal or even better channel than the legitimate receiver. We introduce a strengthened security gap notion, where reliability is assured by typical bit-error rate (BER) measurements, but secrecy is guaranteed by considering the entire distribution of messages upon reception, instead of average measures. Relying on this new security gap notion, we then propose a scheme that combines concatenated coding with self-jamming by the legitimate receiver for effective security and reliability even when eavesdroppers possess a channel with equal or better conditions than the legitimate receiver. © 2019 IEEE.
810 a57210288854 Carreira M. p241 True Conference 59 Adaptive Physical-Layer Security Through Punctured Coding for Secrecy We propose a coding methodology for physical layer security with adaptive characteristics, whereby adaptive we mean that the system must be tunable to different operational points/signal-to-noise ratio levels of both the legitimate receiver and the eavesdropper. Based on interleaving and scrambling as techniques that shuffle the original message before transmission, we consider puncturing over an interleaving/scrambling key and/or over the message as a mechanism to provide the required adaptability to channel conditions. The proposed techniques have shown suitable adaptability to different channel quality levels of the legitimate receiver and eavesdropper, while still guaranteeing the desired reliability for the legitimate receiver and secrecy against the eavesdropper. © 2019 IEEE.
811 a57214559823 Monteiro T. p241 False Conference 59 Adaptive Physical-Layer Security Through Punctured Coding for Secrecy We propose a coding methodology for physical layer security with adaptive characteristics, whereby adaptive we mean that the system must be tunable to different operational points/signal-to-noise ratio levels of both the legitimate receiver and the eavesdropper. Based on interleaving and scrambling as techniques that shuffle the original message before transmission, we consider puncturing over an interleaving/scrambling key and/or over the message as a mechanism to provide the required adaptability to channel conditions. The proposed techniques have shown suitable adaptability to different channel quality levels of the legitimate receiver and eavesdropper, while still guaranteeing the desired reliability for the legitimate receiver and secrecy against the eavesdropper. © 2019 IEEE.
812 a6602749964 Gibby W. p242 True Journal 158 The use of a binary chelate formulation: Could gadolinium based linear contrast agents be rescued by the addition of zinc selective chelates? Tissue and bone retention of gadolinium based contrast agents (GBCAs) has become a clinical concern because of the potential short and long term toxic effects of free gadolinium. This is a critical problem for most open-chain agents that more readily transmetallate in vivo, in comparison to macrocyclic compounds. Gadolinium diethylene tri-aminepentaacetic acid bis-glucosamide (Gd-DTPA-BIGA) is an experimental, open-chain contrast agent which has a significantly increased relaxivity coefficient in comparison to other GBCAs. This results in greater signal intensity and improved contrast enhancement. These superior imaging qualities initiated a search for a solution to the transmetallation of this agent. Plasma zinc is a well-known GBCA transmettalation agent. Since the base chelate of Gadodiamide (Gd-DPTA-Bis-Methylamide or Omniscan), DTPA-Bis-Methylamide (DTPA-BMA), readily transmettalates with and binds serum zinc, we hypothesized that a plasma “zinc sink,” may significantly reduce transmetallation of linear agents. 5% DTPA-BMA was added to a formulation of Gd-DTPA-BIGA, which was tested against the original formulation of Gd-DTPA-BIGA with 0.2% of the base chelate DTPA-BIGA. These formulations, including gadodiamide, were labeled with 153 GdCl 3 followed by infusion into cohorts of Sprague Dawley rats which were sacrificed at 1, 30 and 60 days. Internal organs were harvested, along with blood, skin and femur, and analyzed for residual gadolinium. A subset of tissues were also interrogated with ICP-MS. Labeled Gadodiamide and saline where used as controls. Conclusion: The addition of 5% DTPA-BMA, as a zinc binding agent, reduced the transmetallation of the linear agent Gd-DTPA-BIGA, in comparison to its original formulation supplemented with 0.2% BIGA. This result indicates that supplementing linear GBCAs with ancillary chelates may hold promise for reducing, or eliminating the biological archiving of gadolinium in tissues. In addition, this paper provides valuable animal data on the long term retention of gadolinium from linear based contrast agents. © 2019 Elsevier Inc.
813 a57205512220 Parish W. p242 False Journal 158 The use of a binary chelate formulation: Could gadolinium based linear contrast agents be rescued by the addition of zinc selective chelates? Tissue and bone retention of gadolinium based contrast agents (GBCAs) has become a clinical concern because of the potential short and long term toxic effects of free gadolinium. This is a critical problem for most open-chain agents that more readily transmetallate in vivo, in comparison to macrocyclic compounds. Gadolinium diethylene tri-aminepentaacetic acid bis-glucosamide (Gd-DTPA-BIGA) is an experimental, open-chain contrast agent which has a significantly increased relaxivity coefficient in comparison to other GBCAs. This results in greater signal intensity and improved contrast enhancement. These superior imaging qualities initiated a search for a solution to the transmetallation of this agent. Plasma zinc is a well-known GBCA transmettalation agent. Since the base chelate of Gadodiamide (Gd-DPTA-Bis-Methylamide or Omniscan), DTPA-Bis-Methylamide (DTPA-BMA), readily transmettalates with and binds serum zinc, we hypothesized that a plasma “zinc sink,” may significantly reduce transmetallation of linear agents. 5% DTPA-BMA was added to a formulation of Gd-DTPA-BIGA, which was tested against the original formulation of Gd-DTPA-BIGA with 0.2% of the base chelate DTPA-BIGA. These formulations, including gadodiamide, were labeled with 153 GdCl 3 followed by infusion into cohorts of Sprague Dawley rats which were sacrificed at 1, 30 and 60 days. Internal organs were harvested, along with blood, skin and femur, and analyzed for residual gadolinium. A subset of tissues were also interrogated with ICP-MS. Labeled Gadodiamide and saline where used as controls. Conclusion: The addition of 5% DTPA-BMA, as a zinc binding agent, reduced the transmetallation of the linear agent Gd-DTPA-BIGA, in comparison to its original formulation supplemented with 0.2% BIGA. This result indicates that supplementing linear GBCAs with ancillary chelates may hold promise for reducing, or eliminating the biological archiving of gadolinium in tissues. In addition, this paper provides valuable animal data on the long term retention of gadolinium from linear based contrast agents. © 2019 Elsevier Inc.
814 a7102985794 Merrill R.M. p242 False Journal 158 The use of a binary chelate formulation: Could gadolinium based linear contrast agents be rescued by the addition of zinc selective chelates? Tissue and bone retention of gadolinium based contrast agents (GBCAs) has become a clinical concern because of the potential short and long term toxic effects of free gadolinium. This is a critical problem for most open-chain agents that more readily transmetallate in vivo, in comparison to macrocyclic compounds. Gadolinium diethylene tri-aminepentaacetic acid bis-glucosamide (Gd-DTPA-BIGA) is an experimental, open-chain contrast agent which has a significantly increased relaxivity coefficient in comparison to other GBCAs. This results in greater signal intensity and improved contrast enhancement. These superior imaging qualities initiated a search for a solution to the transmetallation of this agent. Plasma zinc is a well-known GBCA transmettalation agent. Since the base chelate of Gadodiamide (Gd-DPTA-Bis-Methylamide or Omniscan), DTPA-Bis-Methylamide (DTPA-BMA), readily transmettalates with and binds serum zinc, we hypothesized that a plasma “zinc sink,” may significantly reduce transmetallation of linear agents. 5% DTPA-BMA was added to a formulation of Gd-DTPA-BIGA, which was tested against the original formulation of Gd-DTPA-BIGA with 0.2% of the base chelate DTPA-BIGA. These formulations, including gadodiamide, were labeled with 153 GdCl 3 followed by infusion into cohorts of Sprague Dawley rats which were sacrificed at 1, 30 and 60 days. Internal organs were harvested, along with blood, skin and femur, and analyzed for residual gadolinium. A subset of tissues were also interrogated with ICP-MS. Labeled Gadodiamide and saline where used as controls. Conclusion: The addition of 5% DTPA-BMA, as a zinc binding agent, reduced the transmetallation of the linear agent Gd-DTPA-BIGA, in comparison to its original formulation supplemented with 0.2% BIGA. This result indicates that supplementing linear GBCAs with ancillary chelates may hold promise for reducing, or eliminating the biological archiving of gadolinium in tissues. In addition, this paper provides valuable animal data on the long term retention of gadolinium from linear based contrast agents. © 2019 Elsevier Inc.
814 a7102985794 Merrill R.M. p698 False Journal 341 Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
815 a9739395200 Fernandez D. p242 False Journal 158 The use of a binary chelate formulation: Could gadolinium based linear contrast agents be rescued by the addition of zinc selective chelates? Tissue and bone retention of gadolinium based contrast agents (GBCAs) has become a clinical concern because of the potential short and long term toxic effects of free gadolinium. This is a critical problem for most open-chain agents that more readily transmetallate in vivo, in comparison to macrocyclic compounds. Gadolinium diethylene tri-aminepentaacetic acid bis-glucosamide (Gd-DTPA-BIGA) is an experimental, open-chain contrast agent which has a significantly increased relaxivity coefficient in comparison to other GBCAs. This results in greater signal intensity and improved contrast enhancement. These superior imaging qualities initiated a search for a solution to the transmetallation of this agent. Plasma zinc is a well-known GBCA transmettalation agent. Since the base chelate of Gadodiamide (Gd-DPTA-Bis-Methylamide or Omniscan), DTPA-Bis-Methylamide (DTPA-BMA), readily transmettalates with and binds serum zinc, we hypothesized that a plasma “zinc sink,” may significantly reduce transmetallation of linear agents. 5% DTPA-BMA was added to a formulation of Gd-DTPA-BIGA, which was tested against the original formulation of Gd-DTPA-BIGA with 0.2% of the base chelate DTPA-BIGA. These formulations, including gadodiamide, were labeled with 153 GdCl 3 followed by infusion into cohorts of Sprague Dawley rats which were sacrificed at 1, 30 and 60 days. Internal organs were harvested, along with blood, skin and femur, and analyzed for residual gadolinium. A subset of tissues were also interrogated with ICP-MS. Labeled Gadodiamide and saline where used as controls. Conclusion: The addition of 5% DTPA-BMA, as a zinc binding agent, reduced the transmetallation of the linear agent Gd-DTPA-BIGA, in comparison to its original formulation supplemented with 0.2% BIGA. This result indicates that supplementing linear GBCAs with ancillary chelates may hold promise for reducing, or eliminating the biological archiving of gadolinium in tissues. In addition, this paper provides valuable animal data on the long term retention of gadolinium from linear based contrast agents. © 2019 Elsevier Inc.
816 a57202736299 Anderson C.R. p242 False Journal 158 The use of a binary chelate formulation: Could gadolinium based linear contrast agents be rescued by the addition of zinc selective chelates? Tissue and bone retention of gadolinium based contrast agents (GBCAs) has become a clinical concern because of the potential short and long term toxic effects of free gadolinium. This is a critical problem for most open-chain agents that more readily transmetallate in vivo, in comparison to macrocyclic compounds. Gadolinium diethylene tri-aminepentaacetic acid bis-glucosamide (Gd-DTPA-BIGA) is an experimental, open-chain contrast agent which has a significantly increased relaxivity coefficient in comparison to other GBCAs. This results in greater signal intensity and improved contrast enhancement. These superior imaging qualities initiated a search for a solution to the transmetallation of this agent. Plasma zinc is a well-known GBCA transmettalation agent. Since the base chelate of Gadodiamide (Gd-DPTA-Bis-Methylamide or Omniscan), DTPA-Bis-Methylamide (DTPA-BMA), readily transmettalates with and binds serum zinc, we hypothesized that a plasma “zinc sink,” may significantly reduce transmetallation of linear agents. 5% DTPA-BMA was added to a formulation of Gd-DTPA-BIGA, which was tested against the original formulation of Gd-DTPA-BIGA with 0.2% of the base chelate DTPA-BIGA. These formulations, including gadodiamide, were labeled with 153 GdCl 3 followed by infusion into cohorts of Sprague Dawley rats which were sacrificed at 1, 30 and 60 days. Internal organs were harvested, along with blood, skin and femur, and analyzed for residual gadolinium. A subset of tissues were also interrogated with ICP-MS. Labeled Gadodiamide and saline where used as controls. Conclusion: The addition of 5% DTPA-BMA, as a zinc binding agent, reduced the transmetallation of the linear agent Gd-DTPA-BIGA, in comparison to its original formulation supplemented with 0.2% BIGA. This result indicates that supplementing linear GBCAs with ancillary chelates may hold promise for reducing, or eliminating the biological archiving of gadolinium in tissues. In addition, this paper provides valuable animal data on the long term retention of gadolinium from linear based contrast agents. © 2019 Elsevier Inc.
817 a57205515588 Merchel E. p242 False Journal 158 The use of a binary chelate formulation: Could gadolinium based linear contrast agents be rescued by the addition of zinc selective chelates? Tissue and bone retention of gadolinium based contrast agents (GBCAs) has become a clinical concern because of the potential short and long term toxic effects of free gadolinium. This is a critical problem for most open-chain agents that more readily transmetallate in vivo, in comparison to macrocyclic compounds. Gadolinium diethylene tri-aminepentaacetic acid bis-glucosamide (Gd-DTPA-BIGA) is an experimental, open-chain contrast agent which has a significantly increased relaxivity coefficient in comparison to other GBCAs. This results in greater signal intensity and improved contrast enhancement. These superior imaging qualities initiated a search for a solution to the transmetallation of this agent. Plasma zinc is a well-known GBCA transmettalation agent. Since the base chelate of Gadodiamide (Gd-DPTA-Bis-Methylamide or Omniscan), DTPA-Bis-Methylamide (DTPA-BMA), readily transmettalates with and binds serum zinc, we hypothesized that a plasma “zinc sink,” may significantly reduce transmetallation of linear agents. 5% DTPA-BMA was added to a formulation of Gd-DTPA-BIGA, which was tested against the original formulation of Gd-DTPA-BIGA with 0.2% of the base chelate DTPA-BIGA. These formulations, including gadodiamide, were labeled with 153 GdCl 3 followed by infusion into cohorts of Sprague Dawley rats which were sacrificed at 1, 30 and 60 days. Internal organs were harvested, along with blood, skin and femur, and analyzed for residual gadolinium. A subset of tissues were also interrogated with ICP-MS. Labeled Gadodiamide and saline where used as controls. Conclusion: The addition of 5% DTPA-BMA, as a zinc binding agent, reduced the transmetallation of the linear agent Gd-DTPA-BIGA, in comparison to its original formulation supplemented with 0.2% BIGA. This result indicates that supplementing linear GBCAs with ancillary chelates may hold promise for reducing, or eliminating the biological archiving of gadolinium in tissues. In addition, this paper provides valuable animal data on the long term retention of gadolinium from linear based contrast agents. © 2019 Elsevier Inc.
818 a57205514839 Parr R. p242 False Journal 158 The use of a binary chelate formulation: Could gadolinium based linear contrast agents be rescued by the addition of zinc selective chelates? Tissue and bone retention of gadolinium based contrast agents (GBCAs) has become a clinical concern because of the potential short and long term toxic effects of free gadolinium. This is a critical problem for most open-chain agents that more readily transmetallate in vivo, in comparison to macrocyclic compounds. Gadolinium diethylene tri-aminepentaacetic acid bis-glucosamide (Gd-DTPA-BIGA) is an experimental, open-chain contrast agent which has a significantly increased relaxivity coefficient in comparison to other GBCAs. This results in greater signal intensity and improved contrast enhancement. These superior imaging qualities initiated a search for a solution to the transmetallation of this agent. Plasma zinc is a well-known GBCA transmettalation agent. Since the base chelate of Gadodiamide (Gd-DPTA-Bis-Methylamide or Omniscan), DTPA-Bis-Methylamide (DTPA-BMA), readily transmettalates with and binds serum zinc, we hypothesized that a plasma “zinc sink,” may significantly reduce transmetallation of linear agents. 5% DTPA-BMA was added to a formulation of Gd-DTPA-BIGA, which was tested against the original formulation of Gd-DTPA-BIGA with 0.2% of the base chelate DTPA-BIGA. These formulations, including gadodiamide, were labeled with 153 GdCl 3 followed by infusion into cohorts of Sprague Dawley rats which were sacrificed at 1, 30 and 60 days. Internal organs were harvested, along with blood, skin and femur, and analyzed for residual gadolinium. A subset of tissues were also interrogated with ICP-MS. Labeled Gadodiamide and saline where used as controls. Conclusion: The addition of 5% DTPA-BMA, as a zinc binding agent, reduced the transmetallation of the linear agent Gd-DTPA-BIGA, in comparison to its original formulation supplemented with 0.2% BIGA. This result indicates that supplementing linear GBCAs with ancillary chelates may hold promise for reducing, or eliminating the biological archiving of gadolinium in tissues. In addition, this paper provides valuable animal data on the long term retention of gadolinium from linear based contrast agents. © 2019 Elsevier Inc.
819 a57194392244 Hicks D. p244 True Journal 159 The AFLOW Library of Crystallographic Prototypes: Part 2 Materials discovery via high-throughput methods relies on the availability of structural prototypes, which are generally decorated with varying combinations of elements to produce potential new materials. To facilitate the automatic generation of these materials, we developed The AFLOW Library of Crystallographic Prototypes — a collection of crystal prototypes that can be rapidly decorated using the AFLOW software. Part 2 of this work introduces an additional 302 crystal structure prototypes, including at least one from each of the 138 space groups not included in Part 1. Combined with Part 1, the entire library consists of 590 unique crystallographic prototypes covering all 230 space groups. We also present discussions of enantiomorphic space groups, Wigner-Seitz cells, the two-dimensional plane groups, and the various different space group notations used throughout crystallography. All structures — from both Part 1 and Part 2 — are listed in the web version of the library available at http://www.aflow.org/CrystalDatabase. © 2018 Elsevier B.V.
819 a57194392244 Hicks D. p714 False Journal 349 The AFLOW Library of Crystallographic Prototypes: Part 1 An easily available resource of common crystal structures is essential for researchers, teachers, and students. For many years this was provided by the U.S. Naval Research Laboratory's Crystal Lattice Structures web page, which contained nearly 300 crystal structures, including a majority of those which were given Strukturbericht designations. This article presents the updated version of the database, now including 288 standardized structures in 92 space groups. Similar to what was available on the web page before, we present a complete description of each structure, including the formulas for the primitive vectors, all of the basis vectors, and the AFLOW commands to generate the standardized cells. We also present a brief discussion of crystal systems, space groups, primitive and conventional lattices, Wyckoff positions, Pearson symbols and Strukturbericht designations. The web version of this database is located at http://aflow.org/CrystalDatabase. © 2017 Elsevier B.V.
820 a7006214218 Mehl M.J. p244 False Journal 159 The AFLOW Library of Crystallographic Prototypes: Part 2 Materials discovery via high-throughput methods relies on the availability of structural prototypes, which are generally decorated with varying combinations of elements to produce potential new materials. To facilitate the automatic generation of these materials, we developed The AFLOW Library of Crystallographic Prototypes — a collection of crystal prototypes that can be rapidly decorated using the AFLOW software. Part 2 of this work introduces an additional 302 crystal structure prototypes, including at least one from each of the 138 space groups not included in Part 1. Combined with Part 1, the entire library consists of 590 unique crystallographic prototypes covering all 230 space groups. We also present discussions of enantiomorphic space groups, Wigner-Seitz cells, the two-dimensional plane groups, and the various different space group notations used throughout crystallography. All structures — from both Part 1 and Part 2 — are listed in the web version of the library available at http://www.aflow.org/CrystalDatabase. © 2018 Elsevier B.V.
820 a7006214218 Mehl M.J. p714 True Journal 349 The AFLOW Library of Crystallographic Prototypes: Part 1 An easily available resource of common crystal structures is essential for researchers, teachers, and students. For many years this was provided by the U.S. Naval Research Laboratory's Crystal Lattice Structures web page, which contained nearly 300 crystal structures, including a majority of those which were given Strukturbericht designations. This article presents the updated version of the database, now including 288 standardized structures in 92 space groups. Similar to what was available on the web page before, we present a complete description of each structure, including the formulas for the primitive vectors, all of the basis vectors, and the AFLOW commands to generate the standardized cells. We also present a brief discussion of crystal systems, space groups, primitive and conventional lattices, Wyckoff positions, Pearson symbols and Strukturbericht designations. The web version of this database is located at http://aflow.org/CrystalDatabase. © 2017 Elsevier B.V.
821 a57194503011 Gossett E. p244 False Journal 159 The AFLOW Library of Crystallographic Prototypes: Part 2 Materials discovery via high-throughput methods relies on the availability of structural prototypes, which are generally decorated with varying combinations of elements to produce potential new materials. To facilitate the automatic generation of these materials, we developed The AFLOW Library of Crystallographic Prototypes — a collection of crystal prototypes that can be rapidly decorated using the AFLOW software. Part 2 of this work introduces an additional 302 crystal structure prototypes, including at least one from each of the 138 space groups not included in Part 1. Combined with Part 1, the entire library consists of 590 unique crystallographic prototypes covering all 230 space groups. We also present discussions of enantiomorphic space groups, Wigner-Seitz cells, the two-dimensional plane groups, and the various different space group notations used throughout crystallography. All structures — from both Part 1 and Part 2 — are listed in the web version of the library available at http://www.aflow.org/CrystalDatabase. © 2018 Elsevier B.V.
822 a9845705900 Toher C. p244 False Journal 159 The AFLOW Library of Crystallographic Prototypes: Part 2 Materials discovery via high-throughput methods relies on the availability of structural prototypes, which are generally decorated with varying combinations of elements to produce potential new materials. To facilitate the automatic generation of these materials, we developed The AFLOW Library of Crystallographic Prototypes — a collection of crystal prototypes that can be rapidly decorated using the AFLOW software. Part 2 of this work introduces an additional 302 crystal structure prototypes, including at least one from each of the 138 space groups not included in Part 1. Combined with Part 1, the entire library consists of 590 unique crystallographic prototypes covering all 230 space groups. We also present discussions of enantiomorphic space groups, Wigner-Seitz cells, the two-dimensional plane groups, and the various different space group notations used throughout crystallography. All structures — from both Part 1 and Part 2 — are listed in the web version of the library available at http://www.aflow.org/CrystalDatabase. © 2018 Elsevier B.V.
822 a9845705900 Toher C. p714 False Journal 349 The AFLOW Library of Crystallographic Prototypes: Part 1 An easily available resource of common crystal structures is essential for researchers, teachers, and students. For many years this was provided by the U.S. Naval Research Laboratory's Crystal Lattice Structures web page, which contained nearly 300 crystal structures, including a majority of those which were given Strukturbericht designations. This article presents the updated version of the database, now including 288 standardized structures in 92 space groups. Similar to what was available on the web page before, we present a complete description of each structure, including the formulas for the primitive vectors, all of the basis vectors, and the AFLOW commands to generate the standardized cells. We also present a brief discussion of crystal systems, space groups, primitive and conventional lattices, Wyckoff positions, Pearson symbols and Strukturbericht designations. The web version of this database is located at http://aflow.org/CrystalDatabase. © 2017 Elsevier B.V.
823 a7004929818 Levy O. p244 False Journal 159 The AFLOW Library of Crystallographic Prototypes: Part 2 Materials discovery via high-throughput methods relies on the availability of structural prototypes, which are generally decorated with varying combinations of elements to produce potential new materials. To facilitate the automatic generation of these materials, we developed The AFLOW Library of Crystallographic Prototypes — a collection of crystal prototypes that can be rapidly decorated using the AFLOW software. Part 2 of this work introduces an additional 302 crystal structure prototypes, including at least one from each of the 138 space groups not included in Part 1. Combined with Part 1, the entire library consists of 590 unique crystallographic prototypes covering all 230 space groups. We also present discussions of enantiomorphic space groups, Wigner-Seitz cells, the two-dimensional plane groups, and the various different space group notations used throughout crystallography. All structures — from both Part 1 and Part 2 — are listed in the web version of the library available at http://www.aflow.org/CrystalDatabase. © 2018 Elsevier B.V.
823 a7004929818 Levy O. p714 False Journal 349 The AFLOW Library of Crystallographic Prototypes: Part 1 An easily available resource of common crystal structures is essential for researchers, teachers, and students. For many years this was provided by the U.S. Naval Research Laboratory's Crystal Lattice Structures web page, which contained nearly 300 crystal structures, including a majority of those which were given Strukturbericht designations. This article presents the updated version of the database, now including 288 standardized structures in 92 space groups. Similar to what was available on the web page before, we present a complete description of each structure, including the formulas for the primitive vectors, all of the basis vectors, and the AFLOW commands to generate the standardized cells. We also present a brief discussion of crystal systems, space groups, primitive and conventional lattices, Wyckoff positions, Pearson symbols and Strukturbericht designations. The web version of this database is located at http://aflow.org/CrystalDatabase. © 2017 Elsevier B.V.
824 a57194379165 Hanson R.M. p244 False Journal 159 The AFLOW Library of Crystallographic Prototypes: Part 2 Materials discovery via high-throughput methods relies on the availability of structural prototypes, which are generally decorated with varying combinations of elements to produce potential new materials. To facilitate the automatic generation of these materials, we developed The AFLOW Library of Crystallographic Prototypes — a collection of crystal prototypes that can be rapidly decorated using the AFLOW software. Part 2 of this work introduces an additional 302 crystal structure prototypes, including at least one from each of the 138 space groups not included in Part 1. Combined with Part 1, the entire library consists of 590 unique crystallographic prototypes covering all 230 space groups. We also present discussions of enantiomorphic space groups, Wigner-Seitz cells, the two-dimensional plane groups, and the various different space group notations used throughout crystallography. All structures — from both Part 1 and Part 2 — are listed in the web version of the library available at http://www.aflow.org/CrystalDatabase. © 2018 Elsevier B.V.
824 a57194379165 Hanson R.M. p714 False Journal 349 The AFLOW Library of Crystallographic Prototypes: Part 1 An easily available resource of common crystal structures is essential for researchers, teachers, and students. For many years this was provided by the U.S. Naval Research Laboratory's Crystal Lattice Structures web page, which contained nearly 300 crystal structures, including a majority of those which were given Strukturbericht designations. This article presents the updated version of the database, now including 288 standardized structures in 92 space groups. Similar to what was available on the web page before, we present a complete description of each structure, including the formulas for the primitive vectors, all of the basis vectors, and the AFLOW commands to generate the standardized cells. We also present a brief discussion of crystal systems, space groups, primitive and conventional lattices, Wyckoff positions, Pearson symbols and Strukturbericht designations. The web version of this database is located at http://aflow.org/CrystalDatabase. © 2017 Elsevier B.V.
825 a6603325558 Curtarolo S. p244 False Journal 159 The AFLOW Library of Crystallographic Prototypes: Part 2 Materials discovery via high-throughput methods relies on the availability of structural prototypes, which are generally decorated with varying combinations of elements to produce potential new materials. To facilitate the automatic generation of these materials, we developed The AFLOW Library of Crystallographic Prototypes — a collection of crystal prototypes that can be rapidly decorated using the AFLOW software. Part 2 of this work introduces an additional 302 crystal structure prototypes, including at least one from each of the 138 space groups not included in Part 1. Combined with Part 1, the entire library consists of 590 unique crystallographic prototypes covering all 230 space groups. We also present discussions of enantiomorphic space groups, Wigner-Seitz cells, the two-dimensional plane groups, and the various different space group notations used throughout crystallography. All structures — from both Part 1 and Part 2 — are listed in the web version of the library available at http://www.aflow.org/CrystalDatabase. © 2018 Elsevier B.V.
825 a6603325558 Curtarolo S. p714 False Journal 349 The AFLOW Library of Crystallographic Prototypes: Part 1 An easily available resource of common crystal structures is essential for researchers, teachers, and students. For many years this was provided by the U.S. Naval Research Laboratory's Crystal Lattice Structures web page, which contained nearly 300 crystal structures, including a majority of those which were given Strukturbericht designations. This article presents the updated version of the database, now including 288 standardized structures in 92 space groups. Similar to what was available on the web page before, we present a complete description of each structure, including the formulas for the primitive vectors, all of the basis vectors, and the AFLOW commands to generate the standardized cells. We also present a brief discussion of crystal systems, space groups, primitive and conventional lattices, Wyckoff positions, Pearson symbols and Strukturbericht designations. The web version of this database is located at http://aflow.org/CrystalDatabase. © 2017 Elsevier B.V.
826 a57191586637 Chatterjee S. p245 True Journal 160 Informatics analysis of capillary electropherograms of autologously doped and undoped blood An ‘Autologous Blood Transfusion' (ABT) is the reinjection of blood previously taken from an athlete to increase its oxygen transport capabilities. Despite the World Anti-Doping Agency's ban on such practices, ABT abuse continues. Autologous blood doping (ABD) is challenging to detect because of the similarities between an individual's doped and undoped blood. Recently, Harrison et al. reported that high-speed capillary electrophoresis may identify ABD. In their work, first order derivatives of the electropherograms were used to identify doping. However, this method suffered from false negatives due to the subjective nature of the analysis. Here, we provide an informatics analysis of the data from this study, contrasting the results of traditional statistical methods and less traditional mathematical techniques. First, three well-known multivariate statistical tools: cluster analysis, principal component analysis (PCA), and partial least squares (PLS) are applied to develop calibrations and/or group electropherograms of undoped (0%) and doped (5% and 10%) blood samples. (These doping levels were chosen due to the low physiological effect of doping below 5%, with 10% corresponding to the approximate ‘gain' derived from the transfusion of a single unit of blood into an adult.) Different preprocessing and variable selection methods were considered. Due to variation in the electropherograms and the limited sample size, these methods were inadequate. We next considered four less commonly used mathematical/informatics tools: pattern recognition entropy (PRE), the Euclidean distance between vectors, a peak fitting/integration method, and the second moment (SM). Each of these techniques showed some ability to differentiate between the 0, 5, and 10% doped samples. We then evaluated the prediction capabilities of inverse least squares (ILS) models based on these summary statistics. An ILS calibration based on PRE, the Euclidean distance, and peak fitting/integration proved more successful than the PLS model at predicting levels of blood doping from the corresponding electropherograms; the ILS model distinguished between doped (5% and 10%) and undoped (0%) blood. This methodology may be applicable to other challenging informatics problems like determining risk factors for genetically linked diseases, robust pattern finding in peak-like data such as ChIP-seq, or other genomic sequencing for understanding the 3D genome. © The Royal Society of Chemistry.
827 a57208184650 Chapman S.C. p245 False Journal 160 Informatics analysis of capillary electropherograms of autologously doped and undoped blood An ‘Autologous Blood Transfusion' (ABT) is the reinjection of blood previously taken from an athlete to increase its oxygen transport capabilities. Despite the World Anti-Doping Agency's ban on such practices, ABT abuse continues. Autologous blood doping (ABD) is challenging to detect because of the similarities between an individual's doped and undoped blood. Recently, Harrison et al. reported that high-speed capillary electrophoresis may identify ABD. In their work, first order derivatives of the electropherograms were used to identify doping. However, this method suffered from false negatives due to the subjective nature of the analysis. Here, we provide an informatics analysis of the data from this study, contrasting the results of traditional statistical methods and less traditional mathematical techniques. First, three well-known multivariate statistical tools: cluster analysis, principal component analysis (PCA), and partial least squares (PLS) are applied to develop calibrations and/or group electropherograms of undoped (0%) and doped (5% and 10%) blood samples. (These doping levels were chosen due to the low physiological effect of doping below 5%, with 10% corresponding to the approximate ‘gain' derived from the transfusion of a single unit of blood into an adult.) Different preprocessing and variable selection methods were considered. Due to variation in the electropherograms and the limited sample size, these methods were inadequate. We next considered four less commonly used mathematical/informatics tools: pattern recognition entropy (PRE), the Euclidean distance between vectors, a peak fitting/integration method, and the second moment (SM). Each of these techniques showed some ability to differentiate between the 0, 5, and 10% doped samples. We then evaluated the prediction capabilities of inverse least squares (ILS) models based on these summary statistics. An ILS calibration based on PRE, the Euclidean distance, and peak fitting/integration proved more successful than the PLS model at predicting levels of blood doping from the corresponding electropherograms; the ILS model distinguished between doped (5% and 10%) and undoped (0%) blood. This methodology may be applicable to other challenging informatics problems like determining risk factors for genetically linked diseases, robust pattern finding in peak-like data such as ChIP-seq, or other genomic sequencing for understanding the 3D genome. © The Royal Society of Chemistry.
828 a57189294915 Major G.H. p245 False Journal 160 Informatics analysis of capillary electropherograms of autologously doped and undoped blood An ‘Autologous Blood Transfusion' (ABT) is the reinjection of blood previously taken from an athlete to increase its oxygen transport capabilities. Despite the World Anti-Doping Agency's ban on such practices, ABT abuse continues. Autologous blood doping (ABD) is challenging to detect because of the similarities between an individual's doped and undoped blood. Recently, Harrison et al. reported that high-speed capillary electrophoresis may identify ABD. In their work, first order derivatives of the electropherograms were used to identify doping. However, this method suffered from false negatives due to the subjective nature of the analysis. Here, we provide an informatics analysis of the data from this study, contrasting the results of traditional statistical methods and less traditional mathematical techniques. First, three well-known multivariate statistical tools: cluster analysis, principal component analysis (PCA), and partial least squares (PLS) are applied to develop calibrations and/or group electropherograms of undoped (0%) and doped (5% and 10%) blood samples. (These doping levels were chosen due to the low physiological effect of doping below 5%, with 10% corresponding to the approximate ‘gain' derived from the transfusion of a single unit of blood into an adult.) Different preprocessing and variable selection methods were considered. Due to variation in the electropherograms and the limited sample size, these methods were inadequate. We next considered four less commonly used mathematical/informatics tools: pattern recognition entropy (PRE), the Euclidean distance between vectors, a peak fitting/integration method, and the second moment (SM). Each of these techniques showed some ability to differentiate between the 0, 5, and 10% doped samples. We then evaluated the prediction capabilities of inverse least squares (ILS) models based on these summary statistics. An ILS calibration based on PRE, the Euclidean distance, and peak fitting/integration proved more successful than the PLS model at predicting levels of blood doping from the corresponding electropherograms; the ILS model distinguished between doped (5% and 10%) and undoped (0%) blood. This methodology may be applicable to other challenging informatics problems like determining risk factors for genetically linked diseases, robust pattern finding in peak-like data such as ChIP-seq, or other genomic sequencing for understanding the 3D genome. © The Royal Society of Chemistry.
829 a6701755273 Lunt B.M. p245 False Journal 160 Informatics analysis of capillary electropherograms of autologously doped and undoped blood An ‘Autologous Blood Transfusion' (ABT) is the reinjection of blood previously taken from an athlete to increase its oxygen transport capabilities. Despite the World Anti-Doping Agency's ban on such practices, ABT abuse continues. Autologous blood doping (ABD) is challenging to detect because of the similarities between an individual's doped and undoped blood. Recently, Harrison et al. reported that high-speed capillary electrophoresis may identify ABD. In their work, first order derivatives of the electropherograms were used to identify doping. However, this method suffered from false negatives due to the subjective nature of the analysis. Here, we provide an informatics analysis of the data from this study, contrasting the results of traditional statistical methods and less traditional mathematical techniques. First, three well-known multivariate statistical tools: cluster analysis, principal component analysis (PCA), and partial least squares (PLS) are applied to develop calibrations and/or group electropherograms of undoped (0%) and doped (5% and 10%) blood samples. (These doping levels were chosen due to the low physiological effect of doping below 5%, with 10% corresponding to the approximate ‘gain' derived from the transfusion of a single unit of blood into an adult.) Different preprocessing and variable selection methods were considered. Due to variation in the electropherograms and the limited sample size, these methods were inadequate. We next considered four less commonly used mathematical/informatics tools: pattern recognition entropy (PRE), the Euclidean distance between vectors, a peak fitting/integration method, and the second moment (SM). Each of these techniques showed some ability to differentiate between the 0, 5, and 10% doped samples. We then evaluated the prediction capabilities of inverse least squares (ILS) models based on these summary statistics. An ILS calibration based on PRE, the Euclidean distance, and peak fitting/integration proved more successful than the PLS model at predicting levels of blood doping from the corresponding electropherograms; the ILS model distinguished between doped (5% and 10%) and undoped (0%) blood. This methodology may be applicable to other challenging informatics problems like determining risk factors for genetically linked diseases, robust pattern finding in peak-like data such as ChIP-seq, or other genomic sequencing for understanding the 3D genome. © The Royal Society of Chemistry.
829 a6701755273 Lunt B.M. p482 False Conference 174 A cognitive approach to predicting academic success in computing [No abstract available]
829 a6701755273 Lunt B.M. p493 False Conference 185 Crafting the future of computing education in CC2020: A workshop A consortium of national and international computing and engineering organizations are currently developing a new set of curricular resources titled Computing Curricula 2020 (CC2020). This project, based on its predecessor CC2005, aims to reflect the state-of-the-art in computing education and practice as well as provide insights into the future of the computing educational field for the 2020s and beyond. This workshop provides an overview of the CC2005 and related reports and links them to the transition into the CC2020 project. It also provides participants with a unique opportunity to collaborate with members of the CC2020 task force and contribute to the development of the resources the project will deliver. The workshop authors and participants will engage in activities to help define how Computing is defined within the project and discuss how to extend its influence in global undergraduate computing education for the future. The authors anticipate full audience involvement and participation in formulating this vision. © American Society for Engineering Education, 2018.
829 a6701755273 Lunt B.M. p731 True Conference 312 Technology and design programs During the summer of 2016, visits were undertaken to six post-secondary academic institutions with programs in construction management, industrial design, information technology, manufacturing or mechanical engineering technology, and technology & engineering education. The purpose of these visits was to learn more about how they are structured, their history, their faculty, and other related items. This paper presents findings from these visits, in the areas of types of faculty, teaching loads, enrollment trends, local organization, placement, experiential learning, scholarship & scholarly productivity, industry experience, industry advisory boards, and program accreditation. © American Society for Engineering Education, 2017.
830 a55200909800 Harrison C.R. p245 False Journal 160 Informatics analysis of capillary electropherograms of autologously doped and undoped blood An ‘Autologous Blood Transfusion' (ABT) is the reinjection of blood previously taken from an athlete to increase its oxygen transport capabilities. Despite the World Anti-Doping Agency's ban on such practices, ABT abuse continues. Autologous blood doping (ABD) is challenging to detect because of the similarities between an individual's doped and undoped blood. Recently, Harrison et al. reported that high-speed capillary electrophoresis may identify ABD. In their work, first order derivatives of the electropherograms were used to identify doping. However, this method suffered from false negatives due to the subjective nature of the analysis. Here, we provide an informatics analysis of the data from this study, contrasting the results of traditional statistical methods and less traditional mathematical techniques. First, three well-known multivariate statistical tools: cluster analysis, principal component analysis (PCA), and partial least squares (PLS) are applied to develop calibrations and/or group electropherograms of undoped (0%) and doped (5% and 10%) blood samples. (These doping levels were chosen due to the low physiological effect of doping below 5%, with 10% corresponding to the approximate ‘gain' derived from the transfusion of a single unit of blood into an adult.) Different preprocessing and variable selection methods were considered. Due to variation in the electropherograms and the limited sample size, these methods were inadequate. We next considered four less commonly used mathematical/informatics tools: pattern recognition entropy (PRE), the Euclidean distance between vectors, a peak fitting/integration method, and the second moment (SM). Each of these techniques showed some ability to differentiate between the 0, 5, and 10% doped samples. We then evaluated the prediction capabilities of inverse least squares (ILS) models based on these summary statistics. An ILS calibration based on PRE, the Euclidean distance, and peak fitting/integration proved more successful than the PLS model at predicting levels of blood doping from the corresponding electropherograms; the ILS model distinguished between doped (5% and 10%) and undoped (0%) blood. This methodology may be applicable to other challenging informatics problems like determining risk factors for genetically linked diseases, robust pattern finding in peak-like data such as ChIP-seq, or other genomic sequencing for understanding the 3D genome. © The Royal Society of Chemistry.
831 a7004234161 Linford M.R. p245 False Journal 160 Informatics analysis of capillary electropherograms of autologously doped and undoped blood An ‘Autologous Blood Transfusion' (ABT) is the reinjection of blood previously taken from an athlete to increase its oxygen transport capabilities. Despite the World Anti-Doping Agency's ban on such practices, ABT abuse continues. Autologous blood doping (ABD) is challenging to detect because of the similarities between an individual's doped and undoped blood. Recently, Harrison et al. reported that high-speed capillary electrophoresis may identify ABD. In their work, first order derivatives of the electropherograms were used to identify doping. However, this method suffered from false negatives due to the subjective nature of the analysis. Here, we provide an informatics analysis of the data from this study, contrasting the results of traditional statistical methods and less traditional mathematical techniques. First, three well-known multivariate statistical tools: cluster analysis, principal component analysis (PCA), and partial least squares (PLS) are applied to develop calibrations and/or group electropherograms of undoped (0%) and doped (5% and 10%) blood samples. (These doping levels were chosen due to the low physiological effect of doping below 5%, with 10% corresponding to the approximate ‘gain' derived from the transfusion of a single unit of blood into an adult.) Different preprocessing and variable selection methods were considered. Due to variation in the electropherograms and the limited sample size, these methods were inadequate. We next considered four less commonly used mathematical/informatics tools: pattern recognition entropy (PRE), the Euclidean distance between vectors, a peak fitting/integration method, and the second moment (SM). Each of these techniques showed some ability to differentiate between the 0, 5, and 10% doped samples. We then evaluated the prediction capabilities of inverse least squares (ILS) models based on these summary statistics. An ILS calibration based on PRE, the Euclidean distance, and peak fitting/integration proved more successful than the PLS model at predicting levels of blood doping from the corresponding electropherograms; the ILS model distinguished between doped (5% and 10%) and undoped (0%) blood. This methodology may be applicable to other challenging informatics problems like determining risk factors for genetically linked diseases, robust pattern finding in peak-like data such as ChIP-seq, or other genomic sequencing for understanding the 3D genome. © The Royal Society of Chemistry.
831 a7004234161 Linford M.R. p331 False Conference 107 Using ellipsometry and X-ray photoelectron spectroscopy for real-time monitoring of the oxidation of aluminum mirrors protected by ultrathin MgF2 layers To maintain high, broad-band reflectance, thin transparent fluoride layers, such as MgF2, are used to protect the of aluminum mirrors against oxidation since aluminum oxide absorbs short wavelength light. In this study, we present, for the first time, combined X-ray photoelectron spectroscopy (XPS) and ellipsometric (SE) studies of aluminum oxidation as a function of MgF2 over a range of layer thickness (0-6 nm). We also show for the first time, dynamic SE data which, with appropriate modeling, tracks the extent of oxide growth every few seconds over a period of several hours after the evaporated Al + MgF2 bilayer is removed from the deposition chamber, exposing it to the air. For each SE data set, because the optical constants of ultrathin metals films depend strongly on deposition conditions and their thickness, the optical constants for Al, as well as the Al and Al2O3 thicknesses, were fit. SE trends were confirmed by X-ray photoelectron spectroscopy. There is a chemical shift in the Al 2s electron emission peak toward higher binding energy as the metal oxidizes to Al+3. The extent of oxide growth can be modeled from the relative area of each peak once they are corrected for the attenuation through MgF2 layer. This generates an empirical formula: oxide thickness= k∗log(t) +b, for the time-dependent aluminum-oxide thickness on aluminum surfaces protected by MgF2 as a function of MgF2 layer thickness. Here, k is a factor which depends only on MgF2 thickness, and decreases with increasing MgF2 thickness. The techniques developed can illuminate other protected mirror systems. © 2019 SPIE.
831 a7004234161 Linford M.R. p426 False Journal 236 Tutorial on interpreting x-ray photoelectron spectroscopy survey spectra: Questions and answers on spectra from the atomic layer deposition of Al2O3 on silicon X-ray photoelectron spectroscopy (XPS) has become the most widely used method for chemically analyzing surfaces. In XPS, photoelectrons are generated by irradiating a surface with x rays. As the importance and popularity of XPS have grown, it has drawn users without significant XPS experience, and incorrect and incomplete interpretations of XPS spectra regularly appear in the literature. This tutorial is designed as a tool to guide less experienced users in analyzing XPS survey spectra. Here, the authors examine a series of XPS survey spectra collected during the atomic layer deposition (ALD) of Al2O3 from trimethylaluminum and water precursors. Prior to this, brief explanations of XPS and ALD are presented. This tutorial is structured as a series of questions and answers that the interested reader may choose to engage in. The XPS spectra are scrutinized to extract information about the elements present in the film, the presence of contamination, and the nature of the film growth process. The questions and answers in this tutorial address important fundamental issues common to the interpretation of many XPS survey spectra in the context of ALD. © 2018 Author(s).
832 a56330970800 Defigueiredo B.P. p246 True Journal 161 Origami-Based Design of Conceal-and-Reveal Systems This work introduces a type of motion termed "conceal-and-reveal" which is characterized by a state that protects a payload, a state that exposes the payload, and coupled motions between these two states. As techniques for thick, rigid origami-based engineering designs are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design similar thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns can be used to initiate viable approaches to achieving conceal-and-reveal motion. © 2019 by ASME.
832 a56330970800 Defigueiredo B.P. p409 True Journal 219 Regional Stiffness Reduction Using Lamina Emergent Torsional Joints for Flexible Printed Circuit Board Design Flexible printed circuit boards (PCBs) make it possible for engineers to design devices that use space efficiently and can undergo changes in shape and configuration. However, they also suffer from tradeoffs due to nonideal material properties. Here, a method is presented that allows engineers to introduce regions of flexibility in otherwise rigid PCB substrates. This method employs geometric features to reduce local stiffness in the PCB, rather than reducing the global stiffness by material selection. Analytical and finite element models are presented to calculate the maximum stresses caused by deflection. An example device is produced and tested to verify the models. Copyright © 2018 by ASME.
832 a56330970800 Defigueiredo B.P. p581 True Conference 226 Origami-based design of conceal-and-reveal systems This work introduces a type of motion termed “conceal-and-reveal” which is characterized by a state that protects a payload, a state that exposes the payload, and continuous motion between these two states. As techniques for thick, rigid origami-based engineering design are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design other thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns represent viable approaches to achieving conceal-and-reveal motion. Copyright © 2018 ASME
832 a56330970800 Defigueiredo B.P. p816 False Conference 351 Designing for power transfer across fold-lines in mechanisms with origami-like movement using surrogate folds As mechanisms with origami-like movement increase in popularity, there is a need for conducting electrical power across folds. This need could potentially be filled by the use of surrogate folds. Surrogate folds are a localized reduction in stiffness in a given direction allowing the material to function like a fold. Current methods for conducting across folds are reviewed along with current opportunities. A framework for designing conductive surrogate folds that can be adapted to fit specific applications is presented. Equations for calculating the resistance in single surrogate folds as well as arrays are given. Prototypes of several conductive joints are presented and discussed. The framework is then followed in the designing and manufacturing of a conductive origami-inspired mechanism. Copyright © 2017 ASME.
833 a57190247942 Tolman K.A. p246 False Journal 161 Origami-Based Design of Conceal-and-Reveal Systems This work introduces a type of motion termed "conceal-and-reveal" which is characterized by a state that protects a payload, a state that exposes the payload, and coupled motions between these two states. As techniques for thick, rigid origami-based engineering designs are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design similar thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns can be used to initiate viable approaches to achieving conceal-and-reveal motion. © 2019 by ASME.
833 a57190247942 Tolman K.A. p581 False Conference 226 Origami-based design of conceal-and-reveal systems This work introduces a type of motion termed “conceal-and-reveal” which is characterized by a state that protects a payload, a state that exposes the payload, and continuous motion between these two states. As techniques for thick, rigid origami-based engineering design are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design other thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns represent viable approaches to achieving conceal-and-reveal motion. Copyright © 2018 ASME
833 a57190247942 Tolman K.A. p598 False Journal 306 A Review of Thickness-Accommodation Techniques in Origami-Inspired Engineering Origami has served as the inspiration for a number of engineered systems. In most cases, they require nonpaper materials where material thickness is non-negligible. Foldable mechanisms based on origami-like forms present special challenges for preserving kinematics and assuring non-self-intersection when the thickness of the panels must be accommodated. Several design approaches for constructing thick origami mechanisms by beginning with a zero-thickness origami pattern and transforming it into a rigidly foldable mechanism with thick panels are reviewed. The review includes existing approaches and introduces new hybrid approaches. The approaches are compared and contrasted and their manufacturability analyzed. © 2018 by ASME.
833 a57190247942 Tolman K.A. p599 False Journal 306 Closure to "discussion of 'a review of thickness-accommodation techniques in origami-inspired engineering'" (Lang, R. J., Tolman, K. A., Crampton, E. B., Magleby, S. P., and Howell, L. L., 2018, ASME Appl. Mech. Rev., 70(1), p. 010805) [No abstract available]
833 a57190247942 Tolman K.A. p817 False Conference 352 Optimization of origami-based tubes for lightweight deployable structures Tubular origami may provide both the needed deployment displacement and sufficient strength to be useful as deployable structures. This paper reviews origami tube-based deployable mechanisms and a structural optimization of FEA models is performed. Symmetric and non-symmetric 4-sided tubes are evaluated. Panel geometries and thicknesses are varied to produce rigidly foldable origami-tube-based mechanisms that are both strong and lightweight. The mechanical properties of these tubes over various deployment lengths are discussed. Three different configurations of this mechanism are compared and the advantages of each are discussed. Copyright © 2017 ASME.
833 a57190247942 Tolman K.A. p855 True Conference 379 Split-vertex technique for thickness-accommodation in origami-based mechanisms A novel thickness-accommodation technique for origami based mechanisms is introduced. This technique modifies a zerothickness pattern by splitting each vertex along the minor folds into a system of two vertices. The modified fold pattern then has thickness applied to it and the resulting mechanism is kinematically equivalent to the modified fold pattern. Origami patterns that are rigid-foldable and only have two panels that stack between folds are utilized in the technique. The technique produces thick origami mechanisms where all panels lie in a plane in the unfolded state without any holes or protrusions and maintain a single degree of freedom. Steps for synthesizing split-vertex mechanisms are presented and examples of split-vertex mechanisms are shown. Advantages and potential applications of the technique are discussed. Copyright © 2017 ASME.
834 a57197791798 Crampton E. p246 False Journal 161 Origami-Based Design of Conceal-and-Reveal Systems This work introduces a type of motion termed "conceal-and-reveal" which is characterized by a state that protects a payload, a state that exposes the payload, and coupled motions between these two states. As techniques for thick, rigid origami-based engineering designs are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design similar thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns can be used to initiate viable approaches to achieving conceal-and-reveal motion. © 2019 by ASME.
834 a57197791798 Crampton E. p581 False Conference 226 Origami-based design of conceal-and-reveal systems This work introduces a type of motion termed “conceal-and-reveal” which is characterized by a state that protects a payload, a state that exposes the payload, and continuous motion between these two states. As techniques for thick, rigid origami-based engineering design are being developed, origami is becoming increasingly more attractive as inspiration for complex systems. This paper proposes a process for designing origami-based conceal-and-reveal systems, which can be generalized to design other thick, rigid origami-based systems. The process is demonstrated through the development of three conceal-and-reveal systems that present a luxury product to the consumer. The three designs also confirm that multiple origami crease patterns represent viable approaches to achieving conceal-and-reveal motion. Copyright © 2018 ASME
834 a57197791798 Crampton E. p582 True Conference 227 Automating the design of thick-origami mechanisms Applying an origami pattern to thick, non-paper-like materials is a challenging task. Though many techniques have been developed to accommodate thickness in origami, creating 3D models of such thick-origami mechanisms is complex. The time and knowledge required to manually model an origami mechanism can impede the exploration of the design space and creation of robust designs. This work presents data structures based on origami that can be used in the automation of thick-origami mechanism design. These structures are described and an example computer program that implements them is investigated. The program automatically generates all the necessary 3D CAD part models and an assembly model for a user-specified origami crease pattern. Models resulting from the program for several crease patterns are demonstrated with a discussion of the advantages and limitations of the system. With further development of the data structures and program, this framework has the potential to help mitigate some of the barriers to more widespread use of origami-based design. Copyright © 2018 ASME
834 a57197791798 Crampton E. p598 False Journal 306 A Review of Thickness-Accommodation Techniques in Origami-Inspired Engineering Origami has served as the inspiration for a number of engineered systems. In most cases, they require nonpaper materials where material thickness is non-negligible. Foldable mechanisms based on origami-like forms present special challenges for preserving kinematics and assuring non-self-intersection when the thickness of the panels must be accommodated. Several design approaches for constructing thick origami mechanisms by beginning with a zero-thickness origami pattern and transforming it into a rigidly foldable mechanism with thick panels are reviewed. The review includes existing approaches and introduces new hybrid approaches. The approaches are compared and contrasted and their manufacturability analyzed. © 2018 by ASME.
834 a57197791798 Crampton E. p599 False Journal 306 Closure to "discussion of 'a review of thickness-accommodation techniques in origami-inspired engineering'" (Lang, R. J., Tolman, K. A., Crampton, E. B., Magleby, S. P., and Howell, L. L., 2018, ASME Appl. Mech. Rev., 70(1), p. 010805) [No abstract available]
834 a57197791798 Crampton E. p815 True Conference 350 Realizing origami mechanisms from metal sheets Consideration of a product's manufacturability is a vital aspect of product design. When considering manufacturability of panels for origami-adapted products, there are tradeoffs between panel design approaches as well as thicknessaccommodation techniques. The use of bent sheet metal for panels shows promise as a panel design approach that mitigates several of these trade-offs. This paper describes a process that can be employed to use sheet metal in designs of origami-adapted mechanisms that utilize specific thickness-accommodation techniques. The process is demonstrated for a square-twist mechanism designed using the hinge shift technique for accommodating thickness in origami patterns. A Miura-ori mechanism is also shown in sheet metal. The characteristics of these bent panel approaches are discussed and compared to other approaches for designing panels for manufacturing. The use of bent sheet metal panels allows for mitigation of several trade-offs and shows the applicability of origami-adapted design to sheet metal. Copyright © 2017 ASME.
835 a57191995887 Andersen J. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
835 a57191995887 Andersen J. p348 False Conference 120 A comparative usability study of key management in secure email We conducted a user study that compares three secure email tools that share a common user interface and differ only by key management scheme: passwords, public key directory (PKD), and identity-based encryption (IBE). Our work is the first comparative (i.e., A/B) usability evaluation of three different key management schemes and utilizes a standard quantitative metric for cross-system comparisons. We also share qualitative feedback from participants that provides valuable insights into user attitudes regarding each key management approach and secure email generally. The study serves as a model for future secure email research with A/B studies, standard metrics, and the two-person study methodology. © 2018 by The USENIX Association All Rights Reserved.
836 a57203240784 Dickinson L. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
836 a57203240784 Dickinson L. p471 False Conference 173 A Tale of Two Studies: The Best and Worst of YubiKey Usability Two-factor authentication (2FA) significantly improves the security of password-based authentication. Recently, there has been increased interest in Universal 2nd Factor (U2F) security keys-small hardware devices that require users to press a button on the security key to authenticate. To examine the usability of security keys in non-enterprise usage, we conducted two user studies of the YubiKey, a popular line of U2F security keys. The first study tasked 31 participants with configuring a Windows, Google, and Facebook account to authenticate using a YubiKey. This study revealed problems with setup instructions and workflow including users locking themselves out of their operating system or thinking they had successfully enabled 2FA when they had not. In contrast, the second study had 25 participants use a YubiKey in their daily lives over a period of four weeks, revealing that participants generally enjoyed the experience. Conducting both a laboratory and longitudinal study yielded insights into the usability of security keys that would not have been evident from either study in isolation. Based on our analysis, we recommend standardizing the setup process, enabling verification of success, allowing shared accounts, integrating with operating systems, and preventing lockouts. © 2018 IEEE.
836 a57203240784 Dickinson L. p557 False Conference 206 The secure socket API: TLS as an operating system service SSL/TLS libraries are notoriously hard for developers to use, leaving system administrators at the mercy of buggy and vulnerable applications. We explore the use of the standard POSIX socket API as a vehicle for a simplified TLS API, while also giving administrators the ability to control applications and tailor TLS configuration to their needs. We first assess OpenSSL and its uses in open source software, recommending how this functionality should be accommodated within the POSIX API. We then propose the Secure Socket API (SSA), a minimalist TLS API built using existing network functions and find that it can be employed by existing network applications by modifications requiring as little as one line of code. We next describe a prototype SSA implementation that leverages network system calls to provide privilege separation and support for other programming languages. We end with a discussion of the benefits and limitations of the SSA and our accompanying implementation, noting avenues for future work. © 2018 Proceedings of the 27th USENIX Security Symposium. All rights reserved.
836 a57203240784 Dickinson L. p793 False Conference 330 TrustBase: An architecture to repair and strengthen certificate-based authentication The current state of certificate-based authentication is messy, with broken authentication in applications and proxies, along with serious flaws in the CA system. To solve these problems, we design TrustBase, an architecture that provides certificate-based authentication as an operating system service, with system administrator control over authentication policy. TrustBase transparently enforces best practices for certificate validation on all applications, while also providing a variety of authentication services to strengthen the CA system. We describe a research prototype of TrustBase for Linux, which uses a loadable kernel module to intercept traffic in the socket layer, then consults a userspace policy engine to evaluate certificate validity using a variety of plugins. We evaluate the security of TrustBase, including a threat analysis, application coverage, and hardening of the Linux prototype. We also describe prototypes of TrustBase for Android and Windows, illustrating the generality of our approach. We show that TrustBase has negligible overhead and universal compatibility with applications. We demonstrate its utility by describing eight authentication services that extend CA hardening to all applications. © 2017 by The USENIX Association. All Rights Reserved.
837 a57193574682 Heidbrink S. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
837 a57193574682 Heidbrink S. p303 False Conference 84 Is that you, Alice? A usability study of the authentication ceremony of secure messaging applications The effective security provided by secure messaging applications depends heavily on users completing an authentication ceremony-a sequence of manual operations enabling users to verify they are indeed communicating with one another. Unfortunately, evidence to date suggests users are unable to do this. Accordingly, we study in detail how well users can locate and complete the authentication ceremony when they are aware of the need for authentication. We execute a two-phase study involving 36 pairs of participants, using three popular messaging applications with support for secure messaging functionality: WhatsApp, Viber, and Facebook Messenger. The first phase included instruction about potential threats, while the second phase also included instructions about the importance of the authentication ceremony. We find that, across the three apps, the average success rates of finding and completing the authentication ceremony increases from 14% to 79% from the first to second phase, with second-phase success rates as high as 96% for Viber. However, the time required to find and complete the ceremony is undesirably long from a usability standpoint, and our data is inconclusive on whether users make the connection between this ceremony and the security guarantees it brings. We discuss in detail the success rates, task timings, and user feedback for each application, as well as common mistakes and user grievances. We conclude by exploring user threat models, finding significant gaps in user awareness and understanding. © 2017 by The USENIX Association. All rights reserved.
837 a57193574682 Heidbrink S. p557 False Conference 206 The secure socket API: TLS as an operating system service SSL/TLS libraries are notoriously hard for developers to use, leaving system administrators at the mercy of buggy and vulnerable applications. We explore the use of the standard POSIX socket API as a vehicle for a simplified TLS API, while also giving administrators the ability to control applications and tailor TLS configuration to their needs. We first assess OpenSSL and its uses in open source software, recommending how this functionality should be accommodated within the POSIX API. We then propose the Secure Socket API (SSA), a minimalist TLS API built using existing network functions and find that it can be employed by existing network applications by modifications requiring as little as one line of code. We next describe a prototype SSA implementation that leverages network system calls to provide privilege separation and support for other programming languages. We end with a discussion of the benefits and limitations of the SSA and our accompanying implementation, noting avenues for future work. © 2018 Proceedings of the 27th USENIX Security Symposium. All rights reserved.
837 a57193574682 Heidbrink S. p793 False Conference 330 TrustBase: An architecture to repair and strengthen certificate-based authentication The current state of certificate-based authentication is messy, with broken authentication in applications and proxies, along with serious flaws in the CA system. To solve these problems, we design TrustBase, an architecture that provides certificate-based authentication as an operating system service, with system administrator control over authentication policy. TrustBase transparently enforces best practices for certificate validation on all applications, while also providing a variety of authentication services to strengthen the CA system. We describe a research prototype of TrustBase for Linux, which uses a loadable kernel module to intercept traffic in the socket layer, then consults a userspace policy engine to evaluate certificate validity using a variety of plugins. We evaluate the security of TrustBase, including a threat analysis, application coverage, and hardening of the Linux prototype. We also describe prototypes of TrustBase for Android and Windows, illustrating the generality of our approach. We show that TrustBase has negligible overhead and universal compatibility with applications. We demonstrate its utility by describing eight authentication services that extend CA hardening to all applications. © 2017 by The USENIX Association. All Rights Reserved.
838 a57208784903 Monson T. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
838 a57208784903 Monson T. p348 False Conference 120 A comparative usability study of key management in secure email We conducted a user study that compares three secure email tools that share a common user interface and differ only by key management scheme: passwords, public key directory (PKD), and identity-based encryption (IBE). Our work is the first comparative (i.e., A/B) usability evaluation of three different key management schemes and utilizes a standard quantitative metric for cross-system comparisons. We also share qualitative feedback from participants that provides valuable insights into user attitudes regarding each key management approach and secure email generally. The study serves as a model for future secure email research with A/B studies, standard metrics, and the two-person study methodology. © 2018 by The USENIX Association All Rights Reserved.
838 a57208784903 Monson T. p352 False Conference 123 Weighing Context and Trade-offs: How suburban adults selected their online security posture Understanding how people behave when faced with complex security situations is essential to designing usable security tools. To better understand users' perceptions of their digital lives and how they managed their online security posture, we conducted a series of 23 semi-structured interviews with mostly middle-aged parents from suburban Washington state. Using a grounded theory methodology, we analyzed the interview data and found that participants chose their security posture based on the immense value the Internet provides and their belief that no combination of technology could make them perfectly safe. Within this context, users have a four-stage process for determining which security measures to adopt: learning, evaluation of risks, estimation of impact, and weighing trade-offs to various coping strategies. Our results also revealed that a majority of participants understand the basic principles of symmetric encryption. We found that participants' misconceptions related to browser-based TLS indicators lead to insecure behavior, and it is the permanence of encrypted email that causes participants to doubt that it is secure. We conclude with a discussion of possible responses to this research and avenues for future research. © 2017 by The USENIX Association. All rights reserved.
839 a56417117600 O'Neill M. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
839 a56417117600 O'Neill M. p303 False Conference 84 Is that you, Alice? A usability study of the authentication ceremony of secure messaging applications The effective security provided by secure messaging applications depends heavily on users completing an authentication ceremony-a sequence of manual operations enabling users to verify they are indeed communicating with one another. Unfortunately, evidence to date suggests users are unable to do this. Accordingly, we study in detail how well users can locate and complete the authentication ceremony when they are aware of the need for authentication. We execute a two-phase study involving 36 pairs of participants, using three popular messaging applications with support for secure messaging functionality: WhatsApp, Viber, and Facebook Messenger. The first phase included instruction about potential threats, while the second phase also included instructions about the importance of the authentication ceremony. We find that, across the three apps, the average success rates of finding and completing the authentication ceremony increases from 14% to 79% from the first to second phase, with second-phase success rates as high as 96% for Viber. However, the time required to find and complete the ceremony is undesirably long from a usability standpoint, and our data is inconclusive on whether users make the connection between this ceremony and the security guarantees it brings. We discuss in detail the success rates, task timings, and user feedback for each application, as well as common mistakes and user grievances. We conclude by exploring user threat models, finding significant gaps in user awareness and understanding. © 2017 by The USENIX Association. All rights reserved.
839 a56417117600 O'Neill M. p305 False Conference 86 Action needed! Helping users find and complete the authentication ceremony in signal The security guarantees of secure messaging applications are contingent upon users performing an authentication ceremony, which typically involves verifying the fingerprints of encryption keys. However, recent lab studies have shown that users are unable to do this without being told in advance about the ceremony and its importance. A recent study showed that even with this instruction, the time it takes users to find and complete the ceremony is excessively long-about 11 minutes. To remedy these problems, we modified Signal to include prompts for the ceremony and also simplified the ceremony itself. To gauge the effect of these changes, we conducted a between-subject user study involving 30 pairs of participants. Our study methodology includes no user training and only a small performance bonus to encourage the secure behavior. Our results show that users are able to both find and complete the ceremony more quickly in our new version of Signal. Despite these improvements, many users are still unsure or confused about the purpose of the authentication ceremony. We discuss the need for better risk communication and methods to promote trust. © 2018 by The USENIX Association All Rights Reserved.
839 a56417117600 O'Neill M. p351 False Conference 122 User attitudes toward the inspection of encrypted traffic This paper reports the results of a survey of 1,976 individuals regarding their opinions on TLS inspection, a controversial technique that can be used for both benevolent and malicious purposes. Responses indicate that participants hold nuanced opinions on security and privacy trade-offs, with most recognizing legitimate uses for the practice, but also concerned about threats from hackers or government surveillance. There is strong support for notification and consent when a system is intercepting their encrypted traffic, although this support varies depending on the situation. A significant concern about malicious uses of TLS inspection is identity theft, and many would react negatively and some would change their behavior if they discovered inspection occurring without their knowledge. We also find that a small but significant number of participants are jaded by the current state of affairs and have lost any expectation of privacy. © 2016 by The USENIX Association All Rights Reserved.
839 a56417117600 O'Neill M. p557 True Conference 206 The secure socket API: TLS as an operating system service SSL/TLS libraries are notoriously hard for developers to use, leaving system administrators at the mercy of buggy and vulnerable applications. We explore the use of the standard POSIX socket API as a vehicle for a simplified TLS API, while also giving administrators the ability to control applications and tailor TLS configuration to their needs. We first assess OpenSSL and its uses in open source software, recommending how this functionality should be accommodated within the POSIX API. We then propose the Secure Socket API (SSA), a minimalist TLS API built using existing network functions and find that it can be employed by existing network applications by modifications requiring as little as one line of code. We next describe a prototype SSA implementation that leverages network system calls to provide privilege separation and support for other programming languages. We end with a discussion of the benefits and limitations of the SSA and our accompanying implementation, noting avenues for future work. © 2018 Proceedings of the 27th USENIX Security Symposium. All rights reserved.
840 a57203245208 Reese K. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
840 a57203245208 Reese K. p300 True Conference 82 A usability study of five two-factor authentication methods Two-factor authentication (2FA) defends against account compromise. An account secured with 2FA typically requires an individual to authenticate using something they know-typically a password-as well as something they have, such as a cell phone or hardware token. Many 2FA methods in widespread use today have not been subjected to adequate usability testing. Furthermore, previous 2FA usability research is difficult to compare due to widely-varying contexts across different studies. We conducted a two-week, between-subjects usability study of five common 2FA methods with 72 participants, collecting both quantitative and qualitative data. Participants logged into a simulated banking website nearly every day using 2FA and completed an assigned task. Participants generally gave high marks to the methods studied, and many expressed an interest in using 2FA to provide more security for their sensitive online accounts. We also conducted a within-subjects laboratory study with 30 participants to assess the general usability of the setup procedure for the five methods. While a few participants experienced difficulty setting up a hardware token and a one-time password, in general, users found the methods easy to set up. © is held by the author/owner.
840 a57203245208 Reese K. p471 False Conference 173 A Tale of Two Studies: The Best and Worst of YubiKey Usability Two-factor authentication (2FA) significantly improves the security of password-based authentication. Recently, there has been increased interest in Universal 2nd Factor (U2F) security keys-small hardware devices that require users to press a button on the security key to authenticate. To examine the usability of security keys in non-enterprise usage, we conducted two user studies of the YubiKey, a popular line of U2F security keys. The first study tasked 31 participants with configuring a Windows, Google, and Facebook account to authenticate using a YubiKey. This study revealed problems with setup instructions and workflow including users locking themselves out of their operating system or thinking they had successfully enabled 2FA when they had not. In contrast, the second study had 25 participants use a YubiKey in their daily lives over a period of four weeks, revealing that participants generally enjoyed the experience. Conducting both a laboratory and longitudinal study yielded insights into the usability of security keys that would not have been evident from either study in isolation. Based on our analysis, we recommend standardizing the setup process, enabling verification of success, allowing shared accounts, integrating with operating systems, and preventing lockouts. © 2018 IEEE.
841 a57208771517 Spendlove B. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
842 a35621274900 Vaziripour E. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
842 a35621274900 Vaziripour E. p303 True Conference 84 Is that you, Alice? A usability study of the authentication ceremony of secure messaging applications The effective security provided by secure messaging applications depends heavily on users completing an authentication ceremony-a sequence of manual operations enabling users to verify they are indeed communicating with one another. Unfortunately, evidence to date suggests users are unable to do this. Accordingly, we study in detail how well users can locate and complete the authentication ceremony when they are aware of the need for authentication. We execute a two-phase study involving 36 pairs of participants, using three popular messaging applications with support for secure messaging functionality: WhatsApp, Viber, and Facebook Messenger. The first phase included instruction about potential threats, while the second phase also included instructions about the importance of the authentication ceremony. We find that, across the three apps, the average success rates of finding and completing the authentication ceremony increases from 14% to 79% from the first to second phase, with second-phase success rates as high as 96% for Viber. However, the time required to find and complete the ceremony is undesirably long from a usability standpoint, and our data is inconclusive on whether users make the connection between this ceremony and the security guarantees it brings. We discuss in detail the success rates, task timings, and user feedback for each application, as well as common mistakes and user grievances. We conclude by exploring user threat models, finding significant gaps in user awareness and understanding. © 2017 by The USENIX Association. All rights reserved.
842 a35621274900 Vaziripour E. p305 True Conference 86 Action needed! Helping users find and complete the authentication ceremony in signal The security guarantees of secure messaging applications are contingent upon users performing an authentication ceremony, which typically involves verifying the fingerprints of encryption keys. However, recent lab studies have shown that users are unable to do this without being told in advance about the ceremony and its importance. A recent study showed that even with this instruction, the time it takes users to find and complete the ceremony is excessively long-about 11 minutes. To remedy these problems, we modified Signal to include prompts for the ceremony and also simplified the ceremony itself. To gauge the effect of these changes, we conducted a between-subject user study involving 30 pairs of participants. Our study methodology includes no user training and only a small performance bonus to encourage the secure behavior. Our results show that users are able to both find and complete the ceremony more quickly in our new version of Signal. Despite these improvements, many users are still unsure or confused about the purpose of the authentication ceremony. We discuss the need for better risk communication and methods to promote trust. © 2018 by The USENIX Association All Rights Reserved.
842 a35621274900 Vaziripour E. p344 False Conference 117 “Something isn't secure, but I'm not sure how that translates into a problem”: Promoting autonomy by designing for understanding in Signal Security designs that presume enacting secure behaviors to be beneficial in all circumstances discount the impact of response cost on users' lives and assume that all data is equally worth protecting. However, this has the effect of reducing user autonomy by diminishing the role personal values and priorities play in the decision-making process. In this study, we demonstrate an alternative approach that emphasizes users' comprehension over compliance, with the goal of helping users to make more informed decisions regarding their own security. To this end, we conducted a three-phase redesign of the warning notifications surrounding the authentication ceremony in Signal. Our results show how improved comprehension can be achieved while still promoting favorable privacy outcomes among users. Our experience reaffirms existing arguments that users should be empowered to make personal trade-offs between perceived risk and response cost. We also find that system trust is a major factor in users' interpretation of system determinations of risk, and that properly communicating risk requires an understanding of user perceptions of the larger security ecosystem in whole. © is held by the author/owner.
843 a55681652500 Wu J. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
843 a55681652500 Wu J. p303 False Conference 84 Is that you, Alice? A usability study of the authentication ceremony of secure messaging applications The effective security provided by secure messaging applications depends heavily on users completing an authentication ceremony-a sequence of manual operations enabling users to verify they are indeed communicating with one another. Unfortunately, evidence to date suggests users are unable to do this. Accordingly, we study in detail how well users can locate and complete the authentication ceremony when they are aware of the need for authentication. We execute a two-phase study involving 36 pairs of participants, using three popular messaging applications with support for secure messaging functionality: WhatsApp, Viber, and Facebook Messenger. The first phase included instruction about potential threats, while the second phase also included instructions about the importance of the authentication ceremony. We find that, across the three apps, the average success rates of finding and completing the authentication ceremony increases from 14% to 79% from the first to second phase, with second-phase success rates as high as 96% for Viber. However, the time required to find and complete the ceremony is undesirably long from a usability standpoint, and our data is inconclusive on whether users make the connection between this ceremony and the security guarantees it brings. We discuss in detail the success rates, task timings, and user feedback for each application, as well as common mistakes and user grievances. We conclude by exploring user threat models, finding significant gaps in user awareness and understanding. © 2017 by The USENIX Association. All rights reserved.
843 a55681652500 Wu J. p305 False Conference 86 Action needed! Helping users find and complete the authentication ceremony in signal The security guarantees of secure messaging applications are contingent upon users performing an authentication ceremony, which typically involves verifying the fingerprints of encryption keys. However, recent lab studies have shown that users are unable to do this without being told in advance about the ceremony and its importance. A recent study showed that even with this instruction, the time it takes users to find and complete the ceremony is excessively long-about 11 minutes. To remedy these problems, we modified Signal to include prompts for the ceremony and also simplified the ceremony itself. To gauge the effect of these changes, we conducted a between-subject user study involving 30 pairs of participants. Our study methodology includes no user training and only a small performance bonus to encourage the secure behavior. Our results show that users are able to both find and complete the ceremony more quickly in our new version of Signal. Despite these improvements, many users are still unsure or confused about the purpose of the authentication ceremony. We discuss the need for better risk communication and methods to promote trust. © 2018 by The USENIX Association All Rights Reserved.
843 a55681652500 Wu J. p306 True Conference 87 When is a tree really a truck? Exploring mental models of encryption Mental models are a driving force in the way users interact with systems, and thus have important implications for design. This is especially true for encryption because the cost of mistakes can be disastrous. Nevertheless, until now, mental models of encryption have only been tangentially explored as part of more broadly focused studies. In this work, we present the first directed effort at exploring user perceptions of encryption: both mental models of what encryption is and how it works as well as views on its role in everyday life. We performed 19 semi-structured phone interviews with participants across the United States, using both standard interview techniques and a diagramming exercise where participants visually demonstrated their perception of the encryption process. We identified four mental models of encryption which, though varying in detail and complexity, ultimately reduce to a functional abstraction of restrictive access control and naturally coincide with a model of symmetric encryption. Additionally, we find the impersonal use of encryption to be an important part of participants' models of security, with a widespread belief that encryption is frequently employed by service providers to encrypt data at rest. In contrast, the personal use of encryption is viewed as reserved for illicit or immoral activity, or for the paranoid. © 2018 by The USENIX Association All Rights Reserved.
843 a55681652500 Wu J. p344 True Conference 117 “Something isn't secure, but I'm not sure how that translates into a problem”: Promoting autonomy by designing for understanding in Signal Security designs that presume enacting secure behaviors to be beneficial in all circumstances discount the impact of response cost on users' lives and assume that all data is equally worth protecting. However, this has the effect of reducing user autonomy by diminishing the role personal values and priorities play in the decision-making process. In this study, we demonstrate an alternative approach that emphasizes users' comprehension over compliance, with the goal of helping users to make more informed decisions regarding their own security. To this end, we conducted a three-phase redesign of the warning notifications surrounding the authentication ceremony in Signal. Our results show how improved comprehension can be achieved while still promoting favorable privacy outcomes among users. Our experience reaffirms existing arguments that users should be empowered to make personal trade-offs between perceived risk and response cost. We also find that system trust is a major factor in users' interpretation of system determinations of risk, and that properly communicating risk requires an understanding of user perceptions of the larger security ecosystem in whole. © is held by the author/owner.
843 a55681652500 Wu J. p352 False Conference 123 Weighing Context and Trade-offs: How suburban adults selected their online security posture Understanding how people behave when faced with complex security situations is essential to designing usable security tools. To better understand users' perceptions of their digital lives and how they managed their online security posture, we conducted a series of 23 semi-structured interviews with mostly middle-aged parents from suburban Washington state. Using a grounded theory methodology, we analyzed the interview data and found that participants chose their security posture based on the immense value the Internet provides and their belief that no combination of technology could make them perfectly safe. Within this context, users have a four-stage process for determining which security measures to adopt: learning, evaluation of risks, estimation of impact, and weighing trade-offs to various coping strategies. Our results also revealed that a majority of participants understand the basic principles of symmetric encryption. We found that participants' misconceptions related to browser-based TLS indicators lead to insecure behavior, and it is the permanence of encrypted email that causes participants to doubt that it is secure. We conclude with a discussion of possible responses to this research and avenues for future research. © 2017 by The USENIX Association. All rights reserved.
844 a7003445799 Zappala D. p247 False Journal 162 A usability study of four secure email tools using paired participants Secure email is increasingly being touted as usable by novice users, with a push for adoption based on recent concerns about government surveillance. To determine whether secure email is ready for grassroots adoption, we employ a laboratory user study that recruits pairs of novice users to install and use several of the latest systems to exchange secure messages. We present both quantitative and qualitative results from 28 pairs of novices as they use Private WebMail (Pwm), Tutanota, and Virtru and 10 pairs of novices as they use Mailvelope. Participants report being more at ease with this type of study and better able to cope with mistakes since both participants are “on the same page.” We find that users prefer integrated solutions over depot-based solutions and that tutorials are important in helping first-time users. Finally, our results demonstrate that Pretty Good Privacy using manual key management is still unusable for novice users, with 9 of 10 participant pairs failing to complete the study. © 2019 Association for Computing Machinery.
844 a7003445799 Zappala D. p303 False Conference 84 Is that you, Alice? A usability study of the authentication ceremony of secure messaging applications The effective security provided by secure messaging applications depends heavily on users completing an authentication ceremony-a sequence of manual operations enabling users to verify they are indeed communicating with one another. Unfortunately, evidence to date suggests users are unable to do this. Accordingly, we study in detail how well users can locate and complete the authentication ceremony when they are aware of the need for authentication. We execute a two-phase study involving 36 pairs of participants, using three popular messaging applications with support for secure messaging functionality: WhatsApp, Viber, and Facebook Messenger. The first phase included instruction about potential threats, while the second phase also included instructions about the importance of the authentication ceremony. We find that, across the three apps, the average success rates of finding and completing the authentication ceremony increases from 14% to 79% from the first to second phase, with second-phase success rates as high as 96% for Viber. However, the time required to find and complete the ceremony is undesirably long from a usability standpoint, and our data is inconclusive on whether users make the connection between this ceremony and the security guarantees it brings. We discuss in detail the success rates, task timings, and user feedback for each application, as well as common mistakes and user grievances. We conclude by exploring user threat models, finding significant gaps in user awareness and understanding. © 2017 by The USENIX Association. All rights reserved.
844 a7003445799 Zappala D. p305 False Conference 86 Action needed! Helping users find and complete the authentication ceremony in signal The security guarantees of secure messaging applications are contingent upon users performing an authentication ceremony, which typically involves verifying the fingerprints of encryption keys. However, recent lab studies have shown that users are unable to do this without being told in advance about the ceremony and its importance. A recent study showed that even with this instruction, the time it takes users to find and complete the ceremony is excessively long-about 11 minutes. To remedy these problems, we modified Signal to include prompts for the ceremony and also simplified the ceremony itself. To gauge the effect of these changes, we conducted a between-subject user study involving 30 pairs of participants. Our study methodology includes no user training and only a small performance bonus to encourage the secure behavior. Our results show that users are able to both find and complete the ceremony more quickly in our new version of Signal. Despite these improvements, many users are still unsure or confused about the purpose of the authentication ceremony. We discuss the need for better risk communication and methods to promote trust. © 2018 by The USENIX Association All Rights Reserved.
844 a7003445799 Zappala D. p306 False Conference 87 When is a tree really a truck? Exploring mental models of encryption Mental models are a driving force in the way users interact with systems, and thus have important implications for design. This is especially true for encryption because the cost of mistakes can be disastrous. Nevertheless, until now, mental models of encryption have only been tangentially explored as part of more broadly focused studies. In this work, we present the first directed effort at exploring user perceptions of encryption: both mental models of what encryption is and how it works as well as views on its role in everyday life. We performed 19 semi-structured phone interviews with participants across the United States, using both standard interview techniques and a diagramming exercise where participants visually demonstrated their perception of the encryption process. We identified four mental models of encryption which, though varying in detail and complexity, ultimately reduce to a functional abstraction of restrictive access control and naturally coincide with a model of symmetric encryption. Additionally, we find the impersonal use of encryption to be an important part of participants' models of security, with a widespread belief that encryption is frequently employed by service providers to encrypt data at rest. In contrast, the personal use of encryption is viewed as reserved for illicit or immoral activity, or for the paranoid. © 2018 by The USENIX Association All Rights Reserved.
844 a7003445799 Zappala D. p344 False Conference 117 “Something isn't secure, but I'm not sure how that translates into a problem”: Promoting autonomy by designing for understanding in Signal Security designs that presume enacting secure behaviors to be beneficial in all circumstances discount the impact of response cost on users' lives and assume that all data is equally worth protecting. However, this has the effect of reducing user autonomy by diminishing the role personal values and priorities play in the decision-making process. In this study, we demonstrate an alternative approach that emphasizes users' comprehension over compliance, with the goal of helping users to make more informed decisions regarding their own security. To this end, we conducted a three-phase redesign of the warning notifications surrounding the authentication ceremony in Signal. Our results show how improved comprehension can be achieved while still promoting favorable privacy outcomes among users. Our experience reaffirms existing arguments that users should be empowered to make personal trade-offs between perceived risk and response cost. We also find that system trust is a major factor in users' interpretation of system determinations of risk, and that properly communicating risk requires an understanding of user perceptions of the larger security ecosystem in whole. © is held by the author/owner.
844 a7003445799 Zappala D. p348 False Conference 120 A comparative usability study of key management in secure email We conducted a user study that compares three secure email tools that share a common user interface and differ only by key management scheme: passwords, public key directory (PKD), and identity-based encryption (IBE). Our work is the first comparative (i.e., A/B) usability evaluation of three different key management schemes and utilizes a standard quantitative metric for cross-system comparisons. We also share qualitative feedback from participants that provides valuable insights into user attitudes regarding each key management approach and secure email generally. The study serves as a model for future secure email research with A/B studies, standard metrics, and the two-person study methodology. © 2018 by The USENIX Association All Rights Reserved.
844 a7003445799 Zappala D. p351 False Conference 122 User attitudes toward the inspection of encrypted traffic This paper reports the results of a survey of 1,976 individuals regarding their opinions on TLS inspection, a controversial technique that can be used for both benevolent and malicious purposes. Responses indicate that participants hold nuanced opinions on security and privacy trade-offs, with most recognizing legitimate uses for the practice, but also concerned about threats from hackers or government surveillance. There is strong support for notification and consent when a system is intercepting their encrypted traffic, although this support varies depending on the situation. A significant concern about malicious uses of TLS inspection is identity theft, and many would react negatively and some would change their behavior if they discovered inspection occurring without their knowledge. We also find that a small but significant number of participants are jaded by the current state of affairs and have lost any expectation of privacy. © 2016 by The USENIX Association All Rights Reserved.
844 a7003445799 Zappala D. p352 False Conference 123 Weighing Context and Trade-offs: How suburban adults selected their online security posture Understanding how people behave when faced with complex security situations is essential to designing usable security tools. To better understand users' perceptions of their digital lives and how they managed their online security posture, we conducted a series of 23 semi-structured interviews with mostly middle-aged parents from suburban Washington state. Using a grounded theory methodology, we analyzed the interview data and found that participants chose their security posture based on the immense value the Internet provides and their belief that no combination of technology could make them perfectly safe. Within this context, users have a four-stage process for determining which security measures to adopt: learning, evaluation of risks, estimation of impact, and weighing trade-offs to various coping strategies. Our results also revealed that a majority of participants understand the basic principles of symmetric encryption. We found that participants' misconceptions related to browser-based TLS indicators lead to insecure behavior, and it is the permanence of encrypted email that causes participants to doubt that it is secure. We conclude with a discussion of possible responses to this research and avenues for future research. © 2017 by The USENIX Association. All rights reserved.
844 a7003445799 Zappala D. p557 False Conference 206 The secure socket API: TLS as an operating system service SSL/TLS libraries are notoriously hard for developers to use, leaving system administrators at the mercy of buggy and vulnerable applications. We explore the use of the standard POSIX socket API as a vehicle for a simplified TLS API, while also giving administrators the ability to control applications and tailor TLS configuration to their needs. We first assess OpenSSL and its uses in open source software, recommending how this functionality should be accommodated within the POSIX API. We then propose the Secure Socket API (SSA), a minimalist TLS API built using existing network functions and find that it can be employed by existing network applications by modifications requiring as little as one line of code. We next describe a prototype SSA implementation that leverages network system calls to provide privilege separation and support for other programming languages. We end with a discussion of the benefits and limitations of the SSA and our accompanying implementation, noting avenues for future work. © 2018 Proceedings of the 27th USENIX Security Symposium. All rights reserved.
844 a7003445799 Zappala D. p679 False Conference 292 Layering Security at Global Control Points to Secure Unmodified Software Developing secure software is inherently difficult, and is further hampered by a rush to market, the lack of cybersecurity-trained architects and developers, and the difficulty of identifying flaws and deploying mitigations. To address these problems, we advocate for an alternative paradigm-layering security onto applications from global control points, such as the browser, operating system, or network. This approach adds security to existing applications, relieving developers of this burden. The benefits of this paradigm are three-fold-(1) increased correctness in the implementation of security features, (2) coverage for all software, even non-maintained legacy software, and (3) more rapid and consistent deployment of threat mitigations and new security features. To demonstrate these benefits, we describe three concrete instantiations of this paradigm- MessageGuard, a system that layers end-to-end encryption in the browser; TrustBase, a system that layers authentication in the operating system; and software-defined perimeter, which layers access control at network middleboxes. © 2017 IEEE.
844 a7003445799 Zappala D. p793 False Conference 330 TrustBase: An architecture to repair and strengthen certificate-based authentication The current state of certificate-based authentication is messy, with broken authentication in applications and proxies, along with serious flaws in the CA system. To solve these problems, we design TrustBase, an architecture that provides certificate-based authentication as an operating system service, with system administrator control over authentication policy. TrustBase transparently enforces best practices for certificate validation on all applications, while also providing a variety of authentication services to strengthen the CA system. We describe a research prototype of TrustBase for Linux, which uses a loadable kernel module to intercept traffic in the socket layer, then consults a userspace policy engine to evaluate certificate validity using a variety of plugins. We evaluate the security of TrustBase, including a threat analysis, application coverage, and hardening of the Linux prototype. We also describe prototypes of TrustBase for Android and Windows, illustrating the generality of our approach. We show that TrustBase has negligible overhead and universal compatibility with applications. We demonstrate its utility by describing eight authentication services that extend CA hardening to all applications. © 2017 by The USENIX Association. All Rights Reserved.
845 a55855376400 Nysetvold T.B. p248 True Journal 163 Deconfliction in high-density unmanned aerial vehicle systems Small unmanned aerial vehicles play increasingly important roles in many industries and organizations in the United States and around the globe. As usage becomes more widespread, airspace will become increasingly crowded. These high-density unmanned aerial vehicle (UAV) situations will pose many unique challenges, including in conflict resolution. Using agent-based models, conflict resolution and the well-clear and action-distance concepts for small multirotor UAVs in dense environments were explored. Specifically, the safety and efficiency of several collision-avoidance mechanisms under different possible densities, accelerations, and action distances were investigated. The results suggest that selecting appropriate action distances and collision-avoidance mechanisms will be vital to maintaining safety and efficiency. Interestingly, excessive action distances quickly degrade performance: using a simple method under high-density conditions (1 UAV∕km2), well-clear distances above approximately 750 m have extremely low efficiency (∼1% as many deliveries accomplished in 5000 simulation hours compared to lower distances). More advanced algorithms also suffer from low efficiency at higher (∼1 km) response distances. Different definitions for near-midair collisions and their effects on system safety and well-clear distance are discussed. © 2018 by John Salmon. Published by the American Institute of Aeronautics and Astronautics, Inc.,.
845 a55855376400 Nysetvold T.B. p569 True Conference 217 Exploration of three dimensional, hierarchical, large scale UAV system interactions Unmanned aerial vehicles (UAVs) have the potential to revolutionize airspaces across the world. As they increase in prevalence, how UAVs interact with each other and their environments will become increasingly important. The UAV air traffic control system will play an important role in keeping UAV-human interactions safe, effective, and efficient. The large number of automated agents, and the complex interactions between them, make this air traffic control system unusually complex. In this paper, the authors consider how the vertical distribution of UAVs affects an air traffic control system’s safety and efficiency. Several possible frameworks are examined, including a free-flight system in which UAVs are allowed to distribute themselves within the entire airspace; a stratified system where different layers are used for travel in different directions, and a compromise system where layers are specified, but vertical course deviation for conflict avoidance is permitted. Investigations are made into how prioritizing some UAVs over others in a hierarchy (for instance, giving emergency services UAVs a separate layer, independent of recreational or commercial users) could affect this system. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
845 a55855376400 Nysetvold T.B. p747 True Conference 320 Simulation and exploration of high-density unmanned aerial vehicle systems Systems of unmanned aerial vehicles (UAVs), such as the Amazon Air delivery system, will play a large part in future aerospace development. The design and implementation of these systems will be economically, transportationally, and environmentally important. In this paper, we use agent-based models to analyze the emergent behavior of several types of UAV systems with varying parameters and environments. We find that while increasing the number of UAVs initially has a more-than-linear effect on the reported separation incidents, this effect quickly levels off due to carrying capacity limitations. We also find that while different behaviors (objectives and movement patterns) of UAVs affects the locations of the separation incidents, the number of separation incidents is not strongly influenced by these changes. We then explore the implementation of separation-assurance mechanisms using varying levels of information, and examine effects on the emergent behavior. © 2017 IEEE.
846 a57126390100 Gagakuma E. p249 False Journal 111 Approximate MLSE Equalization of SOQPSK-TG in Aeronautical Telemetry An approximate maximum likelihood sequence estimator (MLSE) equalizer for shaped offset QPSK, version TG (SOQPSK-TG) is derived based on the pulse amplitude modulation (PAM) approximation of SOQPSK-TG using the two principal PAM pulses. The resulting equalizer is a generalization of the equalizer based on the Ungerboeck observation model, where the generalization is to two parallel, cross-correlated symbol streams over parallel intersymbol interference channels. The bit error rate (BER) performance and computational complexity of the approximate MLSE equalizer operating over three example channels, motivated by multipath propagation in aeronautical telemetry and with increasing selectivity, are presented. The BER performance was evaluated using computer simulations and shown to be approximately 5-8 dB better than the best frequency-domain minimum mean-squared error (MMSE) equalizers published in the open literature. The computational complexity, measured by the number of real-valued multiplications, is comparable to that of the frequency-domain MMSE equalizers. © 1965-2011 IEEE.
847 a57214523209 Thomas M. p250 True Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
848 a57205509268 Fronk Z. p250 False Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
849 a57208845618 Gross A. p250 False Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
850 a57205502574 Willmore D. p250 False Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
851 a57205849200 Arango A. p250 False Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
852 a57205504743 Higham C. p250 False Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
853 a57207222602 Nguyen V. p250 False Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
854 a57205501457 Lim H. p250 False Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
855 a57205504946 Kale V. p250 False Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
856 a57205502490 McMillan G. p250 False Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
857 a7004339080 Seegmiller R.E. p250 False Journal 155 Losartan attenuates progression of osteoarthritis in the synovial temporomandibular and knee joints of a chondrodysplasia mouse model through inhibition of TGF-β1 signaling pathway Objective: Transforming growth factor beta 1 (TGF-β1) is implicated in osteoarthritis (OA). The purpose of this study was to explore the ability of Losartan to inhibit the inflammatory signaling pathway of TGF-β1 observed during osteoarthritic progression in the temporomandibular joint (TMJ) and knee joint using a genetic mouse model. Methods: A murine OA model displaying the heterozygous chondrodysplasia gene (cho/+), a col11a1 mutation, was used to test this hypothesis. Following a 7-month treatment period with Losartan, the synovial joints were analyzed for histopathological improvement comparing two experimental groups. Tissues were fixed in paraformaldehyde, processed to paraffin section, and stained with Safranin O and Fast Green to visualize proteoglycans and collagen proteins in cartilage. Using the Modified Mankin scoring system, the degree of staining and OA progression were evaluated. Results: Results show heterozygous animals receiving Losartan having diminished degeneration of TMJ condylar and knee joint articular cartilage. This was confirmed in the TMJ and knee by a statistically significant decrease in the Mankin histopathology score. Decreased expression of HtrA1, a key regulator to the TGF-β1 signaling pathway, was demonstrated in vitro as well as in vivo, via Losartan inhibition. Conclusion: Using a genetic mouse model of OA, this study demonstrated the utility of Losartan to improve treatment of human OA in the TMJ and knee joint through inhibition of the TGF-β1 signaling cascade. We further demonstrated inhibition of HtrA1, the lowering of Mankin scores to wild type control levels, and the limiting of OA progressive damage with treatment of Losartan. © 2019 Osteoarthritis Research Society International
858 a57200375892 Pierce J. p251 True Journal 164 Impact of pulse length on the accuracy of defect depth measurements in pulse thermography Pulse thermography (PT) is a nondestructive testing method in which an energy pulse is applied to a surface while the surface temperature evolution is measured to detect sub surface defects and estimate their depth. This nondestructive test method was developed on the assumption of instantaneous surface heating, but recent work has shown that relatively long pulses can be used to accurately determine defect depth in polymers. This paper examines the impact of varying input pulse length on the accuracy of defect depth quantification as a function of the material properties. Simulations using both thermoplastics and metals show that measurement error is dependent on a nondimensionalized pulse length. The simulation results agree with experimental results for three-dimensional (3D) printed acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) components. Analysis and experiments show that defects can be accurately detected with minor modification to the standard methods as long as the pulse ends before the characteristic defect signal is detected. © 2019 by ASME.
859 a57193720916 Gunter C. p252 False Journal 165 Predicting recrystallized grain size in friction stir processed 304L stainless steel A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone (HAZ). Friction stir processing (FSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304L stainless steel. A numerical simulation of the FSP process in 304L was developed to predict temperatures and recrystallized grain size in the stir zone. The model employed an Eulerian finite element approach, where flow stresses for a large range of strain rates and temperatures inherent in FSP were used as input. Temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. The predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. The maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%. © 2019
859 a57193720916 Gunter C. p573 True Journal 303 Solid state crack repair by friction stir processing in 304L stainless steel Friction stir processing (FSP) was investigated as a method of repairing cracks in 12 mm thick 304L stainless steel plate. Healing feasibility was demonstrated by processing a tapered crack using a PCBN/W-Re tool with a 25 mm diameter shoulder and a pin length of 6.4 mm. The experiment showed that it was possible to heal a crack that begins narrow and then progressively grows up to a width of 2 mm. Bead on plate experiments were used to find the best parameters for creating a consolidated stir zone with the least amount of hardness difference compared to the base metal. Grain refinement in some specimens resulted in much higher stir zone hardness, compared to base metal. A plot of grain size versus microhardness showed a very strong inverse correlation between grain size and hardness, as expected from the Hall-Petch relationship. Corrosion testing was carried out in order to evaluate the effect of FSP on potential sensitization of the stir zone. After 1000 h of intermittent immersion in 3.5% saline solution at room temperature it was found that no corrosion products formed on the base material controls or on any of the friction stir processed specimens. © 2017
860 a6701421652 Fourment L. p252 False Journal 165 Predicting recrystallized grain size in friction stir processed 304L stainless steel A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone (HAZ). Friction stir processing (FSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304L stainless steel. A numerical simulation of the FSP process in 304L was developed to predict temperatures and recrystallized grain size in the stir zone. The model employed an Eulerian finite element approach, where flow stresses for a large range of strain rates and temperatures inherent in FSP were used as input. Temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. The predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. The maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%. © 2019
861 a57205270902 Mathis T. p252 False Journal 165 Predicting recrystallized grain size in friction stir processed 304L stainless steel A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone (HAZ). Friction stir processing (FSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304L stainless steel. A numerical simulation of the FSP process in 304L was developed to predict temperatures and recrystallized grain size in the stir zone. The model employed an Eulerian finite element approach, where flow stresses for a large range of strain rates and temperatures inherent in FSP were used as input. Temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. The predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. The maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%. © 2019
862 a57209887692 Pinto T. p253 True Conference 60 Polar coding for physical-layer security without knowledge of the eavesdropper's channel We propose an adaptive secrecy scheme using polar codes with random frozen bits for a general wiretap channel, in which to protect the data from a potential eavesdropper, part or all of the frozen bits are randomly generated per message. To assess the secrecy level of the proposed scheme, three types of decoding strategies are evaluated: a matching decoder which knows the positions of all inserted bits inside the blocklength and tries to estimate them using the same decoding techniques, a blind decoder which treats all the frozen bits as the same value, and a random decoder which considers those dynamic bits as random at the receiver. Results are presented in terms of the system security gap, assuming an adaptive decoding strategy. It is shown that the system achieves combined secrecy and reliability. The proposed scheme does not assume knowledge of the eavesdropper's channel when defining the indices of information and frozen bits. © 2019 IEEE.
863 a57205763350 Forsgren B. p254 False Journal 166 Direct Relative Edge Optimization, A Robust Alternative for Pose Graph Optimization Pose graph optimization is a common problem in robotics and associated fields. Most commonly, pose graph optimization is performed by finding the set of pose estimates which are the most likely for a given set of measurements. In some situations, arbitrarily large errors in pose graph initialization are unavoidable and can cause these pose-based methods to diverge or fail especially in cases where global inputs become available after some time after initialization. This letter details the parameterization of the classic pose graph problem in a relative context, optimizing directly over relative edge constraints between vertices in the pose graph and not on the poses themselves. Unlike previous literature on relative optimization, this letter details relative optimization over an entire pose graph, instead of a subset of edges, resulting in greater robustness to arbitrarily large errors than the classic pose-based or prior relative edge-based methods. Several small-scale simulation comparison studies, along with single and multi-agent hardware experiments, are presented. Results point to relative edge optimization as a strong candidate for solving real-world pose graph optimization problems that contain large heading propagation or initialization errors. © 2016 IEEE.
863 a57205763350 Forsgren B. p360 False Journal 190 A CAD assembly simplification approach with ray casting We present novel methods for the removal of interior bodies from complex assemblies using ray casting. These methods locate and preserve bodies that represent the high-fidelity exterior surface of an assembly while removing all interior bodies that do not contribute to the exterior assembly surface. In so doing we create parts that can accurately be used for assembly packaging and other tasks without sufiering from the ineficiencies that come from working with the full assembly. We further present an analysis of the process on assemblies of known properties and several use cases with simplification results. Finally, we present directions for future research that could enhance this work. © 2019 CAD Solutions, LLC.
864 a7004435321 Fonseca F.S. p255 True Journal 167 Compressive strength of high-strength concrete masonry grouted prisms An experimental program was devised to assess the influence of the compressive strength of the grout on the compressive strength of masonry constructed with high-strength concrete masonry units. Three different compressive strengths of mortar, grout, and concrete masonry units were used. Grouts were made without and with a shrinkage-compensating admixture. The various components were combined to construct several hollow and grouted prisms, which were then tested. The results show that very high-strength blocks were not as efficient as medium-strength blocks and that there was a difference between the compressive strengths of ungrouted and grouted masonry; depending on the combination of the materials used, grouted masonry can be less or more efficient than ungrouted masonry. For one combination of materials, the shrinkage-compensating admixture was shown to be effective in reducing the grout shrinkage, and the grouted prisms constructed with that combination of materials were more efficient than their hollow prisms counterpart. Grouted prisms constructed with grouts without the shrinkage-compensating admixture were, on average, less efficient than hollow prisms. The efficiency of grouted masonry depends on many factors including compatibility of deformation between the masonry components, compaction of the grout, shrinkage characteristics of the grout, block geometry, and bond between grout and block. Further research is needed to determine the influence of these factors and obtain a complete understanding of the behavior and capacity of high strength masonry. © 2019 Elsevier Ltd
864 a7004435321 Fonseca F.S. p339 False Journal 193 A Proposed Test to Evaluate Efflorescence Potential of Ceramic Blocks Masonry is susceptible to efflorescence, which in itself is an aesthetic problem, but the condition of efflorescence indicates that water is moving through the masonry in unintended ways and the presence of uncontrolled water can lead to serious issues, including structural problems. In this paper, the results obtained from a proposed test method to evaluate the potential of efflorescence of ceramic blocks are compared to that obtained using the method described in ASTM C67. The proposed method was developed because until 2017 there was no Brazilian Standard to evaluate the efflorescence potential for brick and structural clay tile. The method uses 2 × 2 × 20-cm specimens immersed in 5-cm of distilled water for 5 days in recipients covered with a rubber membrane. The method uses smaller samples than the standard method and has a 5-day instead of 7-day duration. Ceramic blocks from ten manufacturers from different Brazilian regions were used in this study. Results from the standard test method indicated that blocks from three manufacturers were susceptible to efflorescence while the results from the proposed method indicated that the blocks were not susceptible to efflorescence. The discrepancy in results may have been caused by the very small size of the specimens and the large amount of water in the containers used in the proposed method. The amount of soluble salts in the small specimens may not have been enough to detect their presence and the soluble salts in the submerged part of a specimen may have simply dissolved by the water. © 2019, RILEM.
864 a7004435321 Fonseca F.S. p371 False Journal 193 The Sobrado Vallim Rehabilitation Project This paper presents the assessment of the historical two story Sobrado Vallim building located in Bananal, in the state of São Paulo, Brazil. The Sobrado Vallim was built as the house of the local coffee Baron. Since being unoccupied by the family, the building has served as a school and as the City Hall; more recently the building has housed a local community association. The first story is formed by rammed earth walls supporting a wood floor. The walls on the second floor are built with adobe blocks, and several wood columns embedded into the walls support the wood roof trusses. The building has been unoccupied for several years and a temporary shoring system has been designed and installed to prevent possible collapse. The analyses included measuring and defining the building structural elements to determine their capacity. The rammed earth walls compression strength was determined using flatjacks. Samples of the adobe blocks were obtained so that their physical and mechanical properties could be determined through laboratory testing. Thermography was used to assess the wood elements condition. The proposed structural solution was to maintain the shell of the building and construct a steel frame structure within the existing elements. The steel frame would reduce the span and partially support the roof trusses at their mid-length. The ends of the wood trusses would still bear on the existing second floor walls. The proposed solution reduced significantly the loads on the existing elements, allowing the form the building to be maintained. © 2019, RILEM.
864 a7004435321 Fonseca F.S. p376 False Journal 205 Testing and analysis of masonry hollow clay block prisms filled with mortar In some design situations, in construction systems with structural masonry, an increase in the capacity of the walls is required, which can be achieved with the filling of empty cells of masonry blocks with grout. The Brazilian technical standard for clay masonry blocks aiming at attaining greater agility and flexibility in the construction process allows the use of bedding mortar instead of grout to fill the cells of the blocks. In this context, the objective of this study was to evaluate the mechanical behaviour of prisms filled with bedding mortar. Six classes of mortar and one type of clay block with nominal resistance of 6 MPa were studied. The results of the compressive strength of the prisms indicate the viability of using bedding mortar with the same structural function as grout. This article presents also an analytical study to evaluate the mechanical behaviour of clay block prisms filled with mortar. Analyses were conducted using general-purpose, nonlinear finite element software that simulates structural behaviour under different loading scenarios. A three-dimensional model of the prisms was developed using eight-node brick elements for both block and mortar with nonlinear properties assigned to each material. Copyright © 2019 Inderscience Enterprises Ltd.
864 a7004435321 Fonseca F.S. p389 False Journal 212 Numerical analyses of mortar incorporating the variation in Poisson’s ratio with increasing axial load The work presented herein evaluated the influence of compressive strength and confinement on the stress-strain behaviour of axially loaded mortar specimens by means of experimental and numerical analyses. Two mortars were tested, with volume proportions of cement: Lime: Sand of 1:0.5:4 and 1:1:6. From these two specimen heights, 50 and 140mm, with diameter of 45mm, resulting in diameter/height ratios of 1.0 and 0.3, were manufactured. The experimental results indicated that the confinement and strength of the mortar influence its stress-strain behaviour, the larger the confinement, the more, nonlinear the behaviour. In addition, the results indicated that the Poisson’s ratio and tangent modulus of elasticity vary with increasing applied load. Two numerical models were tested using the same finite element mesh, boundary conditions and load. The first model was based on the Total Strain Smeared Crack Model and the second model accounted for the observations from the experimental phase with a nonlinear “elastic phased” analysis, which updates the modulus of elasticity and the Poisson’s ratio at each new phase. The tangent modulus of elasticity was calculated directly from the experimental results while the Poisson’s ratio was approximated using the model proposed by OTTOSEN [16]. The numerical model based on the total strain smeared crack was not able to reproduce the behaviour of the compressed mortar near failure while the phased model presented satisfactory results, even close to failure, when cracking is significant. © 2019, International Masonry Society. All rights reserved.
864 a7004435321 Fonseca F.S. p504 False Journal 275 High-Strength Concrete Masonry Walls under Concentric and Eccentric Loadings Masonry walls and columns are common structural members that typically resist compressive loads, with a number of such members being required to resist combined axial load and out-of-plane bending due to direct out-of-plane loads or an eccentricity of the axial compressive load. Flexural compression strength is usually greater than axial compression strength, and a reasonable experimental data set supports this assertion. However, little information exists for high-strength concrete block masonry subjected to combined axial and flexural loadings. This paper presents axial and flexural compression strengths and deformation properties of high-strength concrete block masonry. Seventy-two masonry prisms were constructed and tested to evaluate the capacity and behavior of high-strength structural masonry subject to compressive concentric and eccentric loading; both grouted and hollow prisms were used. Block strengths of 44, 56, and 67 MPa are considered. The results show an increase of flexural compression strength of 15-29% for the hollow prisms and of 70-79% for the grouted prisms compared with their axial compression strength. Measured ultimate strain varies from 0.14 to 0.19% for the axial compression and from 0.20 to 0.25% for the flexural compression. Hollow prism strength varies from 52 to 62% of the block strength, whereas grouted prism strength varies from 43 to 59% of the block strength. © 2018 American Society of Civil Engineers.
864 a7004435321 Fonseca F.S. p601 False Conference 241 Strut-and-tie models for masonry walls with openings There is a large collection of masonry models due to the highly complex and heterogeneous nature of masonry as a structural material. While the individual masonry components can be considered isotropic at the material level, masonry assemblages are anisotropic at the structural level. These properties of masonry make it difficult to develop models that accurately describe the material behavior for all analysis and design scenarios. One analysis tool that is efficient and reliable is the use of stress fields. Stress fields are based on the lower-bound theorem of the theory of plasticity. Stress fields have been combined with the truss analogy to produce what is known as the strut-and-tie modelling procedure. This article presents ongoing research that has the objective to develop strut-and-tie modelling procedures for masonry. The presented methodology uses the existing strut-and-tie guidelines for reinforced concrete as starting point and applies that methodology to the modelling of several masonry shear walls with openings. The shear strength predictions from the proposed strut-and-tie modelling methodology are shown to perform well compared to the experimental strengths. This is associated with the ability of the strut-and-tie modelling procedure to account for the geometric particularities of each wall. © 2018 The International Masonry Society (IMS).
864 a7004435321 Fonseca F.S. p602 False Conference 242 Finite element model of dry-stack masonry shear walls Dry-stack masonry systems are constructed without mortar between the blocks. This reduces the cost of specialty laborers and the variability in construction that exists from the application of mortar. Several dry-stack systems exist and can be subcategorized as interlocking systems or surface bonded systems. In interlocking systems, the blocks are connected by their geometry while in surface bonded systems the blocks are connected by a structural coating applied to the surface of the wall. This article describes a finite element model that can be used to predict the in-plane capacity and behavior of dry-stack masonry walls with a surface coating. Four walls were built and tested for their in-plane shear capacity. Two walls were unreinforced and ungrouted and two walls were reinforced and grouted at 1.22 m both vertically and horizontally. The results of these tests were used to validate the finite element model. The finite element model was developed using VecTor2. The numerical response is in good agreement to measured response. For the ungrouted unreinforced walls, the calculated maximum load was within 4% and 14% of the measured maximum loads. For the reinforced and grouted walls, the calculated maximum load was within 8% and 1% of the measured maximum loads. © 2018 The International Masonry Society (IMS).
864 a7004435321 Fonseca F.S. p644 False Conference 276 Numerical analyses of mortar incorporating the variation in poisson's ratio with increasing axial load This work evaluated the influence of compressive strength and confinement on the stress-strain behavior of axial loaded mortar specimens by means of experimental and numerical analyses. Two mortars were tested, with volume proportions of cement, lime and sand of 1:0.5:4 and 1:1:6. Two specimen heights, 50 and 140 mm, with diameter of 45 mm, resulting in diameter/height ratios of 1.0 and 0.3, respectively were used. The experimental results indicated that the confinement and strength of the mortar influence its stress-strain behavior: the larger the confinement, the more the non-linear behavior. In addition, the results indicated that the Poisson's ratio and the tangent modulus of elasticity vary with increasing applied load. A numerical model was developed that accounted for the observations from the experimental phase with a nonlinear elastic phased analysis, which updates the modulus of elasticity and the Poisson's ratio at each new phase. The tangent modulus of elasticity was calculated directly from the experimental results while the Poisson's ratio was approximated using the model proposed by Ottosen. The numerical model presented satisfactory results, even close to the failure, when cracking is significant. © 2018 The International Masonry Society (IMS).
864 a7004435321 Fonseca F.S. p775 False Journal 382 Strength, behavior, and failure mode of hollow concrete masonry constructed with mortars of different strengths This study reports the failure modes of hollow concrete masonry prisms, taking into account the block and mortar stress-strain behavior. An extensive and detailed experimental program has been conducted on three-block high stack-bonded prisms, built using a combination of one hollow block type and three mortars with different strengths. Based on the results of the experiments, masonry failure was assessed. The main conclusion of this is that the mortar in all cases governs the masonry failure mechanism. The ratio between the masonry and block moduli of elasticity, which can be used as a measure of loss of stiffness, indicates that masonry built with a strong mortar behaves almost as a homogenous material. The typical failure mode observed during testing for this type of masonry was due to tensile stresses developed in the block. A crack developed at and propagated instantly through the block face until reaching the mortar bed joint; the crack then propagated through the head joint causing a localized split at the interface between block and mortar. For masonry built with two different weak mortars, as the stress/strength ratio increased, the ratio between the masonry and mortar moduli of elasticity decreased to 0.32 and 0.55, for the weak and the weaker mortar respectively. The observed failure mode, however, was independent of how weak the mortar was since, for both cases, the masonry failed due to localized mortar crushing. Another conclusion from the study presented herein is that a robust and reliable prediction of the masonry compressive strength requires the use of the nonlinear stress-strain relationship of the component materials. © 2016 Elsevier Ltd
865 a56781290700 Fortes E.S. p255 False Journal 167 Compressive strength of high-strength concrete masonry grouted prisms An experimental program was devised to assess the influence of the compressive strength of the grout on the compressive strength of masonry constructed with high-strength concrete masonry units. Three different compressive strengths of mortar, grout, and concrete masonry units were used. Grouts were made without and with a shrinkage-compensating admixture. The various components were combined to construct several hollow and grouted prisms, which were then tested. The results show that very high-strength blocks were not as efficient as medium-strength blocks and that there was a difference between the compressive strengths of ungrouted and grouted masonry; depending on the combination of the materials used, grouted masonry can be less or more efficient than ungrouted masonry. For one combination of materials, the shrinkage-compensating admixture was shown to be effective in reducing the grout shrinkage, and the grouted prisms constructed with that combination of materials were more efficient than their hollow prisms counterpart. Grouted prisms constructed with grouts without the shrinkage-compensating admixture were, on average, less efficient than hollow prisms. The efficiency of grouted masonry depends on many factors including compatibility of deformation between the masonry components, compaction of the grout, shrinkage characteristics of the grout, block geometry, and bond between grout and block. Further research is needed to determine the influence of these factors and obtain a complete understanding of the behavior and capacity of high strength masonry. © 2019 Elsevier Ltd
865 a56781290700 Fortes E.S. p504 True Journal 275 High-Strength Concrete Masonry Walls under Concentric and Eccentric Loadings Masonry walls and columns are common structural members that typically resist compressive loads, with a number of such members being required to resist combined axial load and out-of-plane bending due to direct out-of-plane loads or an eccentricity of the axial compressive load. Flexural compression strength is usually greater than axial compression strength, and a reasonable experimental data set supports this assertion. However, little information exists for high-strength concrete block masonry subjected to combined axial and flexural loadings. This paper presents axial and flexural compression strengths and deformation properties of high-strength concrete block masonry. Seventy-two masonry prisms were constructed and tested to evaluate the capacity and behavior of high-strength structural masonry subject to compressive concentric and eccentric loading; both grouted and hollow prisms were used. Block strengths of 44, 56, and 67 MPa are considered. The results show an increase of flexural compression strength of 15-29% for the hollow prisms and of 70-79% for the grouted prisms compared with their axial compression strength. Measured ultimate strain varies from 0.14 to 0.19% for the axial compression and from 0.20 to 0.25% for the flexural compression. Hollow prism strength varies from 52 to 62% of the block strength, whereas grouted prism strength varies from 43 to 59% of the block strength. © 2018 American Society of Civil Engineers.
866 a36055605700 Parsekian G.A. p255 False Journal 167 Compressive strength of high-strength concrete masonry grouted prisms An experimental program was devised to assess the influence of the compressive strength of the grout on the compressive strength of masonry constructed with high-strength concrete masonry units. Three different compressive strengths of mortar, grout, and concrete masonry units were used. Grouts were made without and with a shrinkage-compensating admixture. The various components were combined to construct several hollow and grouted prisms, which were then tested. The results show that very high-strength blocks were not as efficient as medium-strength blocks and that there was a difference between the compressive strengths of ungrouted and grouted masonry; depending on the combination of the materials used, grouted masonry can be less or more efficient than ungrouted masonry. For one combination of materials, the shrinkage-compensating admixture was shown to be effective in reducing the grout shrinkage, and the grouted prisms constructed with that combination of materials were more efficient than their hollow prisms counterpart. Grouted prisms constructed with grouts without the shrinkage-compensating admixture were, on average, less efficient than hollow prisms. The efficiency of grouted masonry depends on many factors including compatibility of deformation between the masonry components, compaction of the grout, shrinkage characteristics of the grout, block geometry, and bond between grout and block. Further research is needed to determine the influence of these factors and obtain a complete understanding of the behavior and capacity of high strength masonry. © 2019 Elsevier Ltd
866 a36055605700 Parsekian G.A. p339 False Journal 193 A Proposed Test to Evaluate Efflorescence Potential of Ceramic Blocks Masonry is susceptible to efflorescence, which in itself is an aesthetic problem, but the condition of efflorescence indicates that water is moving through the masonry in unintended ways and the presence of uncontrolled water can lead to serious issues, including structural problems. In this paper, the results obtained from a proposed test method to evaluate the potential of efflorescence of ceramic blocks are compared to that obtained using the method described in ASTM C67. The proposed method was developed because until 2017 there was no Brazilian Standard to evaluate the efflorescence potential for brick and structural clay tile. The method uses 2 × 2 × 20-cm specimens immersed in 5-cm of distilled water for 5 days in recipients covered with a rubber membrane. The method uses smaller samples than the standard method and has a 5-day instead of 7-day duration. Ceramic blocks from ten manufacturers from different Brazilian regions were used in this study. Results from the standard test method indicated that blocks from three manufacturers were susceptible to efflorescence while the results from the proposed method indicated that the blocks were not susceptible to efflorescence. The discrepancy in results may have been caused by the very small size of the specimens and the large amount of water in the containers used in the proposed method. The amount of soluble salts in the small specimens may not have been enough to detect their presence and the soluble salts in the submerged part of a specimen may have simply dissolved by the water. © 2019, RILEM.
866 a36055605700 Parsekian G.A. p371 True Journal 193 The Sobrado Vallim Rehabilitation Project This paper presents the assessment of the historical two story Sobrado Vallim building located in Bananal, in the state of São Paulo, Brazil. The Sobrado Vallim was built as the house of the local coffee Baron. Since being unoccupied by the family, the building has served as a school and as the City Hall; more recently the building has housed a local community association. The first story is formed by rammed earth walls supporting a wood floor. The walls on the second floor are built with adobe blocks, and several wood columns embedded into the walls support the wood roof trusses. The building has been unoccupied for several years and a temporary shoring system has been designed and installed to prevent possible collapse. The analyses included measuring and defining the building structural elements to determine their capacity. The rammed earth walls compression strength was determined using flatjacks. Samples of the adobe blocks were obtained so that their physical and mechanical properties could be determined through laboratory testing. Thermography was used to assess the wood elements condition. The proposed structural solution was to maintain the shell of the building and construct a steel frame structure within the existing elements. The steel frame would reduce the span and partially support the roof trusses at their mid-length. The ends of the wood trusses would still bear on the existing second floor walls. The proposed solution reduced significantly the loads on the existing elements, allowing the form the building to be maintained. © 2019, RILEM.
866 a36055605700 Parsekian G.A. p504 False Journal 275 High-Strength Concrete Masonry Walls under Concentric and Eccentric Loadings Masonry walls and columns are common structural members that typically resist compressive loads, with a number of such members being required to resist combined axial load and out-of-plane bending due to direct out-of-plane loads or an eccentricity of the axial compressive load. Flexural compression strength is usually greater than axial compression strength, and a reasonable experimental data set supports this assertion. However, little information exists for high-strength concrete block masonry subjected to combined axial and flexural loadings. This paper presents axial and flexural compression strengths and deformation properties of high-strength concrete block masonry. Seventy-two masonry prisms were constructed and tested to evaluate the capacity and behavior of high-strength structural masonry subject to compressive concentric and eccentric loading; both grouted and hollow prisms were used. Block strengths of 44, 56, and 67 MPa are considered. The results show an increase of flexural compression strength of 15-29% for the hollow prisms and of 70-79% for the grouted prisms compared with their axial compression strength. Measured ultimate strain varies from 0.14 to 0.19% for the axial compression and from 0.20 to 0.25% for the flexural compression. Hollow prism strength varies from 52 to 62% of the block strength, whereas grouted prism strength varies from 43 to 59% of the block strength. © 2018 American Society of Civil Engineers.
867 a16041305200 Camacho J.S. p255 False Journal 167 Compressive strength of high-strength concrete masonry grouted prisms An experimental program was devised to assess the influence of the compressive strength of the grout on the compressive strength of masonry constructed with high-strength concrete masonry units. Three different compressive strengths of mortar, grout, and concrete masonry units were used. Grouts were made without and with a shrinkage-compensating admixture. The various components were combined to construct several hollow and grouted prisms, which were then tested. The results show that very high-strength blocks were not as efficient as medium-strength blocks and that there was a difference between the compressive strengths of ungrouted and grouted masonry; depending on the combination of the materials used, grouted masonry can be less or more efficient than ungrouted masonry. For one combination of materials, the shrinkage-compensating admixture was shown to be effective in reducing the grout shrinkage, and the grouted prisms constructed with that combination of materials were more efficient than their hollow prisms counterpart. Grouted prisms constructed with grouts without the shrinkage-compensating admixture were, on average, less efficient than hollow prisms. The efficiency of grouted masonry depends on many factors including compatibility of deformation between the masonry components, compaction of the grout, shrinkage characteristics of the grout, block geometry, and bond between grout and block. Further research is needed to determine the influence of these factors and obtain a complete understanding of the behavior and capacity of high strength masonry. © 2019 Elsevier Ltd
867 a16041305200 Camacho J.S. p504 False Journal 275 High-Strength Concrete Masonry Walls under Concentric and Eccentric Loadings Masonry walls and columns are common structural members that typically resist compressive loads, with a number of such members being required to resist combined axial load and out-of-plane bending due to direct out-of-plane loads or an eccentricity of the axial compressive load. Flexural compression strength is usually greater than axial compression strength, and a reasonable experimental data set supports this assertion. However, little information exists for high-strength concrete block masonry subjected to combined axial and flexural loadings. This paper presents axial and flexural compression strengths and deformation properties of high-strength concrete block masonry. Seventy-two masonry prisms were constructed and tested to evaluate the capacity and behavior of high-strength structural masonry subject to compressive concentric and eccentric loading; both grouted and hollow prisms were used. Block strengths of 44, 56, and 67 MPa are considered. The results show an increase of flexural compression strength of 15-29% for the hollow prisms and of 70-79% for the grouted prisms compared with their axial compression strength. Measured ultimate strain varies from 0.14 to 0.19% for the axial compression and from 0.20 to 0.25% for the flexural compression. Hollow prism strength varies from 52 to 62% of the block strength, whereas grouted prism strength varies from 43 to 59% of the block strength. © 2018 American Society of Civil Engineers.
868 a57215322624 Stanley Fujimoto M. p256 True Conference 61 The polygraph: A data structure for genome alignment and variation detection Comparing whole genomes and finding variation is an important and difficult bioinfor-matic task. We present the Polygraph, a data structure for reference-free, multiple whole genome alignment that can be used to identify genomic structural variation. This data structure is built from assembled genomes and preserves the genomic structure from the assembly. It avoids the “hairball” graph structure that can occur in other graph methods such as de Bruijn graphs. The Polygraph can easily be visualized and be used for identification of structural variants. We apply the Polygraph to Escherichia coli and Saccharomyces cerevisiae for finding Structural Variants. Copyright © 2012-2020 easychair.org. All rights reserved.
869 a57204552603 Barton T.J. p257 False Journal 168 Quantifying accuracy of a concept laser metal additive machine through the NIST test artifact Purpose: The purpose of this paper is to describe the use of a test artifact proposed by NIST to quantify the dimensional accuracy of a metal additive manufacturing process. Insights from this paper are given concerning both the performance of the machine, a concept laser Mlab cusing machine, and the applicability of the NIST test artifact in characterizing accuracy. Recommendations are given for improving the artifact and standardizing a process for evaluating dimensional accuracy across the additive manufacturing industry. Design/methodology/approach: Three builds of the NIST additive manufacturing test artifact were fabricated in 316 stainless steel on a concept laser Mlab cusing machine. The paper follows the procedure described by NIST for characterizing dimensional accuracy of the additive process. Features including pins, holes and staircase flats of various sizes were measured using an optical measurement system, a touch probe and a profilometer. Findings: This paper describes the accuracy of printed features’ size and position on the test artifact, as well as surface finish on flat and inclined surfaces. Trends in variation of these dimensions are identified, along with possible root causes and remedies. This paper also describes several strengths and weaknesses in the design of the test artifact and the proposed measurement strategy, with recommendations on how to improve and standardize the process. Originality/value: This paper reviews a previously proposed design and process for measuring the capabilities of additive manufacturing processes. It also suggests improvements that can be incorporated into future designs and standardized across the industry. © 2018, Emerald Publishing Limited.
870 a57204551844 Linn J. p257 False Journal 168 Quantifying accuracy of a concept laser metal additive machine through the NIST test artifact Purpose: The purpose of this paper is to describe the use of a test artifact proposed by NIST to quantify the dimensional accuracy of a metal additive manufacturing process. Insights from this paper are given concerning both the performance of the machine, a concept laser Mlab cusing machine, and the applicability of the NIST test artifact in characterizing accuracy. Recommendations are given for improving the artifact and standardizing a process for evaluating dimensional accuracy across the additive manufacturing industry. Design/methodology/approach: Three builds of the NIST additive manufacturing test artifact were fabricated in 316 stainless steel on a concept laser Mlab cusing machine. The paper follows the procedure described by NIST for characterizing dimensional accuracy of the additive process. Features including pins, holes and staircase flats of various sizes were measured using an optical measurement system, a touch probe and a profilometer. Findings: This paper describes the accuracy of printed features’ size and position on the test artifact, as well as surface finish on flat and inclined surfaces. Trends in variation of these dimensions are identified, along with possible root causes and remedies. This paper also describes several strengths and weaknesses in the design of the test artifact and the proposed measurement strategy, with recommendations on how to improve and standardize the process. Originality/value: This paper reviews a previously proposed design and process for measuring the capabilities of additive manufacturing processes. It also suggests improvements that can be incorporated into future designs and standardized across the industry. © 2018, Emerald Publishing Limited.
871 a57204547933 Jenkins D. p257 False Journal 168 Quantifying accuracy of a concept laser metal additive machine through the NIST test artifact Purpose: The purpose of this paper is to describe the use of a test artifact proposed by NIST to quantify the dimensional accuracy of a metal additive manufacturing process. Insights from this paper are given concerning both the performance of the machine, a concept laser Mlab cusing machine, and the applicability of the NIST test artifact in characterizing accuracy. Recommendations are given for improving the artifact and standardizing a process for evaluating dimensional accuracy across the additive manufacturing industry. Design/methodology/approach: Three builds of the NIST additive manufacturing test artifact were fabricated in 316 stainless steel on a concept laser Mlab cusing machine. The paper follows the procedure described by NIST for characterizing dimensional accuracy of the additive process. Features including pins, holes and staircase flats of various sizes were measured using an optical measurement system, a touch probe and a profilometer. Findings: This paper describes the accuracy of printed features’ size and position on the test artifact, as well as surface finish on flat and inclined surfaces. Trends in variation of these dimensions are identified, along with possible root causes and remedies. This paper also describes several strengths and weaknesses in the design of the test artifact and the proposed measurement strategy, with recommendations on how to improve and standardize the process. Originality/value: This paper reviews a previously proposed design and process for measuring the capabilities of additive manufacturing processes. It also suggests improvements that can be incorporated into future designs and standardized across the industry. © 2018, Emerald Publishing Limited.
872 a57195217444 Smith R. p257 False Journal 168 Quantifying accuracy of a concept laser metal additive machine through the NIST test artifact Purpose: The purpose of this paper is to describe the use of a test artifact proposed by NIST to quantify the dimensional accuracy of a metal additive manufacturing process. Insights from this paper are given concerning both the performance of the machine, a concept laser Mlab cusing machine, and the applicability of the NIST test artifact in characterizing accuracy. Recommendations are given for improving the artifact and standardizing a process for evaluating dimensional accuracy across the additive manufacturing industry. Design/methodology/approach: Three builds of the NIST additive manufacturing test artifact were fabricated in 316 stainless steel on a concept laser Mlab cusing machine. The paper follows the procedure described by NIST for characterizing dimensional accuracy of the additive process. Features including pins, holes and staircase flats of various sizes were measured using an optical measurement system, a touch probe and a profilometer. Findings: This paper describes the accuracy of printed features’ size and position on the test artifact, as well as surface finish on flat and inclined surfaces. Trends in variation of these dimensions are identified, along with possible root causes and remedies. This paper also describes several strengths and weaknesses in the design of the test artifact and the proposed measurement strategy, with recommendations on how to improve and standardize the process. Originality/value: This paper reviews a previously proposed design and process for measuring the capabilities of additive manufacturing processes. It also suggests improvements that can be incorporated into future designs and standardized across the industry. © 2018, Emerald Publishing Limited.
873 a57200690449 Arnold B.T. p259 True Journal 101 The Effect of Antenna Mutual Coupling on MIMO Radar System Performance Multiple-input multiple-output (MIMO) radar systems use orthogonal signaling to enable combined transmit and receive beamforming through signal processing on the received signals. Because of the combined role of transmit and receive arrays in this processing for monostatic MIMO radar, mutual coupling present in these arrays impacts the beamforming in a unique way. This paper presents a mathematical model of a MIMO radar with coupled antennas and appropriate radio frequency circuitry. Application of the model to evaluate radar detection of a single target demonstrates that coupling can result in target detection angles that are in error by as much as 12° and increase beamformer response sidelobe levels by as much as 8 dB. The results also show that a simple matching network can improve detection performance, particularly when array mutual coupling is high. © 1963-2012 IEEE.
873 a57200690449 Arnold B.T. p549 True Conference 199 Moment method analysis of a reconfigurable OTA reverberation chamber While determining modes in a rectangular cavity is a straightforward analytical exercise, fully understanding the behavior of the fields in a large over-moded cavity whose walls are lined with antennas, such as the reconfigurable over-the-air chamber, is a more complicated undertaking. This paper uses the Moment Method to analyze such a chamber, where each wall is lined with 9 monopole antennas. The evaluation of the cavity Green's function used in the numerical computation is accelerated through the use of Ewald's method. A comparison of scattering parameters between monopoles on the walls obtained both by the Moment Method analysis and experimental measurements shows that the technique is highly accurate in predicting the chamber field behavior. © 2018 Institution of Engineering and Technology.All Rights Reserved.
874 a57208717150 Lee A. p260 True Journal 170 Turning depths: Evanescent to propagating wave kinetic energy density Tidal flow over oceanic topography generates internal waves when the natural frequency N of the water is greater than the tidal frequency ω. When N<ω, evanescent waves are generated. Although the amplitude and kinetic energy of evanescent waves decay rapidly, if the wave reaches a turning depth, where N=ω, and moves into a region where N>ω, the evanescent wave becomes an internal wave. This work expands upon previous research of varying stratifications by investigating the kinetic energy density in internal waves generated by evanescent waves passing through a turning depth. An analytical model is presented and compared to synthetic schlieren experiments of two Gaussian-shaped topographies. The model and experiments both indicate that the kinetic energy density of internal waves increases with decreasing topographic slope, when the distance between the topography and the turning depth decreases and when the average Froude number in the evanescent region is close to one. The model is used to estimate the normalized kinetic energy density of internal waves generated from an oceanic feature located within an evanescent region. © 2019 American Physical Society.
875 a57204091960 Allen Q.S. p261 True Journal 171 Microstructural evaluation of hydrogen embrittlement and successive recovery in advanced high strength steel Advanced high strength steels (AHSS) have high susceptibility to hydrogen embrittlement, and are often exposed to hydrogen environments in processing. In order to study the embrittlement and recovery of steel, tensile tests were conducted on two different types of AHSS over time after hydrogen charging. Concentration measurements and hydrogen microprinting were carried out at the same time steps to visualize the hydrogen behavior during recovery. The diffusible hydrogen concentration was found to decay exponentially, and empirical relations were found for both types of steel. Hydrogen concentration decay rates were determined to be -0.355 /hr in TBF-980, and -0.225 /hr in DP-980. Hydrogen concentration thresholds for embrittlement were found to be 1.04 mL/100 g for TBF, and 0.87 mL/100 g for DP steel. TBF steel is predicted to recover from embrittlement within 4.2 h, compared to 7.2 h in DP steel. A two-factor method of evaluating recovery from embrittlement, requiring hydrogen concentration threshold and decay rate, is explained for use in predicting recovery after exposure to hydrogen. Anisotropic hydrogen diffusion rates were also observed on the surface of both steels for a short time after charging, as hydrogen left the surface through <001> and <101> grains faster than grains with <111> orientations. This could be explained by differences in surface energies between the different orientations. © 2018 Elsevier B.V.
876 a56353116200 Allen J.D. p262 True Journal 172 Over-Design Versus Redesign as a Response to Future Requirements Though little research has been done in the field of over-design as a product development strategy, an over-design approach can help products avoid the issue of premature obsolescence. This paper compares over-design to redesign as approaches to address the emergence of future requirements. Net present value (NPV) analyses of several real world applications are examined from the perspective of manufacturers (i.e., defense contractors, automobile, pharmaceutical, and microprocessor manufactures) and customers (i.e., purchases of vehicles, televisions, cell phones, washing machines, and buildings). This analysis is used to determine the conditions under which an over-design approach provides a greater benefit than a redesign approach. Over-design is found to have a higher NPV than redesign when future requirements occur soon after the initial release, discount rates are low, initial research, and development cost or price is high, and when the incremental costs of the future requirements are low. © 2019 by ASME.
876 a56353116200 Allen J.D. p585 True Conference 230 Over-design versus redesign as a response to future requirements Though little research has been done in the field of overdesign as a product development strategy, an over-design approach can help products avoid the issue of premature obsolescence. This paper compares over-design to redesign as approaches to address the emergence of future requirements. Net present value (NPV) analyses of several real world applications are examined from the perspective of manufacturers and customers. This analysis is used to determine the conditions under which an over-design approach provides a greater benefit than a redesign approach. Over-design is found to have a higher net present value than redesign when future requirements occur soon after the initial release, discount rates are low, initial research and development cost or price is high, and when the incremental costs of the future requirements are low. Copyright © 2018 ASME.
876 a56353116200 Allen J.D. p689 True Journal 335 Design for excess capability to handle uncertain product requirements in a developing world setting Products designed for the developing world often go unused or underused by the intended customers. One cause of this problem is uncertainty regarding the actual requirements of customers in the developing world. This can result when designers, with experience in technologically advanced countries, apply their own value structure to the products they design. Because of the designers’ lack of experience in the culture and environment of the developing world, the actual requirements are only partially known to them. This problem can be mitigated by (i) optimizing product flexibility and adaptability to react to uncertain requirements, and (ii) reducing the most critical uncertainties. The flexibility of a product to adapt to new or changing requirements has been shown to extend the service life of large complex engineered systems (e.g., aircraft carriers, aircraft, communication systems, and space craft). These systems must remain in service for extended periods of time, even though the environments and requirements may change dramatically. Applying these proven techniques to products designed for the developing world can alleviate the problem of uncertain requirements. This paper presents and demonstrates a technique aimed at improving the success of developing world engineering projects. Flexibility and adaptability minimize the impact of uncertainties, and are enabled by numerically optimized amounts of designed-in excess. A sensitivity analysis performed on the system model helps the designer prioritize the set of uncertain requirements and parameters for refinement. The technique is demonstrated in the design of a cookstove intended for use in the developing world. © 2017, Springer-Verlag London.
877 a6603717022 Hatch N.W. p262 False Journal 172 Over-Design Versus Redesign as a Response to Future Requirements Though little research has been done in the field of over-design as a product development strategy, an over-design approach can help products avoid the issue of premature obsolescence. This paper compares over-design to redesign as approaches to address the emergence of future requirements. Net present value (NPV) analyses of several real world applications are examined from the perspective of manufacturers (i.e., defense contractors, automobile, pharmaceutical, and microprocessor manufactures) and customers (i.e., purchases of vehicles, televisions, cell phones, washing machines, and buildings). This analysis is used to determine the conditions under which an over-design approach provides a greater benefit than a redesign approach. Over-design is found to have a higher NPV than redesign when future requirements occur soon after the initial release, discount rates are low, initial research, and development cost or price is high, and when the incremental costs of the future requirements are low. © 2019 by ASME.
877 a6603717022 Hatch N.W. p585 False Conference 230 Over-design versus redesign as a response to future requirements Though little research has been done in the field of overdesign as a product development strategy, an over-design approach can help products avoid the issue of premature obsolescence. This paper compares over-design to redesign as approaches to address the emergence of future requirements. Net present value (NPV) analyses of several real world applications are examined from the perspective of manufacturers and customers. This analysis is used to determine the conditions under which an over-design approach provides a greater benefit than a redesign approach. Over-design is found to have a higher net present value than redesign when future requirements occur soon after the initial release, discount rates are low, initial research and development cost or price is high, and when the incremental costs of the future requirements are low. Copyright © 2018 ASME.
878 a57210923446 Chen J. p264 True Journal 173 Biocompatible and sustainable power supply for self-powered wearable and implantable electronics using III-nitride thin-film-based flexible piezoelectric generator Energy harvesters that scavenge biomechanical energy are promising power supply candidates for wearable and implantable electronics. Of the most widely used energy harvesters, piezoelectric generators can generate more electric charge than their triboelectric counterparts with similar device size, thus are more suitable to make compact wearable devices. However, most high-power piezoelectric generators are made from lead zirconate titanate, making them undesirable for wearable applications due to the toxic lead element. In this study, a flexible piezoelectric generator (F-PEG) is fabricated with chemically stable and biocompatible Group-III-nitride (III-N) thin film by a layer-transfer method. The III-N thin-film F-PEG can generate an open-circuit voltage of 50 V, a short-circuit current of 15 µA, and a maximum power of 167 µW at a load resistance of 5 MΩ. Applications of the III-N thin-film F-PEG are demonstrated by directly powering electronics such as light-emitting diodes and electric watches, and by charging commercial capacitors and batteries to operate an optical pulse sensor. Furthermore, the III-N thin-film F-PEG shows good durability and a stable output after being subjected to severe buckling tests of over 30,000 cycles. © 2019 Elsevier Ltd
879 a55652695700 Oh S.K. p264 False Journal 173 Biocompatible and sustainable power supply for self-powered wearable and implantable electronics using III-nitride thin-film-based flexible piezoelectric generator Energy harvesters that scavenge biomechanical energy are promising power supply candidates for wearable and implantable electronics. Of the most widely used energy harvesters, piezoelectric generators can generate more electric charge than their triboelectric counterparts with similar device size, thus are more suitable to make compact wearable devices. However, most high-power piezoelectric generators are made from lead zirconate titanate, making them undesirable for wearable applications due to the toxic lead element. In this study, a flexible piezoelectric generator (F-PEG) is fabricated with chemically stable and biocompatible Group-III-nitride (III-N) thin film by a layer-transfer method. The III-N thin-film F-PEG can generate an open-circuit voltage of 50 V, a short-circuit current of 15 µA, and a maximum power of 167 µW at a load resistance of 5 MΩ. Applications of the III-N thin-film F-PEG are demonstrated by directly powering electronics such as light-emitting diodes and electric watches, and by charging commercial capacitors and batteries to operate an optical pulse sensor. Furthermore, the III-N thin-film F-PEG shows good durability and a stable output after being subjected to severe buckling tests of over 30,000 cycles. © 2019 Elsevier Ltd
880 a57205329719 Nabulsi N. p264 False Journal 173 Biocompatible and sustainable power supply for self-powered wearable and implantable electronics using III-nitride thin-film-based flexible piezoelectric generator Energy harvesters that scavenge biomechanical energy are promising power supply candidates for wearable and implantable electronics. Of the most widely used energy harvesters, piezoelectric generators can generate more electric charge than their triboelectric counterparts with similar device size, thus are more suitable to make compact wearable devices. However, most high-power piezoelectric generators are made from lead zirconate titanate, making them undesirable for wearable applications due to the toxic lead element. In this study, a flexible piezoelectric generator (F-PEG) is fabricated with chemically stable and biocompatible Group-III-nitride (III-N) thin film by a layer-transfer method. The III-N thin-film F-PEG can generate an open-circuit voltage of 50 V, a short-circuit current of 15 µA, and a maximum power of 167 µW at a load resistance of 5 MΩ. Applications of the III-N thin-film F-PEG are demonstrated by directly powering electronics such as light-emitting diodes and electric watches, and by charging commercial capacitors and batteries to operate an optical pulse sensor. Furthermore, the III-N thin-film F-PEG shows good durability and a stable output after being subjected to severe buckling tests of over 30,000 cycles. © 2019 Elsevier Ltd
881 a57199801999 Johnson H. p264 False Journal 173 Biocompatible and sustainable power supply for self-powered wearable and implantable electronics using III-nitride thin-film-based flexible piezoelectric generator Energy harvesters that scavenge biomechanical energy are promising power supply candidates for wearable and implantable electronics. Of the most widely used energy harvesters, piezoelectric generators can generate more electric charge than their triboelectric counterparts with similar device size, thus are more suitable to make compact wearable devices. However, most high-power piezoelectric generators are made from lead zirconate titanate, making them undesirable for wearable applications due to the toxic lead element. In this study, a flexible piezoelectric generator (F-PEG) is fabricated with chemically stable and biocompatible Group-III-nitride (III-N) thin film by a layer-transfer method. The III-N thin-film F-PEG can generate an open-circuit voltage of 50 V, a short-circuit current of 15 µA, and a maximum power of 167 µW at a load resistance of 5 MΩ. Applications of the III-N thin-film F-PEG are demonstrated by directly powering electronics such as light-emitting diodes and electric watches, and by charging commercial capacitors and batteries to operate an optical pulse sensor. Furthermore, the III-N thin-film F-PEG shows good durability and a stable output after being subjected to severe buckling tests of over 30,000 cycles. © 2019 Elsevier Ltd
882 a57193242858 Wang W. p264 False Journal 173 Biocompatible and sustainable power supply for self-powered wearable and implantable electronics using III-nitride thin-film-based flexible piezoelectric generator Energy harvesters that scavenge biomechanical energy are promising power supply candidates for wearable and implantable electronics. Of the most widely used energy harvesters, piezoelectric generators can generate more electric charge than their triboelectric counterparts with similar device size, thus are more suitable to make compact wearable devices. However, most high-power piezoelectric generators are made from lead zirconate titanate, making them undesirable for wearable applications due to the toxic lead element. In this study, a flexible piezoelectric generator (F-PEG) is fabricated with chemically stable and biocompatible Group-III-nitride (III-N) thin film by a layer-transfer method. The III-N thin-film F-PEG can generate an open-circuit voltage of 50 V, a short-circuit current of 15 µA, and a maximum power of 167 µW at a load resistance of 5 MΩ. Applications of the III-N thin-film F-PEG are demonstrated by directly powering electronics such as light-emitting diodes and electric watches, and by charging commercial capacitors and batteries to operate an optical pulse sensor. Furthermore, the III-N thin-film F-PEG shows good durability and a stable output after being subjected to severe buckling tests of over 30,000 cycles. © 2019 Elsevier Ltd
883 a7005512824 Ryou J.-H. p264 False Journal 173 Biocompatible and sustainable power supply for self-powered wearable and implantable electronics using III-nitride thin-film-based flexible piezoelectric generator Energy harvesters that scavenge biomechanical energy are promising power supply candidates for wearable and implantable electronics. Of the most widely used energy harvesters, piezoelectric generators can generate more electric charge than their triboelectric counterparts with similar device size, thus are more suitable to make compact wearable devices. However, most high-power piezoelectric generators are made from lead zirconate titanate, making them undesirable for wearable applications due to the toxic lead element. In this study, a flexible piezoelectric generator (F-PEG) is fabricated with chemically stable and biocompatible Group-III-nitride (III-N) thin film by a layer-transfer method. The III-N thin-film F-PEG can generate an open-circuit voltage of 50 V, a short-circuit current of 15 µA, and a maximum power of 167 µW at a load resistance of 5 MΩ. Applications of the III-N thin-film F-PEG are demonstrated by directly powering electronics such as light-emitting diodes and electric watches, and by charging commercial capacitors and batteries to operate an optical pulse sensor. Furthermore, the III-N thin-film F-PEG shows good durability and a stable output after being subjected to severe buckling tests of over 30,000 cycles. © 2019 Elsevier Ltd
884 a57205263313 Hogg S.M. p265 True Journal 174 Nonlinear resonant ultrasound spectroscopy of stress corrosion cracking in stainless steel rods Stainless steel containers are susceptible to stress corrosion cracking (SCC) under certain stress and corrosion conditions. Nonlinear ultrasonic techniques are very sensitive to the early presence of damage, more so than linear techniques. Nonlinear Resonant Ultrasound Spectroscopy (NRUS) is used here to measure a nonlinear shift in the resonance frequency due to a cumulative amount of SCC. Steel rods are immersed in a heated magnesium chloride solution and removed after different exposure times. NRUS measurements are conducted using the fundamental longitudinal mode of vibration. Rods exposed longer generally have a larger resonance frequency shift and are therefore more nonlinear. Thus NRUS might offer a means of detecting a cumulative SCC damage in a sample. © 2018 Elsevier Ltd
885 a36953700600 Le Bas P.-Y. p265 False Journal 174 Nonlinear resonant ultrasound spectroscopy of stress corrosion cracking in stainless steel rods Stainless steel containers are susceptible to stress corrosion cracking (SCC) under certain stress and corrosion conditions. Nonlinear ultrasonic techniques are very sensitive to the early presence of damage, more so than linear techniques. Nonlinear Resonant Ultrasound Spectroscopy (NRUS) is used here to measure a nonlinear shift in the resonance frequency due to a cumulative amount of SCC. Steel rods are immersed in a heated magnesium chloride solution and removed after different exposure times. NRUS measurements are conducted using the fundamental longitudinal mode of vibration. Rods exposed longer generally have a larger resonance frequency shift and are therefore more nonlinear. Thus NRUS might offer a means of detecting a cumulative SCC damage in a sample. © 2018 Elsevier Ltd
885 a36953700600 Le Bas P.-Y. p620 False Journal 310 Time reversal techniques Time reversal is a technique to focus wave energy to a selected point in space and time, localize and characterize a source of wave propagation, and/or communicate information between two points. This chapter will introduce the reader to the concept of time reversal and different implementations of this concept. The focus will then be directed to non-destructive evaluation applications using nonlinear elasto-dynamics together with time reversal. © Springer Nature Switzerland AG 2019.
886 a23970286000 Bathe M. p266 True Journal 175 Roadmap on biological pathways for electronic nanofabrication and materials Conventional microchip fabrication is energy and resource intensive. Thus, the discovery of new manufacturing approaches that reduce these expenditures would be highly beneficial to the semiconductor industry. In comparison, living systems construct complex nanometer-scale structures with high yields and low energy utilization. Combining the capabilities of living systems with synthetic DNA-/protein-based self-assembly may offer intriguing potential for revolutionizing the synthesis of complex sub-10 nm information processing architectures. The successful discovery of new biologically based paradigms would not only help extend the current semiconductor technology roadmap, but also offer additional potential growth areas in biology, medicine, agriculture and sustainability for the semiconductor industry. This article summarizes discussions surrounding key emerging technologies explored at the Workshop on Biological Pathways for Electronic Nanofabrication and Materials that was held on 16–17 November 2016 at the IBM Almaden Research Center in San Jose, CA. © 2019 IOP Publishing Ltd.
887 a57194276793 Chrisey L.A. p266 False Journal 175 Roadmap on biological pathways for electronic nanofabrication and materials Conventional microchip fabrication is energy and resource intensive. Thus, the discovery of new manufacturing approaches that reduce these expenditures would be highly beneficial to the semiconductor industry. In comparison, living systems construct complex nanometer-scale structures with high yields and low energy utilization. Combining the capabilities of living systems with synthetic DNA-/protein-based self-assembly may offer intriguing potential for revolutionizing the synthesis of complex sub-10 nm information processing architectures. The successful discovery of new biologically based paradigms would not only help extend the current semiconductor technology roadmap, but also offer additional potential growth areas in biology, medicine, agriculture and sustainability for the semiconductor industry. This article summarizes discussions surrounding key emerging technologies explored at the Workshop on Biological Pathways for Electronic Nanofabrication and Materials that was held on 16–17 November 2016 at the IBM Almaden Research Center in San Jose, CA. © 2019 IOP Publishing Ltd.
888 a57208827685 Herr D.J.C. p266 False Journal 175 Roadmap on biological pathways for electronic nanofabrication and materials Conventional microchip fabrication is energy and resource intensive. Thus, the discovery of new manufacturing approaches that reduce these expenditures would be highly beneficial to the semiconductor industry. In comparison, living systems construct complex nanometer-scale structures with high yields and low energy utilization. Combining the capabilities of living systems with synthetic DNA-/protein-based self-assembly may offer intriguing potential for revolutionizing the synthesis of complex sub-10 nm information processing architectures. The successful discovery of new biologically based paradigms would not only help extend the current semiconductor technology roadmap, but also offer additional potential growth areas in biology, medicine, agriculture and sustainability for the semiconductor industry. This article summarizes discussions surrounding key emerging technologies explored at the Workshop on Biological Pathways for Electronic Nanofabrication and Materials that was held on 16–17 November 2016 at the IBM Almaden Research Center in San Jose, CA. © 2019 IOP Publishing Ltd.
889 a7401703652 Lin Q. p266 False Journal 175 Roadmap on biological pathways for electronic nanofabrication and materials Conventional microchip fabrication is energy and resource intensive. Thus, the discovery of new manufacturing approaches that reduce these expenditures would be highly beneficial to the semiconductor industry. In comparison, living systems construct complex nanometer-scale structures with high yields and low energy utilization. Combining the capabilities of living systems with synthetic DNA-/protein-based self-assembly may offer intriguing potential for revolutionizing the synthesis of complex sub-10 nm information processing architectures. The successful discovery of new biologically based paradigms would not only help extend the current semiconductor technology roadmap, but also offer additional potential growth areas in biology, medicine, agriculture and sustainability for the semiconductor industry. This article summarizes discussions surrounding key emerging technologies explored at the Workshop on Biological Pathways for Electronic Nanofabrication and Materials that was held on 16–17 November 2016 at the IBM Almaden Research Center in San Jose, CA. © 2019 IOP Publishing Ltd.
890 a57202228997 Rasic D. p266 False Journal 175 Roadmap on biological pathways for electronic nanofabrication and materials Conventional microchip fabrication is energy and resource intensive. Thus, the discovery of new manufacturing approaches that reduce these expenditures would be highly beneficial to the semiconductor industry. In comparison, living systems construct complex nanometer-scale structures with high yields and low energy utilization. Combining the capabilities of living systems with synthetic DNA-/protein-based self-assembly may offer intriguing potential for revolutionizing the synthesis of complex sub-10 nm information processing architectures. The successful discovery of new biologically based paradigms would not only help extend the current semiconductor technology roadmap, but also offer additional potential growth areas in biology, medicine, agriculture and sustainability for the semiconductor industry. This article summarizes discussions surrounding key emerging technologies explored at the Workshop on Biological Pathways for Electronic Nanofabrication and Materials that was held on 16–17 November 2016 at the IBM Almaden Research Center in San Jose, CA. © 2019 IOP Publishing Ltd.
891 a54415129200 Zadegan R.M. p266 False Journal 175 Roadmap on biological pathways for electronic nanofabrication and materials Conventional microchip fabrication is energy and resource intensive. Thus, the discovery of new manufacturing approaches that reduce these expenditures would be highly beneficial to the semiconductor industry. In comparison, living systems construct complex nanometer-scale structures with high yields and low energy utilization. Combining the capabilities of living systems with synthetic DNA-/protein-based self-assembly may offer intriguing potential for revolutionizing the synthesis of complex sub-10 nm information processing architectures. The successful discovery of new biologically based paradigms would not only help extend the current semiconductor technology roadmap, but also offer additional potential growth areas in biology, medicine, agriculture and sustainability for the semiconductor industry. This article summarizes discussions surrounding key emerging technologies explored at the Workshop on Biological Pathways for Electronic Nanofabrication and Materials that was held on 16–17 November 2016 at the IBM Almaden Research Center in San Jose, CA. © 2019 IOP Publishing Ltd.
892 a7005373645 Zhirnov V.V. p266 False Journal 175 Roadmap on biological pathways for electronic nanofabrication and materials Conventional microchip fabrication is energy and resource intensive. Thus, the discovery of new manufacturing approaches that reduce these expenditures would be highly beneficial to the semiconductor industry. In comparison, living systems construct complex nanometer-scale structures with high yields and low energy utilization. Combining the capabilities of living systems with synthetic DNA-/protein-based self-assembly may offer intriguing potential for revolutionizing the synthesis of complex sub-10 nm information processing architectures. The successful discovery of new biologically based paradigms would not only help extend the current semiconductor technology roadmap, but also offer additional potential growth areas in biology, medicine, agriculture and sustainability for the semiconductor industry. This article summarizes discussions surrounding key emerging technologies explored at the Workshop on Biological Pathways for Electronic Nanofabrication and Materials that was held on 16–17 November 2016 at the IBM Almaden Research Center in San Jose, CA. © 2019 IOP Publishing Ltd.
893 a57202047395 Noronha D.H. p268 True Conference 63 On-chip FPGA debug instrumentation for machine learning applications FPGAs provide a promising implementation option for many machine learning applications. Although simulations or software models can be used to explore the design space of these applications, often the final behaviour can not be evaluated until the design is mapped to the FPGA and integrated into the target system. This may be because long run-times are required, or because the environment can not be adequately described using a software model. Once unexpected behaviour is observed, on-chip debug is notoriously difficult; typically a design is instrumented with on-chip trace buffers that record the run-time behaviour for later interrogation. In this paper, we describe instrumentation that can accelerate the process of debugging machine learning applications implemented on an FPGA. Unlike previous work, our instrumentation is optimized to take advantage of characteristics of this application domain. Our instruments gather useful domain-specific information about the observed variables instead of recording the raw values of those elements. Results show that the proposed instruments provide at least 17.8x longer visibility in the most conservative of our experiments at a low area and latency cost. © 2019 Association for Computing Machinery.
894 a57193927413 Zhao R. p268 False Conference 63 On-chip FPGA debug instrumentation for machine learning applications FPGAs provide a promising implementation option for many machine learning applications. Although simulations or software models can be used to explore the design space of these applications, often the final behaviour can not be evaluated until the design is mapped to the FPGA and integrated into the target system. This may be because long run-times are required, or because the environment can not be adequately described using a software model. Once unexpected behaviour is observed, on-chip debug is notoriously difficult; typically a design is instrumented with on-chip trace buffers that record the run-time behaviour for later interrogation. In this paper, we describe instrumentation that can accelerate the process of debugging machine learning applications implemented on an FPGA. Unlike previous work, our instrumentation is optimized to take advantage of characteristics of this application domain. Our instruments gather useful domain-specific information about the observed variables instead of recording the raw values of those elements. Results show that the proposed instruments provide at least 17.8x longer visibility in the most conservative of our experiments at a low area and latency cost. © 2019 Association for Computing Machinery.
895 a26029526200 Luk W. p268 False Conference 63 On-chip FPGA debug instrumentation for machine learning applications FPGAs provide a promising implementation option for many machine learning applications. Although simulations or software models can be used to explore the design space of these applications, often the final behaviour can not be evaluated until the design is mapped to the FPGA and integrated into the target system. This may be because long run-times are required, or because the environment can not be adequately described using a software model. Once unexpected behaviour is observed, on-chip debug is notoriously difficult; typically a design is instrumented with on-chip trace buffers that record the run-time behaviour for later interrogation. In this paper, we describe instrumentation that can accelerate the process of debugging machine learning applications implemented on an FPGA. Unlike previous work, our instrumentation is optimized to take advantage of characteristics of this application domain. Our instruments gather useful domain-specific information about the observed variables instead of recording the raw values of those elements. Results show that the proposed instruments provide at least 17.8x longer visibility in the most conservative of our experiments at a low area and latency cost. © 2019 Association for Computing Machinery.
896 a7006799143 Wilton S.J.E. p268 False Conference 63 On-chip FPGA debug instrumentation for machine learning applications FPGAs provide a promising implementation option for many machine learning applications. Although simulations or software models can be used to explore the design space of these applications, often the final behaviour can not be evaluated until the design is mapped to the FPGA and integrated into the target system. This may be because long run-times are required, or because the environment can not be adequately described using a software model. Once unexpected behaviour is observed, on-chip debug is notoriously difficult; typically a design is instrumented with on-chip trace buffers that record the run-time behaviour for later interrogation. In this paper, we describe instrumentation that can accelerate the process of debugging machine learning applications implemented on an FPGA. Unlike previous work, our instrumentation is optimized to take advantage of characteristics of this application domain. Our instruments gather useful domain-specific information about the observed variables instead of recording the raw values of those elements. Results show that the proposed instruments provide at least 17.8x longer visibility in the most conservative of our experiments at a low area and latency cost. © 2019 Association for Computing Machinery.
896 a7006799143 Wilton S.J.E. p538 False Conference 194 Architecture exploration for HLS-oriented FPGA debug overlays High-Level Synthesis (HLS) promises improved designer productivity, but requires a debug ecosystem that allows designers to debug in the context of the original source code. Recent work has presented in-system debug frameworks where instrumentation added to the design collects trace data as the circuit runs, and a software tool that allows the user to replay the execution using the captured data. When searching for the root cause of a bug, the designer may need to modify the instrumentation to collect data from a new part of the design, requiring a lengthy recompile. In this paper, we propose a flexible debug overlay family that provides software-like debug turn-around times for HLS generated circuits. At compile time, the overlay is added to the design and compiled. At debug time, the overlay can be configured many times to implement specific debug scenarios without a recompilation. This paper first outlines a number of “capabilities” that such an overlay should have, and then describes architectural support for each of these capabilities. The cheapest overlay variant allows selective variable tracing with only a 1.7% increase in area overhead from the baseline debug instrumentation, while the deluxe variant offers 2x-7x improvement in trace buffer memory utilization with conditional buffer freeze support. © 2018 Association for Computing Machinery.
897 a57203922639 Stubbs C.J. p269 True Journal 176 Measuring the transverse Young's modulus of maize rind and pith tissues Wind-induced bending loads frequently cause failure of maize (corn) stalks. When failure occurs, it usually manifests as transverse buckling. Because this failure mode is closely related to transverse tissue stiffness, the purpose of this study was to develop a method for measuring the transverse Young's modulus of maize stalk rind and pith tissues. Short, disc-shaped stalk segments were used for this purpose. X-ray computed tomography was used to obtain the geometry of each specimen prior to testing. Each specimen was tested in two different configurations. Computed tomography data was used to create a specimen-specific finite element model of each test specimen. Data from the first testing configuration was used in conjunction with the finite element model to determine the Young's Modulus values for each specimen. The specimen-specific finite element models provided estimates of the stress states in the stem under transverse loading, and these stress states accurately predicted the location of failure in transverse test specimens. The entire testing method was validated using data from one test configuration to predict the structural response of each specimen during the second test configuration. © 2018
898 a57196487336 Sun W. p269 False Journal 176 Measuring the transverse Young's modulus of maize rind and pith tissues Wind-induced bending loads frequently cause failure of maize (corn) stalks. When failure occurs, it usually manifests as transverse buckling. Because this failure mode is closely related to transverse tissue stiffness, the purpose of this study was to develop a method for measuring the transverse Young's modulus of maize stalk rind and pith tissues. Short, disc-shaped stalk segments were used for this purpose. X-ray computed tomography was used to obtain the geometry of each specimen prior to testing. Each specimen was tested in two different configurations. Computed tomography data was used to create a specimen-specific finite element model of each test specimen. Data from the first testing configuration was used in conjunction with the finite element model to determine the Young's Modulus values for each specimen. The specimen-specific finite element models provided estimates of the stress states in the stem under transverse loading, and these stress states accurately predicted the location of failure in transverse test specimens. The entire testing method was validated using data from one test configuration to predict the structural response of each specimen during the second test configuration. © 2018
899 a16199522200 Cook D.D. p269 False Journal 176 Measuring the transverse Young's modulus of maize rind and pith tissues Wind-induced bending loads frequently cause failure of maize (corn) stalks. When failure occurs, it usually manifests as transverse buckling. Because this failure mode is closely related to transverse tissue stiffness, the purpose of this study was to develop a method for measuring the transverse Young's modulus of maize stalk rind and pith tissues. Short, disc-shaped stalk segments were used for this purpose. X-ray computed tomography was used to obtain the geometry of each specimen prior to testing. Each specimen was tested in two different configurations. Computed tomography data was used to create a specimen-specific finite element model of each test specimen. Data from the first testing configuration was used in conjunction with the finite element model to determine the Young's Modulus values for each specimen. The specimen-specific finite element models provided estimates of the stress states in the stem under transverse loading, and these stress states accurately predicted the location of failure in transverse test specimens. The entire testing method was validated using data from one test configuration to predict the structural response of each specimen during the second test configuration. © 2018
900 a56985459400 Kraus D. p270 False Journal 177 Configuration estimation for accurate position control of large-scale soft robots There is a significant trend in robotics of exploring passively compliant and low inertia systems that can safely make contact with the environment. This paper defines many of the problems associated with developing effective control of soft, pneumatically actuated, inflatable robots, and proposes an approach to solving a subset of these problems. We show that we can obtain a global measurement of orientation for a given soft-robot link using two different types of sensors (not including motion capture). Given the orientation measurement, it is possible to estimate relative configurations of the soft actuators and joints. In order to validate the ability to control position and orientation at the end effector, we show a new method for calibrating the coordinate frames of two unrelated measurement systems. Then, using one of our configuration estimation methods, we demonstrate its viability by performing simple behaviors with a large-scale (approximately 1.5 m long) soft-robot platform attached to the K-Rex rover at NASA Ames in an outdoor environment. Our results also show the importance of soft-robot kinematic calibration and the sensitivity of a soft robot to simple perturbations in the structure like deflation and reinflation. Finally, we show that end effector error can be significantly reduced by doing a form of servoing. In summary, our approach and demonstrations show effective soft-robot configuration estimation and control for large-scale soft robots capable of performing manipulation tasks. © 1996-2012 IEEE.
901 a57195343816 Sherrod V. p270 False Journal 177 Configuration estimation for accurate position control of large-scale soft robots There is a significant trend in robotics of exploring passively compliant and low inertia systems that can safely make contact with the environment. This paper defines many of the problems associated with developing effective control of soft, pneumatically actuated, inflatable robots, and proposes an approach to solving a subset of these problems. We show that we can obtain a global measurement of orientation for a given soft-robot link using two different types of sensors (not including motion capture). Given the orientation measurement, it is possible to estimate relative configurations of the soft actuators and joints. In order to validate the ability to control position and orientation at the end effector, we show a new method for calibrating the coordinate frames of two unrelated measurement systems. Then, using one of our configuration estimation methods, we demonstrate its viability by performing simple behaviors with a large-scale (approximately 1.5 m long) soft-robot platform attached to the K-Rex rover at NASA Ames in an outdoor environment. Our results also show the importance of soft-robot kinematic calibration and the sensitivity of a soft robot to simple perturbations in the structure like deflation and reinflation. Finally, we show that end effector error can be significantly reduced by doing a form of servoing. In summary, our approach and demonstrations show effective soft-robot configuration estimation and control for large-scale soft robots capable of performing manipulation tasks. © 1996-2012 IEEE.
902 a57201722090 Day N. p270 False Journal 177 Configuration estimation for accurate position control of large-scale soft robots There is a significant trend in robotics of exploring passively compliant and low inertia systems that can safely make contact with the environment. This paper defines many of the problems associated with developing effective control of soft, pneumatically actuated, inflatable robots, and proposes an approach to solving a subset of these problems. We show that we can obtain a global measurement of orientation for a given soft-robot link using two different types of sensors (not including motion capture). Given the orientation measurement, it is possible to estimate relative configurations of the soft actuators and joints. In order to validate the ability to control position and orientation at the end effector, we show a new method for calibrating the coordinate frames of two unrelated measurement systems. Then, using one of our configuration estimation methods, we demonstrate its viability by performing simple behaviors with a large-scale (approximately 1.5 m long) soft-robot platform attached to the K-Rex rover at NASA Ames in an outdoor environment. Our results also show the importance of soft-robot kinematic calibration and the sensitivity of a soft robot to simple perturbations in the structure like deflation and reinflation. Finally, we show that end effector error can be significantly reduced by doing a form of servoing. In summary, our approach and demonstrations show effective soft-robot configuration estimation and control for large-scale soft robots capable of performing manipulation tasks. © 1996-2012 IEEE.
902 a57201722090 Day N. p520 True Journal 289 Scalable fabric tactile sensor arrays for soft bodies Soft robots have the potential to transform the way robots interact with their environment. This is due to their low inertia and inherent ability to more safely interact with the world without damaging themselves or the people around them. However, existing sensing for soft robots has at least partially limited their ability to control interactions with their environment. Tactile sensors could enable soft robots to sense interaction, but most tactile sensors are made from rigid substrates and are not well suited to applications for soft robots which can deform. In addition, the benefit of being able to cheaply manufacture soft robots may be lost if the tactile sensors that cover them are expensive and their resolution does not scale well for manufacturability. This paper discusses the development of a method to make affordable, high-resolution, tactile sensor arrays (manufactured in rows and columns) that can be used for sensorizing soft robots and other soft bodies. However, the construction results in a sensor array that exhibits significant amounts of cross-talk when two taxels in the same row are compressed. Using the same fabric-based tactile sensor array construction design, two different methods for cross-talk compensation are presented. The first uses a mathematical model to calculate a change in resistance of each taxel directly. The second method introduces additional simple circuit components that enable us to isolate each taxel electrically and relate voltage to force directly. Fabric sensor arrays are demonstrated for two different soft-bodied applications: an inflatable single link robot and a human wrist. © 2018 IOP Publishing Ltd.
903 a56237421600 Cowley A. p271 True Journal 178 Influence of micro-structured superhydrophobic surfaces on nucleation and natural convection in a heated pool This work experimentally explores sub-boiling pool nucleation on micro-structured superhydrophobic surfaces. All surfaces tested were submerged in a 20 mm deep pool of water and heated from below to maintain a constant surface temperature, while the side walls of the pool were insulated, and the top was covered. Three thermocouples positioned in the pool obtain the average pool temperature. A heat flux sensor is placed directly beneath the surface to measure the heat flux supplied to the pool. Free convection heat transfer coefficients are obtained for the sub-boiling temperature range of 40–90 °C. Six surface types are studied: smooth hydrophilic, smooth hydrophobic, superhydrophobic with rib/cavity structures, superhydrophobic with rib/cavity structures and additional sparsely spaced ribs to close off the cavities, circular posts, and circular holes. It is found that structured superhydrophobic surfaces provide cavities for nucleation to occur. More dissolved air effervesces from the water as the surface temperature increases due to an increased level of supersaturation and convection. The nucleation leads to large air bubble formations that reduce the overall convection coefficient when compared to the smooth surfaces. For the rib/cavity structured surfaces, the bubbles form in an anisotropic manner and are aligned with the surface structure. More bubbles are observed on the superhydrophobic surfaces where the cavities are bounded. Since water's ability to dissolve air is dependent on temperature, heat and mass transfer cannot be treated independently on any of the superhydrophobic surfaces studied here. © 2018 Elsevier Ltd
903 a56237421600 Cowley A. p500 True Journal 271 Bubble nucleation in superhydrophobic microchannels due to subcritical heating This work experimentally studies the effects of single wall heating on laminar flow in a high-aspect ratio superhydrophobic microchannel. When water that is saturated with air is used as the working liquid, the non-wetted cavities on the superhydrophobic surfaces act as nucleation sites and allow air to effervesce out of the water and onto the surface when heated. Previous works in the literature have only considered the opposite case where the water is undersaturated and absorbs air out the cavities for a microchannel setting. The microchannel considered in this work consists of a rib/cavity structured superhydrophobic surface and a glass surface separated by spacers. The microchannel is 60 mm long by 14 mm wide and two channel heights of nominally 183 μm and 366 μm are explored. The superhydrophobic side is in contact with a heated aluminum block and a camera is used to visualize the flow through the glass side. Thermocouples are embedded in the aluminum to record the temperature profile along the length of the channel. Temperatures are maintained below the boiling temperature of the working liquid. The friction factor-Reynolds product (fRe) is obtained via pressure drop and volumetric flow-rate measurements. Five surface types/configurations are investigated: smooth hydrophilic, smooth hydrophobic, superhydrophobic with ribs perpendicular to the flow, superhydrophobic with ribs parallel to the flow, and superhydrophobic with ribs parallel to the flow with several breaker ridges perpendicular to the flow. The surface type/configuration has a significant impact on the mass transport dynamics. For surfaces with closed cell micro-structures, large bubbles eventually form and adversely affect fRe and lead to higher temperatures along the channel. When degassed water is used, no bubble nucleation is observed and the air initially trapped in the superhydrophobic cavities is quickly absorbed by the water. © 2018 Elsevier Ltd
904 a55912340300 Vosughi A. p272 True Journal 179 Target control and source estimation metrics for dynamical networks This note examines metrics for target control and source estimation in dynamical networks. Specifically, the energy required to control a target node in a network from a remote input, and dually the fidelity with which a source state can be estimated from a noisy remote measurement, are studied. For both problems, spectral and graph-theoretic analyses are undertaken, and a comparison between the two metrics is also developed. The analyses highlight an essential asymmetry between target control and source estimation. © 2018 Elsevier Ltd
904 a55912340300 Vosughi A. p544 True Conference 198 Local control and estimation performance in dynamical networks: Structural and graph-theoretic results This work examines metrics for target reachability and source observability in dynamical networks, which are especially relevant in a network security context. Specifically, the energy required to control a target node in a network from a remote input is characterized, and dually the fidelity with which a source state can be estimated from a remote measurement is studied. The work highlights an essential asymmetry between the problems: We show that target reachability is often easy, while source observability is almost always impossible. Several spectral and graph-theoretic results are also presented, which give structural insight into how easy or hard target control and source estimation are. © 2017 IEEE.
904 a55912340300 Vosughi A. p635 False Conference 270 A modeling framework for assessing cyber disruptions and attacks to the national airspace system [No abstract available]
905 a57201864184 Johnson C. p272 False Journal 179 Target control and source estimation metrics for dynamical networks This note examines metrics for target control and source estimation in dynamical networks. Specifically, the energy required to control a target node in a network from a remote input, and dually the fidelity with which a source state can be estimated from a noisy remote measurement, are studied. For both problems, spectral and graph-theoretic analyses are undertaken, and a comparison between the two metrics is also developed. The analyses highlight an essential asymmetry between target control and source estimation. © 2018 Elsevier Ltd
905 a57201864184 Johnson C. p462 True Conference 167 A Class of Logistic Functions for Approximating State-Inclusive Koopman Operators An outstanding challenge in nonlinear systems theory is identification or learning of a given nonlinear system's Koopman operator directly from data or models. Advances in extended dynamic mode decomposition approaches and machine learning methods have enabled data-driven discovery of Koopman operators, for both continuous and discrete-time systems. Since Koopman operators are often infinite-dimensional, they are approximated in practice using finite-dimensional systems. The fidelity and convergence of a given finite-dimensional Koopman approximation is a subject of ongoing research. In this paper we introduce a class of Koopman observable functions that confer an approximate closure property on their corresponding finite-dimensional approximations of the Koopman operator. We derive error bounds for the fidelity of this class of observable functions, as well as identify two key learning parameters which can be used to tune performance. We illustrate our approach on two classical nonlinear system models: the Van Der Pol oscillator and the bistable toggle switch. © 2018 AACC.
905 a57201864184 Johnson C. p544 False Conference 198 Local control and estimation performance in dynamical networks: Structural and graph-theoretic results This work examines metrics for target reachability and source observability in dynamical networks, which are especially relevant in a network security context. Specifically, the energy required to control a target node in a network from a remote input is characterized, and dually the fidelity with which a source state can be estimated from a remote measurement is studied. The work highlights an essential asymmetry between the problems: We show that target reachability is often easy, while source observability is almost always impossible. Several spectral and graph-theoretic results are also presented, which give structural insight into how easy or hard target control and source estimation are. © 2017 IEEE.
906 a34874297000 Xue M. p272 False Journal 179 Target control and source estimation metrics for dynamical networks This note examines metrics for target control and source estimation in dynamical networks. Specifically, the energy required to control a target node in a network from a remote input, and dually the fidelity with which a source state can be estimated from a noisy remote measurement, are studied. For both problems, spectral and graph-theoretic analyses are undertaken, and a comparison between the two metrics is also developed. The analyses highlight an essential asymmetry between target control and source estimation. © 2018 Elsevier Ltd
906 a34874297000 Xue M. p544 False Conference 198 Local control and estimation performance in dynamical networks: Structural and graph-theoretic results This work examines metrics for target reachability and source observability in dynamical networks, which are especially relevant in a network security context. Specifically, the energy required to control a target node in a network from a remote input is characterized, and dually the fidelity with which a source state can be estimated from a remote measurement is studied. The work highlights an essential asymmetry between the problems: We show that target reachability is often easy, while source observability is almost always impossible. Several spectral and graph-theoretic results are also presented, which give structural insight into how easy or hard target control and source estimation are. © 2017 IEEE.
906 a34874297000 Xue M. p635 False Conference 270 A modeling framework for assessing cyber disruptions and attacks to the national airspace system [No abstract available]
906 a34874297000 Xue M. p642 False Conference 274 A graph-theoretic understanding of network-wide implications of local cyber protections for mission assurance Modern Department of Defense mission systems are very complex and therefore arduous to defend, especially in the cyber domain. A major cause for this concern arises from the fact that implementation of security protections occur at a local scale, while the important operational security issues stem from a global perspective of the system, e.g., mission assurance. Being able to understand network-wide implications of local cyber protections has the potential to significantly impact the strategies we use to protect modern mission systems. In this work, we present a graph-theoretic perspective on this problem, which is based on a framework for modeling and assessing the integrated cyber-physical dynamics of complex systems. Under the framework, these dynamics (and their relationships) are modeled as a graph and then analyzed using processing techniques from graphtheory. We demonstrate the utility of this framework by conducting insider-attack threat analysis and show how the application of security protections at a local scale impact network-wide security properties from an insider perspective. As a test case, we study the problem of search and rescue (SAR) using unmanned aerial vehicle teams. Unmanned vehicle teams engaged in SAR are prototypical cyber-physical systems, in which local intrusions may cause global disruptions. Here, we describe how the insider modeling framework for cyber-physical dynamics applies to this problem and present results of a network-wide assessment of security properties of the system. We use this assessment to design a security protection for the system in which we use cryptographically secure computation techniques to limit the amount of information sharing required between system components without degrading the correct operation of the system. We show how the application of these techniques on a local scale impacts the security properties of the system on a global scale. © 2018 SPIE.
907 a10639679200 Roy S. p272 False Journal 179 Target control and source estimation metrics for dynamical networks This note examines metrics for target control and source estimation in dynamical networks. Specifically, the energy required to control a target node in a network from a remote input, and dually the fidelity with which a source state can be estimated from a noisy remote measurement, are studied. For both problems, spectral and graph-theoretic analyses are undertaken, and a comparison between the two metrics is also developed. The analyses highlight an essential asymmetry between target control and source estimation. © 2018 Elsevier Ltd
907 a10639679200 Roy S. p544 False Conference 198 Local control and estimation performance in dynamical networks: Structural and graph-theoretic results This work examines metrics for target reachability and source observability in dynamical networks, which are especially relevant in a network security context. Specifically, the energy required to control a target node in a network from a remote input is characterized, and dually the fidelity with which a source state can be estimated from a remote measurement is studied. The work highlights an essential asymmetry between the problems: We show that target reachability is often easy, while source observability is almost always impossible. Several spectral and graph-theoretic results are also presented, which give structural insight into how easy or hard target control and source estimation are. © 2017 IEEE.
907 a10639679200 Roy S. p635 True Conference 270 A modeling framework for assessing cyber disruptions and attacks to the national airspace system [No abstract available]
907 a10639679200 Roy S. p642 False Conference 274 A graph-theoretic understanding of network-wide implications of local cyber protections for mission assurance Modern Department of Defense mission systems are very complex and therefore arduous to defend, especially in the cyber domain. A major cause for this concern arises from the fact that implementation of security protections occur at a local scale, while the important operational security issues stem from a global perspective of the system, e.g., mission assurance. Being able to understand network-wide implications of local cyber protections has the potential to significantly impact the strategies we use to protect modern mission systems. In this work, we present a graph-theoretic perspective on this problem, which is based on a framework for modeling and assessing the integrated cyber-physical dynamics of complex systems. Under the framework, these dynamics (and their relationships) are modeled as a graph and then analyzed using processing techniques from graphtheory. We demonstrate the utility of this framework by conducting insider-attack threat analysis and show how the application of security protections at a local scale impact network-wide security properties from an insider perspective. As a test case, we study the problem of search and rescue (SAR) using unmanned aerial vehicle teams. Unmanned vehicle teams engaged in SAR are prototypical cyber-physical systems, in which local intrusions may cause global disruptions. Here, we describe how the insider modeling framework for cyber-physical dynamics applies to this problem and present results of a network-wide assessment of security properties of the system. We use this assessment to design a security protection for the system in which we use cryptographically secure computation techniques to limit the amount of information sharing required between system components without degrading the correct operation of the system. We show how the application of these techniques on a local scale impacts the security properties of the system on a global scale. © 2018 SPIE.
908 a56854811600 Rich P.J. p273 True Conference 64 Surveying the Landscape: Statewide Data on K-12 CS Education Implementation In the past decade, there have been increasing efforts and initiatives to increase participation in computer science worldwide. In the U.S., these efforts have resulted in national curricula and increased local expectations. The research on actual implementation often reports on efforts of single schools or districts. This paper provides a high-level description of the practices and challenges of teaching CS in K-12 across an entire state. To better understand how these efforts might increase CS education for all, we surveyed every public school in the state of Utah and analyzed enrollment data for all 19 Utah CS courses. The survey consisted of closed and open-ended questions about each school's current CS practices and personnel. Schools from 39 of 42 public school districts responded (including charter schools) representing 46.3% of the state's high schools, 39.3% of middle/junior high schools, and 28% of elementary schools. Course data indicated that enrollment in CS courses increased considerably in the past five years after the introduction of newer, more fundamental courses. Despite the general enrollment increase, there has been a markedly smaller increase in student enrollment in more advanced CS courses. In this paper, we discuss these and other surprising results, as well as challenges that educators reported in promoting and teaching CS. © 2019 IEEE.
909 a55141781300 Hu H.H. p273 False Conference 64 Surveying the Landscape: Statewide Data on K-12 CS Education Implementation In the past decade, there have been increasing efforts and initiatives to increase participation in computer science worldwide. In the U.S., these efforts have resulted in national curricula and increased local expectations. The research on actual implementation often reports on efforts of single schools or districts. This paper provides a high-level description of the practices and challenges of teaching CS in K-12 across an entire state. To better understand how these efforts might increase CS education for all, we surveyed every public school in the state of Utah and analyzed enrollment data for all 19 Utah CS courses. The survey consisted of closed and open-ended questions about each school's current CS practices and personnel. Schools from 39 of 42 public school districts responded (including charter schools) representing 46.3% of the state's high schools, 39.3% of middle/junior high schools, and 28% of elementary schools. Course data indicated that enrollment in CS courses increased considerably in the past five years after the introduction of newer, more fundamental courses. Despite the general enrollment increase, there has been a markedly smaller increase in student enrollment in more advanced CS courses. In this paper, we discuss these and other surprising results, as well as challenges that educators reported in promoting and teaching CS. © 2019 IEEE.
910 a57190384916 Maestre J. p274 True Journal 180 Dynamics of a capsule flowing in a tube under pulsatile flow We analyze numerically the behavior of a deformable micro-capsule confined in a pipe under a pulsatile flow. The capsule moves and is deformed by the action of a pulsatile flow inside the tube with a non-null mean velocity. This configuration can be found in the nature and in many bioengineering systems where artificial capsules are driven by micro-pumps through micro-channels. The capsule is considered as a thin hyperelastic membrane, which encloses an internal fluid. As it has been demonstrated in the literature, this model represents a wide range of artificial capsules, for example, the alginate-based capsules, typically used in bioengineering applications. A hybrid isogeometric finite element method and boundary element method based on a T-spline discretization and formulated in the time domain is used to solve the mechanical and hydrodynamical equations. The influence of the relative rigidity of the membrane, frequency and amplitude of the pulsatile flow is studied. Results show that the behavior of the capsule differs from steady flows and it depends strongly on the frequency of the flow and mechanical characteristic of the capsule. © 2018 Elsevier Ltd
910 a57190384916 Maestre J. p677 True Journal 328 A 3D isogeometric BE–FE analysis with dynamic remeshing for the simulation of a deformable particle in shear flows A three-dimensional isogeometric coupled boundary element and finite element approach based on analysis suitable T-splines is developed for the simulation of deformable capsules suspended in shear flows. Boundary element analysis is used to solve the fluid Stokes equation whereas the hydrodynamic membrane load is computed via isogeometric analysis under the assumption that the membrane is a hyper-elastic thin shell with negligible bending resistance. The smoothness of the T-spline basis functions accommodate large deformations of the capsule without the need for additional smoothing techniques, and can be used to accurately compute the membrane load. A balanced distribution of membrane elements can be constructed using an unstructured locally refined mesh. These properties are coupled with an adaptive temporal implicit integration scheme. Several benchmark examples are solved to illustrate the accuracy and potential of the method. The approach is then applied to simulate the dynamics of a capsule in a real geometry of a brain capillary. © 2017 Elsevier B.V.
911 a7005253700 Pallares J. p274 False Journal 180 Dynamics of a capsule flowing in a tube under pulsatile flow We analyze numerically the behavior of a deformable micro-capsule confined in a pipe under a pulsatile flow. The capsule moves and is deformed by the action of a pulsatile flow inside the tube with a non-null mean velocity. This configuration can be found in the nature and in many bioengineering systems where artificial capsules are driven by micro-pumps through micro-channels. The capsule is considered as a thin hyperelastic membrane, which encloses an internal fluid. As it has been demonstrated in the literature, this model represents a wide range of artificial capsules, for example, the alginate-based capsules, typically used in bioengineering applications. A hybrid isogeometric finite element method and boundary element method based on a T-spline discretization and formulated in the time domain is used to solve the mechanical and hydrodynamical equations. The influence of the relative rigidity of the membrane, frequency and amplitude of the pulsatile flow is studied. Results show that the behavior of the capsule differs from steady flows and it depends strongly on the frequency of the flow and mechanical characteristic of the capsule. © 2018 Elsevier Ltd
911 a7005253700 Pallares J. p677 False Journal 328 A 3D isogeometric BE–FE analysis with dynamic remeshing for the simulation of a deformable particle in shear flows A three-dimensional isogeometric coupled boundary element and finite element approach based on analysis suitable T-splines is developed for the simulation of deformable capsules suspended in shear flows. Boundary element analysis is used to solve the fluid Stokes equation whereas the hydrodynamic membrane load is computed via isogeometric analysis under the assumption that the membrane is a hyper-elastic thin shell with negligible bending resistance. The smoothness of the T-spline basis functions accommodate large deformations of the capsule without the need for additional smoothing techniques, and can be used to accurately compute the membrane load. A balanced distribution of membrane elements can be constructed using an unstructured locally refined mesh. These properties are coupled with an adaptive temporal implicit integration scheme. Several benchmark examples are solved to illustrate the accuracy and potential of the method. The approach is then applied to simulate the dynamics of a capsule in a real geometry of a brain capillary. © 2017 Elsevier B.V.
912 a7004060735 Cuesta I. p274 False Journal 180 Dynamics of a capsule flowing in a tube under pulsatile flow We analyze numerically the behavior of a deformable micro-capsule confined in a pipe under a pulsatile flow. The capsule moves and is deformed by the action of a pulsatile flow inside the tube with a non-null mean velocity. This configuration can be found in the nature and in many bioengineering systems where artificial capsules are driven by micro-pumps through micro-channels. The capsule is considered as a thin hyperelastic membrane, which encloses an internal fluid. As it has been demonstrated in the literature, this model represents a wide range of artificial capsules, for example, the alginate-based capsules, typically used in bioengineering applications. A hybrid isogeometric finite element method and boundary element method based on a T-spline discretization and formulated in the time domain is used to solve the mechanical and hydrodynamical equations. The influence of the relative rigidity of the membrane, frequency and amplitude of the pulsatile flow is studied. Results show that the behavior of the capsule differs from steady flows and it depends strongly on the frequency of the flow and mechanical characteristic of the capsule. © 2018 Elsevier Ltd
912 a7004060735 Cuesta I. p677 False Journal 328 A 3D isogeometric BE–FE analysis with dynamic remeshing for the simulation of a deformable particle in shear flows A three-dimensional isogeometric coupled boundary element and finite element approach based on analysis suitable T-splines is developed for the simulation of deformable capsules suspended in shear flows. Boundary element analysis is used to solve the fluid Stokes equation whereas the hydrodynamic membrane load is computed via isogeometric analysis under the assumption that the membrane is a hyper-elastic thin shell with negligible bending resistance. The smoothness of the T-spline basis functions accommodate large deformations of the capsule without the need for additional smoothing techniques, and can be used to accurately compute the membrane load. A balanced distribution of membrane elements can be constructed using an unstructured locally refined mesh. These properties are coupled with an adaptive temporal implicit integration scheme. Several benchmark examples are solved to illustrate the accuracy and potential of the method. The approach is then applied to simulate the dynamics of a capsule in a real geometry of a brain capillary. © 2017 Elsevier B.V.
913 a55413434100 Collins D.H. p275 True Journal 181 Failure time distributions for complex equipment The exponential distribution is inadequate as a failure time model for most components; however, under certain conditions (in particular, that component failure rates are small and mutually independent, and failed components are immediately replaced or perfectly repaired), it is applicable to complex repairable systems with large numbers of components in series, regardless of component distributions, as shown by Drenick in 1960. This result implies that system behavior may become simpler as more components are added. We review necessary conditions for the result and present some simulation studies to assess how well it holds in systems with finite numbers of components. We also note that Drenick's result is analogous to similar results in other systems disciplines, again resulting in simpler behavior as the number of entities in the system increases. © 2018 John Wiley & Sons, Ltd.
914 a57197733358 Janke D. p277 True Journal 182 A 9-Bit 10-MHz 28-μW SAR ADC Using Tapered Bit Periods and a Partially Interdigitated DAC A successive-approximation-register (SAR) analogto- digital converter (ADC) incorporates "tapered bit periods" to reduce power consumption by minimizing the digital-to-analog converter (DAC) timing overhead. Utilizing a variable delay line and the standard SAR logic, the proposed technique reduces power by downsizing the DAC drivers and digital logic without decreasing the sampling rate. A detailed analysis derives, for the first time, a closed-form solution of the capacitive DAC settling time accounting for parasitics, and determines the time savings of the proposed design. In addition, this brief proposes a "partially interdigitated" DAC layout to reduce the bottom-plate parasitic capacitance to minimize the DAC power. A 9-bit prototype fabricated in 180-nm technology achieves a signal-to-noise-distortion ratio (SNDR) of 55.5 dB at a 10-MHz sampling rate while consuming 28 μW, yielding a figure-of-merit of 5.7 fJ/conversionstep, the lowest among published ADCs at similar speeds and resolutions. © 2004-2012 IEEE.
914 a57197733358 Janke D. p676 False Journal 327 High-Precision, Mixed-Signal Mismatch Measurement of Metal-Oxide-Metal Capacitors This brief presents a high-precision, mixed-signal mismatch measurement technique for metal-oxide-metal capacitors. The proposed technique incorporates a switched-capacitor op amp within the measurement circuit to significantly improve the measurement precision while relaxing the resolution requirement on the backend analog-to-digital converter (ADC). The proposed technique is also robust against multiple types of errors. A detailed analysis is presented to quantify the sensitivity improvement of the proposed technique over the conventional one. In addition, this brief proposes a multiplexing technique to measure a large number of capacitors in a single chip and a new layout to improve matching. A prototype fabricated in 180 nm technology demonstrates the ability to sense capacitor mismatch standard deviation as low as 0.045% with excellent repeatability, all without the need of a high-resolution ADC. © 2004-2012 IEEE.
915 a57200390842 Monk A. p277 False Journal 182 A 9-Bit 10-MHz 28-μW SAR ADC Using Tapered Bit Periods and a Partially Interdigitated DAC A successive-approximation-register (SAR) analogto- digital converter (ADC) incorporates "tapered bit periods" to reduce power consumption by minimizing the digital-to-analog converter (DAC) timing overhead. Utilizing a variable delay line and the standard SAR logic, the proposed technique reduces power by downsizing the DAC drivers and digital logic without decreasing the sampling rate. A detailed analysis derives, for the first time, a closed-form solution of the capacitive DAC settling time accounting for parasitics, and determines the time savings of the proposed design. In addition, this brief proposes a "partially interdigitated" DAC layout to reduce the bottom-plate parasitic capacitance to minimize the DAC power. A 9-bit prototype fabricated in 180-nm technology achieves a signal-to-noise-distortion ratio (SNDR) of 55.5 dB at a 10-MHz sampling rate while consuming 28 μW, yielding a figure-of-merit of 5.7 fJ/conversionstep, the lowest among published ADCs at similar speeds and resolutions. © 2004-2012 IEEE.
916 a8392459500 Hunter A. p278 True Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
917 a57200730892 Moore B.A. p278 False Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
918 a53984647600 Mudunuru M. p278 False Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
919 a56806547100 Chau V. p278 False Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
920 a57201199846 Tchoua R. p278 False Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
921 a57201509548 Karra S. p278 False Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
922 a7006051256 O'Malley D. p278 False Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
923 a6505878659 Rougier E. p278 False Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
924 a8298784700 Viswanathan H. p278 False Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
925 a35747244700 Srinivasan G. p278 False Journal 183 Reduced-order modeling through machine learning and graph-theoretic approaches for brittle fracture applications Typically, thousands of computationally expensive micro-scale simulations of brittle crack propagation are needed to upscale lower length scale phenomena to the macro-continuum scale. Running such a large number of crack propagation simulations presents a significant computational challenge, making reduced-order models (ROMs) attractive for this task. The ultimate goal of this research is to develop ROMs that have sufficient accuracy and low computational cost so that these upscaling simulations can be readily performed. However, constructing ROMs for these complex simulations presents its own challenge. Here, we present and compare four different approaches for reduced-order modeling of brittle crack propagation in geomaterials. These methods rely on machine learning (ML) and graph-theoretic algorithms to approximate key aspects of the brittle crack problem. These methods also incorporate different physics-based assumptions in order to reduce the training requirements while maintaining accurate physics as much as possible. Results from the ROMs are directly compared against a high-fidelity model of brittle crack propagation. Further, the strengths and weaknesses of the ROMs are discussed, and we conclude that combining smart physics-informed feature engineering with highly trainable ML models provides the best performance. The ROMs considered here have computational costs that are orders-of-magnitude less than the cost associated with high-fidelity physical models while maintaining good accuracy. © 2018
926 a57193565771 Leung H. p279 True Conference 65 Necessary and Sufficient Conditions on State Transformations That Preserve the Causal Structure of LTI Dynamical Networks Linear time-invariant (LTI) dynamic networks are described by their dynamical structure function, and generally they have many possible state space realizations. This work characterizes the necessary and sufficient conditions on a state transformation that preserves the dynamical structure function, thereby generating the entire set of realizations of a given order for a specific dynamic network. © 2018 IEEE.
927 a16177635300 Dankers A. p280 False Conference 66 Dynamic Networks: Representations, Abstractions, and Well-Posedness This paper introduces notions of abstraction and realization for dynamic networks. These processes generate dynamically equivalent representations of a system, but with varying degrees of structural detail. Nuanced definitions and associated conditions for maintaining well-posedness for these multi-resolution representations of a dynamic system are then detailed, ensuring that hierarchies of network representations are sensible as multi-resolution models of dynamic networks. Although the ideas are developed precisely here for LTI networks, many of the concepts remain fundamental in the nonlinear setting. © 2018 IEEE.
927 a16177635300 Dankers A. p542 False Conference 196 On the well-posedness of LTI networks We consider networks of linear, time-invariant systems defined over matrices of rational functions in a complex variable where each element of the matrix represents a link in the network. When these rational functions are proper, but not necessarily strictly proper, we demonstrate the necessary and sufficient conditions under which such a network configuration is well-posed. We include multiple examples of network configurations and their respective well-posedness conditions, including cases where two or more ill-posed network configurations can be interconnected to form a well-posed network. © 2017 IEEE.
928 a57207108623 Brodie M. p281 True Conference 67 Alpha Model Domination in Multiple Choice Learning Multiple Choice Learning (MCL) algorithms involve an 'oracle' user with unmodeled biases that selects a preferred output among several possible hypotheses. We identify a shortcoming and training obstacle of the recent Stochastic Multiple Choice Learning (sMCL) algorithm. When an ensemble of neural networks trains under sMCL, the best performing model receives the majority of parameter updates at the expense of other ensemble members. We refer to this sMCL training issue as Alpha Model Domination (AMD) and empirically demonstrate that AMD does not resolve itself with longer training time. We introduce several novel MCL loss functions that both avoid AMD and yield statistically significant improvements in oracle accuracy (OA) compared to sMCL. Using the MNIST, CIFAR-10, and ImageNet classification datasets, we empirically demonstrate the superior performance of our proposed loss functions. © 2018 IEEE.
929 a57200290256 Tensmeyer C. p281 False Conference 67 Alpha Model Domination in Multiple Choice Learning Multiple Choice Learning (MCL) algorithms involve an 'oracle' user with unmodeled biases that selects a preferred output among several possible hypotheses. We identify a shortcoming and training obstacle of the recent Stochastic Multiple Choice Learning (sMCL) algorithm. When an ensemble of neural networks trains under sMCL, the best performing model receives the majority of parameter updates at the expense of other ensemble members. We refer to this sMCL training issue as Alpha Model Domination (AMD) and empirically demonstrate that AMD does not resolve itself with longer training time. We introduce several novel MCL loss functions that both avoid AMD and yield statistically significant improvements in oracle accuracy (OA) compared to sMCL. Using the MNIST, CIFAR-10, and ImageNet classification datasets, we empirically demonstrate the superior performance of our proposed loss functions. © 2018 IEEE.
930 a57207112163 Ackerman W. p281 False Conference 67 Alpha Model Domination in Multiple Choice Learning Multiple Choice Learning (MCL) algorithms involve an 'oracle' user with unmodeled biases that selects a preferred output among several possible hypotheses. We identify a shortcoming and training obstacle of the recent Stochastic Multiple Choice Learning (sMCL) algorithm. When an ensemble of neural networks trains under sMCL, the best performing model receives the majority of parameter updates at the expense of other ensemble members. We refer to this sMCL training issue as Alpha Model Domination (AMD) and empirically demonstrate that AMD does not resolve itself with longer training time. We introduce several novel MCL loss functions that both avoid AMD and yield statistically significant improvements in oracle accuracy (OA) compared to sMCL. Using the MNIST, CIFAR-10, and ImageNet classification datasets, we empirically demonstrate the superior performance of our proposed loss functions. © 2018 IEEE.
931 a7102270639 Martinez T. p281 False Conference 67 Alpha Model Domination in Multiple Choice Learning Multiple Choice Learning (MCL) algorithms involve an 'oracle' user with unmodeled biases that selects a preferred output among several possible hypotheses. We identify a shortcoming and training obstacle of the recent Stochastic Multiple Choice Learning (sMCL) algorithm. When an ensemble of neural networks trains under sMCL, the best performing model receives the majority of parameter updates at the expense of other ensemble members. We refer to this sMCL training issue as Alpha Model Domination (AMD) and empirically demonstrate that AMD does not resolve itself with longer training time. We introduce several novel MCL loss functions that both avoid AMD and yield statistically significant improvements in oracle accuracy (OA) compared to sMCL. Using the MNIST, CIFAR-10, and ImageNet classification datasets, we empirically demonstrate the superior performance of our proposed loss functions. © 2018 IEEE.
932 a57205388766 Pettingill D. p282 True Journal 184 Static structures in leaky mode waveguides In this work, we suggest a new method of expanding the field of view in bottom-exit, leaky mode devices for transparent, monolithic, holographic, near-eye display. In this approach, we propose the use of static, laser-induced, grating structures within the device substrate to break the leaky mode light into diffracted orders. We then propose to use carefully timed illumination pulses to select which diffracted order is visible to the eye at every display refresh interval (up to 100 kHz). Each of these orders becomes a view for a different image point. To describe this new method, we use K-vector analysis. We give the relevant equations and a list of parameters which lead to a near-eye geometry with little or no overlap in higher-order view zones. We conclude that it should be possible to increase the field of view of our bottom-exit, leaky mode devices by as much as one order of magnitude by simply adding a laser-induced grating structure to the substrate and by carefully timing the device illumination. If successful, this method would make possible a transparent, holographic, near-eye display that is simple to fabricate, relative to pixelated approaches, and which has a wide field-of-view relative to our current bottom-exit displays. © 2019 by the authors.
933 a57205393448 Kurtz D. p282 False Journal 184 Static structures in leaky mode waveguides In this work, we suggest a new method of expanding the field of view in bottom-exit, leaky mode devices for transparent, monolithic, holographic, near-eye display. In this approach, we propose the use of static, laser-induced, grating structures within the device substrate to break the leaky mode light into diffracted orders. We then propose to use carefully timed illumination pulses to select which diffracted order is visible to the eye at every display refresh interval (up to 100 kHz). Each of these orders becomes a view for a different image point. To describe this new method, we use K-vector analysis. We give the relevant equations and a list of parameters which lead to a near-eye geometry with little or no overlap in higher-order view zones. We conclude that it should be possible to increase the field of view of our bottom-exit, leaky mode devices by as much as one order of magnitude by simply adding a laser-induced grating structure to the substrate and by carefully timing the device illumination. If successful, this method would make possible a transparent, holographic, near-eye display that is simple to fabricate, relative to pixelated approaches, and which has a wide field-of-view relative to our current bottom-exit displays. © 2019 by the authors.
934 a16313800700 Smalley D. p282 False Journal 184 Static structures in leaky mode waveguides In this work, we suggest a new method of expanding the field of view in bottom-exit, leaky mode devices for transparent, monolithic, holographic, near-eye display. In this approach, we propose the use of static, laser-induced, grating structures within the device substrate to break the leaky mode light into diffracted orders. We then propose to use carefully timed illumination pulses to select which diffracted order is visible to the eye at every display refresh interval (up to 100 kHz). Each of these orders becomes a view for a different image point. To describe this new method, we use K-vector analysis. We give the relevant equations and a list of parameters which lead to a near-eye geometry with little or no overlap in higher-order view zones. We conclude that it should be possible to increase the field of view of our bottom-exit, leaky mode devices by as much as one order of magnitude by simply adding a laser-induced grating structure to the substrate and by carefully timing the device illumination. If successful, this method would make possible a transparent, holographic, near-eye display that is simple to fabricate, relative to pixelated approaches, and which has a wide field-of-view relative to our current bottom-exit displays. © 2019 by the authors.
934 a16313800700 Smalley D. p295 False Conference 77 Progress on static structures for leaky mode waveguides This work reports progress toward increased field of view from multi-order leaky mode devices. Specifically, we move from our previously published simulation toward physical instantiation including a glass-based test rig. ©2019TheAuthor(s)
934 a16313800700 Smalley D. p301 False Journal 121 Improving photophoretic trap volumetric displays [Invited] Since the introduction of optical trap displays in 2018, there has been significant interest in further developing this technology. In an effort to channel interest in the most productive directions, this work seeks to illuminate those areas that, in the authors’ opinion, are most critical to the ultimate success of optical trap displays as a platform for aerial 3D imaging. These areas include trapping, scanning, scaling, robustness, safety, and occlusion. © 2019 Optical Society of America
934 a16313800700 Smalley D. p364 False Conference 127 Experimental characterization of leaky-mode spatial light modulators fabricated via direct laser writing We have previously presented a novel spatial light modulator appropriate for use in transparent, flat-panel holographic display applications. Our architecture consists of an anisotropic leaky-mode coupler and integrated Bragg reflection grating as a monolithic device implemented in lithium niobate and is fabricated using direct femtosecond laser writing techniques. In this paper, we present a methodology for the experimental characterization of holographically-reconstructed point spread functions from sample devices. © 2019 SPIE.
934 a16313800700 Smalley D. p437 False Journal 242 Erratum: Hardware and software improvements to a low-cost horizontal parallax holographic video monitor (Applied Optics (2018) 57 (A122-A133) DOI: 10.1364/AO.57.00A122) In [1], the trademarked term "HoloMonitor," which belongs to Phase Holographic Imaging PHI AB, was removed. The article was corrected online on 10 September 2018. © 2018 Optical Society of America.
934 a16313800700 Smalley D. p507 True Journal 278 Volumetric displays [No abstract available]
934 a16313800700 Smalley D. p562 True Conference 211 Progress on photophoretic trap displays We review the fundamentals photophoretic trap displays and discuss the possibility of creating occlusion capable image points. Anisotropic scattering is observed independently in single and double point traps. © 2018 The Author(s).
934 a16313800700 Smalley D. p571 False Journal 242 Hardware and software improvements to a low-cost horizontal parallax holographic video monitor Displays capable of true holographic video have been prohibitively expensive and difficult to build. With this paper, we present a suite of modularized hardware components and software tools needed to build a HoloMonitor with basic “hacker-space” equipment, highlighting improvements that have enabled the total materials cost to fall to $820, well below that of other holographic displays. It is our hope that the current level of simplicity, development, design flexibility, and documentation will enable the lay engineer, programmer, and scientist to relatively easily replicate, modify, and build upon our designs, bringing true holographic video to the masses. © 2017 Optical Society of America.
934 a16313800700 Smalley D. p591 False Conference 234 Volumetric display by movement of particles trapped in a laser via photophoresis Photophoresis can stably hold opaque microscopic particles in a laser focus surrounded by room air with strength sufficient to enable centimeter-scale patterns to be drawn by sweeping the laser beam. The resulting images rely on visual persistence as laser light scatters from the particle, which is rapidly swept through the 3-D pattern. Control can be maintained while moving the particle with air speeds up to 2 m/s. A desire to greatly increase the sweep speed motivates a re-examination of the fundamentals of photophoresis-based laser-particle traps. Most explanations offered are qualitative, with differing opinions as to whether, for example, asymmetric heating or asymmetric thermal accommodation is primarily at work. Which particles become trapped in the beam is typically based on self-selection, as a variety of particles with possible differing shapes and sizes are offered to the laser focus for capture. Characteristics that make some particles preferred over others are especially relevant. There is broad consensus that structure in the laser focus greatly aids in stable trapping. Nevertheless, it is still possible for even a relatively smooth TEM00 beam to capture and hold particles. Moreover, even in a structured focus (i.e. with aberrations and local intensity minima and maxima), questions remain as to exactly how a particle becomes stably trapped in certain beam locations. A zoomed-in look at trapped particles reveals oscillations or orbits with excursions over tens of microns and accelerations up to 10 gs. We trapped particles in zero-gravity as well as 2-g environments with no noticeable difference in stability. © 2018 SPIE.
934 a16313800700 Smalley D. p641 False Conference 273 Progress in transparent flat-panel holographic displays enabled by guided-wave acousto-optics We have previously introduced a monolithic, integrated optical platform for transparent, flat-panel holographic displays suitable for near-to-eye displays in augmented reality systems. This platform employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram. In this paper, we depict analysis of three key system attributes that inform and influence the display system performance: 1) single-axis diffraction-driven astigmatism, 2) strobed illumination to enforce acousto-optic grating stationarity, and 3) acousto-optically driven spatial Nyquist rate. Copyright © 2018 SPIE. Downloading of the abstract is permitted for personal use only.
934 a16313800700 Smalley D. p878 False Conference 394 Near-to-eye electroholography via guided-wave acousto-optics for augmented reality Near-to-eye holographic displays act to directly project wavefronts into a viewer's eye in order to recreate 3-D scenes for augmented or virtual reality applications. Recently, several solutions for near-to-eye electroholography have been proposed based on digital spatial light modulators in conjunction with supporting optics, such as holographic waveguides for light delivery; however, such schemes are limited by the inherent low space-bandwidth product available with current digital SLMs. In this paper, we depict a fully monolithic, integrated optical platform for transparent near-to-eye holographic display requiring no supporting optics. Our solution employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram. © 2017 SPIE.
935 a55638504300 Youn C.C. p284 False Conference 68 Geometrically Motivated Reparameterization for Identifiability Analysis in Power Systems Models This paper describes a geometric approach to parameter identifiability analysis in models of power systems dynamics. When a model of a power system is to be compared with measurements taken at discrete times, it can be interpreted as a mapping from parameter space into a data or prediction space. Generically, model mappings can be interpreted as manifolds with dimensionality equal to the number of structurally identifiable parameters. Empirically it is observed that model mappings often correspond to bounded manifolds. We propose a new definition of practical identifiability based the topological definition of a manifold with boundary. In many ways, our proposed definition extends the properties of structural identifiability. We construct numerical approximations to geodesics on the model manifold and use the results, combined with insights derived from the mathematical form of the equations, to identify combinations of practically identifiable and unidentifiable parameters. We give several examples of application to dynamic power systems models. © 2018 IEEE.
936 a56798055200 Gates N.S. p286 True Conference 69 Combined trajectory, propulsion and battery mass optimization for solar-regenerative high-altitude long endurance unmanned aircraft Combined optimization of propulsion system design, flight trajectory planning and battery mass optimization for solar-regenerative high-altitude long endurance (SRHALE) aircraft through a sequential iterative approach yields an increase of 20.2% in the end-of-day energy available on the winter solstice at 35°N latitude, resulting in an increase in flight time of 2.36 hours. The optimized flight path is obtained by using nonlinear model predictive control to solve flight and energy system dynamics over a 24 hour period with a 15 second time resolution. The optimization objective is to maximize the total energy in the system while flying a station-keeping mission, staying within a 3 km radius and above 60,000 ft. The propulsion system design optimization minimizes the total energy required to fly the optimal path. It uses a combination of blade element momentum theory, blade composite structures, empirical motor and motor controller mass data, as well as a first order motor performance model. The battery optimization seeks to optimally size the battery for a circular orbit. Fixed point iteration between these optimization frameworks yields a flight path and propulsion system that slightly decreases solar capture, but signif-icantly decreases power expended. Fully coupling the trajectory and design optimizations with this level of accuracy is infeasible with current computing resources. These efforts show the benefits of combining design and trajectory optimization to enable the feasibility of SRHALE flight. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
936 a56798055200 Gates N.S. p327 False Journal 189 Dynamic optimization of high-altitude solar aircraft trajectories under station-keeping constraints This paper demonstrates the use of nonlinear dynamic optimization to calculate energy-optimal trajectories for a high-altitude, solar-powered unmanned aerial vehicle (UAV). The objective is to maximize the total energy in the system while staying within a 3 km mission radius and meeting other system constraints. Solar energy capture is modeled using the vehicle orientation and solar position, and energy isstored both in batteries and in potential energy through elevation gain. Energy capture is maximized by optimally adjusting the angle of the aircraft surface relative to the sun. The UAV flight and energy system dynamics are optimized over a 24h period at an 8s time resolution using nonlinear model predictive control. Results of the simulated flights are presented for all four seasons, showing an 8.2% increase in end-of-day battery energy for the most limiting flight condition of the winter solstice. © 2018 by R. Abraham Martin, Nathaniel S. Gates, Andrew Ning, and John D. Hedengren.
937 a57192697616 Moore K.R. p286 False Conference 69 Combined trajectory, propulsion and battery mass optimization for solar-regenerative high-altitude long endurance unmanned aircraft Combined optimization of propulsion system design, flight trajectory planning and battery mass optimization for solar-regenerative high-altitude long endurance (SRHALE) aircraft through a sequential iterative approach yields an increase of 20.2% in the end-of-day energy available on the winter solstice at 35°N latitude, resulting in an increase in flight time of 2.36 hours. The optimized flight path is obtained by using nonlinear model predictive control to solve flight and energy system dynamics over a 24 hour period with a 15 second time resolution. The optimization objective is to maximize the total energy in the system while flying a station-keeping mission, staying within a 3 km radius and above 60,000 ft. The propulsion system design optimization minimizes the total energy required to fly the optimal path. It uses a combination of blade element momentum theory, blade composite structures, empirical motor and motor controller mass data, as well as a first order motor performance model. The battery optimization seeks to optimally size the battery for a circular orbit. Fixed point iteration between these optimization frameworks yields a flight path and propulsion system that slightly decreases solar capture, but signif-icantly decreases power expended. Fully coupling the trajectory and design optimizations with this level of accuracy is infeasible with current computing resources. These efforts show the benefits of combining design and trajectory optimization to enable the feasibility of SRHALE flight. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
937 a57192697616 Moore K.R. p290 True Journal 187 Takeoff and performance trade-offs of retrofit distributed electric propulsion for urban transport While vertical takeoff and landing aircraft have shown promise for urban air transport, distributed electric propulsion on existing aircraft may offer immediately implementable alternatives. Distributed electric propulsion could potentially decrease takeoff distances enough to enable thousands of potential intercity runways. This conceptual study explores the effects of a retrofit of open-bladed electric propulsion units. To model and explore the design space, blade element momentum method, vortex lattice method, linear-beam finite element analysis, classical laminate theory, composite failure, empirically based blade noise modeling, motor and motor-controller mass models, and gradient-based optimization are used. With liftoff time of seconds and the safe total field length for this aircraft type undefined, this paper focused on the minimum conceptual takeoff distance. It was found that 16 propellers could reduce the takeoff distance by over 50% compared with the optimal 2-propeller case. This resulted in a conceptual minimum takeoff distance of 20.5 m to clear a 50 ft (15.24 m) obstacle. It was also found that, when decreasing the allowable noise by approximately 10 dBa, the 8-propeller case performed the best with a 43% reduction in takeoff distance compared with the optimal 2-propeller case. This resulted in a noise-restricted conceptual minimum takeoff distance of 95 m. Copyright © 2019 by Kevin R. Moore and Andrew Ning. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.
937 a57192697616 Moore K.R. p554 True Conference 204 Distributed electric propulsion effects on traditional aircraft through multidisciplinary optimization Electric aircraft face a steep tradeoff between the demand for runway performance and range. While fuel based propulsion technologies typically increase in specific power with increasing size, electric propulsion is typically much more scalable. This system scalability enables alternative designs including distributed propulsion, optionally powered propulsion units, and vectored thrust, which can all contribute to better runway performance and range. In this paper, we explore how continuously powered distributed propulsion can reduce takeoff distance while still satisfying range constraints. We use a combination of a blade element momentum method, a vortex lattice method, experimental data, and nonlinear optimization techniques to model and explore the design space. We have found that for this conceptual design study, a fully blown wing with propellers at the optimal diameter for the load (8 propellers for a 300 km range constraint) can reduce the takeoff distance by over 80% when compared to the optimal 2 propeller case using the same models. There is over a 2x increase in the wing lift coefficient which leads to a 36% reduction in liftoff speed. Also, the optimal fully blown case produced 2.9 more thrust during takeoff with only an 11% increase in total aircraft mass. Using propeller tip speed as a surrogate for noise, we found that the propeller tip speed decreased takeoff performance in an exponential manner: the tip speed could be decreased from Mach 0.8 to Mach 0.5 with only a 2x increase in takeoff rolling distance while decreasing the constraint to Mach 0.3 produced an 8x increase. © 2018, (publisher Name). All rights reserved.
938 a8621794000 Ning A. p286 False Conference 69 Combined trajectory, propulsion and battery mass optimization for solar-regenerative high-altitude long endurance unmanned aircraft Combined optimization of propulsion system design, flight trajectory planning and battery mass optimization for solar-regenerative high-altitude long endurance (SRHALE) aircraft through a sequential iterative approach yields an increase of 20.2% in the end-of-day energy available on the winter solstice at 35°N latitude, resulting in an increase in flight time of 2.36 hours. The optimized flight path is obtained by using nonlinear model predictive control to solve flight and energy system dynamics over a 24 hour period with a 15 second time resolution. The optimization objective is to maximize the total energy in the system while flying a station-keeping mission, staying within a 3 km radius and above 60,000 ft. The propulsion system design optimization minimizes the total energy required to fly the optimal path. It uses a combination of blade element momentum theory, blade composite structures, empirical motor and motor controller mass data, as well as a first order motor performance model. The battery optimization seeks to optimally size the battery for a circular orbit. Fixed point iteration between these optimization frameworks yields a flight path and propulsion system that slightly decreases solar capture, but signif-icantly decreases power expended. Fully coupling the trajectory and design optimizations with this level of accuracy is infeasible with current computing resources. These efforts show the benefits of combining design and trajectory optimization to enable the feasibility of SRHALE flight. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
938 a8621794000 Ning A. p287 False Conference 70 The effect of communication and vehicle properties on the search performance of a swarm of unmanned aerial vehicles An unmanned aerial vehicle (UAV) swarm allows for a more time-efficient method of searching a specified area than a single UAV or piloted plane. There are a variety of factors that affect how well an area is surveyed. We specifically analyzed the effect both vehicle properties and communication had on the swarm search performance. We used non-dimensionalization to examine the effect vehicle properties had on search performance so the results can be applied to any domain size with any number and type of vehicle. We found that even if vehicles could only sense 10% of the grid area at any given time step, 92% of the grid could still be searched by using a vehicle with good maneuverability and endurance. Conversely, if the chosen vehicle had poor maneuverability 92% of the grid could still be searched by keeping the endurance high and increasing the amount of area the vehicles could sense at one time to 70% of the domain area. In addition, we also examined four communication cases with different amounts of information regarding vehicle location. We found communication increased search performance by at least 6.3%. However, increasing the amount of information only changed the performance by 2.3%. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
938 a8621794000 Ning A. p290 False Journal 187 Takeoff and performance trade-offs of retrofit distributed electric propulsion for urban transport While vertical takeoff and landing aircraft have shown promise for urban air transport, distributed electric propulsion on existing aircraft may offer immediately implementable alternatives. Distributed electric propulsion could potentially decrease takeoff distances enough to enable thousands of potential intercity runways. This conceptual study explores the effects of a retrofit of open-bladed electric propulsion units. To model and explore the design space, blade element momentum method, vortex lattice method, linear-beam finite element analysis, classical laminate theory, composite failure, empirically based blade noise modeling, motor and motor-controller mass models, and gradient-based optimization are used. With liftoff time of seconds and the safe total field length for this aircraft type undefined, this paper focused on the minimum conceptual takeoff distance. It was found that 16 propellers could reduce the takeoff distance by over 50% compared with the optimal 2-propeller case. This resulted in a conceptual minimum takeoff distance of 20.5 m to clear a 50 ft (15.24 m) obstacle. It was also found that, when decreasing the allowable noise by approximately 10 dBa, the 8-propeller case performed the best with a 43% reduction in takeoff distance compared with the optimal 2-propeller case. This resulted in a noise-restricted conceptual minimum takeoff distance of 95 m. Copyright © 2019 by Kevin R. Moore and Andrew Ning. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.
938 a8621794000 Ning A. p327 False Journal 189 Dynamic optimization of high-altitude solar aircraft trajectories under station-keeping constraints This paper demonstrates the use of nonlinear dynamic optimization to calculate energy-optimal trajectories for a high-altitude, solar-powered unmanned aerial vehicle (UAV). The objective is to maximize the total energy in the system while staying within a 3 km mission radius and meeting other system constraints. Solar energy capture is modeled using the vehicle orientation and solar position, and energy isstored both in batteries and in potential energy through elevation gain. Energy capture is maximized by optimally adjusting the angle of the aircraft surface relative to the sun. The UAV flight and energy system dynamics are optimized over a 24h period at an 8s time resolution using nonlinear model predictive control. Results of the simulated flights are presented for all four seasons, showing an 8.2% increase in end-of-day battery energy for the most limiting flight condition of the winter solstice. © 2018 by R. Abraham Martin, Nathaniel S. Gates, Andrew Ning, and John D. Hedengren.
938 a8621794000 Ning A. p333 False Conference 109 Best practices for wake model and optimization algorithm selection in wind farm layout optimization This paper presents the results of two case studies regarding the wind farm layout optimization problem. We asked members of the computational optimization and wind communities to take part in the studies that we designed. Nine individuals participated. Case study 1 considered variations in optimization strategies for a given simple Gaussian wake model. Participants were provided with a wake model that outputs annual energy production (AEP) for an input set of wind turbine locations. Participants used an optimization method of their choosing to find an optimal wind farm layout. Case study 2 looked at trade-offs in performance resulting from variation in both physics model and optimization strategy. For case study 2, participants calculated AEP using a wake model of their choice while also using their chosen optimization method. Participants then used their wake model to calculate the AEP of all other participants’ optimized layouts. Results for case study 1 show that the best optimal wind farm layouts in this study were achieved by participants who used gradient-based optimization methods. A front-runner emerged with the Sparse Nonlinear OPTimizer plus Wake Expansion Continua-tion (SNOPT+WEC) optimization method, which consistently discovered the highest submitted AEP. For case study 2, two participants found a similar layout that was judged to be superior by all five participants. It is unclear if the better solution resulted from an improved optimization process, or a wake model that was more amenable to optimization. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
938 a8621794000 Ning A. p334 False Conference 110 Comparison of wind farm layout optimization results using a simple wake model and gradient-based optimization to large-eddy simulations The models used during wind farm layout optimization use simplifying assumptions that can alter the design space. Some characteristics of the simple models may negatively influence the resulting layouts. In this paper, we perform wind farm layout optimization using a simple wake model and compare the resulting improvements to large-eddy simulation (LES) results to confirm that the layout was actually improved. We begin by describing the models used, including changes specific for use with gradient-based optimization. We then compare our models’ output to previously published model and LES results. Using the models described, we performed gradient-based wind farm layout optimization using exact gradients. Power production for the original and optimized layouts were recalculated using LES. The model and LES results were then compared. The simple models predicted an improvement in annual energy production (AEP) of 7.4%, while the LES reported an AEP improvement of 9.9%. We concluded that the improvements found by optimizing with the simple models are not just an artifact of the model characteristics, but are real improvements. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
938 a8621794000 Ning A. p551 False Conference 201 Development of a vortex particle code for the modeling of wake interaction in distributed propulsion Recent developments in electric aircraft technology have enabled the use of distributed propulsion for the next generation of vertical lift vehicles. However, the ability to rapidly assess the performance of these design concepts, with sufficient fidelity, is a current weakness of this nascent industry. This paper explores the capacity of the viscous Vortex Particle Method (VPM) to model wake interactions found in distributed propulsion. The elements of the vortex particle method are summarized, and a new approach for the calculation of vortex stretching through the complex-step derivative approximation is presented. Preliminary validation is performed on vortex ring cases resembling the fundamental dynamics encountered in propeller wakes. Unsteady wake dynamics of individual propellers are successfully modeled, replicating the instabilities that lead to vortex breakdown as observed experimentally. Comparing the method with results from momentum theory, it is shown that VPM is consistent with theoretical values of near and far field induced velocities, and a notable feature is its ability to model near/far field transition. Furthermore, VPM is able to fully characterize induced velocities across the entire wake, from the stable region where momentum theory operates, through instability transition and eventual vortex breakdown. The simulation of a multirotor configuration of two tip-to-tip propellers is shown, displaying the capacity of VPM to model wake mixing. The results presented here are intermediate steps in the development of a mid-fidelity modeling tool for the early design stages of distributed-propulsion electric aircraft. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
938 a8621794000 Ning A. p553 False Conference 203 Multidisciplinary design optimization of flexible solar-regenerative high-altitude long-endurance aircraft Solar-Regenerative High-Altitude Long-Endurance (SR-HALE) aircraft are designed to sustain year-round ight at high altitudes indefinitely. No SR-HALE aircraft has yet accomplished this task due to the complex network of environmental, solar, structural, and aerodynamic trade-offs, among which aircraft exibility plays a key role. A comprehensive SR-HALE aircraft multidisciplinary design optimization framework is developed in which the exible aircraft analysis tool ASWING is incorporated in order to constrain nonlinear aeroelasticity. Energy, battery, ply thickness, material failure, local buckling, aerodynamic stall, longitudinal stability, and general stability (including utter) constraints are applied in order to reasonably constrain the optimized SR-HALE aircraft design. An SR-HALE aircraft design with a span length of 60:15m and a total aircraft weight of 432:2 kg is found which fulfills all SR-HALE mission requirements and minimizes aircraft mass. A further 21% reduction in total aircraft mass is found through the use of high modulus carbon fiber reinforced polymer. Significant decreases in aircraft mass, down to a total aircraft mass of 250.6 kg, are found to be possible if altitude requirements for SR-HALE aircraft are lowered from 18;288m to 16;764 m. A feasible SR-HALE aircraft with a mass of 357:9 kg was also found to be possible if battery specific energies of 360Wh kg–1 are developed. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
938 a8621794000 Ning A. p554 False Conference 204 Distributed electric propulsion effects on traditional aircraft through multidisciplinary optimization Electric aircraft face a steep tradeoff between the demand for runway performance and range. While fuel based propulsion technologies typically increase in specific power with increasing size, electric propulsion is typically much more scalable. This system scalability enables alternative designs including distributed propulsion, optionally powered propulsion units, and vectored thrust, which can all contribute to better runway performance and range. In this paper, we explore how continuously powered distributed propulsion can reduce takeoff distance while still satisfying range constraints. We use a combination of a blade element momentum method, a vortex lattice method, experimental data, and nonlinear optimization techniques to model and explore the design space. We have found that for this conceptual design study, a fully blown wing with propellers at the optimal diameter for the load (8 propellers for a 300 km range constraint) can reduce the takeoff distance by over 80% when compared to the optimal 2 propeller case using the same models. There is over a 2x increase in the wing lift coefficient which leads to a 36% reduction in liftoff speed. Also, the optimal fully blown case produced 2.9 more thrust during takeoff with only an 11% increase in total aircraft mass. Using propeller tip speed as a surrogate for noise, we found that the propeller tip speed decreased takeoff performance in an exponential manner: the tip speed could be decreased from Mach 0.8 to Mach 0.5 with only a 2x increase in takeoff rolling distance while decreasing the constraint to Mach 0.3 produced an 8x increase. © 2018, (publisher Name). All rights reserved.
938 a8621794000 Ning A. p596 False Conference 239 Universal airfoil parametrization using B-splines In this paper, we apply well-known techniques for parametric curves to the definition and deformation of airfoil sections. While it has already been shown that many versions of Kulfan’s Class Shape Transformation (CST) are exactly equivalent to Bézier curves, we show here that all NACA 4-digit thickness distributions and the PARSEC parametrization of Sobiezcky are also higher-order Bézier curves. As with CST, Béziers and B-Splines provide direct control over aerodynamically meaningful features such as nose radius and boat-tail angle, but also provide more a intuitive parametrization of the rest of the airfoil surface. We show the efficacy of B-Spline-based parametrizations for approximating airfoil coordinates and for clean-sheet airfoil design. Finally, we show that this parametrization is ideally suited for progressive design. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
938 a8621794000 Ning A. p616 False Conference 254 Benefits of two turbine rotor diameters and hub heights in the same wind farm Significant turbine-wake interactions greatly reduce power output in a wind farm. If different turbine hub heights and rotor diameters are included in the same wind farm, the wake interference in the farm will be reduced, resulting in a lower cost of energy (COE) than a farm with identical turbines. In this paper, we present a method to model wind farm COE in farms with hub heights and rotor diameters that vary across the wind farm. We also demonstrate how to optimize these wind farms to minimize COE. The results show that COE can be greatly reduced in wind farms with non-homogeneous turbines, especially when the turbines are spaced close together. For a unidirectional wind rose, including different turbine design in the wind farm has a similar decrease in COE to spreading the wind turbines farther apart. When the rotor diameter and hub height of the wind turbines in a farm are optimized uniformly, a COE decrease of 4% to 13% (depending on the grid spacing and wind shear exponent) is achieved compared to the baseline. When the rotor diameter and turbine heights are optimized non-uniformly, with two different diameters and heights throughout the farm, there is a COE decrease of 22% to 41% compared to the baseline. For a more spread wind rose with a dominant probability from the west, there is a COE decrease between 3% and 10% for uniformly optimized rotor diameter and height compared to the baseline. With two optimized rotor diameters and heights through the farm, a COE decrease of 3% to 19% is achieved. For a similar wind rose shifted such that the dominant wind direction is from the northwest, a COE decrease between 3% and 10% results from uniformly optimized wind turbines compared to the baseline. A COE decrease of 3% to 17% compared to the baseline occurs with two different turbines are optimized throughout the wind farm. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
938 a8621794000 Ning A. p627 False Conference 263 Large-scale multidisciplinary optimization of an electric aircraft for on-demand mobility Distributed electric propulsion is a key enabling technology for on-demand electric aircraft concepts. NASA’s X-57 Maxwell X-plane is a demonstrator for this technology, and it features a row of high-lift propellers distributed along the leading edge of its wing to enable better aerodynamic efficiency at cruise and improved ride quality in addition to less noise and emissions. This study applies adjointbased multidisciplinary design optimization to this highly coupled design problem. The propulsion, aerodynamics, and structures are modeled using blade element momentum theory, the vortex lattice method, and finite element analysis, respectively, and the full mission profile is discretized and analyzed. The design variables in the optimization problem include the altitude profile, the velocity profile, battery weight, propeller diameter, blade profile parameters, wing thickness distribution, and angle of attack. Optimizations take on the order of 10 hours, and a 12% increase in range is observed. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
938 a8621794000 Ning A. p836 False Conference 364 Gradient-based optimization of wind farms with different turbine heights Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the cost of energy of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and low wind shear exponent. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
939 a57215306633 Newcomb J.E. p287 True Conference 70 The effect of communication and vehicle properties on the search performance of a swarm of unmanned aerial vehicles An unmanned aerial vehicle (UAV) swarm allows for a more time-efficient method of searching a specified area than a single UAV or piloted plane. There are a variety of factors that affect how well an area is surveyed. We specifically analyzed the effect both vehicle properties and communication had on the swarm search performance. We used non-dimensionalization to examine the effect vehicle properties had on search performance so the results can be applied to any domain size with any number and type of vehicle. We found that even if vehicles could only sense 10% of the grid area at any given time step, 92% of the grid could still be searched by using a vehicle with good maneuverability and endurance. Conversely, if the chosen vehicle had poor maneuverability 92% of the grid could still be searched by keeping the endurance high and increasing the amount of area the vehicles could sense at one time to 70% of the domain area. In addition, we also examined four communication cases with different amounts of information regarding vehicle location. We found communication increased search performance by at least 6.3%. However, increasing the amount of information only changed the performance by 2.3%. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
940 a57201367093 Unrau M.A. p288 True Conference 71 Simulating stall inception in a high-performance fan using createt m-av kestrel The presented research uses a CFD code developed as part of the Computational Research and Engineering Acquisition Tools and Environment (CREATE), Kestrel, to evaluate a single stage compressor at various operating conditions. Time-accurate, full annulus simulations were carried out to capture and analyze the processes leading to stall inception for uniform inlet conditions. Unsteady interaction between tip clearance flow and the detached normal shock inside of the blade passages became more prevalent at flow rates close to stall, and this unsteadiness likely provides a way for leading edge spillage to occur and initiate the stall process. Although reversed flow at the trailing edge plane was not observed to be more prevalent in simulations near stall than in simulations away from stall, the phenomenon was shown to occur in blade passages that were approaching a stall cell. Understanding the physical processes that lead to stall inception allows fan designers to design more robust fans that can safely take advantage of the better performance associated with operating closer to stall. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
940 a57201367093 Unrau M.A. p555 True Conference 205 Mixing plane simulation of a high-performance fan using kestrel Kestrel is a tool developed by the Computational Research and Engineering Acquisition Tools and Environments-Air Vehicles (CREATE-AV) Program to expedite the acquisition process of fixed-wing aircraft. Kestrel’s capabilities include simulating internal flow, including within turbomachinery. Mixing plane methods are often used for modeling flow in gas turbine engine turbomachinery in order to evaluate multiple designs quickly. Because Kestrel’s mixing plane capabilities have been demonstrated in only limited cases, this research seeks to further validate the model using the Air Force Research Lab’s (AFRL) Rotor 4 fan. Extensive experimental data has been gathered for Rotor 4, allowing for in-depth comparisons to be made. Following the validation study, differences between the experimental results and the predictions from the mixing plane model are highlighted and discussed. These comparisons lead the authors to conclude that Kestrel’s mixing planes can be utilized to predict performance at various operating conditions and rotor speeds. This research serves to further Kestrel’s development and use by the Department of Defense (DoD) for aircraft acquisition. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
941 a57189445479 Sanchez D. p289 True Conference 72 Microfluidic temperature behavior in a multi-material 3D printed chip As analysis systems shrink in size to microfluidic scales and devices, there is a need to improve temperature control in the microscale for temperature-sensitive processes. Technology that combines accurate temperature measurement and 3D spatial control of the temperature distribution is limited by common 2D layer-based microfluidic fabrication techniques but can be realized with 3D printed microfluidic chips. This work presents an iterative process to create a microfluidic chip using multimaterial 3D printing to improve temperature sensing and create an even temperature around a target volume. Through an iterative process, verification is presented of fluorophore viability (specifically CdTe quantum dots) after being secured in place by cured PR48 3D printing resin, thus confirming the possibility of fluorescent thermometry as an accurate non-contact temperature sensing method. Numerical analyses of various geometries of chip design iterations are also presented verifying spatially even heating due to the placement of heating sources in the microfluidic chip. Combining the fluorescent thermometry and improved heating will lead to improved temperature control in microfluidic devices. Copyright © 2019 ASME.
942 a55812232700 Munro T. p289 False Conference 72 Microfluidic temperature behavior in a multi-material 3D printed chip As analysis systems shrink in size to microfluidic scales and devices, there is a need to improve temperature control in the microscale for temperature-sensitive processes. Technology that combines accurate temperature measurement and 3D spatial control of the temperature distribution is limited by common 2D layer-based microfluidic fabrication techniques but can be realized with 3D printed microfluidic chips. This work presents an iterative process to create a microfluidic chip using multimaterial 3D printing to improve temperature sensing and create an even temperature around a target volume. Through an iterative process, verification is presented of fluorophore viability (specifically CdTe quantum dots) after being secured in place by cured PR48 3D printing resin, thus confirming the possibility of fluorescent thermometry as an accurate non-contact temperature sensing method. Numerical analyses of various geometries of chip design iterations are also presented verifying spatially even heating due to the placement of heating sources in the microfluidic chip. Combining the fluorescent thermometry and improved heating will lead to improved temperature control in microfluidic devices. Copyright © 2019 ASME.
942 a55812232700 Munro T. p335 False Conference 111 Thermal properties of thin film uranium oxides and thorium oxides Uranium and thorium oxides have critical roles as fuels in existing nuclear power plants, as well as in proposed reactor concepts. The thermal conductivity of these materials determines their ability to transfer heat from the reactor core to the surrounding coolant. Additionally, these actinide compounds are of interest in condensed matter physics because of the 5f orbitals and unique electron interaction, coupling, and scattering events that can occur. Because of the radioactivity of thorium and uranium, thin film measurements of actinide materials are used to limit the amount of operator exposure, but standard thermal characterization methods are not well suited for thin films. This paper presents the process of depositing thin film UOx and ThOx samples of nm-μm thicknesses and the results of thermal property measurements. Thin films were deposited on silicon and glass substrates via dc-magnetron sputtering using an argon/oxygen mixture as the working gas. The thermal properties of the films were measured by the Thermal Conductivity Microscope (TCM). This uses one laser to generate thermal waves and a second laser to measure the magnitude and phases of the thermal waves to obtain the conductivity of materials. The results of the research show that the UOx film properties are lower than bulk values and that the role of the substrate has a considerable effect on determining the measured properties. Future work aims at improving the deposition process. Epitaxial film growth is planned. Additional understanding of thermal property measurements is targeted. Copyright © 2019 ASME.
942 a55812232700 Munro T. p560 False Conference 209 Thermal diffusivity measurements with fluorescent scanning microscope [No abstract available]
942 a55812232700 Munro T. p649 False Journal 313 From lignocellulose to biocomposite: Multi-level modelling and experimental investigation of the thermal properties of kenaf fiber reinforced composites based on constituent materials Natural fibers (such as kenaf) have garnered interest recently for use in composites because of their relatively high specific properties, low cost, and low environmental impact. Their thermal property information is limited, lacking experimental data on key properties such as thermal conductivity, specific heat, and CTE of the component fiber. This paper presents, for the first time, the thermal property data on kenaf fiber reinforced composites, and an approach to obtain the composite thermal properties based on constituent properties. Individual, plant-based fibers were measured independently and were then used to inform successful predictions of the effective thermal conductivity of the fiber reinforced composites. A unit cell model has been developed to predict the thermal properties of a planar, randomly oriented kenaf fiber-reinforced composite (near 22% volume fraction loading), which includes the effect of void content on the predicted thermal conductivity. A lower-level model is also developed for individual fiber thermal properties based on its constituents (lignin, cellulose, and hemicellulose). To validate this multi-level model, experimental measurements of the thermal diffusivity, coefficient of thermal expansion, and specific heat for the composite, the matrix, and the fibers were performed in the range from 30 °C to 160 °C, based on TMA, DSC, LFA, and transient electro-thermal (TET) techniques. Model results compare favorably with the experimental data, and are consistent with FEM modelling results based on fiber properties and fiber constituent materials (lignin, cellulose, and hemicellulose). This approach provides the basis for understanding component contribution to the fiber properties, as well as a technique to obtain fiber composite thermal property based on component properties. The composite thermal property data also fills an information gap and can be directly used in component design. © 2017 Elsevier Ltd
942 a55812232700 Munro T. p760 False Journal 370 Thermal characterization of natural and synthetic spider silks by both the 3ω and transient electrothermal methods Thermal conductivity, thermal diffusivity, and volumetric heat capacity of three spider silks are measured in this paper as a benchmark for further studies. These silks include the major and minor ampullate silks of the Nephila clavipes spider, and a synthetic spider silk fiber made from recombinant dragline silk proteins purified from transgenic goats’ milk. Two complementary measurement techniques are employed in the thermal characterization of these microscale single fibers for self-verification. One is the transient electrothermal technique (TET) and the other is the 3ω method. Experimental measurements indicate that thermal properties of the dragline silk are very close to those of the minor ampullate silk, whereas the ones for the synthetic silk are much lower due in part to its low crystallinity. The directly measured thermal conductivity, thermal diffusivity, and volumetric heat capacity of the major and minor ampullate silks are 1.2–1.26 W m− 1 K− 1, 5.7–6 × 10− 7 m2 s− 1, and 2–2.17 MJm− 3 K− 1, respectively. The thermal conductivity and thermal diffusivity of the as-spun synthetic silk are 0.24 W m− 1 K− 1 and 1.6 × 10− 7 m2 s− 1 respectively. As part of this study, a detailed comparison of the TET and 3ω methods is provided showing the complementary nature of the techniques and illustrating the strengths and weaknesses of each. © 2017 Elsevier Ltd
942 a55812232700 Munro T. p883 True Journal 410 Thermophysical properties of thin fibers via photothermal quantum dot fluorescence spectral shape-based thermometry To improve predictions of composite behavior under thermal loads, there is a need to measure the axial thermophysical properties of thin fibers. Current methods to accomplish this have prohibitively long lead times due to extensive sample preparation. This work details the use of quantum dots thermomarkers to measure the surface temperature of thin fibers in a non-contact manner and determine the fibers’ thermal diffusivity. Neural networks are trained on extracting the temperature of a sample from fluorescence spectra in calibrated, steady-state conditions, based on different spectral features such as peak intensity and peak wavelength. The trained neural networks are then used to reconstruct the evolution of the surface temperature in transient heating experiments. In order to determine the thermal properties of a thin fiber, modulated laser heating is applied and an FFT-based method is used to extract the phase and amplitude response of the temperature field at the modulation frequency. The spatiotemporal dependence of the fluorescence signal, obtained by scanning the distance between the excitation and detection laser spots and varying the frequency response due to an axial scan and a frequency scan, is then curve-fit to the resulting decay curves by a photothermal model in order to determine the thermal diffusivity of the fiber. The measured thermal diffusivity (3.3 ± 0.8 × 10−7 m2 s−1) of a synthetic spider silk fiber by the current method has similar properties to other synthetic silk fibers, and demonstrates the ability of the current method to more rapidly measure thermophysical properties of thin fibers. © 2017 Elsevier Ltd
943 a57192955909 La A. p291 True Conference 73 Identifying mode shapes of turbo-machinery blades using principal component analysis and support vector machines Manually identifying mode shapes generated from finite element solvers images is an expensive task. This paper proposes an automated process to identify mode shapes from gray-scale images of compressor blades within a jetengine. This work introduces mode shape identification using principal component analysis (PCA), similar to approaches in facial and other recognition tasks in computer vision. This technique calculates the projected values of potentially linearly correlated values onto P-linearly orthogonal axes, where P is the number of principal axes that define a subset space. Classification was done using support vector machines (SVM). Using the PCA and SVM algorithm, approximately 5300 training images representative of 16 different modes were used to create a classifier. The classifier achieved on average 98% accuracy when tested using a test set of approximately 2000 images given P D 70. The results suggest that using digital images to perform mode shape identification can be achieved with high accuracy. Potential generalization of this method could be applied to other engineering design and analysis applications. © The Society for Experimental Mechanics, Inc. 2019.
943 a57192955909 La A. p715 False Journal 352 Methods for determining the optimal number of simultaneous contributors for multi-user CAD parts The development of multi-user CAD (MUCAD) tools has opened up exciting new opportunities and applications. The capability for multiple users to simultaneously model and design a CAD part has far-reaching potential. However, many basic questions remains unanswered, such as how many users should work together on a given part. This research proposes and develops a set of methods to determine the optimal number of users for a given part within a MUCAD environment, based on the characteristics of the part itself. Two candidate models are evaluated with a set of 60 experiments with design teams composed of different numbers of users. The models show modest correlations with the test data while more-refined models are explored to improve predictive power. On the other hand, highly significant correlations between the ability to predict completion time and multi-user team size were identified in the experimental data. Observations regarding the speed and quality of MUCAD teams are also made with future areas of research suggested. © 2017 CAD Solutions, LLC.
944 a55161739600 Howell B. p292 True Conference 74 New uses of instagram in design history education Last year we initiated the use of Instagram into our design history course at an introductory level. This year we explored further integration of Instagram as an academic tool. This study included twenty-two undergraduate participants who prototyped five new classroom uses of Instagram: posting full student presentations, utilising Instagram desktop view as the primary in-class presentation tool, employing templates enabling a cohesive visual identity and a simple search process, and methods to enhance student comments. We surveyed course participants mid-semester asking students about their personal Instagram use, the value and purpose they felt Instagram had in the course, and on the usefulness of the presentation templates. We learned that while the majority of students use Instagram in their daily life, few of them make comments on personal or course posts and will only do so for credit. We also learned that while students might not enjoy using Instagram in the course, they find it of value and highly meaningful. Finally, the students prefer using formatted templates over an open style like PowerPoint to build their presentations in. These templates enabled the students to post their full presentations and created a visual cohesiveness for the account while providing a rudimentary search process for individual posts. We will continue using Instagram in future courses with the exception of requiring comments. We believe that students will reference their class posts in years to come, and as they do, it will re-enforce their design knowledge and provide evidence of their personal growth. © 2019 Institution of Engineering Designers, The Design Society. All rights reserved.
944 a55161739600 Howell B. p293 False Conference 75 Exploring play interventions in design education This study reports a collection of surveyed responses from industrial design students at Brigham Young University over six semesters regarding high levels of perceived stress in a competitive class environment, and it outlines playful interventions in coursework and classroom settings to measure if play can make any significant impact on students’ perceptions of stress and feelings of frustration. This study is inspired by existing play studies that continue to demonstrate the positive relationship between the freedom to be playful and psychological wellbeing. The methods used in this study include a consolidation of 99 anonymous free-response student surveys over the course of six semesters that are organised in terms of stress level and frustration word indicators. These comments provide a historical baseline for understanding the student perceptions of their classroom learning experience as it relates to their emotional wellbeing. We then compare those comments with comments made after a semester of playful interventions to discover how they differ. The results indicate that levels of “stress” and “frustration” were decreased with playful interventions, however students spent more hours outside of class lecture on their assignments and the overall student course rating nominally decreased. These results are discussed as well as how pedagogical changes to traditional classroom environments such as this may not only impact stress and frustration but also significantly contribute to the holistic learning experience for university students. © 2019 Institution of Engineering Designers, The Design Society. All rights reserved.
944 a55161739600 Howell B. p294 False Conference 76 Exploring the moral differences, between industrial design, engineering and entrepreneurship students Over the last two years our industrial design programme has been involved in a number of interdisciplinary team projects. We have observed that in successful teams, the education and skills of team members matters less than how the team members interact, structure their work and view their contributions. We believe that there are distinct and innate differences between students in different academic disciplines when it comes to moral positions and these differences in worldview inherently causes friction in interdisciplinary teams. Consequently, we feel that if students could understand these differences extrinsically, they could potentially improve their experience within their interdisciplinary team work. We ran a pilot study with students from Brigham Young University comparing the industrial design, engineering and entrepreneurship majors using The Moral Foundations Questionnaire (Graham, Haidt & Nosek, 2008) This survey measures five facets of one’s moral position: Care/Harm, Fairness/Reciprocity, In-group/Loyalty, Authority/Respect and Sanctity/Purity. Results show that designers scored higher in liberal values than their more conservative leaning engineering and business student counterparts. These results support our hypothesis. Understanding the fundamental value differences between disciplinary training should reduce friction and enhance interdisciplinary team communication. This ability to appreciate other mindsets in order to communicate and effectively design with individuals from differing disciplines will be an “essential skill for workers in the coming decades” (Colombo and Grilli, 2005). © 2019 Institution of Engineering Designers, The Design Society. All rights reserved.
944 a55161739600 Howell B. p564 False Conference 213 Using instagram to increase student engagement with design history In today’s rapidly evolving design disciplines, design history students should demonstrate an understanding of the social and cultural impact of design of both historical and contemporary designers and their methods. To increase student engagement with design history and discourse, we prototyped a new format for our design history course in Brigham Young University’s Industrial Design department. Our goal was to enable students to process designs they encounter, both in person and social media, through a critical and cultural perspective, and then turn those lenses towards their own design work with greater social and cultural awareness. To do this, we utilized Instagram as the primary platform (@byudesignhistory) for course discussion and altered the way we framed student assignments. This new curriculum was prototyped in the spring of 2018. Outcomes were measured by monitoring student engagement, responses, and comprehension scores on verbal and written assignments and examinations. Students also responded to a series of reviews to gather their perspectives on the class. Results indicate an increase in their understanding of the cultural position design holds in a way that was absent in student results from the previous course structure. If our course interventions are effective, students should move from concrete to abstract knowledge as well as from lower order to higher order thinking skills. Students will thus be better prepared to assess, understand and discuss both current and historical design cultures and trends while influencing their own design work through an informed perspective. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
944 a55161739600 Howell B. p565 False Conference 214 Increasing the educational impact following a field study programme Design students return from field trips abroad brimming with new ideas and a greater understanding of their chosen discipline. However, if their observations and knowledge are not soon applied, the students hold only fond memories of a fun trip abroad. We believe that student’s retention and application of concepts will increase if educators give students greater autonomy on the trip and also expect and enable opportunities to apply their accrued knowledge on their own projects upon returning home. Nine third and fourth-year industrial design students Brigham Young University participated in a weeklong field study abroad to Dutch Design Week (DDW) in Eindhoven, Netherlands. A week after the completion of the study abroad the students filled out a survey about their motivations, feelings, criticisms, and aspects of the trip that influenced them as designers. Three and a half months later the students took a second survey asking about how they have applied insights gained from participation in DDW to their current projects. The results from the both surveys suggest the impact of the field study trip decreased over time. The observations and more open-ended questions in the survey helped determine if and how the students applied their conceptual knowledge to their current projects as well as other outcomes of the trip. In addition, the paper suggests possible strategies and research opportunities for future field study experiences. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
944 a55161739600 Howell B. p646 False Conference 278 Application of “CODeve” methodology in transatlantic student design project COllaborative DEsign in Virtual Environment (CODEVE) is a teaching methodology developed within the European Global Product Realisation (EGPR) course over a number of years. It was developed to establish suitable teaching practice to educate students on efficient design methods in a distributed product realisation projects in conjunction with an industrial partner. Students work in international teams formed from multiple partner universities. Communication is primarily through video-conferencing and other synchronous and asynchronous means of communication to perform design tasks including the vision, conceptual design, detail design and prototyping. Students ultimately meet during the final workshop at the end of the course to assemble and test prototypes and to disseminate their work to the company and wider public. The CODEVE methodology was tested in the Erasmus+ funded project called Networked Activities for Realisation of Innovative Products (NARIP) from 2015-2107. It has been implemented in academic institution in Europe. This paper discusses applicability of this methodology in the project which connects universities and industry across the Atlantic. Three universities are participating this year: Brigham Young University from Utah, USA with Industrial Design students, University of Technology and Economics of Budapest in Hungary with product design students and City, University of London from the UK with mechanical, aeronautical and electrical engineering students. The industrial partner is Black Diamond, a global company based in Utah, USA, while the manufacturing of prototypes and final workshop are hosted at City, University of London. Time difference, culture and the discipline of study make implementation of CODEVE methodology in this transatlantic project more difficult than if the project is kept within European Universities. This paper outlines challenges and learning outcomes of students on both sides of Atlantic. Recommendations to modifications in CODEVE methodology to suit transatlantic projects are discussed in the paper. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
944 a55161739600 Howell B. p797 True Conference 334 Design education and the new culture of design centric intellectual property This paper addresses the relevance of integrating intellectual property (IP) rights studies within contemporary industrial design studio courses. As recently as 2014, an article on design and IP argues that “recent legal and cultural evolutions within the United States Intellectual Property system”… “do not favour student inventors and hinder their ability to protect their creative work” and students would be better served using their resources on more fruitful pursuits. However, IP culture surrounding Design Patents/Design Rights has substantially changed in the last decade and it is time for this position to be readdressed. This paper reviews the reframing of Brigham Young University’s third-year industrial design studio course to include training on IP. It appraises the current state of IP training in design schools and how design related IP has markedly shifted in recent years. It outlines basic IP exercises and introduces case studies for the four the primary types of IP: Copyrights, Trademarks, Design and Utility Patents. Students are exposed to two opposing mindsets regarding IP: the traditional position that views IP as a defensive tool to build a fence around an individual’s rights; and more importantly, how to use IP as a collaborative bridge between other market players enabling meaningful market offerings.
944 a55161739600 Howell B. p798 False Conference 335 Integrating a multidisciplinary design methods mindset into classroom practice Sanders and Stappers (2013) propose a new interpretation of design disciplines that is not delineated by traditional fields such as industrial design, graphic design, or architecture, but by themes focusing on “people in the context of their lives” such as design for sustainability and design for well-being. Howell, Stark, et al (2016) teaches that multiple design fields May be employed in tandem to explore human centered design projects. This mindset allows for more holistic design solutions. When students are introduced to this framework, they are opened up to more flexibility in their design process and potential solutions. This paper outlines an industrial design student’s self-directed thesis project on encouraging self-compassionate thought patterns. We will examine how the process was affected by viewing the project as a multidisciplinary design field challenge instead of a traditional form, color and material-driven industrial design challenge. Importantly, the paper will discuss how research and design methods from industrial design, graphic design, interaction design, storytelling, and psychological science played into the creation of a meaningful designed project and experience. The paper concludes with several suggestions for integrating multidisciplinary design methods into classroom practice.
944 a55161739600 Howell B. p799 False Conference 336 Using local invasive species and flora to manufacture collagen based biodegradable plastic tableware This paper explains how we designed, developed and tested a locally sourced; environmentally sensitive, biodegradable collagen plastic. It discusses the creation of simple moulds for manufacturing tableware and the accompanying workshop proving the viability of both the process and product. Tests were conducted using commercially available collagen materials to understand its attributes. A unique formulation was developed from hides of local agricultural vermin and powders derived from invasive flora. Plaster and concrete moulds were created for the manufacture of simple tableware. A workshop occurred were 12 participants tested the quality of the plastic, the robustness of the moulds, the simplicity of the manufacturing process and the aesthetics of the tableware. Finally, four of the bowls were successfully tested for bio-degradability and fully degraded within 12 weeks of contact with soil. The workshop demonstrated the success of all aspects of the process and how this development process could be used in emerging communities globally to encourage local manufacture of sustainable products.
945 a57211281996 Siebert J. p292 False Conference 74 New uses of instagram in design history education Last year we initiated the use of Instagram into our design history course at an introductory level. This year we explored further integration of Instagram as an academic tool. This study included twenty-two undergraduate participants who prototyped five new classroom uses of Instagram: posting full student presentations, utilising Instagram desktop view as the primary in-class presentation tool, employing templates enabling a cohesive visual identity and a simple search process, and methods to enhance student comments. We surveyed course participants mid-semester asking students about their personal Instagram use, the value and purpose they felt Instagram had in the course, and on the usefulness of the presentation templates. We learned that while the majority of students use Instagram in their daily life, few of them make comments on personal or course posts and will only do so for credit. We also learned that while students might not enjoy using Instagram in the course, they find it of value and highly meaningful. Finally, the students prefer using formatted templates over an open style like PowerPoint to build their presentations in. These templates enabled the students to post their full presentations and created a visual cohesiveness for the account while providing a rudimentary search process for individual posts. We will continue using Instagram in future courses with the exception of requiring comments. We believe that students will reference their class posts in years to come, and as they do, it will re-enforce their design knowledge and provide evidence of their personal growth. © 2019 Institution of Engineering Designers, The Design Society. All rights reserved.
946 a57211282830 Hill M. p292 False Conference 74 New uses of instagram in design history education Last year we initiated the use of Instagram into our design history course at an introductory level. This year we explored further integration of Instagram as an academic tool. This study included twenty-two undergraduate participants who prototyped five new classroom uses of Instagram: posting full student presentations, utilising Instagram desktop view as the primary in-class presentation tool, employing templates enabling a cohesive visual identity and a simple search process, and methods to enhance student comments. We surveyed course participants mid-semester asking students about their personal Instagram use, the value and purpose they felt Instagram had in the course, and on the usefulness of the presentation templates. We learned that while the majority of students use Instagram in their daily life, few of them make comments on personal or course posts and will only do so for credit. We also learned that while students might not enjoy using Instagram in the course, they find it of value and highly meaningful. Finally, the students prefer using formatted templates over an open style like PowerPoint to build their presentations in. These templates enabled the students to post their full presentations and created a visual cohesiveness for the account while providing a rudimentary search process for individual posts. We will continue using Instagram in future courses with the exception of requiring comments. We believe that students will reference their class posts in years to come, and as they do, it will re-enforce their design knowledge and provide evidence of their personal growth. © 2019 Institution of Engineering Designers, The Design Society. All rights reserved.
947 a57204903122 Hazen G. p293 True Conference 75 Exploring play interventions in design education This study reports a collection of surveyed responses from industrial design students at Brigham Young University over six semesters regarding high levels of perceived stress in a competitive class environment, and it outlines playful interventions in coursework and classroom settings to measure if play can make any significant impact on students’ perceptions of stress and feelings of frustration. This study is inspired by existing play studies that continue to demonstrate the positive relationship between the freedom to be playful and psychological wellbeing. The methods used in this study include a consolidation of 99 anonymous free-response student surveys over the course of six semesters that are organised in terms of stress level and frustration word indicators. These comments provide a historical baseline for understanding the student perceptions of their classroom learning experience as it relates to their emotional wellbeing. We then compare those comments with comments made after a semester of playful interventions to discover how they differ. The results indicate that levels of “stress” and “frustration” were decreased with playful interventions, however students spent more hours outside of class lecture on their assignments and the overall student course rating nominally decreased. These results are discussed as well as how pedagogical changes to traditional classroom environments such as this may not only impact stress and frustration but also significantly contribute to the holistic learning experience for university students. © 2019 Institution of Engineering Designers, The Design Society. All rights reserved.
947 a57204903122 Hazen G. p646 False Conference 278 Application of “CODeve” methodology in transatlantic student design project COllaborative DEsign in Virtual Environment (CODEVE) is a teaching methodology developed within the European Global Product Realisation (EGPR) course over a number of years. It was developed to establish suitable teaching practice to educate students on efficient design methods in a distributed product realisation projects in conjunction with an industrial partner. Students work in international teams formed from multiple partner universities. Communication is primarily through video-conferencing and other synchronous and asynchronous means of communication to perform design tasks including the vision, conceptual design, detail design and prototyping. Students ultimately meet during the final workshop at the end of the course to assemble and test prototypes and to disseminate their work to the company and wider public. The CODEVE methodology was tested in the Erasmus+ funded project called Networked Activities for Realisation of Innovative Products (NARIP) from 2015-2107. It has been implemented in academic institution in Europe. This paper discusses applicability of this methodology in the project which connects universities and industry across the Atlantic. Three universities are participating this year: Brigham Young University from Utah, USA with Industrial Design students, University of Technology and Economics of Budapest in Hungary with product design students and City, University of London from the UK with mechanical, aeronautical and electrical engineering students. The industrial partner is Black Diamond, a global company based in Utah, USA, while the manufacturing of prototypes and final workshop are hosted at City, University of London. Time difference, culture and the discipline of study make implementation of CODEVE methodology in this transatlantic project more difficult than if the project is kept within European Universities. This paper outlines challenges and learning outcomes of students on both sides of Atlantic. Recommendations to modifications in CODEVE methodology to suit transatlantic projects are discussed in the paper. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
948 a57187178400 Morgan D. p293 False Conference 75 Exploring play interventions in design education This study reports a collection of surveyed responses from industrial design students at Brigham Young University over six semesters regarding high levels of perceived stress in a competitive class environment, and it outlines playful interventions in coursework and classroom settings to measure if play can make any significant impact on students’ perceptions of stress and feelings of frustration. This study is inspired by existing play studies that continue to demonstrate the positive relationship between the freedom to be playful and psychological wellbeing. The methods used in this study include a consolidation of 99 anonymous free-response student surveys over the course of six semesters that are organised in terms of stress level and frustration word indicators. These comments provide a historical baseline for understanding the student perceptions of their classroom learning experience as it relates to their emotional wellbeing. We then compare those comments with comments made after a semester of playful interventions to discover how they differ. The results indicate that levels of “stress” and “frustration” were decreased with playful interventions, however students spent more hours outside of class lecture on their assignments and the overall student course rating nominally decreased. These results are discussed as well as how pedagogical changes to traditional classroom environments such as this may not only impact stress and frustration but also significantly contribute to the holistic learning experience for university students. © 2019 Institution of Engineering Designers, The Design Society. All rights reserved.
948 a57187178400 Morgan D. p484 False Conference 176 Outreach potential of displaying research artifacts in art museums This paper explores how displaying engineering research artifacts in art museums can facilitate expanded outreach opportunities. A combination of visual art and innovative engineering offers an unusual opportunity to engage a wide spectrum of society. To evaluate the potential, faculty and students collaborated with the Brigham Young University Museum of Art to create a museum exhibition that connected the art of origami to engineering, math, science, and product design. A framework is introduced that includes the creation of a museum exhibition; and once the initial investment is made to create the central exhibition, the results are efficiently used to extend outreach efforts through first-generation products (coincident with the exhibition) and then through second-generation products (after the exhibition). The paper describes a detailed example of this framework and provides evidence to support the concept that displaying research artifacts in an art museum can expand research opportunities. Products from the exhibition that provided expanded outreach opportunities include the following: an exhibit catalog originally created for the gift shop that was expanded for publication with a national publisher; a tablet/smart phone app that includes origami instructions followed by related engineering activities, which has had broad use beyond the museum activity room; a video that was prepared for museum patrons but has since been made available to larger audiences; materials created for hands-on museum activities that were used for outreach activities after the exhibition; and leverage for industry visits that led to additional applications and research projects. This paper describes the museum exhibition, the first- and second-generation products, the impact of each product, and the benefits and pitfalls of using a museum exhibition to extend outreach impact. © American Society for Engineering Education, 2018.
948 a57187178400 Morgan D. p796 True Conference 333 Sell it: Design project assessment by the public This investigation contributes to design assessment practice by examining how public assessment can enhance project-based learning. Project-based learning is designed to provide students with an opportunity to engage in authentic problem finding and solving. Students often become very involved with the specifics of their project without always noticing what they are learning. As such, it becomes essential to engage them in reflection during the process and at the completion of the project. A constellation of formative and summative assessment activities that include self, group, and instructor, can aid the learner in this contemplation. We propose that public assessment in the form of a student-run sale can provide distinctive feedback to students. Our experience with student-run retail sales over multiple years has lead us to identify some unique characteristics of this type of public assessment. These include a positive effect on student motivation, independent validation in a face-to-face setting, and providing direct consumer feedback to students. In this paper we discuss assessment practice as it relates to the sale and review student reflections on the experience to determine its usefulness.
949 a57211282935 Hamilton M. p294 True Conference 76 Exploring the moral differences, between industrial design, engineering and entrepreneurship students Over the last two years our industrial design programme has been involved in a number of interdisciplinary team projects. We have observed that in successful teams, the education and skills of team members matters less than how the team members interact, structure their work and view their contributions. We believe that there are distinct and innate differences between students in different academic disciplines when it comes to moral positions and these differences in worldview inherently causes friction in interdisciplinary teams. Consequently, we feel that if students could understand these differences extrinsically, they could potentially improve their experience within their interdisciplinary team work. We ran a pilot study with students from Brigham Young University comparing the industrial design, engineering and entrepreneurship majors using The Moral Foundations Questionnaire (Graham, Haidt & Nosek, 2008) This survey measures five facets of one’s moral position: Care/Harm, Fairness/Reciprocity, In-group/Loyalty, Authority/Respect and Sanctity/Purity. Results show that designers scored higher in liberal values than their more conservative leaning engineering and business student counterparts. These results support our hypothesis. Understanding the fundamental value differences between disciplinary training should reduce friction and enhance interdisciplinary team communication. This ability to appreciate other mindsets in order to communicate and effectively design with individuals from differing disciplines will be an “essential skill for workers in the coming decades” (Colombo and Grilli, 2005). © 2019 Institution of Engineering Designers, The Design Society. All rights reserved.
950 a57216747100 Korimi M. p295 True Conference 77 Progress on static structures for leaky mode waveguides This work reports progress toward increased field of view from multi-order leaky mode devices. Specifically, we move from our previously published simulation toward physical instantiation including a glass-based test rig. ©2019TheAuthor(s)
951 a57216739000 Adams M.R. p295 False Conference 77 Progress on static structures for leaky mode waveguides This work reports progress toward increased field of view from multi-order leaky mode devices. Specifically, we move from our previously published simulation toward physical instantiation including a glass-based test rig. ©2019TheAuthor(s)
952 a57212553003 Pham H. p298 False Conference 80 Cooperating in long-term relationships with time-varying structure Extended interactions between agents have commonly been studied in the context of repeated games (RGs), in which the same players repeatedly interact in the same scenario. However, such interactions are uncommon in practice. Typically, the players' goals, action sets, and payoffs change from encounter to encounter, often in ways the players cannot easily model or control. These more realistic interactions, which we model as a form of stochastic game called interaction games (IGs), have attributes which prohibit the straightforward application of many often-used algorithms developed for RGs. In this paper, we generalize several algorithms previously designed for RGs, and explore their behavior and performance in IGs. Our results suggest that at least some of the methodologies designed for RGs can, with some modifications, be extended to IGs. © 2019 International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.
953 a57200205435 Schroedter T.L. p299 False Conference 81 Modeling pressurized dense phase coal fluidization and transport A transient gas-solid model based on CPFD Software’s Barracuda Virtual Reactor was developed for a feed system to a pilot-scale pressurized oxy-coal (POC) reactor. A simplified geometry with a vertical coal hopper feeding into a 0.635-cm diameter horizontal pipe was used to represent key elements of the feed system. Coal particles were transported with 20-atm CO2 gas. The feed system was required to maintain a steady flow of gas and solids at a coal flow rate of approximately 3.8 g/s and a CO2 to coal mass ratio in the range 1-2. Sensitivity of model results to mesh size and particle interaction sub-model settings was assessed. Two design concepts were evaluated. A gravity-fed concept was found to be infeasible due to inadequate coal flow rates even at very high CO2 to coal flow ratios. This was due to gravitational forces being insufficient to move the pressurized coal from the hopper into the CO2 stream at the desired rate. A fluidized bed concept was found to provide the desired coal flow rate and CO2 to coal flow ratio. CO2 injected at the hopper base first fluidized the vertical coal bed before transporting it through a horizontal exit pipe. A second CO2 inlet downstream of the hopper exit pipe was used to dilute the fluidized coal and increase pipe velocities to minimize coal drop out. The amount of coal transported from the hopper was dependent on the net CO2 hopper flow but independent of the CO2 dilution flow. This meant that the coal flow rate and CO2 to coal flow ratio could be controlled independently. Pipe exit coal flow rates were found to fluctuate at levels acceptable for steady burner operation. Copyright © 2019 ASME.
953 a57200205435 Schroedter T.L. p813 True Conference 348 Modeling a pressurized coal feed system A gas-solid model was developed for a feed system to a pressurized oxy-coal (POC) reactor utilizing the multiphase particle-in-cell (MP-PIC) method. The model was created using CPFD Software's Barracuda Virtual Reactor 17.2.0. The geometry of the feed system was simple and contained a vertical standpipe of five inches feeding into a horizontal pipe of twelve inches. The coal particles from the standpipe were transported into the reactor with gas. To ensure appropriate combustion in the reactor, the feed system needed to maintain both a steady flow rate of gas and solids in the pipe and uniform distribution of solids through the cross-section of the channel. Steadiness was determined by the mass flow rate of the coal leaving the feed system. Uniformity was assessed by plotting gas and particle velocities at the end of the channel. The uniformity and steadiness of the flow was assessed for different grid sizes, starting pressure and boundary conditions, and other parameters within Barracuda.
954 a57203241931 Smith T. p300 False Conference 82 A usability study of five two-factor authentication methods Two-factor authentication (2FA) defends against account compromise. An account secured with 2FA typically requires an individual to authenticate using something they know-typically a password-as well as something they have, such as a cell phone or hardware token. Many 2FA methods in widespread use today have not been subjected to adequate usability testing. Furthermore, previous 2FA usability research is difficult to compare due to widely-varying contexts across different studies. We conducted a two-week, between-subjects usability study of five common 2FA methods with 72 participants, collecting both quantitative and qualitative data. Participants logged into a simulated banking website nearly every day using 2FA and completed an assigned task. Participants generally gave high marks to the methods studied, and many expressed an interest in using 2FA to provide more security for their sensitive online accounts. We also conducted a within-subjects laboratory study with 30 participants to assess the general usability of the setup procedure for the five methods. While a few participants experienced difficulty setting up a hardware token and a one-time password, in general, users found the methods easy to set up. © is held by the author/owner.
954 a57203241931 Smith T. p471 False Conference 173 A Tale of Two Studies: The Best and Worst of YubiKey Usability Two-factor authentication (2FA) significantly improves the security of password-based authentication. Recently, there has been increased interest in Universal 2nd Factor (U2F) security keys-small hardware devices that require users to press a button on the security key to authenticate. To examine the usability of security keys in non-enterprise usage, we conducted two user studies of the YubiKey, a popular line of U2F security keys. The first study tasked 31 participants with configuring a Windows, Google, and Facebook account to authenticate using a YubiKey. This study revealed problems with setup instructions and workflow including users locking themselves out of their operating system or thinking they had successfully enabled 2FA when they had not. In contrast, the second study had 25 participants use a YubiKey in their daily lives over a period of four weeks, revealing that participants generally enjoyed the experience. Conducting both a laboratory and longitudinal study yielded insights into the usability of security keys that would not have been evident from either study in isolation. Based on our analysis, we recommend standardizing the setup process, enabling verification of success, allowing shared accounts, integrating with operating systems, and preventing lockouts. © 2018 IEEE.
955 a57212168814 Armknecht J. p300 False Conference 82 A usability study of five two-factor authentication methods Two-factor authentication (2FA) defends against account compromise. An account secured with 2FA typically requires an individual to authenticate using something they know-typically a password-as well as something they have, such as a cell phone or hardware token. Many 2FA methods in widespread use today have not been subjected to adequate usability testing. Furthermore, previous 2FA usability research is difficult to compare due to widely-varying contexts across different studies. We conducted a two-week, between-subjects usability study of five common 2FA methods with 72 participants, collecting both quantitative and qualitative data. Participants logged into a simulated banking website nearly every day using 2FA and completed an assigned task. Participants generally gave high marks to the methods studied, and many expressed an interest in using 2FA to provide more security for their sensitive online accounts. We also conducted a within-subjects laboratory study with 30 participants to assess the general usability of the setup procedure for the five methods. While a few participants experienced difficulty setting up a hardware token and a one-time password, in general, users found the methods easy to set up. © is held by the author/owner.
956 a57212172095 Cameron J. p300 False Conference 82 A usability study of five two-factor authentication methods Two-factor authentication (2FA) defends against account compromise. An account secured with 2FA typically requires an individual to authenticate using something they know-typically a password-as well as something they have, such as a cell phone or hardware token. Many 2FA methods in widespread use today have not been subjected to adequate usability testing. Furthermore, previous 2FA usability research is difficult to compare due to widely-varying contexts across different studies. We conducted a two-week, between-subjects usability study of five common 2FA methods with 72 participants, collecting both quantitative and qualitative data. Participants logged into a simulated banking website nearly every day using 2FA and completed an assigned task. Participants generally gave high marks to the methods studied, and many expressed an interest in using 2FA to provide more security for their sensitive online accounts. We also conducted a within-subjects laboratory study with 30 participants to assess the general usability of the setup procedure for the five methods. While a few participants experienced difficulty setting up a hardware token and a one-time password, in general, users found the methods easy to set up. © is held by the author/owner.
957 a57205292526 Rogers W. p301 True Journal 121 Improving photophoretic trap volumetric displays [Invited] Since the introduction of optical trap displays in 2018, there has been significant interest in further developing this technology. In an effort to channel interest in the most productive directions, this work seeks to illuminate those areas that, in the authors’ opinion, are most critical to the ultimate success of optical trap displays as a platform for aerial 3D imaging. These areas include trapping, scanning, scaling, robustness, safety, and occlusion. © 2019 Optical Society of America
957 a57205292526 Rogers W. p562 False Conference 211 Progress on photophoretic trap displays We review the fundamentals photophoretic trap displays and discuss the possibility of creating occlusion capable image points. Anisotropic scattering is observed independently in single and double point traps. © 2018 The Author(s).
957 a57205292526 Rogers W. p591 False Conference 234 Volumetric display by movement of particles trapped in a laser via photophoresis Photophoresis can stably hold opaque microscopic particles in a laser focus surrounded by room air with strength sufficient to enable centimeter-scale patterns to be drawn by sweeping the laser beam. The resulting images rely on visual persistence as laser light scatters from the particle, which is rapidly swept through the 3-D pattern. Control can be maintained while moving the particle with air speeds up to 2 m/s. A desire to greatly increase the sweep speed motivates a re-examination of the fundamentals of photophoresis-based laser-particle traps. Most explanations offered are qualitative, with differing opinions as to whether, for example, asymmetric heating or asymmetric thermal accommodation is primarily at work. Which particles become trapped in the beam is typically based on self-selection, as a variety of particles with possible differing shapes and sizes are offered to the laser focus for capture. Characteristics that make some particles preferred over others are especially relevant. There is broad consensus that structure in the laser focus greatly aids in stable trapping. Nevertheless, it is still possible for even a relatively smooth TEM00 beam to capture and hold particles. Moreover, even in a structured focus (i.e. with aberrations and local intensity minima and maxima), questions remain as to exactly how a particle becomes stably trapped in certain beam locations. A zoomed-in look at trapped particles reveals oscillations or orbits with excursions over tens of microns and accelerations up to 10 gs. We trapped particles in zero-gravity as well as 2-g environments with no noticeable difference in stability. © 2018 SPIE.
958 a57195066838 Neupane A. p302 True Conference 83 Designing emergent swarm behaviors using behavior trees and grammatical evolution Results show that a recursively defined BT-based grammar, built from common agent behaviors, can be used by the GEESE algorithm to evolve solutions to single-source foraging task. Because of the difficulty of solving the credit assignment problem, bootstrapping methods must be added to the fitness function to find solutions in reasonable time. © 2019 International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.
958 a57195066838 Neupane A. p567 True Conference 216 GEESE: Grammatical evolution algorithm for evolution of swarm behaviors [No abstract available]
959 a57212106357 Clinton R. p303 False Conference 84 Is that you, Alice? A usability study of the authentication ceremony of secure messaging applications The effective security provided by secure messaging applications depends heavily on users completing an authentication ceremony-a sequence of manual operations enabling users to verify they are indeed communicating with one another. Unfortunately, evidence to date suggests users are unable to do this. Accordingly, we study in detail how well users can locate and complete the authentication ceremony when they are aware of the need for authentication. We execute a two-phase study involving 36 pairs of participants, using three popular messaging applications with support for secure messaging functionality: WhatsApp, Viber, and Facebook Messenger. The first phase included instruction about potential threats, while the second phase also included instructions about the importance of the authentication ceremony. We find that, across the three apps, the average success rates of finding and completing the authentication ceremony increases from 14% to 79% from the first to second phase, with second-phase success rates as high as 96% for Viber. However, the time required to find and complete the ceremony is undesirably long from a usability standpoint, and our data is inconclusive on whether users make the connection between this ceremony and the security guarantees it brings. We discuss in detail the success rates, task timings, and user feedback for each application, as well as common mistakes and user grievances. We conclude by exploring user threat models, finding significant gaps in user awareness and understanding. © 2017 by The USENIX Association. All rights reserved.
960 a57212103171 Whitehead J. p303 False Conference 84 Is that you, Alice? A usability study of the authentication ceremony of secure messaging applications The effective security provided by secure messaging applications depends heavily on users completing an authentication ceremony-a sequence of manual operations enabling users to verify they are indeed communicating with one another. Unfortunately, evidence to date suggests users are unable to do this. Accordingly, we study in detail how well users can locate and complete the authentication ceremony when they are aware of the need for authentication. We execute a two-phase study involving 36 pairs of participants, using three popular messaging applications with support for secure messaging functionality: WhatsApp, Viber, and Facebook Messenger. The first phase included instruction about potential threats, while the second phase also included instructions about the importance of the authentication ceremony. We find that, across the three apps, the average success rates of finding and completing the authentication ceremony increases from 14% to 79% from the first to second phase, with second-phase success rates as high as 96% for Viber. However, the time required to find and complete the ceremony is undesirably long from a usability standpoint, and our data is inconclusive on whether users make the connection between this ceremony and the security guarantees it brings. We discuss in detail the success rates, task timings, and user feedback for each application, as well as common mistakes and user grievances. We conclude by exploring user threat models, finding significant gaps in user awareness and understanding. © 2017 by The USENIX Association. All rights reserved.
960 a57212103171 Whitehead J. p305 False Conference 86 Action needed! Helping users find and complete the authentication ceremony in signal The security guarantees of secure messaging applications are contingent upon users performing an authentication ceremony, which typically involves verifying the fingerprints of encryption keys. However, recent lab studies have shown that users are unable to do this without being told in advance about the ceremony and its importance. A recent study showed that even with this instruction, the time it takes users to find and complete the ceremony is excessively long-about 11 minutes. To remedy these problems, we modified Signal to include prompts for the ceremony and also simplified the ceremony itself. To gauge the effect of these changes, we conducted a between-subject user study involving 30 pairs of participants. Our study methodology includes no user training and only a small performance bonus to encourage the secure behavior. Our results show that users are able to both find and complete the ceremony more quickly in our new version of Signal. Despite these improvements, many users are still unsure or confused about the purpose of the authentication ceremony. We discuss the need for better risk communication and methods to promote trust. © 2018 by The USENIX Association All Rights Reserved.
960 a57212103171 Whitehead J. p557 False Conference 206 The secure socket API: TLS as an operating system service SSL/TLS libraries are notoriously hard for developers to use, leaving system administrators at the mercy of buggy and vulnerable applications. We explore the use of the standard POSIX socket API as a vehicle for a simplified TLS API, while also giving administrators the ability to control applications and tailor TLS configuration to their needs. We first assess OpenSSL and its uses in open source software, recommending how this functionality should be accommodated within the POSIX API. We then propose the Secure Socket API (SSA), a minimalist TLS API built using existing network functions and find that it can be employed by existing network applications by modifications requiring as little as one line of code. We next describe a prototype SSA implementation that leverages network system calls to provide privilege separation and support for other programming languages. We end with a discussion of the benefits and limitations of the SSA and our accompanying implementation, noting avenues for future work. © 2018 Proceedings of the 27th USENIX Security Symposium. All rights reserved.
960 a57212103171 Whitehead J. p793 False Conference 330 TrustBase: An architecture to repair and strengthen certificate-based authentication The current state of certificate-based authentication is messy, with broken authentication in applications and proxies, along with serious flaws in the CA system. To solve these problems, we design TrustBase, an architecture that provides certificate-based authentication as an operating system service, with system administrator control over authentication policy. TrustBase transparently enforces best practices for certificate validation on all applications, while also providing a variety of authentication services to strengthen the CA system. We describe a research prototype of TrustBase for Linux, which uses a loadable kernel module to intercept traffic in the socket layer, then consults a userspace policy engine to evaluate certificate validity using a variety of plugins. We evaluate the security of TrustBase, including a threat analysis, application coverage, and hardening of the Linux prototype. We also describe prototypes of TrustBase for Android and Windows, illustrating the generality of our approach. We show that TrustBase has negligible overhead and universal compatibility with applications. We demonstrate its utility by describing eight authentication services that extend CA hardening to all applications. © 2017 by The USENIX Association. All Rights Reserved.
961 a57211214561 Seat M.L. p304 True Conference 85 Analyzing the safety impacts of raised medians A hierarchical Bayesian statistical before-after model was used to analyze locations where raised medians have been installed. Twenty locations where raised medians were installed in Utah from 2002 to 2014 were used in this analysis. A model was developed that analyzed raised medians by access category (AC). Only three AC were represented in the data. Regression plots depicting a decrease in crashes before and after installation and crash modification factor (CMF) plots presenting the CMF values estimated for different vehicle miles traveled values were created as output from the before-after model. Overall, installing a raised median gives an approximate average reduction of 53 percent for all crashes. Individual AC analysis yielded results ranging from 32 to 44 percent reduction for all severity groups except severity 4 and 5. When the model was only run for crash severity 4 and 5, a larger reduction of 57 to 58 percent was found. © 2019 American Society of Civil Engineers.
962 a57211216470 Wyatt Clegg B. p304 False Conference 85 Analyzing the safety impacts of raised medians A hierarchical Bayesian statistical before-after model was used to analyze locations where raised medians have been installed. Twenty locations where raised medians were installed in Utah from 2002 to 2014 were used in this analysis. A model was developed that analyzed raised medians by access category (AC). Only three AC were represented in the data. Regression plots depicting a decrease in crashes before and after installation and crash modification factor (CMF) plots presenting the CMF values estimated for different vehicle miles traveled values were created as output from the before-after model. Overall, installing a raised median gives an approximate average reduction of 53 percent for all crashes. Individual AC analysis yielded results ranging from 32 to 44 percent reduction for all severity groups except severity 4 and 5. When the model was only run for crash severity 4 and 5, a larger reduction of 57 to 58 percent was found. © 2019 American Society of Civil Engineers.
963 a57212107036 Metro D. p305 False Conference 86 Action needed! Helping users find and complete the authentication ceremony in signal The security guarantees of secure messaging applications are contingent upon users performing an authentication ceremony, which typically involves verifying the fingerprints of encryption keys. However, recent lab studies have shown that users are unable to do this without being told in advance about the ceremony and its importance. A recent study showed that even with this instruction, the time it takes users to find and complete the ceremony is excessively long-about 11 minutes. To remedy these problems, we modified Signal to include prompts for the ceremony and also simplified the ceremony itself. To gauge the effect of these changes, we conducted a between-subject user study involving 30 pairs of participants. Our study methodology includes no user training and only a small performance bonus to encourage the secure behavior. Our results show that users are able to both find and complete the ceremony more quickly in our new version of Signal. Despite these improvements, many users are still unsure or confused about the purpose of the authentication ceremony. We discuss the need for better risk communication and methods to promote trust. © 2018 by The USENIX Association All Rights Reserved.
964 a57212104751 Cockrell J. p305 False Conference 86 Action needed! Helping users find and complete the authentication ceremony in signal The security guarantees of secure messaging applications are contingent upon users performing an authentication ceremony, which typically involves verifying the fingerprints of encryption keys. However, recent lab studies have shown that users are unable to do this without being told in advance about the ceremony and its importance. A recent study showed that even with this instruction, the time it takes users to find and complete the ceremony is excessively long-about 11 minutes. To remedy these problems, we modified Signal to include prompts for the ceremony and also simplified the ceremony itself. To gauge the effect of these changes, we conducted a between-subject user study involving 30 pairs of participants. Our study methodology includes no user training and only a small performance bonus to encourage the secure behavior. Our results show that users are able to both find and complete the ceremony more quickly in our new version of Signal. Despite these improvements, many users are still unsure or confused about the purpose of the authentication ceremony. We discuss the need for better risk communication and methods to promote trust. © 2018 by The USENIX Association All Rights Reserved.
965 a57212106857 Moffett T. p305 False Conference 86 Action needed! Helping users find and complete the authentication ceremony in signal The security guarantees of secure messaging applications are contingent upon users performing an authentication ceremony, which typically involves verifying the fingerprints of encryption keys. However, recent lab studies have shown that users are unable to do this without being told in advance about the ceremony and its importance. A recent study showed that even with this instruction, the time it takes users to find and complete the ceremony is excessively long-about 11 minutes. To remedy these problems, we modified Signal to include prompts for the ceremony and also simplified the ceremony itself. To gauge the effect of these changes, we conducted a between-subject user study involving 30 pairs of participants. Our study methodology includes no user training and only a small performance bonus to encourage the secure behavior. Our results show that users are able to both find and complete the ceremony more quickly in our new version of Signal. Despite these improvements, many users are still unsure or confused about the purpose of the authentication ceremony. We discuss the need for better risk communication and methods to promote trust. © 2018 by The USENIX Association All Rights Reserved.
966 a57212104028 Bonner N. p305 False Conference 86 Action needed! Helping users find and complete the authentication ceremony in signal The security guarantees of secure messaging applications are contingent upon users performing an authentication ceremony, which typically involves verifying the fingerprints of encryption keys. However, recent lab studies have shown that users are unable to do this without being told in advance about the ceremony and its importance. A recent study showed that even with this instruction, the time it takes users to find and complete the ceremony is excessively long-about 11 minutes. To remedy these problems, we modified Signal to include prompts for the ceremony and also simplified the ceremony itself. To gauge the effect of these changes, we conducted a between-subject user study involving 30 pairs of participants. Our study methodology includes no user training and only a small performance bonus to encourage the secure behavior. Our results show that users are able to both find and complete the ceremony more quickly in our new version of Signal. Despite these improvements, many users are still unsure or confused about the purpose of the authentication ceremony. We discuss the need for better risk communication and methods to promote trust. © 2018 by The USENIX Association All Rights Reserved.
966 a57212104028 Bonner N. p557 False Conference 206 The secure socket API: TLS as an operating system service SSL/TLS libraries are notoriously hard for developers to use, leaving system administrators at the mercy of buggy and vulnerable applications. We explore the use of the standard POSIX socket API as a vehicle for a simplified TLS API, while also giving administrators the ability to control applications and tailor TLS configuration to their needs. We first assess OpenSSL and its uses in open source software, recommending how this functionality should be accommodated within the POSIX API. We then propose the Secure Socket API (SSA), a minimalist TLS API built using existing network functions and find that it can be employed by existing network applications by modifications requiring as little as one line of code. We next describe a prototype SSA implementation that leverages network system calls to provide privilege separation and support for other programming languages. We end with a discussion of the benefits and limitations of the SSA and our accompanying implementation, noting avenues for future work. © 2018 Proceedings of the 27th USENIX Security Symposium. All rights reserved.
967 a57204799155 Kincaid C.J. p307 True Journal 188 Frequency response of the leap motion controller and its suitability for measuring tremor Although tremor is one of the most common movement disorders, it is evaluated using relatively coarse clinical scales. We propose to measure tremor in clinical settings using the Leap Motion Controller (LMC), which is a markerless motion capture sensor that has a low cost, zero set-up time, and dynamic accuracy of 1.2 mm. However, the frequency response of the LMC has not been characterized, so its ability to track oscillations such as tremor is unknown. To characterize the frequency response of the LMC, we measured the position of a mannequin hand simultaneously with the LMC and a high-resolution encoder while the mannequin hand oscillated at various combinations of frequency (1–15 Hz) and amplitudes (0.01–30 mm). We calculated the magnitude ratio and phase shift of the LMC and found the bandwidth of the LMC to range from 0–3 Hz to 0–5 Hz for tremor amplitudes greater than the dynamic accuracy. This bandwidth is too small to accurately measure most tremors. However, we developed an inverse filter to estimate the actual tremor amplitude and phase despite the limited bandwidth. Over the combinations of frequency and amplitude mentioned above, the inverse filter estimated the actual tremor amplitude and phase with errors of 3% and 2%, respectively. © 2018
968 a57204803477 Vaterlaus A.C. p307 False Journal 188 Frequency response of the leap motion controller and its suitability for measuring tremor Although tremor is one of the most common movement disorders, it is evaluated using relatively coarse clinical scales. We propose to measure tremor in clinical settings using the Leap Motion Controller (LMC), which is a markerless motion capture sensor that has a low cost, zero set-up time, and dynamic accuracy of 1.2 mm. However, the frequency response of the LMC has not been characterized, so its ability to track oscillations such as tremor is unknown. To characterize the frequency response of the LMC, we measured the position of a mannequin hand simultaneously with the LMC and a high-resolution encoder while the mannequin hand oscillated at various combinations of frequency (1–15 Hz) and amplitudes (0.01–30 mm). We calculated the magnitude ratio and phase shift of the LMC and found the bandwidth of the LMC to range from 0–3 Hz to 0–5 Hz for tremor amplitudes greater than the dynamic accuracy. This bandwidth is too small to accurately measure most tremors. However, we developed an inverse filter to estimate the actual tremor amplitude and phase despite the limited bandwidth. Over the combinations of frequency and amplitude mentioned above, the inverse filter estimated the actual tremor amplitude and phase with errors of 3% and 2%, respectively. © 2018
969 a57204802622 Stanford N.R. p307 False Journal 188 Frequency response of the leap motion controller and its suitability for measuring tremor Although tremor is one of the most common movement disorders, it is evaluated using relatively coarse clinical scales. We propose to measure tremor in clinical settings using the Leap Motion Controller (LMC), which is a markerless motion capture sensor that has a low cost, zero set-up time, and dynamic accuracy of 1.2 mm. However, the frequency response of the LMC has not been characterized, so its ability to track oscillations such as tremor is unknown. To characterize the frequency response of the LMC, we measured the position of a mannequin hand simultaneously with the LMC and a high-resolution encoder while the mannequin hand oscillated at various combinations of frequency (1–15 Hz) and amplitudes (0.01–30 mm). We calculated the magnitude ratio and phase shift of the LMC and found the bandwidth of the LMC to range from 0–3 Hz to 0–5 Hz for tremor amplitudes greater than the dynamic accuracy. This bandwidth is too small to accurately measure most tremors. However, we developed an inverse filter to estimate the actual tremor amplitude and phase despite the limited bandwidth. Over the combinations of frequency and amplitude mentioned above, the inverse filter estimated the actual tremor amplitude and phase with errors of 3% and 2%, respectively. © 2018
970 a57219001134 Redd B. p308 True Conference 88 DFT-based frequency offset estimators for 16-APSK In this paper, we analyze several DFT-based frequency offset estimators for use with the 16-APSK digital modulation scheme. Even a small frequency offset between radio transmitters and receivers can cause phase information to be lost, so a system to align the phases is required to reliably demodulate PSK signals. These estimators have been adapted for 16-APSK from methods originally intended for use with QPSK and CPM. These methods consist of a coarse search and a fine search with an optional dichotomous search to improve accuracy. We analyze the estimator error variance and bit error rate associated with several methods of frequency estimation. These estimators exhibit small estimate error and variance and can provide bit error rates close to the ideal AWGN BER. © 2019 International Foundation for Telemetering. All rights reserved.
970 a57219001134 Redd B. p311 False Conference 91 On carrier frequency and phase synchronization for coded 16-APSK in aeronautical mobile telemetry This paper examines the problem of carrier phase and frequency estimation for coded 16-APSK in aeronautical mobile telemetry. Given the fact that coded systems tend to operate at lower signal-to-noise ratios than uncoded systems, the synchronizer must operate at these lower signal-to-noise ratios. For a 30 kHz frequency offset and a 10 Mbit/s 16-APSK signal, the conventional phase lock loop (PLL) system does not achieve consistent lock to be a useful approach. Consequently, a blind feed-forward approach, based on the FFT, and an initialized feedback approach based on the PLL were examined. The feed-forward estimator is capable of achieving BER ideal performance for Eb/N0 ≥ 6 dB using 1024 symbols. The feedback estimator, initialized using a feed-forward estimate based on 1024 symbols is also capable of achieving BER ideal performance for Eb/N0 ≥ 6 dB. Both synchronizers require a sufficiently good blind estimate: the estimate based on 2014 symbols appears to be the minimum value to achieve good performance. © 2019 International Foundation for Telemetering. All rights reserved.
971 a57218994430 Ebert J. p308 False Conference 88 DFT-based frequency offset estimators for 16-APSK In this paper, we analyze several DFT-based frequency offset estimators for use with the 16-APSK digital modulation scheme. Even a small frequency offset between radio transmitters and receivers can cause phase information to be lost, so a system to align the phases is required to reliably demodulate PSK signals. These estimators have been adapted for 16-APSK from methods originally intended for use with QPSK and CPM. These methods consist of a coarse search and a fine search with an optional dichotomous search to improve accuracy. We analyze the estimator error variance and bit error rate associated with several methods of frequency estimation. These estimators exhibit small estimate error and variance and can provide bit error rates close to the ideal AWGN BER. © 2019 International Foundation for Telemetering. All rights reserved.
972 a57218994299 Twitchell A. p308 False Conference 88 DFT-based frequency offset estimators for 16-APSK In this paper, we analyze several DFT-based frequency offset estimators for use with the 16-APSK digital modulation scheme. Even a small frequency offset between radio transmitters and receivers can cause phase information to be lost, so a system to align the phases is required to reliably demodulate PSK signals. These estimators have been adapted for 16-APSK from methods originally intended for use with QPSK and CPM. These methods consist of a coarse search and a fine search with an optional dichotomous search to improve accuracy. We analyze the estimator error variance and bit error rate associated with several methods of frequency estimation. These estimators exhibit small estimate error and variance and can provide bit error rates close to the ideal AWGN BER. © 2019 International Foundation for Telemetering. All rights reserved.
973 a57218995344 Long D.G. p310 False Conference 90 Analysis of inertial measurement data from a model rocket payload As part of a student-educational experience in telemetry, beginning undergraduates build, program, and test small payloads flown in model rockets. These payloads, nicknamed 'femtosats,' collect and transmit real time telemetry on the rocket's performance. The femtosats measure the inertial motions of the model rocket, providing info to extract the flight path. The individually student-designed femtosat circuit board includes a simple inertial measurement sensor that collects acceleration data in the form of x, y, z acceleration vectors which are transmitted in real-time to a radio ground station. The focus of this paper is the collection and analysis of the data from the telemetered inertial measurement sensor and how it can be interpreted and applied in simple model rocket motion analysis. © 2019 International Foundation for Telemetering. All rights reserved.
974 a36677010800 Briceño X. p311 False Conference 91 On carrier frequency and phase synchronization for coded 16-APSK in aeronautical mobile telemetry This paper examines the problem of carrier phase and frequency estimation for coded 16-APSK in aeronautical mobile telemetry. Given the fact that coded systems tend to operate at lower signal-to-noise ratios than uncoded systems, the synchronizer must operate at these lower signal-to-noise ratios. For a 30 kHz frequency offset and a 10 Mbit/s 16-APSK signal, the conventional phase lock loop (PLL) system does not achieve consistent lock to be a useful approach. Consequently, a blind feed-forward approach, based on the FFT, and an initialized feedback approach based on the PLL were examined. The feed-forward estimator is capable of achieving BER ideal performance for Eb/N0 ≥ 6 dB using 1024 symbols. The feedback estimator, initialized using a feed-forward estimate based on 1024 symbols is also capable of achieving BER ideal performance for Eb/N0 ≥ 6 dB. Both synchronizers require a sufficiently good blind estimate: the estimate based on 2014 symbols appears to be the minimum value to achieve good performance. © 2019 International Foundation for Telemetering. All rights reserved.
975 a57204692730 Arabian F. p312 True Conference 92 Polarization diversity and equalization of frequency selective channels in telemetry environment for 16APSK Providing RHCP and LHCP outputs from the antennas vertical (V) and horizontal (H) dipoles in the resonant cavity within the antenna feeds is the current practice of ground-based station receivers in aeronautical telemetry. The equalizers on the market, operate on either LHCP or RHCP alone, or a combined signal created by co-phasing and adding the RHCP and LHCP outputs. In this paper, we show how to optimally combine the V and H dipole outputs and demonstrate that an equalizer operating on this optimally-combined signal outperforms an equalizer operating on the RHCP, LHCP, or the combined signals. Finally, we show how to optimally combine the RHCP and LHCP outputs for equalization, where this optimal combination performs as good as the optimally combined V and H signals. © 2019 International Foundation for Telemetering. All rights reserved.
975 a57204692730 Arabian F. p435 True Conference 156 On peak-to-average power ratio optimization for coded APSK The symmetric information rate is used to define the relationship between the APSK constellation parameters, the code rate, and the average and peak Eb=N0. Minimizing the average Eb=N0 reproduces the DVB-S2 constellation parameters for 16- And 32-APSK. Minimizing the peak Eb=N0 produces DVB-S2 constellation parameters for 16- And 32-APSK that minimize the peak-to-average power ratio. The peak-to-average power ratio gains are less than 1 dB, but when used on coded systems with very steep decoded bit error probability vs. Eb=N0 curves, the gains can be significant. © 2018 IEEE.
975 a57204692730 Arabian F. p574 True Conference 219 On the performance of filter based equalizers for 16apsk in aeronautical telemetry environment 16APSK is a candidate modulation for aeronautical telemetry because it has better spectral efficiency than SOQPSK-TG, but requires a linear RF power amplifier. This paper investigates the BER performance of filter-based equalizers for 16APSK operating over multipath channels measured at Edwards AFB. The results show that decision feedback equalizers outperform the other equalizers and are capable of providing excellent multipath mitigation. © held by the author; distribution rights International Foundation for Telemetering.
976 a56747516900 Warner W.Y. p313 False Conference 93 Characterization and validation of in situ void formation during resin infusion An experimental methodology to photograph bubbles in-situ during infusion of carbon reinforcements has been developed and demonstrated previously. This method is based on fluorescent photography of bubbles at the surface of the reinforcement during infusion. Previous work with this experimental methodology was done with test oils, but has now been characterized with a curing epoxy resin. The results of in-situ bubble photography at the surface are now compared to standard defect characterization methods including ultrasound and image analysis of polished cross-section micrographs. Such experimental results are meant to provide the data required to build process optimization models capable of prediction of the final void distribution and morphology of voids. © 2019 by Ever J. Barbero. Published by CAMX - The Composites and Advanced Materials Expo.
977 a56071519600 Wilson M.E. p314 True Conference 94 Characteristics of self-deployment in origami-based systems The potential of compliant mechanisms and related origami-based mechanical systems to store strain energy make them ideal candidates for applications requiring an actuation or deployment process, such as space system arrays, minimally invasive surgical devices and deployable barriers. Many origami structures can be thought of as a compliant mechanism because, like compliant mechanisms, its function is performed through the elastic deformation of its members. This stored strain energy could prove useful. There are opportunities using strain energy to develop approaches to deploy particular mechanical systems. In order to better understand the principles of self-actuation and promote the designs of such systems, a taxonomy of deployable origami mechanisms is presented. This taxonomy demonstrates that there are several different types of deployable origami mechanisms and provides an organizational method to better understand the design space. Characteristics of self deployment in concentrated, deployable origami strain energy mechanisms with internal actuation are identified and examples of strain energy based deployment are provided. Copyright © 2019 ASME.
978 a57212342916 Ynchausti C. p315 True Conference 95 Deployable euler spiral connectors (DESCs) Deployable Euler Spiral Connectors (DESCs) are introduced as a way to use compliant flexures that lay flat when under strain in a stowed position. This paper presents the design of DESCs using the Euler spiral equations. An application of a spinal device is presented as a proof-of-concept of the use of DESCs. Copyright © 2019 ASME.
979 a57212351695 Seymour K. p316 True Conference 96 Cylindrical developable mechanisms for minimally invasive surgical instruments Developable mechanisms conform to and emerge from developable, or specially curved, surfaces. The cylindrical developable mechanism can have applications in many industries due to the popularity of cylindrical or tube-based devices. Laparoscopic surgical devices in particular are widely composed of instruments attached at the proximal end of a cylindrical shaft. In this paper, properties of cylindrical developable mechanisms are discussed, including their behaviors, characteristics, and potential functions. One method for designing cylindrical developable mechanisms is discussed. Two example developable surgical devices that exemplify these behaviors, characteristics, and functions, along with the kinematic mechanisms comprising them, are discussed in detail. Copyright © 2019 ASME.
980 a57212342217 Sheffield J. p316 False Conference 96 Cylindrical developable mechanisms for minimally invasive surgical instruments Developable mechanisms conform to and emerge from developable, or specially curved, surfaces. The cylindrical developable mechanism can have applications in many industries due to the popularity of cylindrical or tube-based devices. Laparoscopic surgical devices in particular are widely composed of instruments attached at the proximal end of a cylindrical shaft. In this paper, properties of cylindrical developable mechanisms are discussed, including their behaviors, characteristics, and potential functions. One method for designing cylindrical developable mechanisms is discussed. Two example developable surgical devices that exemplify these behaviors, characteristics, and functions, along with the kinematic mechanisms comprising them, are discussed in detail. Copyright © 2019 ASME.
981 a57212343330 Armstrong A.G. p317 True Conference 97 Factors leading to sustainable social impact on the affected communities of engineering service learning projects University engineering programs across the USA engage in service learning projects. These projects involve student teams designing and implementing products or solutions for communities in need, often in developing nations. There has been much research done relating to pedagogy and the impact of these programs on student learning. However, less research has been done on measuring the impact of these programs on the affected communities. This paper examines factors that practitioners believe are related to successfully delivering a desirable and transferable solution to affected communities. The authors identified 46 distinct factors from the literature that implicitly or explicitly are suggested to contribute to successful project outcomes. Formed as postulates in this paper, these 46 factors have been separated into 5 categories to assist understanding and implementing these factors into service learning programs. Lastly, different methods of analyzing and measuring project success and impact are discussed. Future methods for proving the viability of the 46 postulates are discussed as well. Copyright © 2019 ASME.
982 a57212351059 Hunter J.G. p320 True Conference 100 Benefits of a short-term engineering study abroad: A survey of students over the past 15 years Since 2004, Brigham Young University has offered a graduate study abroad course in mechanical engineering to help prepare students to be leaders in globally-influenced product development organizations. The course is offered as a study abroad program where faculty lead a group of students across several countries to learn about global product development. This is accomplished in a 2-3 week time period consisting of visits to companies and universities as well as participation in cultural activities. While much research has been done on the benefits of study abroad, it remains unclear how effective study abroad programs are at helping engineering students, especially short-term study abroad programs. The purpose of this paper is to present and examine the benefits of a short-term, study abroad program to engineering students. Data was collected from students who have taken the Global Product Development Course over the past 15 years in a mixed methods survey. Trends show that technical and cultural visits positively effect engineering students in their perception of global product development. It is also shown that a short, 2-3 week, engineering study abroad program can be as or more effective than traditional study abroad programs in certain areas. Copyright © 2019 ASME.
983 a57212341630 Andrews D.W. p321 True Conference 101 Kirigami-based deployable transcrease hard stop models usable in origami patterns Stopping origami in arbitrary fold states can present a challenge for origami-based design. In this paper two categories of kirigami-based models are presented for stopping the fold motion of individual creases using deployable hard stops. These models are transcrease (across a crease) and deploy from a flat sheet. The first category is planar and has behavior similar to a four-bar linkage. The second category is spherical and behaves like a degree-4 origami vertex. These models are based on the zero-thickness assumption of paper and can be applied to origami patterns made from thin materials, limiting the motion of the base origami pattern through self-interference within the original facets. Model parameters are based on a desired fold or dihedral angle, as well as facet dimensions. Examples show model benefits and limitations. Copyright © 2019 ASME.
984 a57212277900 Brown T. p322 True Conference 102 Fabrication and testing of a MEMS system for injection of DNA into plant cells This paper describes the fabrication and testing of a system to inject DNA into plant leaves. Arrays of silicon lances were made using photolithographic and STS DRIE Bosch techniques. A nanoinjector device was also made to accept the silicon lance arrays and perform nanoinjections. Nanoinjections were performed on Arabidopsis and cotton cotyledons. Changes in the force applied during a nanoinjection and varying the number of repeated nanoinjections on the same cotyledon were observed. Too much force or too many repeated injections caused physical damage to the cotyledon. An optimal force and number of repeated injections can be performed without causing physical damage to the cotyledon. Several injections using DNA were performed without successful transfection of the leaves. Possible reasons for this failure to transfect were explored. Copyright © 2019 ASME.
985 a57188667076 Hope S. p322 False Conference 102 Fabrication and testing of a MEMS system for injection of DNA into plant cells This paper describes the fabrication and testing of a system to inject DNA into plant leaves. Arrays of silicon lances were made using photolithographic and STS DRIE Bosch techniques. A nanoinjector device was also made to accept the silicon lance arrays and perform nanoinjections. Nanoinjections were performed on Arabidopsis and cotton cotyledons. Changes in the force applied during a nanoinjection and varying the number of repeated nanoinjections on the same cotyledon were observed. Too much force or too many repeated injections caused physical damage to the cotyledon. An optimal force and number of repeated injections can be performed without causing physical damage to the cotyledon. Several injections using DNA were performed without successful transfection of the leaves. Possible reasons for this failure to transfect were explored. Copyright © 2019 ASME.
986 a57200534297 Stringham B.J. p323 True Conference 103 Machine learning for evaluating the social impact of engineered products: A framework Evaluating the social impact indicators of engineered products is crucial to better understanding how products affect individuals’ lives and discover how to design for positive social impact. Most existing methods for evaluating social impact indicators require direct human interaction with users of a product, such as one-on-one interviews. These interactions produce high-fidelity data that are rich in information but provide only a single snapshot in time of the product’s impacts and are less frequently collected due to the significant human resources and cost associated with obtaining them. A framework is proposed that describes how low-fidelity data passively obtained using remote sensors, satellites, and digital technology can be collected and correlated with high-fidelity, low-frequency data using machine learning. Using this framework provides an inexpensive way to continuously monitor the social impact indicators of products by augmenting high-fidelity, low-frequency data with low-fidelity, continuously-collected data using machine learning. We illustrate an application of this framework by demonstrating how it can be used to examine the gender-related social impact indicators of water pumps in Uganda. The provided example uses a deep learning model to correlate pump handle movement (measured via an integrated motion unit) with user type (man, woman, or child) of 1,200 hand pump users. Copyright © 2019 ASME.
986 a57200534297 Stringham B.J. p514 True Journal 283 Non-dimensional modeling of the effects of weld parameters on peak temperature and cooling rate in friction stir welding Experimental data from friction stir welded Al 7075 and HSLA-65 were used to create dimensionless, empirical models relating critical weld parameters to the peak temperature rise and cooling rate of the weld heat-affected zone. Five different backing plate materials and a wide range of travel speeds and weld powers were used in the experimental design to ensure the models are relevant to a broad range of welding parameters. The resulting models have R-squared values of 0.997 and 0.995 for the dimensionless peak temperature rise and cooling rate correlations, respectively. Demonstrations of the models’ practical applications are provided. Herein is shown how the models can identify welding parameter (i.e. travel speed or power) levels needed to produce a desired weld peak temperature rise or cooling rate. Also demonstrated is how the models can be used to explore the relative effects of travel speed and backing plate thermal diffusivity on weld peak temperature rise and cooling rate. © 2017 Elsevier B.V.
987 a57214773567 Smith D.O. p323 False Conference 103 Machine learning for evaluating the social impact of engineered products: A framework Evaluating the social impact indicators of engineered products is crucial to better understanding how products affect individuals’ lives and discover how to design for positive social impact. Most existing methods for evaluating social impact indicators require direct human interaction with users of a product, such as one-on-one interviews. These interactions produce high-fidelity data that are rich in information but provide only a single snapshot in time of the product’s impacts and are less frequently collected due to the significant human resources and cost associated with obtaining them. A framework is proposed that describes how low-fidelity data passively obtained using remote sensors, satellites, and digital technology can be collected and correlated with high-fidelity, low-frequency data using machine learning. Using this framework provides an inexpensive way to continuously monitor the social impact indicators of products by augmenting high-fidelity, low-frequency data with low-fidelity, continuously-collected data using machine learning. We illustrate an application of this framework by demonstrating how it can be used to examine the gender-related social impact indicators of water pumps in Uganda. The provided example uses a deep learning model to correlate pump handle movement (measured via an integrated motion unit) with user type (man, woman, or child) of 1,200 hand pump users. Copyright © 2019 ASME.
988 a57212271263 Naylor T.A. p325 False Conference 105 Establishing baseline performance for off-the-shelf nitrile seals for the India Mark II hand pump system Accessing clean water is a persistent, and life threatening, challenge for millions of people in the world. Mechanical hand pumps have a long history of helping people access clean ground water for drinking and daily use. Among the most ubiquitous are the India Mark II and III pump systems, for which there are more than 4,000,000 installed across the world. These are estimated to serve between 600M and 1B people. All pumps degrade in performance over time, requiring service; many do not receive it causing pumps to become dysfunctional. The purpose of this paper is to establish a baseline for nitrile seal performance of India Mark II hand pump systems. Understanding off-the-shelf performance and using it as a baseline is an important step toward understanding degradation of performance over time, which is the focus of a much larger study to understand – mechanically and socially – how hand pumps perform, degrade, and ultimately meet human needs. In this paper, 110 off-the-shelf nitrile seals that were purchased in Uganda were tested and the following was characterized: (i) geometric variation, (ii) material variation, (iii) leak performance, and (iv) correlation between these. The seal leak performance was found to be very robust to variations in geometry and material at zero cycles. This important baseline supports our future work to understand how and to what degree seals become sensitive to geometric and material degradation during use. Copyright © 2019 ASME.
989 a57111140800 Martin R.A. p327 True Journal 189 Dynamic optimization of high-altitude solar aircraft trajectories under station-keeping constraints This paper demonstrates the use of nonlinear dynamic optimization to calculate energy-optimal trajectories for a high-altitude, solar-powered unmanned aerial vehicle (UAV). The objective is to maximize the total energy in the system while staying within a 3 km mission radius and meeting other system constraints. Solar energy capture is modeled using the vehicle orientation and solar position, and energy isstored both in batteries and in potential energy through elevation gain. Energy capture is maximized by optimally adjusting the angle of the aircraft surface relative to the sun. The UAV flight and energy system dynamics are optimized over a 24h period at an 8s time resolution using nonlinear model predictive control. Results of the simulated flights are presented for all four seasons, showing an 8.2% increase in end-of-day battery energy for the most limiting flight condition of the winter solstice. © 2018 by R. Abraham Martin, Nathaniel S. Gates, Andrew Ning, and John D. Hedengren.
990 a57197737083 Sadler J.E. p328 True Journal 190 A neutral XML design framework for generating parametric parts in multiple CAD systems Engineering companies often require designers to work with and operate between different CAD systems. This motivates the necessity of having a neutral design standard for CAD models to facilitate generation, customization, and parameterization across multiple systems. Current standards often fail to incorporate file history, design intent, and are designed to be an intermediary format for translation. This research proposes a simplified, neutral design format based on XML that can be used to generate models in different CAD systems and versions. The format utilizes advanced features such as finding tools to address issues that arise due to directionality and selection without a user interface. To test the feasibility of the neutral format, scripts were made that generated a quadcopter and an airplane wing rib. Comparisons between the generated models in both NX and CATIA are performed to evaluate the accuracy, flexibility, and similarity of the results of the generated neutral XML design framework. © 2019 CAD Solutions, LLC.
990 a57197737083 Sadler J.E. p548 False Journal 230 Hybrid state transactional database for product lifecycle management features in a multi-engineer synchronous heterogeneous CAD environment As interoperability between Computer Aided Design (CAD) systems becomes a possibility, a need arises for a way for the Neutral Parametric Canonical Form (NPCF), as designed at the BYU Site of the NSF Center for e-Design, to be integrated with Product Lifecycle Management (PLM). The only method currently available to users to sync with a PLM system at this time would be to choose one CAD system and create files based off of the NPCF data then save those part files in the PLM system. This database expansion to the NPCF allows the NPCF to hold the entire part history as well as enable future work revision history and configuration management. Enforcing referential integrity within the database allows for part data to never get corrupted and the NPCF allows any CAD system with the appropriate plug-ins to read the uncorrupted data. © 2017 CAD Solutions, LLC.
991 a57205761514 Day R.D. p328 False Journal 190 A neutral XML design framework for generating parametric parts in multiple CAD systems Engineering companies often require designers to work with and operate between different CAD systems. This motivates the necessity of having a neutral design standard for CAD models to facilitate generation, customization, and parameterization across multiple systems. Current standards often fail to incorporate file history, design intent, and are designed to be an intermediary format for translation. This research proposes a simplified, neutral design format based on XML that can be used to generate models in different CAD systems and versions. The format utilizes advanced features such as finding tools to address issues that arise due to directionality and selection without a user interface. To test the feasibility of the neutral format, scripts were made that generated a quadcopter and an airplane wing rib. Comparisons between the generated models in both NX and CATIA are performed to evaluate the accuracy, flexibility, and similarity of the results of the generated neutral XML design framework. © 2019 CAD Solutions, LLC.
992 a57205766759 Bronson P.G. p328 False Journal 190 A neutral XML design framework for generating parametric parts in multiple CAD systems Engineering companies often require designers to work with and operate between different CAD systems. This motivates the necessity of having a neutral design standard for CAD models to facilitate generation, customization, and parameterization across multiple systems. Current standards often fail to incorporate file history, design intent, and are designed to be an intermediary format for translation. This research proposes a simplified, neutral design format based on XML that can be used to generate models in different CAD systems and versions. The format utilizes advanced features such as finding tools to address issues that arise due to directionality and selection without a user interface. To test the feasibility of the neutral format, scripts were made that generated a quadcopter and an airplane wing rib. Comparisons between the generated models in both NX and CATIA are performed to evaluate the accuracy, flexibility, and similarity of the results of the generated neutral XML design framework. © 2019 CAD Solutions, LLC.
993 a57205762398 Tovar J.L. p328 False Journal 190 A neutral XML design framework for generating parametric parts in multiple CAD systems Engineering companies often require designers to work with and operate between different CAD systems. This motivates the necessity of having a neutral design standard for CAD models to facilitate generation, customization, and parameterization across multiple systems. Current standards often fail to incorporate file history, design intent, and are designed to be an intermediary format for translation. This research proposes a simplified, neutral design format based on XML that can be used to generate models in different CAD systems and versions. The format utilizes advanced features such as finding tools to address issues that arise due to directionality and selection without a user interface. To test the feasibility of the neutral format, scripts were made that generated a quadcopter and an airplane wing rib. Comparisons between the generated models in both NX and CATIA are performed to evaluate the accuracy, flexibility, and similarity of the results of the generated neutral XML design framework. © 2019 CAD Solutions, LLC.
994 a7004511126 Tree D.R. p329 True Journal 191 Measurement of radiative gas and particle emissions in biomass flames Radiation is the dominant mode of heat transfer near the burner of coal and biomass-fired boilers. Predicting and measuring heat transfer is critical to the design and operation of new boiler concepts. The individual contributions of gas and particle phases are dependent on gas and particle concentration, particle size, and gas and particle temperature which vary with location relative to the flame. A method for measuring the contributions of both gas and particle radiation capable of being applied in harsh high temperature and pressure environments has been demonstrated using emission from particles and water vapor using an optical fiber probe transmitting a signal to a Fourier Transform Infrared (FTIR) spectrometer. The method was demonstrated in four environments of varying gas and particle loading using natural gas and pulverized wood flames in a down-fired 130 kWth cylindrical reactor. The method generates a gas and particle temperature, gas concentrations (H2O and CO2), total gas and particle intensities, and gas and particle total effective emissivity from line-of-sight emission measurements. For the conditions measured, downstream of the luminous flame zone, water vapor and CO2 radiation were the dominant modes of heat transfer (effective emissivity 0.13-0.19) with particles making a minor contribution (effective emissivity 0.01-0.02). Within a lean natural gas flame, soot emission was low (effective emissivity 0.02) compared to gas (0.14) but within a luminous flame of burning wood particles (500 μm mean diameter) the particles (soot and burning wood) produced a higher effective emissivity (0.17) than the gas (0.12). The measurement technique was therefore found to be effective for several types of combustion environments. © 2018 The Combustion Institute.
994 a7004511126 Tree D.R. p421 False Journal 231 An optical method for the measurement of combustion gas temperature in particle laden flows Temperature measurements in combustion systems are challenging due to the physical limitations of measurement devices and the complexity of combustion flows. The objective of this work is to investigate the Integrated Spectral Band Ratio (ISBR) method for measuring the temperature of combustion product gases surrounded by radiating walls or within a mixture of gas and particles. Five conditions in a multi-fuel reactor were investigated using an optical probe. A Fourier Transform Infrared spectrometer provided detailed spectral measurements of hot gas and particle emissions at wavelengths of 1.69–2.15 μm, focusing on a spectral region where H2O is the dominant participating gas. These measurements were used to infer the gas temperature of the flows. It was found that the measurement path length needed to be at least 0.25 m in order to obtain a signal large enough to infer temperature accurately. For four of the five operating conditions tested, optically measured gas temperatures were found to be in good agreement with the average temperature along the measured path as taken with a suction pyrometer (aspirated thermocouple). For these four operating conditions the particle media were optically thin. Temperatures for the in-flame fine wood particle condition did not exhibit as good of agreement due to high particle loading causing optically thick zones along the line of sight. Modeling experiments showed that when particles and gasses are optically thin, the optical gas temperature measured with this technique will be near the arithmetic mean of the line of sight temperature. © 2018 Elsevier Inc.
995 a57200687939 Tobiasson J.R. p329 False Journal 191 Measurement of radiative gas and particle emissions in biomass flames Radiation is the dominant mode of heat transfer near the burner of coal and biomass-fired boilers. Predicting and measuring heat transfer is critical to the design and operation of new boiler concepts. The individual contributions of gas and particle phases are dependent on gas and particle concentration, particle size, and gas and particle temperature which vary with location relative to the flame. A method for measuring the contributions of both gas and particle radiation capable of being applied in harsh high temperature and pressure environments has been demonstrated using emission from particles and water vapor using an optical fiber probe transmitting a signal to a Fourier Transform Infrared (FTIR) spectrometer. The method was demonstrated in four environments of varying gas and particle loading using natural gas and pulverized wood flames in a down-fired 130 kWth cylindrical reactor. The method generates a gas and particle temperature, gas concentrations (H2O and CO2), total gas and particle intensities, and gas and particle total effective emissivity from line-of-sight emission measurements. For the conditions measured, downstream of the luminous flame zone, water vapor and CO2 radiation were the dominant modes of heat transfer (effective emissivity 0.13-0.19) with particles making a minor contribution (effective emissivity 0.01-0.02). Within a lean natural gas flame, soot emission was low (effective emissivity 0.02) compared to gas (0.14) but within a luminous flame of burning wood particles (500 μm mean diameter) the particles (soot and burning wood) produced a higher effective emissivity (0.17) than the gas (0.12). The measurement technique was therefore found to be effective for several types of combustion environments. © 2018 The Combustion Institute.
995 a57200687939 Tobiasson J.R. p421 True Journal 231 An optical method for the measurement of combustion gas temperature in particle laden flows Temperature measurements in combustion systems are challenging due to the physical limitations of measurement devices and the complexity of combustion flows. The objective of this work is to investigate the Integrated Spectral Band Ratio (ISBR) method for measuring the temperature of combustion product gases surrounded by radiating walls or within a mixture of gas and particles. Five conditions in a multi-fuel reactor were investigated using an optical probe. A Fourier Transform Infrared spectrometer provided detailed spectral measurements of hot gas and particle emissions at wavelengths of 1.69–2.15 μm, focusing on a spectral region where H2O is the dominant participating gas. These measurements were used to infer the gas temperature of the flows. It was found that the measurement path length needed to be at least 0.25 m in order to obtain a signal large enough to infer temperature accurately. For four of the five operating conditions tested, optically measured gas temperatures were found to be in good agreement with the average temperature along the measured path as taken with a suction pyrometer (aspirated thermocouple). For these four operating conditions the particle media were optically thin. Temperatures for the in-flame fine wood particle condition did not exhibit as good of agreement due to high particle loading causing optically thick zones along the line of sight. Modeling experiments showed that when particles and gasses are optically thin, the optical gas temperature measured with this technique will be near the arithmetic mean of the line of sight temperature. © 2018 Elsevier Inc.
996 a57200688910 Egbert S.C. p329 False Journal 191 Measurement of radiative gas and particle emissions in biomass flames Radiation is the dominant mode of heat transfer near the burner of coal and biomass-fired boilers. Predicting and measuring heat transfer is critical to the design and operation of new boiler concepts. The individual contributions of gas and particle phases are dependent on gas and particle concentration, particle size, and gas and particle temperature which vary with location relative to the flame. A method for measuring the contributions of both gas and particle radiation capable of being applied in harsh high temperature and pressure environments has been demonstrated using emission from particles and water vapor using an optical fiber probe transmitting a signal to a Fourier Transform Infrared (FTIR) spectrometer. The method was demonstrated in four environments of varying gas and particle loading using natural gas and pulverized wood flames in a down-fired 130 kWth cylindrical reactor. The method generates a gas and particle temperature, gas concentrations (H2O and CO2), total gas and particle intensities, and gas and particle total effective emissivity from line-of-sight emission measurements. For the conditions measured, downstream of the luminous flame zone, water vapor and CO2 radiation were the dominant modes of heat transfer (effective emissivity 0.13-0.19) with particles making a minor contribution (effective emissivity 0.01-0.02). Within a lean natural gas flame, soot emission was low (effective emissivity 0.02) compared to gas (0.14) but within a luminous flame of burning wood particles (500 μm mean diameter) the particles (soot and burning wood) produced a higher effective emissivity (0.17) than the gas (0.12). The measurement technique was therefore found to be effective for several types of combustion environments. © 2018 The Combustion Institute.
996 a57200688910 Egbert S.C. p357 False Journal 198 Measurements and modeling of fluid flow and thermal processes in an industrial precalciner Precalciner performance is crucial to the production rate and lifespan of cement kiln systems. The gas-solid flow and pulverized coal combustion processes in an industrial precalciner were numerically modeled to understand the flow patterns and thermal processes in the system. The gas and meal flow rates and properties were measured on-site to determine the boundary conditions for the simulations and to validate the models. The upward swirl of the gas flow in the furnace helped disperse the particles and extend their duration in the precalciner. The O2 and CO2 concentration distributions indicated that the coal particles were well dispersed and fully combusted. The calculations showed that the precalciner outlet temperature was too high which reduces the thermal efficiency and may damage the preheater installed just after the precalciner. Finally, an optimized precalciner was proposed to improve the temperature distribution. The present work can be used for improving the design of industrial precalciners. © 2019, Global Digital Central. All rights reserved.
996 a57200688910 Egbert S.C. p421 False Journal 231 An optical method for the measurement of combustion gas temperature in particle laden flows Temperature measurements in combustion systems are challenging due to the physical limitations of measurement devices and the complexity of combustion flows. The objective of this work is to investigate the Integrated Spectral Band Ratio (ISBR) method for measuring the temperature of combustion product gases surrounded by radiating walls or within a mixture of gas and particles. Five conditions in a multi-fuel reactor were investigated using an optical probe. A Fourier Transform Infrared spectrometer provided detailed spectral measurements of hot gas and particle emissions at wavelengths of 1.69–2.15 μm, focusing on a spectral region where H2O is the dominant participating gas. These measurements were used to infer the gas temperature of the flows. It was found that the measurement path length needed to be at least 0.25 m in order to obtain a signal large enough to infer temperature accurately. For four of the five operating conditions tested, optically measured gas temperatures were found to be in good agreement with the average temperature along the measured path as taken with a suction pyrometer (aspirated thermocouple). For these four operating conditions the particle media were optically thin. Temperatures for the in-flame fine wood particle condition did not exhibit as good of agreement due to high particle loading causing optically thick zones along the line of sight. Modeling experiments showed that when particles and gasses are optically thin, the optical gas temperature measured with this technique will be near the arithmetic mean of the line of sight temperature. © 2018 Elsevier Inc.
997 a57031187500 Gong H. p330 True Journal 192 3D printed selectable dilution mixer pumps In this paper, we demonstrate the ability to 3D print tightly integrated structures with active valves, pumps, and mixers, and we use our compact chip-to-chip interconnects [Gong et al., Lab Chip 18, 639-647 (2018)] to move bulky world-to-chip connections to separate interface chips for both post-print flushing and post-cure device operation. As example devices, we first examine 3D printed pumps, followed by two types of selectable ratio mixer pumps, a linear dilution mixer pump (LDMP) and a parallelized dilution mixer pump (PDMP), which occupy volumes of only 1.5 mm 3 and 2.6 mm 3, respectively. The LDMP generates a selectable dilution ratio from a linear set of possibilities, while the PDMP generates a denser set of possible dilutions with a maximum dilution ratio of 1/16. The PDMP also incorporates a new 4-to-1 valve to simultaneously control 4 inlet channels. To characterize LDMP and PDMP operation and performance, we present a new, low-cost video method to directly measure the relative concentration of an absorptive dye on a pixel-by-pixel basis for each video frame. Using this method, we find that 6 periods of the active mixer that forms the core of the LDMP and PDMP are sufficient to fully mix the fluid, and that the generated concentrations track the designed dilution ratios as expected. The LDMP mixes 20 nl per 4.6 s mixer pump period, while the PDMP uses parallelized input pumps to process the same fluid volume with greater choice of dilution ratios in a 3.6 s period. © 2019 Author(s).
997 a57031187500 Gong H. p332 False Conference 108 3D printing for lab-on-a-chip devices with 20 μm channels While there is great interest in 3D printing for microfluidic device fabrication, the challenge has been to achieve feature sizes that are in the truly microfluidic regime (<100 μm). The fundamental problem is that commercial tools and materials, which excel in many other application areas, have not been developed to address the unique needs of microfluidic device fabrication. Consequently, we have created our own stereolithographic 3D printer and materials that are specifically tailored to meet these needs. We review our recent work and show that flow channels as small as 18 μm x 20 μm can be reliably fabricated, as well as compact active elements such as valves and pumps. With these capabilities, we demonstrate highly integrated 3D printed microfluidic devices that measure only a few millimeters on a side, and that integrate separate chip-to-world interfaces through high density interconnects (up to 88 interconnects per square mm) that are directly 3D printed as part of a device chip. These advances open the door to 3D printing as a replacement for expensive cleanroom fabrication processes, with the additional advantage of fast (30 minute), parallel fabrication of many devices in a single print run due to their small size. © 2019 SPIE.
997 a57031187500 Gong H. p481 False Journal 237 3D printed microfluidic features using dose control in X, Y, and Z dimensions Interest has grown in recent years to leverage the possibilities offered by three-dimensional (3D) printing, such as rapid iterative changes; the ability to more fully use 3D device volume; and ease of fabrication, especially as it relates to the creation of complex microfluidic devices. A major shortcoming of most commercially available 3D printers is that their resolution is not sufficient to produce features that are truly microfluidic (&lt; 100 × 100 μm2). Here, we test a custom 3D printer for making ~30 μm scale positive and negative surface features, as well as positive and negative features within internal voids (i.e., microfluidic channels). We found that optical dosage control is essential for creating the smallest microfluidic features (~30 μm wide for ridges, ~20 μm wide for trenches), and that this resolution was achieved for a number of different exposure approaches. Additionally, we printed various microfluidic particle traps, showed capture of 25 μm diameter polymer beads, and iteratively improved the trap design. The rapid feedback allowed by 3D printing, as well as the ability to carefully control optical exposure conditions, should lead to new innovations in the types and sizes of devices that can be created for microfluidics. © 2018 by the authors.
997 a57031187500 Gong H. p536 True Journal 217 3D printed high density, reversible, chip-to-chip microfluidic interconnects Our latest developments in miniaturizing 3D printed microfluidics [Gong et al., Lab Chip, 2016, 16, 2450; Gong et al., Lab Chip, 2017, 17, 2899] offer the opportunity to fabricate highly integrated chips that measure only a few mm on a side. For such small chips, an interconnection method is needed to provide the necessary world-to-chip reagent and pneumatic connections. In this paper, we introduce simple integrated microgaskets (SIMs) and controlled-compression integrated microgaskets (CCIMs) to connect a small device chip to a larger interface chip that implements world-to-chip connections. SIMs or CCIMs are directly 3D printed as part of the device chip, and therefore no additional materials or components are required to make the connection to the larger 3D printed interface chip. We demonstrate 121 chip-to-chip interconnections in an 11 × 11 array for both SIMs and CCIMs with an areal density of 53 interconnections per mm2 and show that they withstand fluid pressures of 50 psi. We further demonstrate their reusability by testing the devices 100 times without seal failure. Scaling experiments show that 20 × 20 interconnection arrays are feasible and that the CCIM areal density can be increased to 88 interconnections per mm2. We then show the utility of spatially distributed discrete CCIMs by using an interconnection chip with 28 chip-to-world interconnects to test 45 3D printed valves in a 9 × 5 array. Each valve is only 300 μm in diameter (the smallest yet reported for 3D printed valves). Every row of 5 valves is tested to at least 10000 actuations, with one row tested to 1-000000 actuations. In all cases, there is no sign of valve failure, and the CCIM interconnections prove an effective means of using a single interface chip to test a series of valve array chips. © 2018 The Royal Society of Chemistry.
997 a57031187500 Gong H. p693 True Journal 337 Custom 3D printer and resin for 18 μm × 20 μm microfluidic flow channels While there is great interest in 3D printing for microfluidic device fabrication, to-date the achieved feature sizes have not been in the truly microfluidic regime (&lt;100 μm). In this paper we demonstrate that a custom digital light processor stereolithographic (DLP-SLA) 3D printer and a specifically-designed, low cost, custom resin can readily achieve flow channel cross sections as small as 18 μm × 20 μm. Our 3D printer has a projected image plane resolution of 7.6 μm and uses a 385 nm LED, which dramatically increases the available selection of UV absorbers for resin formulation compared to 3D printers with 405 nm LEDs. Beginning with 20 candidate absorbers, we demonstrate the evaluation criteria and process flow required to develop a high-resolution resin. In doing so, we introduce a new mathematical model for characterizing the resin optical penetration depth based only on measurement of the absorber's molar absorptivity. Our final resin formulation uses 2-nitrophenyl phenyl sulfide (NPS) as the UV absorber. We also develop a novel channel narrowing technique that, together with the new resin and 3D printer resolution, enables small flow channel fabrication. We demonstrate the efficacy of our approach by fabricating 3D serpentine flow channels 41 mm long in a volume of only 0.12 mm3, and by printing high aspect ratio flow channels &lt;25 μm wide and 3 mm tall. These results indicate that 3D printing is finally positioned to challenge the pre-eminence of methods such as soft lithography for microfluidic device prototyping and fabrication. © 2017 The Royal Society of Chemistry.
998 a57089497400 Johnson B.I. p331 True Conference 107 Using ellipsometry and X-ray photoelectron spectroscopy for real-time monitoring of the oxidation of aluminum mirrors protected by ultrathin MgF2 layers To maintain high, broad-band reflectance, thin transparent fluoride layers, such as MgF2, are used to protect the of aluminum mirrors against oxidation since aluminum oxide absorbs short wavelength light. In this study, we present, for the first time, combined X-ray photoelectron spectroscopy (XPS) and ellipsometric (SE) studies of aluminum oxidation as a function of MgF2 over a range of layer thickness (0-6 nm). We also show for the first time, dynamic SE data which, with appropriate modeling, tracks the extent of oxide growth every few seconds over a period of several hours after the evaporated Al + MgF2 bilayer is removed from the deposition chamber, exposing it to the air. For each SE data set, because the optical constants of ultrathin metals films depend strongly on deposition conditions and their thickness, the optical constants for Al, as well as the Al and Al2O3 thicknesses, were fit. SE trends were confirmed by X-ray photoelectron spectroscopy. There is a chemical shift in the Al 2s electron emission peak toward higher binding energy as the metal oxidizes to Al+3. The extent of oxide growth can be modeled from the relative area of each peak once they are corrected for the attenuation through MgF2 layer. This generates an empirical formula: oxide thickness= k∗log(t) +b, for the time-dependent aluminum-oxide thickness on aluminum surfaces protected by MgF2 as a function of MgF2 layer thickness. Here, k is a factor which depends only on MgF2 thickness, and decreases with increasing MgF2 thickness. The techniques developed can illuminate other protected mirror systems. © 2019 SPIE.
999 a57209912956 Avval T.G. p331 False Conference 107 Using ellipsometry and X-ray photoelectron spectroscopy for real-time monitoring of the oxidation of aluminum mirrors protected by ultrathin MgF2 layers To maintain high, broad-band reflectance, thin transparent fluoride layers, such as MgF2, are used to protect the of aluminum mirrors against oxidation since aluminum oxide absorbs short wavelength light. In this study, we present, for the first time, combined X-ray photoelectron spectroscopy (XPS) and ellipsometric (SE) studies of aluminum oxidation as a function of MgF2 over a range of layer thickness (0-6 nm). We also show for the first time, dynamic SE data which, with appropriate modeling, tracks the extent of oxide growth every few seconds over a period of several hours after the evaporated Al + MgF2 bilayer is removed from the deposition chamber, exposing it to the air. For each SE data set, because the optical constants of ultrathin metals films depend strongly on deposition conditions and their thickness, the optical constants for Al, as well as the Al and Al2O3 thicknesses, were fit. SE trends were confirmed by X-ray photoelectron spectroscopy. There is a chemical shift in the Al 2s electron emission peak toward higher binding energy as the metal oxidizes to Al+3. The extent of oxide growth can be modeled from the relative area of each peak once they are corrected for the attenuation through MgF2 layer. This generates an empirical formula: oxide thickness= k∗log(t) +b, for the time-dependent aluminum-oxide thickness on aluminum surfaces protected by MgF2 as a function of MgF2 layer thickness. Here, k is a factor which depends only on MgF2 thickness, and decreases with increasing MgF2 thickness. The techniques developed can illuminate other protected mirror systems. © 2019 SPIE.
1000 a57209911428 Hodges G.T. p331 False Conference 107 Using ellipsometry and X-ray photoelectron spectroscopy for real-time monitoring of the oxidation of aluminum mirrors protected by ultrathin MgF2 layers To maintain high, broad-band reflectance, thin transparent fluoride layers, such as MgF2, are used to protect the of aluminum mirrors against oxidation since aluminum oxide absorbs short wavelength light. In this study, we present, for the first time, combined X-ray photoelectron spectroscopy (XPS) and ellipsometric (SE) studies of aluminum oxidation as a function of MgF2 over a range of layer thickness (0-6 nm). We also show for the first time, dynamic SE data which, with appropriate modeling, tracks the extent of oxide growth every few seconds over a period of several hours after the evaporated Al + MgF2 bilayer is removed from the deposition chamber, exposing it to the air. For each SE data set, because the optical constants of ultrathin metals films depend strongly on deposition conditions and their thickness, the optical constants for Al, as well as the Al and Al2O3 thicknesses, were fit. SE trends were confirmed by X-ray photoelectron spectroscopy. There is a chemical shift in the Al 2s electron emission peak toward higher binding energy as the metal oxidizes to Al+3. The extent of oxide growth can be modeled from the relative area of each peak once they are corrected for the attenuation through MgF2 layer. This generates an empirical formula: oxide thickness= k∗log(t) +b, for the time-dependent aluminum-oxide thickness on aluminum surfaces protected by MgF2 as a function of MgF2 layer thickness. Here, k is a factor which depends only on MgF2 thickness, and decreases with increasing MgF2 thickness. The techniques developed can illuminate other protected mirror systems. © 2019 SPIE.
1001 a57211503118 Carver V. p331 False Conference 107 Using ellipsometry and X-ray photoelectron spectroscopy for real-time monitoring of the oxidation of aluminum mirrors protected by ultrathin MgF2 layers To maintain high, broad-band reflectance, thin transparent fluoride layers, such as MgF2, are used to protect the of aluminum mirrors against oxidation since aluminum oxide absorbs short wavelength light. In this study, we present, for the first time, combined X-ray photoelectron spectroscopy (XPS) and ellipsometric (SE) studies of aluminum oxidation as a function of MgF2 over a range of layer thickness (0-6 nm). We also show for the first time, dynamic SE data which, with appropriate modeling, tracks the extent of oxide growth every few seconds over a period of several hours after the evaporated Al + MgF2 bilayer is removed from the deposition chamber, exposing it to the air. For each SE data set, because the optical constants of ultrathin metals films depend strongly on deposition conditions and their thickness, the optical constants for Al, as well as the Al and Al2O3 thicknesses, were fit. SE trends were confirmed by X-ray photoelectron spectroscopy. There is a chemical shift in the Al 2s electron emission peak toward higher binding energy as the metal oxidizes to Al+3. The extent of oxide growth can be modeled from the relative area of each peak once they are corrected for the attenuation through MgF2 layer. This generates an empirical formula: oxide thickness= k∗log(t) +b, for the time-dependent aluminum-oxide thickness on aluminum surfaces protected by MgF2 as a function of MgF2 layer thickness. Here, k is a factor which depends only on MgF2 thickness, and decreases with increasing MgF2 thickness. The techniques developed can illuminate other protected mirror systems. © 2019 SPIE.
1002 a57211500187 Membreno K. p331 False Conference 107 Using ellipsometry and X-ray photoelectron spectroscopy for real-time monitoring of the oxidation of aluminum mirrors protected by ultrathin MgF2 layers To maintain high, broad-band reflectance, thin transparent fluoride layers, such as MgF2, are used to protect the of aluminum mirrors against oxidation since aluminum oxide absorbs short wavelength light. In this study, we present, for the first time, combined X-ray photoelectron spectroscopy (XPS) and ellipsometric (SE) studies of aluminum oxidation as a function of MgF2 over a range of layer thickness (0-6 nm). We also show for the first time, dynamic SE data which, with appropriate modeling, tracks the extent of oxide growth every few seconds over a period of several hours after the evaporated Al + MgF2 bilayer is removed from the deposition chamber, exposing it to the air. For each SE data set, because the optical constants of ultrathin metals films depend strongly on deposition conditions and their thickness, the optical constants for Al, as well as the Al and Al2O3 thicknesses, were fit. SE trends were confirmed by X-ray photoelectron spectroscopy. There is a chemical shift in the Al 2s electron emission peak toward higher binding energy as the metal oxidizes to Al+3. The extent of oxide growth can be modeled from the relative area of each peak once they are corrected for the attenuation through MgF2 layer. This generates an empirical formula: oxide thickness= k∗log(t) +b, for the time-dependent aluminum-oxide thickness on aluminum surfaces protected by MgF2 as a function of MgF2 layer thickness. Here, k is a factor which depends only on MgF2 thickness, and decreases with increasing MgF2 thickness. The techniques developed can illuminate other protected mirror systems. © 2019 SPIE.
1003 a7006120837 Allred D.D. p331 False Conference 107 Using ellipsometry and X-ray photoelectron spectroscopy for real-time monitoring of the oxidation of aluminum mirrors protected by ultrathin MgF2 layers To maintain high, broad-band reflectance, thin transparent fluoride layers, such as MgF2, are used to protect the of aluminum mirrors against oxidation since aluminum oxide absorbs short wavelength light. In this study, we present, for the first time, combined X-ray photoelectron spectroscopy (XPS) and ellipsometric (SE) studies of aluminum oxidation as a function of MgF2 over a range of layer thickness (0-6 nm). We also show for the first time, dynamic SE data which, with appropriate modeling, tracks the extent of oxide growth every few seconds over a period of several hours after the evaporated Al + MgF2 bilayer is removed from the deposition chamber, exposing it to the air. For each SE data set, because the optical constants of ultrathin metals films depend strongly on deposition conditions and their thickness, the optical constants for Al, as well as the Al and Al2O3 thicknesses, were fit. SE trends were confirmed by X-ray photoelectron spectroscopy. There is a chemical shift in the Al 2s electron emission peak toward higher binding energy as the metal oxidizes to Al+3. The extent of oxide growth can be modeled from the relative area of each peak once they are corrected for the attenuation through MgF2 layer. This generates an empirical formula: oxide thickness= k∗log(t) +b, for the time-dependent aluminum-oxide thickness on aluminum surfaces protected by MgF2 as a function of MgF2 layer thickness. Here, k is a factor which depends only on MgF2 thickness, and decreases with increasing MgF2 thickness. The techniques developed can illuminate other protected mirror systems. © 2019 SPIE.
1003 a7006120837 Allred D.D. p335 False Conference 111 Thermal properties of thin film uranium oxides and thorium oxides Uranium and thorium oxides have critical roles as fuels in existing nuclear power plants, as well as in proposed reactor concepts. The thermal conductivity of these materials determines their ability to transfer heat from the reactor core to the surrounding coolant. Additionally, these actinide compounds are of interest in condensed matter physics because of the 5f orbitals and unique electron interaction, coupling, and scattering events that can occur. Because of the radioactivity of thorium and uranium, thin film measurements of actinide materials are used to limit the amount of operator exposure, but standard thermal characterization methods are not well suited for thin films. This paper presents the process of depositing thin film UOx and ThOx samples of nm-μm thicknesses and the results of thermal property measurements. Thin films were deposited on silicon and glass substrates via dc-magnetron sputtering using an argon/oxygen mixture as the working gas. The thermal properties of the films were measured by the Thermal Conductivity Microscope (TCM). This uses one laser to generate thermal waves and a second laser to measure the magnitude and phases of the thermal waves to obtain the conductivity of materials. The results of the research show that the UOx film properties are lower than bulk values and that the role of the substrate has a considerable effect on determining the measured properties. Future work aims at improving the deposition process. Epitaxial film growth is planned. Additional understanding of thermal property measurements is targeted. Copyright © 2019 ASME.
1003 a7006120837 Allred D.D. p372 True Conference 133 Expanding the far UV range of aluminum-coated mirrors for space-based observations to reflect hydrogen Lyman lines via fluoride multilayers While no solid barrier layer is transparent below ~103nm, simulations show that ~9.5nm LiF on 8.5nm MgF2 on Al could reflect some hydrogen Lyman lines better than a single fluoride layer does. Experiments are promising. © OSA 2019 © 2019 The Author(s)
1003 a7006120837 Allred D.D. p826 True Conference 356 Adding EUV reflectance to aluminum-coated mirrors for space-based observation Protective layers on aluminum mirror surfaces which can be removed via the use of atomic hydrogen or hydrogen plasmas at the point of use in space may allow an expansion of broad-band mirrors into the EUV. LUVOIR (large, UV-optical-IR telescope) is a potential NASA flagship space-based observatory of the 2020's or 30's. It would utilize the largest mirrors ever flown1. Their reflective coating will almost certainly be aluminum, since such telescopes would profit from truly broad-band mirrors. To achieve reflectance over the broadest band, the top surface of such aluminum mirrors, however, needs to be bare, without the oxide layers that naturally form in air. This will open the 11 to 15 eV band. Since thin aluminum films are largely transparent between 15 and 70 eV an EUV mirror under the aluminum could make EUV bands such as 30.4 nm available for space-based astrophysics without sacrificing mirror IR, visible and UV reflectance. The local space environment for the observatory is sufficiently oxygen-free that the surface should remain bare for decades. We discuss protecting as-deposited aluminum mirrors with robust, oxygenimpenetrable, barrier layers applied in vacuo to the aluminum immediately after deposition and before air contact. The goal is that the barrier could also be cleanly, and relatively easily, removed once the mirror is in space. We propose hydrogen atoms as the means for removing the overcoat, since they can be expected to meet the criteria that the means is gentle enough to not roughen the mirror surface, and does not redeposit material on the mirror or other spacecraft components. We have investigated both organic and inorganic (such as, a-Si) hydrogen-removable films that can be applied to the aluminum immediately after its deposition have been investigated. We also examined the REVAP technique, using Cd and Zn. Agglomeration limited their effectiveness as barrier layers. That and dealing with the reevaporated atoms may limit their utility as barrier materials. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
1004 a57209530205 Hooper K. p332 False Conference 108 3D printing for lab-on-a-chip devices with 20 μm channels While there is great interest in 3D printing for microfluidic device fabrication, the challenge has been to achieve feature sizes that are in the truly microfluidic regime (<100 μm). The fundamental problem is that commercial tools and materials, which excel in many other application areas, have not been developed to address the unique needs of microfluidic device fabrication. Consequently, we have created our own stereolithographic 3D printer and materials that are specifically tailored to meet these needs. We review our recent work and show that flow channels as small as 18 μm x 20 μm can be reliably fabricated, as well as compact active elements such as valves and pumps. With these capabilities, we demonstrate highly integrated 3D printed microfluidic devices that measure only a few millimeters on a side, and that integrate separate chip-to-world interfaces through high density interconnects (up to 88 interconnects per square mm) that are directly 3D printed as part of a device chip. These advances open the door to 3D printing as a replacement for expensive cleanroom fabrication processes, with the additional advantage of fast (30 minute), parallel fabrication of many devices in a single print run due to their small size. © 2019 SPIE.
1005 a57215116223 Baker N.F. p333 True Conference 109 Best practices for wake model and optimization algorithm selection in wind farm layout optimization This paper presents the results of two case studies regarding the wind farm layout optimization problem. We asked members of the computational optimization and wind communities to take part in the studies that we designed. Nine individuals participated. Case study 1 considered variations in optimization strategies for a given simple Gaussian wake model. Participants were provided with a wake model that outputs annual energy production (AEP) for an input set of wind turbine locations. Participants used an optimization method of their choosing to find an optimal wind farm layout. Case study 2 looked at trade-offs in performance resulting from variation in both physics model and optimization strategy. For case study 2, participants calculated AEP using a wake model of their choice while also using their chosen optimization method. Participants then used their wake model to calculate the AEP of all other participants’ optimized layouts. Results for case study 1 show that the best optimal wind farm layouts in this study were achieved by participants who used gradient-based optimization methods. A front-runner emerged with the Sparse Nonlinear OPTimizer plus Wake Expansion Continua-tion (SNOPT+WEC) optimization method, which consistently discovered the highest submitted AEP. For case study 2, two participants found a similar layout that was judged to be superior by all five participants. It is unclear if the better solution resulted from an improved optimization process, or a wake model that was more amenable to optimization. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1006 a57191952713 Stanley A.P.J. p333 False Conference 109 Best practices for wake model and optimization algorithm selection in wind farm layout optimization This paper presents the results of two case studies regarding the wind farm layout optimization problem. We asked members of the computational optimization and wind communities to take part in the studies that we designed. Nine individuals participated. Case study 1 considered variations in optimization strategies for a given simple Gaussian wake model. Participants were provided with a wake model that outputs annual energy production (AEP) for an input set of wind turbine locations. Participants used an optimization method of their choosing to find an optimal wind farm layout. Case study 2 looked at trade-offs in performance resulting from variation in both physics model and optimization strategy. For case study 2, participants calculated AEP using a wake model of their choice while also using their chosen optimization method. Participants then used their wake model to calculate the AEP of all other participants’ optimized layouts. Results for case study 1 show that the best optimal wind farm layouts in this study were achieved by participants who used gradient-based optimization methods. A front-runner emerged with the Sparse Nonlinear OPTimizer plus Wake Expansion Continua-tion (SNOPT+WEC) optimization method, which consistently discovered the highest submitted AEP. For case study 2, two participants found a similar layout that was judged to be superior by all five participants. It is unclear if the better solution resulted from an improved optimization process, or a wake model that was more amenable to optimization. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1006 a57191952713 Stanley A.P.J. p616 True Conference 254 Benefits of two turbine rotor diameters and hub heights in the same wind farm Significant turbine-wake interactions greatly reduce power output in a wind farm. If different turbine hub heights and rotor diameters are included in the same wind farm, the wake interference in the farm will be reduced, resulting in a lower cost of energy (COE) than a farm with identical turbines. In this paper, we present a method to model wind farm COE in farms with hub heights and rotor diameters that vary across the wind farm. We also demonstrate how to optimize these wind farms to minimize COE. The results show that COE can be greatly reduced in wind farms with non-homogeneous turbines, especially when the turbines are spaced close together. For a unidirectional wind rose, including different turbine design in the wind farm has a similar decrease in COE to spreading the wind turbines farther apart. When the rotor diameter and hub height of the wind turbines in a farm are optimized uniformly, a COE decrease of 4% to 13% (depending on the grid spacing and wind shear exponent) is achieved compared to the baseline. When the rotor diameter and turbine heights are optimized non-uniformly, with two different diameters and heights throughout the farm, there is a COE decrease of 22% to 41% compared to the baseline. For a more spread wind rose with a dominant probability from the west, there is a COE decrease between 3% and 10% for uniformly optimized rotor diameter and height compared to the baseline. With two optimized rotor diameters and heights through the farm, a COE decrease of 3% to 19% is achieved. For a similar wind rose shifted such that the dominant wind direction is from the northwest, a COE decrease between 3% and 10% results from uniformly optimized wind turbines compared to the baseline. A COE decrease of 3% to 17% compared to the baseline occurs with two different turbines are optimized throughout the wind farm. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1006 a57191952713 Stanley A.P.J. p836 True Conference 364 Gradient-based optimization of wind farms with different turbine heights Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the cost of energy of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and low wind shear exponent. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1007 a57188658434 Thomas J.J. p333 False Conference 109 Best practices for wake model and optimization algorithm selection in wind farm layout optimization This paper presents the results of two case studies regarding the wind farm layout optimization problem. We asked members of the computational optimization and wind communities to take part in the studies that we designed. Nine individuals participated. Case study 1 considered variations in optimization strategies for a given simple Gaussian wake model. Participants were provided with a wake model that outputs annual energy production (AEP) for an input set of wind turbine locations. Participants used an optimization method of their choosing to find an optimal wind farm layout. Case study 2 looked at trade-offs in performance resulting from variation in both physics model and optimization strategy. For case study 2, participants calculated AEP using a wake model of their choice while also using their chosen optimization method. Participants then used their wake model to calculate the AEP of all other participants’ optimized layouts. Results for case study 1 show that the best optimal wind farm layouts in this study were achieved by participants who used gradient-based optimization methods. A front-runner emerged with the Sparse Nonlinear OPTimizer plus Wake Expansion Continua-tion (SNOPT+WEC) optimization method, which consistently discovered the highest submitted AEP. For case study 2, two participants found a similar layout that was judged to be superior by all five participants. It is unclear if the better solution resulted from an improved optimization process, or a wake model that was more amenable to optimization. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1007 a57188658434 Thomas J.J. p334 True Conference 110 Comparison of wind farm layout optimization results using a simple wake model and gradient-based optimization to large-eddy simulations The models used during wind farm layout optimization use simplifying assumptions that can alter the design space. Some characteristics of the simple models may negatively influence the resulting layouts. In this paper, we perform wind farm layout optimization using a simple wake model and compare the resulting improvements to large-eddy simulation (LES) results to confirm that the layout was actually improved. We begin by describing the models used, including changes specific for use with gradient-based optimization. We then compare our models’ output to previously published model and LES results. Using the models described, we performed gradient-based wind farm layout optimization using exact gradients. Power production for the original and optimized layouts were recalculated using LES. The model and LES results were then compared. The simple models predicted an improvement in annual energy production (AEP) of 7.4%, while the LES reported an AEP improvement of 9.9%. We concluded that the improvements found by optimizing with the simple models are not just an artifact of the model characteristics, but are real improvements. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1007 a57188658434 Thomas J.J. p836 False Conference 364 Gradient-based optimization of wind farms with different turbine heights Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the cost of energy of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and low wind shear exponent. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1008 a36682113800 Dykes K. p333 False Conference 109 Best practices for wake model and optimization algorithm selection in wind farm layout optimization This paper presents the results of two case studies regarding the wind farm layout optimization problem. We asked members of the computational optimization and wind communities to take part in the studies that we designed. Nine individuals participated. Case study 1 considered variations in optimization strategies for a given simple Gaussian wake model. Participants were provided with a wake model that outputs annual energy production (AEP) for an input set of wind turbine locations. Participants used an optimization method of their choosing to find an optimal wind farm layout. Case study 2 looked at trade-offs in performance resulting from variation in both physics model and optimization strategy. For case study 2, participants calculated AEP using a wake model of their choice while also using their chosen optimization method. Participants then used their wake model to calculate the AEP of all other participants’ optimized layouts. Results for case study 1 show that the best optimal wind farm layouts in this study were achieved by participants who used gradient-based optimization methods. A front-runner emerged with the Sparse Nonlinear OPTimizer plus Wake Expansion Continua-tion (SNOPT+WEC) optimization method, which consistently discovered the highest submitted AEP. For case study 2, two participants found a similar layout that was judged to be superior by all five participants. It is unclear if the better solution resulted from an improved optimization process, or a wake model that was more amenable to optimization. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1008 a36682113800 Dykes K. p616 False Conference 254 Benefits of two turbine rotor diameters and hub heights in the same wind farm Significant turbine-wake interactions greatly reduce power output in a wind farm. If different turbine hub heights and rotor diameters are included in the same wind farm, the wake interference in the farm will be reduced, resulting in a lower cost of energy (COE) than a farm with identical turbines. In this paper, we present a method to model wind farm COE in farms with hub heights and rotor diameters that vary across the wind farm. We also demonstrate how to optimize these wind farms to minimize COE. The results show that COE can be greatly reduced in wind farms with non-homogeneous turbines, especially when the turbines are spaced close together. For a unidirectional wind rose, including different turbine design in the wind farm has a similar decrease in COE to spreading the wind turbines farther apart. When the rotor diameter and hub height of the wind turbines in a farm are optimized uniformly, a COE decrease of 4% to 13% (depending on the grid spacing and wind shear exponent) is achieved compared to the baseline. When the rotor diameter and turbine heights are optimized non-uniformly, with two different diameters and heights throughout the farm, there is a COE decrease of 22% to 41% compared to the baseline. For a more spread wind rose with a dominant probability from the west, there is a COE decrease between 3% and 10% for uniformly optimized rotor diameter and height compared to the baseline. With two optimized rotor diameters and heights through the farm, a COE decrease of 3% to 19% is achieved. For a similar wind rose shifted such that the dominant wind direction is from the northwest, a COE decrease between 3% and 10% results from uniformly optimized wind turbines compared to the baseline. A COE decrease of 3% to 17% compared to the baseline occurs with two different turbines are optimized throughout the wind farm. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1008 a36682113800 Dykes K. p836 False Conference 364 Gradient-based optimization of wind farms with different turbine heights Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the cost of energy of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and low wind shear exponent. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1009 a56245452300 Annoni J. p334 False Conference 110 Comparison of wind farm layout optimization results using a simple wake model and gradient-based optimization to large-eddy simulations The models used during wind farm layout optimization use simplifying assumptions that can alter the design space. Some characteristics of the simple models may negatively influence the resulting layouts. In this paper, we perform wind farm layout optimization using a simple wake model and compare the resulting improvements to large-eddy simulation (LES) results to confirm that the layout was actually improved. We begin by describing the models used, including changes specific for use with gradient-based optimization. We then compare our models’ output to previously published model and LES results. Using the models described, we performed gradient-based wind farm layout optimization using exact gradients. Power production for the original and optimized layouts were recalculated using LES. The model and LES results were then compared. The simple models predicted an improvement in annual energy production (AEP) of 7.4%, while the LES reported an AEP improvement of 9.9%. We concluded that the improvements found by optimizing with the simple models are not just an artifact of the model characteristics, but are real improvements. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1009 a56245452300 Annoni J. p836 False Conference 364 Gradient-based optimization of wind farms with different turbine heights Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the cost of energy of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and low wind shear exponent. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1010 a35310092900 Fleming P. p334 False Conference 110 Comparison of wind farm layout optimization results using a simple wake model and gradient-based optimization to large-eddy simulations The models used during wind farm layout optimization use simplifying assumptions that can alter the design space. Some characteristics of the simple models may negatively influence the resulting layouts. In this paper, we perform wind farm layout optimization using a simple wake model and compare the resulting improvements to large-eddy simulation (LES) results to confirm that the layout was actually improved. We begin by describing the models used, including changes specific for use with gradient-based optimization. We then compare our models’ output to previously published model and LES results. Using the models described, we performed gradient-based wind farm layout optimization using exact gradients. Power production for the original and optimized layouts were recalculated using LES. The model and LES results were then compared. The simple models predicted an improvement in annual energy production (AEP) of 7.4%, while the LES reported an AEP improvement of 9.9%. We concluded that the improvements found by optimizing with the simple models are not just an artifact of the model characteristics, but are real improvements. © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1010 a35310092900 Fleming P. p836 False Conference 364 Gradient-based optimization of wind farms with different turbine heights Turbine wakes reduce power production in a wind farm. Current wind farms are generally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the cost of energy of a wind farm through layout optimization and varying turbine hub heights. Results indicate that when a farm is optimized for layout and height with two separate height groups, COE can be lowered by as much as 5-9%, compared to a similar layout and height optimization where all the towers are the same. The COE has the best improvement in farms with high turbine density and low wind shear exponent. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1011 a57214589312 Thorum A. p335 True Conference 111 Thermal properties of thin film uranium oxides and thorium oxides Uranium and thorium oxides have critical roles as fuels in existing nuclear power plants, as well as in proposed reactor concepts. The thermal conductivity of these materials determines their ability to transfer heat from the reactor core to the surrounding coolant. Additionally, these actinide compounds are of interest in condensed matter physics because of the 5f orbitals and unique electron interaction, coupling, and scattering events that can occur. Because of the radioactivity of thorium and uranium, thin film measurements of actinide materials are used to limit the amount of operator exposure, but standard thermal characterization methods are not well suited for thin films. This paper presents the process of depositing thin film UOx and ThOx samples of nm-μm thicknesses and the results of thermal property measurements. Thin films were deposited on silicon and glass substrates via dc-magnetron sputtering using an argon/oxygen mixture as the working gas. The thermal properties of the films were measured by the Thermal Conductivity Microscope (TCM). This uses one laser to generate thermal waves and a second laser to measure the magnitude and phases of the thermal waves to obtain the conductivity of materials. The results of the research show that the UOx film properties are lower than bulk values and that the role of the substrate has a considerable effect on determining the measured properties. Future work aims at improving the deposition process. Epitaxial film growth is planned. Additional understanding of thermal property measurements is targeted. Copyright © 2019 ASME.
1012 a57215007775 Page L. p335 False Conference 111 Thermal properties of thin film uranium oxides and thorium oxides Uranium and thorium oxides have critical roles as fuels in existing nuclear power plants, as well as in proposed reactor concepts. The thermal conductivity of these materials determines their ability to transfer heat from the reactor core to the surrounding coolant. Additionally, these actinide compounds are of interest in condensed matter physics because of the 5f orbitals and unique electron interaction, coupling, and scattering events that can occur. Because of the radioactivity of thorium and uranium, thin film measurements of actinide materials are used to limit the amount of operator exposure, but standard thermal characterization methods are not well suited for thin films. This paper presents the process of depositing thin film UOx and ThOx samples of nm-μm thicknesses and the results of thermal property measurements. Thin films were deposited on silicon and glass substrates via dc-magnetron sputtering using an argon/oxygen mixture as the working gas. The thermal properties of the films were measured by the Thermal Conductivity Microscope (TCM). This uses one laser to generate thermal waves and a second laser to measure the magnitude and phases of the thermal waves to obtain the conductivity of materials. The results of the research show that the UOx film properties are lower than bulk values and that the role of the substrate has a considerable effect on determining the measured properties. Future work aims at improving the deposition process. Epitaxial film growth is planned. Additional understanding of thermal property measurements is targeted. Copyright © 2019 ASME.
1013 a36126203400 Hua Z. p335 False Conference 111 Thermal properties of thin film uranium oxides and thorium oxides Uranium and thorium oxides have critical roles as fuels in existing nuclear power plants, as well as in proposed reactor concepts. The thermal conductivity of these materials determines their ability to transfer heat from the reactor core to the surrounding coolant. Additionally, these actinide compounds are of interest in condensed matter physics because of the 5f orbitals and unique electron interaction, coupling, and scattering events that can occur. Because of the radioactivity of thorium and uranium, thin film measurements of actinide materials are used to limit the amount of operator exposure, but standard thermal characterization methods are not well suited for thin films. This paper presents the process of depositing thin film UOx and ThOx samples of nm-μm thicknesses and the results of thermal property measurements. Thin films were deposited on silicon and glass substrates via dc-magnetron sputtering using an argon/oxygen mixture as the working gas. The thermal properties of the films were measured by the Thermal Conductivity Microscope (TCM). This uses one laser to generate thermal waves and a second laser to measure the magnitude and phases of the thermal waves to obtain the conductivity of materials. The results of the research show that the UOx film properties are lower than bulk values and that the role of the substrate has a considerable effect on determining the measured properties. Future work aims at improving the deposition process. Epitaxial film growth is planned. Additional understanding of thermal property measurements is targeted. Copyright © 2019 ASME.
1014 a7102843798 Hurley D. p335 False Conference 111 Thermal properties of thin film uranium oxides and thorium oxides Uranium and thorium oxides have critical roles as fuels in existing nuclear power plants, as well as in proposed reactor concepts. The thermal conductivity of these materials determines their ability to transfer heat from the reactor core to the surrounding coolant. Additionally, these actinide compounds are of interest in condensed matter physics because of the 5f orbitals and unique electron interaction, coupling, and scattering events that can occur. Because of the radioactivity of thorium and uranium, thin film measurements of actinide materials are used to limit the amount of operator exposure, but standard thermal characterization methods are not well suited for thin films. This paper presents the process of depositing thin film UOx and ThOx samples of nm-μm thicknesses and the results of thermal property measurements. Thin films were deposited on silicon and glass substrates via dc-magnetron sputtering using an argon/oxygen mixture as the working gas. The thermal properties of the films were measured by the Thermal Conductivity Microscope (TCM). This uses one laser to generate thermal waves and a second laser to measure the magnitude and phases of the thermal waves to obtain the conductivity of materials. The results of the research show that the UOx film properties are lower than bulk values and that the role of the substrate has a considerable effect on determining the measured properties. Future work aims at improving the deposition process. Epitaxial film growth is planned. Additional understanding of thermal property measurements is targeted. Copyright © 2019 ASME.
1015 a57214451592 Yayoglu Y.E. p336 True Conference 112 Effects of laser ablation parameters to pattern high purity magnesium surfaces Magnesium and magnesium-based alloys have relatively low weight and desirable mechanical properties for many applications in multiple industries including aerospace and automotive. In the past decade, due to its biocompatible nature, the medical field has expressed significant interest in magnesium for biodegradable implant applications. However, utilization of magnesium-based alloys in surgical implant applications is strictly limited by magnesium’s high vulnerability to corrosion causing premature disintegration inside the human body. Hydrophobic (non-wetting) behavior of metal surfaces has been proven to be beneficial for corrosion protection in academic literature. One way of achieving hydrophobic and superhydrophobic surfaces on metal surfaces without using non-biocompatible coatings is creating uniform microstructures that would alter the wetting characteristics of the surface. This work focuses on creating uniform pillar shaped micro-patterns on smooth pure magnesium surfaces by utilizing a picosecond laser (λ = 355 nm). The study reports the effects of average laser power, partial laser beam overlap and number of laser scans on the height, steepness, roughness of the resultant micro-pillars. Information gathered from this study could be useful in creating more complex or finer micro-structures on magnesium and its alloys to alter their wetting or corrosion characteristics using laser ablation which is a fast, repeatable and an un-convoluted process. Copyright © 2019 ASME.
1016 a6603114735 Gallant N.D. p336 False Conference 112 Effects of laser ablation parameters to pattern high purity magnesium surfaces Magnesium and magnesium-based alloys have relatively low weight and desirable mechanical properties for many applications in multiple industries including aerospace and automotive. In the past decade, due to its biocompatible nature, the medical field has expressed significant interest in magnesium for biodegradable implant applications. However, utilization of magnesium-based alloys in surgical implant applications is strictly limited by magnesium’s high vulnerability to corrosion causing premature disintegration inside the human body. Hydrophobic (non-wetting) behavior of metal surfaces has been proven to be beneficial for corrosion protection in academic literature. One way of achieving hydrophobic and superhydrophobic surfaces on metal surfaces without using non-biocompatible coatings is creating uniform microstructures that would alter the wetting characteristics of the surface. This work focuses on creating uniform pillar shaped micro-patterns on smooth pure magnesium surfaces by utilizing a picosecond laser (λ = 355 nm). The study reports the effects of average laser power, partial laser beam overlap and number of laser scans on the height, steepness, roughness of the resultant micro-pillars. Information gathered from this study could be useful in creating more complex or finer micro-structures on magnesium and its alloys to alter their wetting or corrosion characteristics using laser ablation which is a fast, repeatable and an un-convoluted process. Copyright © 2019 ASME.
1017 a8641604600 Toomey R. p336 False Conference 112 Effects of laser ablation parameters to pattern high purity magnesium surfaces Magnesium and magnesium-based alloys have relatively low weight and desirable mechanical properties for many applications in multiple industries including aerospace and automotive. In the past decade, due to its biocompatible nature, the medical field has expressed significant interest in magnesium for biodegradable implant applications. However, utilization of magnesium-based alloys in surgical implant applications is strictly limited by magnesium’s high vulnerability to corrosion causing premature disintegration inside the human body. Hydrophobic (non-wetting) behavior of metal surfaces has been proven to be beneficial for corrosion protection in academic literature. One way of achieving hydrophobic and superhydrophobic surfaces on metal surfaces without using non-biocompatible coatings is creating uniform microstructures that would alter the wetting characteristics of the surface. This work focuses on creating uniform pillar shaped micro-patterns on smooth pure magnesium surfaces by utilizing a picosecond laser (λ = 355 nm). The study reports the effects of average laser power, partial laser beam overlap and number of laser scans on the height, steepness, roughness of the resultant micro-pillars. Information gathered from this study could be useful in creating more complex or finer micro-structures on magnesium and its alloys to alter their wetting or corrosion characteristics using laser ablation which is a fast, repeatable and an un-convoluted process. Copyright © 2019 ASME.
1018 a23027991800 List M.G. p337 False Conference 113 Radial variation in distortion transfer and generation in a highly loaded fan stage from near-stall to choke Understanding distortion transfer and generation through fan and compressor blade rows is able to assist in blade design and performance prediction. Using full annulus URANS simulations, the effects of distortion as it passes through the rotor of a transonic fan at five radial locations (10%, 30%, 50%, 70%, and 90% span) are analyzed. The inlet distortion profile is a 90-degree sector with a 15% total pressure deficit. Fourier distortion descriptors are used in this study to quantitatively describe distortion transfer and generation. Results are presented and compared for three operating points (near-stall, design, and choke). These results are used to explain the relationship between inlet total pressure distortion, pressure-induced swirl, total pressure distortion transfer, total temperature distortion generation, and circumferential rotor power variation. It is shown that very large changes in pressure-induced swirl and distortion transfer and generation occur between near-stall and design, but only small changes are seen between design and choke. The greatest changes are shown to be near the tip. Local power variations are shown to correlate with total pressure distortion transfer and total temperature distortion generation. Copyright © 2019 ASME.
1018 a23027991800 List M.G. p595 False Conference 238 Radial variation in distortion transfer and generation through a highly loaded fan stage An important consideration for fan and compressor design is quantifying distortion transfer and generation blade row by blade row. Detailed information about the magnitude of distortion and the shape of the distortion profile and how it changes through blade rows increases the understanding of flow physics and helps predict aerodynamic performance. Using full annulus URANS simulations, this paper analyzes what happens to distortion as it passes through the rotor and stator blade rows at 10%, 30%, 50%, 70%, and 90% span. Fourier distortion descriptors are used in this study to quantitatively describe distortion transfer and generation. With these descriptors, evidence of pressure-induced swirl is shown at the fan inlet. It is also shown that although there is very little distortion at the 10% span of the inlet, after passing through the rotor blade row the 10% span has the greatest amount of total pressure and total temperature distortion. This radial migration of distortion is attributed to the high hade angle of the hub. The total pressure and total temperature profiles have significant circumferential phase shifts after passing through the rotor and slight phase shifts after passing through the stator. In general, the calculated phase shifts are greatest at the 10% and 90% spans, the nearest locations to the hub and the tip clearance gap, respectively. Copyright © 2018 ASME.
1018 a23027991800 List M.G. p833 False Conference 361 Fourier descriptors for improved analysis of distortion transfer and generation For fan/compressor design, quantifying distortion transfer and generation bladerow by bladerow through a fan/compressor is important to understand the flow physics and predict performance. What is needed are descriptors capable of describing distortion profiles with both high and low distortion content and account for the reshaping of distortion profiles. Four key parameters were identified as desirable to quantitatively capture distortion transfer, generation and effects on performance: distortion magnitude, shape, severity and phase. A set of distortion descriptors based on Fourier analysis are shown to quantitatively capture distortion magnitude, shape and phase change across bladerows. These Fourier descriptors are modal amplitude, total amplitude, and phase shift. When used together, these Fourier descriptors can be used to qualitatively describe any conceivable profile shape for any parameter. Copyright © 2017 ASME.
1019 a7103035939 Rossiter J.A. p338 True Conference 114 Evaluation and demonstration of take home laboratory kit This paper discusses some of the reasons for producing take home laboratory kits. This is then supplemented by detailed presentation of three different types of take home kit, alongside the motivations for their design and an evaluation of their efficacy with students. © 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
1020 a57212228353 Pope S.A. p338 False Conference 114 Evaluation and demonstration of take home laboratory kit This paper discusses some of the reasons for producing take home laboratory kits. This is then supplemented by detailed presentation of three different types of take home kit, alongside the motivations for their design and an evaluation of their efficacy with students. © 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
1021 a7404957607 Jones B.L. p338 False Conference 114 Evaluation and demonstration of take home laboratory kit This paper discusses some of the reasons for producing take home laboratory kits. This is then supplemented by detailed presentation of three different types of take home kit, alongside the motivations for their design and an evaluation of their efficacy with students. © 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
1022 a57203578595 Baptista A. p339 True Journal 193 A Proposed Test to Evaluate Efflorescence Potential of Ceramic Blocks Masonry is susceptible to efflorescence, which in itself is an aesthetic problem, but the condition of efflorescence indicates that water is moving through the masonry in unintended ways and the presence of uncontrolled water can lead to serious issues, including structural problems. In this paper, the results obtained from a proposed test method to evaluate the potential of efflorescence of ceramic blocks are compared to that obtained using the method described in ASTM C67. The proposed method was developed because until 2017 there was no Brazilian Standard to evaluate the efflorescence potential for brick and structural clay tile. The method uses 2 × 2 × 20-cm specimens immersed in 5-cm of distilled water for 5 days in recipients covered with a rubber membrane. The method uses smaller samples than the standard method and has a 5-day instead of 7-day duration. Ceramic blocks from ten manufacturers from different Brazilian regions were used in this study. Results from the standard test method indicated that blocks from three manufacturers were susceptible to efflorescence while the results from the proposed method indicated that the blocks were not susceptible to efflorescence. The discrepancy in results may have been caused by the very small size of the specimens and the large amount of water in the containers used in the proposed method. The amount of soluble salts in the small specimens may not have been enough to detect their presence and the soluble salts in the submerged part of a specimen may have simply dissolved by the water. © 2019, RILEM.
1023 a57203572508 Carneiro A. p339 False Journal 193 A Proposed Test to Evaluate Efflorescence Potential of Ceramic Blocks Masonry is susceptible to efflorescence, which in itself is an aesthetic problem, but the condition of efflorescence indicates that water is moving through the masonry in unintended ways and the presence of uncontrolled water can lead to serious issues, including structural problems. In this paper, the results obtained from a proposed test method to evaluate the potential of efflorescence of ceramic blocks are compared to that obtained using the method described in ASTM C67. The proposed method was developed because until 2017 there was no Brazilian Standard to evaluate the efflorescence potential for brick and structural clay tile. The method uses 2 × 2 × 20-cm specimens immersed in 5-cm of distilled water for 5 days in recipients covered with a rubber membrane. The method uses smaller samples than the standard method and has a 5-day instead of 7-day duration. Ceramic blocks from ten manufacturers from different Brazilian regions were used in this study. Results from the standard test method indicated that blocks from three manufacturers were susceptible to efflorescence while the results from the proposed method indicated that the blocks were not susceptible to efflorescence. The discrepancy in results may have been caused by the very small size of the specimens and the large amount of water in the containers used in the proposed method. The amount of soluble salts in the small specimens may not have been enough to detect their presence and the soluble salts in the submerged part of a specimen may have simply dissolved by the water. © 2019, RILEM.
1024 a55849943100 Lundgreen R. p340 True Journal 96 Increasing Inducer Stability and Suction Performance With a Stability Control Device An inducer is used as the first stage of high suction performance pump. It pressurizes the fluid to delay the onset of cavitation, which can adversely affect performance in a centrifugal pump. In this paper, the performance of a water pump inducer has been explored with and without the implementation of a stability control device (SCD). This device is an inlet cover bleed system that removes high-energy fluid near the blade leading edge and reinjects it back upstream. The research was conducted by running multiphase, time-accurate computational fluid dynamic (CFD) simulations at the design flow coefficient and at low, off-design flow coefficients. The suction performance and stability for the same inducer with and without the implementation of the SCD has been explored. An improvement in stability and suction performance was observed when the SCD was implemented. Without the SCD, the inducer developed backflow at the blade tip, which led to rotating cavitation and larger rotordynamic forces. With the SCD, no significant cavitation instabilities developed, and the rotordynamic forces remained small. The lack of cavitation instabilities also allowed the inducer to operate at lower inlet pressures, increasing the suction performance of the inducer. Copyright © 2018 by ASME.
1025 a35338971800 Bai H. p341 True Journal 194 Relative Heading Estimation and Its Application in Target Handoff in GPS-Denied Environments In this paper, we address the problem of target handoff between two fixed wing aircrafts that do not have access to Global Positioning Systems. The problem requires estimating the relative pose between the vehicles. We assume that onboard inertial measurement units can provide roll and pitch estimates of the aircraft attitude. We examine the observability of other relative states needed to do the handoff problem. In particular, we consider two different scenarios. In the first scenario, we assume that the relative position between the aircrafts is measured, as would be the case for a radar or a lidar sensor. We assume that the two aircrafts do not exchange their airspeed and turn rate information. Under mild assumptions, we show that the relative heading between the two aircrafts is observable. In the second scenario, we assume that only the bearing angle between the two aircrafts is measured, as would be the case for a vision sensor. We prove state observability for maneuvers that are relevant to target tracking and handoff. We also present an estimation algorithm that uses a bank of extended Kalman filters to estimate the relative states. Simulation results with full vehicle dynamics demonstrate the feasibility of the proposed approach. © 1993-2012 IEEE.
1026 a57207260622 Starick T. p342 True Conference 115 One-dimensional turbulence modelling of a lifted methane/air jet flame in a vitiated coflow The present preliminary numerical study investigates a lifted methane/air jet flame in a vitiated coflow by means of the map-based, stochastic One-Dimensional Turbulence (ODT) model. In the considered configuration, a jet flame issues from a central nozzle into a vitiated coflow of hot combustion products from an array of lean H2/air flames. Centreline profiles for mixture fraction, temperature and mass fraction of O2 and OH obtained from ODT simulations with a planar and cylindrical formulation are shown and compared to measurements from Cabra et al. (2005). Additionally, two-dimensional renderings of the jet flame and scatter plots of temperature versus mixture fraction and OH mass fraction versus mixture fraction are provided. Although the application of ODT for reactive flows in jet configurations is not novel, the chosen lifted jet flame in a vitiated coflow represents a challenge for the model. The accurate representation of the subtle interactions of the hot coflow products with the cold unburnt jet flow are crucial for the reaction and autoignition of the jet (Cabra et al., 2005). Considering the reduced order of the model and the taken assumptions, the achieved results reasonably match with the measurement data. © 2019 International Symposium on Turbulence and Shear Flow Phenomena, TSFP. All rights reserved.
1027 a24336460200 Schmidt H. p342 False Conference 115 One-dimensional turbulence modelling of a lifted methane/air jet flame in a vitiated coflow The present preliminary numerical study investigates a lifted methane/air jet flame in a vitiated coflow by means of the map-based, stochastic One-Dimensional Turbulence (ODT) model. In the considered configuration, a jet flame issues from a central nozzle into a vitiated coflow of hot combustion products from an array of lean H2/air flames. Centreline profiles for mixture fraction, temperature and mass fraction of O2 and OH obtained from ODT simulations with a planar and cylindrical formulation are shown and compared to measurements from Cabra et al. (2005). Additionally, two-dimensional renderings of the jet flame and scatter plots of temperature versus mixture fraction and OH mass fraction versus mixture fraction are provided. Although the application of ODT for reactive flows in jet configurations is not novel, the chosen lifted jet flame in a vitiated coflow represents a challenge for the model. The accurate representation of the subtle interactions of the hot coflow products with the cold unburnt jet flow are crucial for the reaction and autoignition of the jet (Cabra et al., 2005). Considering the reduced order of the model and the taken assumptions, the achieved results reasonably match with the measurement data. © 2019 International Symposium on Turbulence and Shear Flow Phenomena, TSFP. All rights reserved.
1027 a24336460200 Schmidt H. p467 False Journal 228 One-dimensional turbulence modeling for cylindrical and spherical flows: model formulation and application The one-dimensional turbulence (ODT) model resolves a full range of time and length scales and is computationally efficient. ODT has been applied to a wide range of complex multi-scale flows, such as turbulent combustion. Previous ODT comparisons to experimental data have focused mainly on planar flows. Applications to cylindrical flows, such as round jets, have been based on rough analogies, e.g., by exploiting the fortuitous consistency of the similarity scalings of temporally developing planar jets and spatially developing round jets. To obtain a more systematic treatment, a new formulation of the ODT model in cylindrical and spherical coordinates is presented here. The model is written in terms of a geometric factor so that planar, cylindrical, and spherical configurations are represented in the same way. Temporal and spatial versions of the model are presented. A Lagrangian finite-volume implementation is used with a dynamically adaptive mesh. The adaptive mesh facilitates the implementation of cylindrical and spherical versions of the triplet map, which is used to model turbulent advection (eddy events) in the one-dimensional flow coordinate. In cylindrical and spherical coordinates, geometric stretching of the three triplet map images occurs due to the radial dependence of volume, with the stretching being strongest near the centerline. Two triplet map variants, TMA and TMB, are presented. In TMA, the three map images have the same volume, but different radial segment lengths. In TMB, the three map images have the same radial segment lengths, but different segment volumes. Cylindrical results are presented for temporal pipe flow, a spatial nonreacting jet, and a spatial nonreacting jet flame. These results compare very well to direct numerical simulation for the pipe flow, and to experimental data for the jets. The nonreacting jet treatment overpredicts velocity fluctuations near the centerline, due to the geometric stretching of the triplet maps and its effect on the eddy event rate distribution. TMB performs better than TMA. A hybrid planar-TMB (PTMB) approach is also presented, which further improves the results. TMA, TMB, and PTMB are nearly identical in the pipe flow where the key dynamics occur near the wall away from the centerline. The jet flame illustrates effects of variable density and viscosity, including dilatational effects. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1028 a57195960835 Nittala S. p343 True Conference 116 Changes in perceptions of ethical climate among undergraduate engineering students Promoting ethical conduct and social responsibility among undergraduate engineering graduates has been an ongoing challenge for many universities around the world. Among many factors shaping such commitments, the ethical climate within engineering degree programs specifically and universities more generally seems especially pertinent. Yet there remains a lack of research on, and understanding about, engineering students' perceptions of ethical climate, including how this changes over time and impacts their professional formation and values. This paper draws on an NSF-funded, mixed-methods, longitudinal research project conducted across four U.S. universities. The larger project aims to investigate perceptions and attitudes around ethics, social responsibility, and related concepts among engineering students. In this paper, we more specifically explore various facets of ethical climate across the three schools through a mixed-method explanatory study. We focus on quantitative survey measures (n=257) and qualitative interview data (n=33) collected from engineering students during their first and final years of college. We more specifically shed light on three main research objectives. First, we investigate how engineering students perceive ethical climate across the four universities. Second, we explore how students' perceptions of ethical climate change over time. Third, we look at how specific experiences may contribute to students' ethical climate perceptions, including changes over time. This study will appeal to engineering educators, policymakers and researchers who are interested in research on ethics, social responsibility, and related topics. By providing foundational insights about students' perceptions of ethical climate, we hope to inform strategies to improve the ethical climate at universities and ethical commitments of engineers. © 2020 SEFI 47th Annual Conference: Varietas Delectat... Complexity is the New Normality, Proceedings. All rights reserved.
1028 a57195960835 Nittala S. p490 True Conference 182 Investigating influences on first-year engineering students' views of ethics and social responsibility According to current ABET accreditation requirements, engineering students need to become aware of the social contexts of engineering and develop ethical and professional responsibilities during their undergraduate training. Concerns also persist about the moral and ethical commitments of engineers once they enter the workplace, as underscored by a number of recent ethics scandals involving engineers and technology. The education of ethically adept engineers therefore remains a pertinent issue for the engineering education community. Yet there remains relatively little research on how students' prior experiences shape their ethical perspectives. Specifically, there is a lack of understanding of the role of pre-college and early college experiences and other influences in shaping first-year engineering students' views on ethics. This paper reports select results from an NSF-funded project aiming to address some of these gaps in the literature. This longitudinal study was conducted across four universities and focused on the ethical development of undergraduate engineering students. Preliminary analysis of interviews from the first phase of this study identified a number of major themes in the data set, two of which are important to highlight here: 1) influences on students' ethical perspectives (e.g., academic curricular, extracurricular activities, family, etc.) and 2) learned outcomes, defined as insights, learning, or realizations related to ethics, morality, and values. Deeper investigation of the relationship between specific influences and students' insights related to ethics can provide a better understanding of first-year engineering students' baseline ethical development. The goal of this paper is to characterize what specific ethical lessons are gained through various types of experiences, as well as to glean how this learning and growth occurs. Data for this study was drawn from 66 interview transcripts and consisted of sections coded simultaneously for influences and learned outcomes. The cross-coded data were analyzed using a thematic analysis approach. The types of influences impacting students' ethical learning, and exemplars of how students report their lived experiences and ethical realizations, are discussed through the lens of what they learned and the mechanisms through which they gained these understandings. Our analysis suggests that several pre-college (e.g., extracurricular activities, service/volunteer roles and social experiences) and early college experiences (e.g., academic courses, part-time employment) play a critical role in shaping students' ethical perspectives. We more specifically present our findings organized around eight types of experiences and influences, which are in turn related to three categories of learned outcomes and three types of learning mechanisms. As we discuss in more detail below, the results of this study will likely be of interest to engineering educators, policymakers, and researchers with an interest in administering and studying high-impact ethics interventions for undergraduate engineering students. More specifically, our results underscore the importance of being more aware of how students' background perspectives and experiences likely play important roles in enabling or disabling their further ethical development. © American Society for Engineering Education, 2018.
1029 a57203300120 Howland S. p343 False Conference 116 Changes in perceptions of ethical climate among undergraduate engineering students Promoting ethical conduct and social responsibility among undergraduate engineering graduates has been an ongoing challenge for many universities around the world. Among many factors shaping such commitments, the ethical climate within engineering degree programs specifically and universities more generally seems especially pertinent. Yet there remains a lack of research on, and understanding about, engineering students' perceptions of ethical climate, including how this changes over time and impacts their professional formation and values. This paper draws on an NSF-funded, mixed-methods, longitudinal research project conducted across four U.S. universities. The larger project aims to investigate perceptions and attitudes around ethics, social responsibility, and related concepts among engineering students. In this paper, we more specifically explore various facets of ethical climate across the three schools through a mixed-method explanatory study. We focus on quantitative survey measures (n=257) and qualitative interview data (n=33) collected from engineering students during their first and final years of college. We more specifically shed light on three main research objectives. First, we investigate how engineering students perceive ethical climate across the four universities. Second, we explore how students' perceptions of ethical climate change over time. Third, we look at how specific experiences may contribute to students' ethical climate perceptions, including changes over time. This study will appeal to engineering educators, policymakers and researchers who are interested in research on ethics, social responsibility, and related topics. By providing foundational insights about students' perceptions of ethical climate, we hope to inform strategies to improve the ethical climate at universities and ethical commitments of engineers. © 2020 SEFI 47th Annual Conference: Varietas Delectat... Complexity is the New Normality, Proceedings. All rights reserved.
1029 a57203300120 Howland S. p490 False Conference 182 Investigating influences on first-year engineering students' views of ethics and social responsibility According to current ABET accreditation requirements, engineering students need to become aware of the social contexts of engineering and develop ethical and professional responsibilities during their undergraduate training. Concerns also persist about the moral and ethical commitments of engineers once they enter the workplace, as underscored by a number of recent ethics scandals involving engineers and technology. The education of ethically adept engineers therefore remains a pertinent issue for the engineering education community. Yet there remains relatively little research on how students' prior experiences shape their ethical perspectives. Specifically, there is a lack of understanding of the role of pre-college and early college experiences and other influences in shaping first-year engineering students' views on ethics. This paper reports select results from an NSF-funded project aiming to address some of these gaps in the literature. This longitudinal study was conducted across four universities and focused on the ethical development of undergraduate engineering students. Preliminary analysis of interviews from the first phase of this study identified a number of major themes in the data set, two of which are important to highlight here: 1) influences on students' ethical perspectives (e.g., academic curricular, extracurricular activities, family, etc.) and 2) learned outcomes, defined as insights, learning, or realizations related to ethics, morality, and values. Deeper investigation of the relationship between specific influences and students' insights related to ethics can provide a better understanding of first-year engineering students' baseline ethical development. The goal of this paper is to characterize what specific ethical lessons are gained through various types of experiences, as well as to glean how this learning and growth occurs. Data for this study was drawn from 66 interview transcripts and consisted of sections coded simultaneously for influences and learned outcomes. The cross-coded data were analyzed using a thematic analysis approach. The types of influences impacting students' ethical learning, and exemplars of how students report their lived experiences and ethical realizations, are discussed through the lens of what they learned and the mechanisms through which they gained these understandings. Our analysis suggests that several pre-college (e.g., extracurricular activities, service/volunteer roles and social experiences) and early college experiences (e.g., academic courses, part-time employment) play a critical role in shaping students' ethical perspectives. We more specifically present our findings organized around eight types of experiences and influences, which are in turn related to three categories of learned outcomes and three types of learning mechanisms. As we discuss in more detail below, the results of this study will likely be of interest to engineering educators, policymakers, and researchers with an interest in administering and studying high-impact ethics interventions for undergraduate engineering students. More specifically, our results underscore the importance of being more aware of how students' background perspectives and experiences likely play important roles in enabling or disabling their further ethical development. © American Society for Engineering Education, 2018.
1029 a57203300120 Howland S. p491 True Conference 183 A longitudinal study of social and ethical responsibility among undergraduate engineering students: Comparing baseline and midpoint survey results In addition to developing technically competent engineers, engineering programs aim to prepare students to be professionally and ethically responsible. Universities have sought to integrate ethics instruction into their curricula through a variety of learning experiences. However, there is a lack of research on foundational understandings of social and ethical responsibility among engineering students, including how their perceptions change over time and following participation in specific types of learning experiences. This study uses a longitudinal mixed-methods study design, collecting and analyzing quantitative and qualitative data from engineering students over the course of their four years as undergraduate students. This paper reports insights gained by a repeat survey of student perceptions of ethics and social responsibility. Our analysis compares student responses (n=319) to a survey administered during their first year of college and again in their junior year (approximately fifth-semester), including variations based on student affiliations and demographics (e.g., comparisons among universities, genders, importance of religion, and other relevant factors) and learning experiences (e.g., service-learning programs, ethics courses, extracurricular organizations, etc.). These mid-point findings contribute to our understandings of the trajectories of students' perceptions and perspectives and are beginning to reveal some specific experiences and contexts that are having the largest measurable impacts on the participating students. © American Society for Engineering Education, 2018.
1030 a13607032600 Jesiek B. p343 False Conference 116 Changes in perceptions of ethical climate among undergraduate engineering students Promoting ethical conduct and social responsibility among undergraduate engineering graduates has been an ongoing challenge for many universities around the world. Among many factors shaping such commitments, the ethical climate within engineering degree programs specifically and universities more generally seems especially pertinent. Yet there remains a lack of research on, and understanding about, engineering students' perceptions of ethical climate, including how this changes over time and impacts their professional formation and values. This paper draws on an NSF-funded, mixed-methods, longitudinal research project conducted across four U.S. universities. The larger project aims to investigate perceptions and attitudes around ethics, social responsibility, and related concepts among engineering students. In this paper, we more specifically explore various facets of ethical climate across the three schools through a mixed-method explanatory study. We focus on quantitative survey measures (n=257) and qualitative interview data (n=33) collected from engineering students during their first and final years of college. We more specifically shed light on three main research objectives. First, we investigate how engineering students perceive ethical climate across the four universities. Second, we explore how students' perceptions of ethical climate change over time. Third, we look at how specific experiences may contribute to students' ethical climate perceptions, including changes over time. This study will appeal to engineering educators, policymakers and researchers who are interested in research on ethics, social responsibility, and related topics. By providing foundational insights about students' perceptions of ethical climate, we hope to inform strategies to improve the ethical climate at universities and ethical commitments of engineers. © 2020 SEFI 47th Annual Conference: Varietas Delectat... Complexity is the New Normality, Proceedings. All rights reserved.
1030 a13607032600 Jesiek B. p490 False Conference 182 Investigating influences on first-year engineering students' views of ethics and social responsibility According to current ABET accreditation requirements, engineering students need to become aware of the social contexts of engineering and develop ethical and professional responsibilities during their undergraduate training. Concerns also persist about the moral and ethical commitments of engineers once they enter the workplace, as underscored by a number of recent ethics scandals involving engineers and technology. The education of ethically adept engineers therefore remains a pertinent issue for the engineering education community. Yet there remains relatively little research on how students' prior experiences shape their ethical perspectives. Specifically, there is a lack of understanding of the role of pre-college and early college experiences and other influences in shaping first-year engineering students' views on ethics. This paper reports select results from an NSF-funded project aiming to address some of these gaps in the literature. This longitudinal study was conducted across four universities and focused on the ethical development of undergraduate engineering students. Preliminary analysis of interviews from the first phase of this study identified a number of major themes in the data set, two of which are important to highlight here: 1) influences on students' ethical perspectives (e.g., academic curricular, extracurricular activities, family, etc.) and 2) learned outcomes, defined as insights, learning, or realizations related to ethics, morality, and values. Deeper investigation of the relationship between specific influences and students' insights related to ethics can provide a better understanding of first-year engineering students' baseline ethical development. The goal of this paper is to characterize what specific ethical lessons are gained through various types of experiences, as well as to glean how this learning and growth occurs. Data for this study was drawn from 66 interview transcripts and consisted of sections coded simultaneously for influences and learned outcomes. The cross-coded data were analyzed using a thematic analysis approach. The types of influences impacting students' ethical learning, and exemplars of how students report their lived experiences and ethical realizations, are discussed through the lens of what they learned and the mechanisms through which they gained these understandings. Our analysis suggests that several pre-college (e.g., extracurricular activities, service/volunteer roles and social experiences) and early college experiences (e.g., academic courses, part-time employment) play a critical role in shaping students' ethical perspectives. We more specifically present our findings organized around eight types of experiences and influences, which are in turn related to three categories of learned outcomes and three types of learning mechanisms. As we discuss in more detail below, the results of this study will likely be of interest to engineering educators, policymakers, and researchers with an interest in administering and studying high-impact ethics interventions for undergraduate engineering students. More specifically, our results underscore the importance of being more aware of how students' background perspectives and experiences likely play important roles in enabling or disabling their further ethical development. © American Society for Engineering Education, 2018.
1030 a13607032600 Jesiek B. p491 False Conference 183 A longitudinal study of social and ethical responsibility among undergraduate engineering students: Comparing baseline and midpoint survey results In addition to developing technically competent engineers, engineering programs aim to prepare students to be professionally and ethically responsible. Universities have sought to integrate ethics instruction into their curricula through a variety of learning experiences. However, there is a lack of research on foundational understandings of social and ethical responsibility among engineering students, including how their perceptions change over time and following participation in specific types of learning experiences. This study uses a longitudinal mixed-methods study design, collecting and analyzing quantitative and qualitative data from engineering students over the course of their four years as undergraduate students. This paper reports insights gained by a repeat survey of student perceptions of ethics and social responsibility. Our analysis compares student responses (n=319) to a survey administered during their first year of college and again in their junior year (approximately fifth-semester), including variations based on student affiliations and demographics (e.g., comparisons among universities, genders, importance of religion, and other relevant factors) and learning experiences (e.g., service-learning programs, ethics courses, extracurricular organizations, etc.). These mid-point findings contribute to our understandings of the trajectories of students' perceptions and perspectives and are beginning to reveal some specific experiences and contexts that are having the largest measurable impacts on the participating students. © American Society for Engineering Education, 2018.
1030 a13607032600 Jesiek B. p738 True Conference 319 Investigating engineering students' understandings of social and ethical responsibility: Coding framework and initial findings [No abstract available]
1031 a57209399640 Tyler J. p344 False Conference 117 “Something isn't secure, but I'm not sure how that translates into a problem”: Promoting autonomy by designing for understanding in Signal Security designs that presume enacting secure behaviors to be beneficial in all circumstances discount the impact of response cost on users' lives and assume that all data is equally worth protecting. However, this has the effect of reducing user autonomy by diminishing the role personal values and priorities play in the decision-making process. In this study, we demonstrate an alternative approach that emphasizes users' comprehension over compliance, with the goal of helping users to make more informed decisions regarding their own security. To this end, we conducted a three-phase redesign of the warning notifications surrounding the authentication ceremony in Signal. Our results show how improved comprehension can be achieved while still promoting favorable privacy outcomes among users. Our experience reaffirms existing arguments that users should be empowered to make personal trade-offs between perceived risk and response cost. We also find that system trust is a major factor in users' interpretation of system determinations of risk, and that properly communicating risk requires an understanding of user perceptions of the larger security ecosystem in whole. © is held by the author/owner.
1032 a57212167791 Gatrell C. p344 False Conference 117 “Something isn't secure, but I'm not sure how that translates into a problem”: Promoting autonomy by designing for understanding in Signal Security designs that presume enacting secure behaviors to be beneficial in all circumstances discount the impact of response cost on users' lives and assume that all data is equally worth protecting. However, this has the effect of reducing user autonomy by diminishing the role personal values and priorities play in the decision-making process. In this study, we demonstrate an alternative approach that emphasizes users' comprehension over compliance, with the goal of helping users to make more informed decisions regarding their own security. To this end, we conducted a three-phase redesign of the warning notifications surrounding the authentication ceremony in Signal. Our results show how improved comprehension can be achieved while still promoting favorable privacy outcomes among users. Our experience reaffirms existing arguments that users should be empowered to make personal trade-offs between perceived risk and response cost. We also find that system trust is a major factor in users' interpretation of system determinations of risk, and that properly communicating risk requires an understanding of user perceptions of the larger security ecosystem in whole. © is held by the author/owner.
1033 a57209394752 Howard D. p344 False Conference 117 “Something isn't secure, but I'm not sure how that translates into a problem”: Promoting autonomy by designing for understanding in Signal Security designs that presume enacting secure behaviors to be beneficial in all circumstances discount the impact of response cost on users' lives and assume that all data is equally worth protecting. However, this has the effect of reducing user autonomy by diminishing the role personal values and priorities play in the decision-making process. In this study, we demonstrate an alternative approach that emphasizes users' comprehension over compliance, with the goal of helping users to make more informed decisions regarding their own security. To this end, we conducted a three-phase redesign of the warning notifications surrounding the authentication ceremony in Signal. Our results show how improved comprehension can be achieved while still promoting favorable privacy outcomes among users. Our experience reaffirms existing arguments that users should be empowered to make personal trade-offs between perceived risk and response cost. We also find that system trust is a major factor in users' interpretation of system determinations of risk, and that properly communicating risk requires an understanding of user perceptions of the larger security ecosystem in whole. © is held by the author/owner.
1034 a57211217749 Gibbons J.D. p345 True Conference 118 A methodology for analyzing intersection safety This paper summarizes the development of the Utah intersection crash prediction model (UICPM) and the intersection safety analysis methodology (ISAM). The UICPM is a Bayesian generalized linear model that creates distributions of the expected number of crashes at each intersection, compares the actual number of crashes to the distribution, and ranks the intersections based on safety concern. The ISAM is the process that was developed to execute the UICPM. The first step is to prepare the model input by combining the roadway and crash data files. Crashes are assigned to intersections if they are located with the functional area of an intersection. The second step is to execute the UICPM using the R graphical user interface (GUI) tool and R software. The third step is to create a two-page intersection safety analysis report (ISAR) for intersections of interest and maps of the state, regions, and counties to visualize the model results. © 2019 American Society of Civil Engineers.
1035 a57203661821 Lusk P.C. p346 True Journal 195 Safe2Ditch: Emergency landing for small unmanned aircraft systems Emergency landing is a critical safety feature for the expected increase of autonomous vehicles in the airspace. This paper presents Safe2Ditch, an autonomous crash management system for landing small unmanned aerial vehicles in populated environments. Using a prepopulated database, the highest-rated landing site is selected. As the vehicle progresses toward the selected landing site, a camera is used to image the area around the landing site. Using a recently developed visual multiple target tracker, moving ground obstacles are tracked and geolocated using a flat Earth model. These inertial target estimates are used to revise the landing site and allow the vehicle to land quickly in the presence of non-cooperative obstacles. The complete system is demonstrated through 2000 Monte Carlo simulations and 16 hardware flight tests. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1035 a57203661821 Lusk P.C. p452 False Conference 158 Autonomous target following with monocular camera on UAS using Recursive-RANSAC tracker This paper presents a vision-based target tracking and following system using a monocular camera on an Unmanned Aerial System (UAS). The R-RANSAC tracker tracks multiple moving objects in the camera field of view and the proposed controller is capable of following a particular target selected by a user while keeping the target in the center of the image. The main contribution of this paper is that multiple objects can be tracked without imposing restrictions such as color, shape, etc. Also, the hardware test shows that the system is able to follow a target autonomously in a real-world outdoor environment. The proposed algorithm is validated on a 3DR X-8 multirotor platform using a downward facing camera. © 2018 IEEE.
1035 a57203661821 Lusk P.C. p461 True Conference 166 Visual Multiple Target Tracking from a Descending Aerial Platform A real-time visual multiple target tracker is demonstrated onboard a descending multirotor. Measurements of moving ground targets are generated using the Kanade-Lucas-Tomasi (KLT) tracking method. Homography-based image registration is used to align the measurements into the same coordinate frame, allowing for the detection of independently moving objects. The recently developed Recursive-RANSAC algorithm uses the visual measurements to estimate targets in clutter. Altitude-dependent tuning increases track continuity and coverage during the descent of the vehicle. The algorithm requires no operator interaction and increases the situation awareness of the unmanned aerial system. Real-time tracking efficiency is analyzed on GPUs and CPUs. Tracking results are presented and discussed using the MOTA and MOTP metrics. © 2018 AACC.
1036 a46961076700 Glaab P.C. p346 False Journal 195 Safe2Ditch: Emergency landing for small unmanned aircraft systems Emergency landing is a critical safety feature for the expected increase of autonomous vehicles in the airspace. This paper presents Safe2Ditch, an autonomous crash management system for landing small unmanned aerial vehicles in populated environments. Using a prepopulated database, the highest-rated landing site is selected. As the vehicle progresses toward the selected landing site, a camera is used to image the area around the landing site. Using a recently developed visual multiple target tracker, moving ground obstacles are tracked and geolocated using a flat Earth model. These inertial target estimates are used to revise the landing site and allow the vehicle to land quickly in the presence of non-cooperative obstacles. The complete system is demonstrated through 2000 Monte Carlo simulations and 16 hardware flight tests. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1037 a7801515665 Glaab L.J. p346 False Journal 195 Safe2Ditch: Emergency landing for small unmanned aircraft systems Emergency landing is a critical safety feature for the expected increase of autonomous vehicles in the airspace. This paper presents Safe2Ditch, an autonomous crash management system for landing small unmanned aerial vehicles in populated environments. Using a prepopulated database, the highest-rated landing site is selected. As the vehicle progresses toward the selected landing site, a camera is used to image the area around the landing site. Using a recently developed visual multiple target tracker, moving ground obstacles are tracked and geolocated using a flat Earth model. These inertial target estimates are used to revise the landing site and allow the vehicle to land quickly in the presence of non-cooperative obstacles. The complete system is demonstrated through 2000 Monte Carlo simulations and 16 hardware flight tests. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1038 a57208012133 Wagstaff K.B. p349 False Conference 121 Passive Force-Deflection Curves for Controlled Low-Strength Material (CLSM) and Lightweight Cellular Concrete (LCC) Contractors are increasingly requesting to use flowable fill (CLSM) or lightweight cellular concrete (LCC) to replace compacted granular backfill at bridge abutments because they can be placed more rapidly. In addition, LCC reduces the settlement of the underlying soils which is attractive to engineers. To evaluate the passive force-deflection curves for these materials, large-scale lab tests were performed with LCC and CLSM backfills in addition to a granular backfill for comparison. The response of the LCC was similar to that of the granular backfill with somewhat higher peak force developing at about 2.5% of the wall height. Although the stiffness was about twice as high as the granular backfill, the post-peak reduction was less than that for the granular fill. In contrast, the CLSM had a stiffness about 10 times higher than the granular fill and reached the peak value at a deflection equal to 1% of the wall height. The CLSM experienced a rapid decease in strength of about 60% after the peak strength was reached. The ductility of the LCC makes it a more suitable material for seismic loading with higher displacement demands. © 2019 American Society of Civil Engineers.
1039 a57208012227 Black R. p349 False Conference 121 Passive Force-Deflection Curves for Controlled Low-Strength Material (CLSM) and Lightweight Cellular Concrete (LCC) Contractors are increasingly requesting to use flowable fill (CLSM) or lightweight cellular concrete (LCC) to replace compacted granular backfill at bridge abutments because they can be placed more rapidly. In addition, LCC reduces the settlement of the underlying soils which is attractive to engineers. To evaluate the passive force-deflection curves for these materials, large-scale lab tests were performed with LCC and CLSM backfills in addition to a granular backfill for comparison. The response of the LCC was similar to that of the granular backfill with somewhat higher peak force developing at about 2.5% of the wall height. Although the stiffness was about twice as high as the granular backfill, the post-peak reduction was less than that for the granular fill. In contrast, the CLSM had a stiffness about 10 times higher than the granular fill and reached the peak value at a deflection equal to 1% of the wall height. The CLSM experienced a rapid decease in strength of about 60% after the peak strength was reached. The ductility of the LCC makes it a more suitable material for seismic loading with higher displacement demands. © 2019 American Society of Civil Engineers.
1040 a55698505100 Black J.A. p350 True Journal 196 Enhanced Detection of Single Viruses On-Chip via Hydrodynamic Focusing Planar optofluidics provide a powerful tool for facilitating chip-scale light-matter interactions. Silicon-based liquid core waveguides have been shown to offer single molecule sensitivity for efficient detection of bioparticles. Recently, a PDMS based planar optofluidic platform was introduced that opens the way to rapid development and prototyping of unique structures, taking advantage of the positive attributes of silicon dioxide-based optofluidics and PDMS based microfluidics. Here, hydrodynamic focusing is integrated into a PDMS based optofluidic chip to enhance the detection of single H1N1 viruses on-chip. Chip-plane focusing is provided by a system of microfluidic channels to force the particles towards a region of high optical collection efficiency. Focusing is demonstrated and enhanced detection is quantified using fluorescent polystyrene beads where the coefficient of variation is found to decrease by a factor of 4 with the addition of hydrodynamic focusing. The mean signal amplitude of fluorescently tagged single H1N1 viruses is found to increase with the addition of focusing by a factor of 1.64. © 1995-2012 IEEE.
1040 a55698505100 Black J.A. p608 False Conference 246 3D hydrodynamic focusing for optofluidics using a stacked channel design We present a 3D hydrodynamic focusing design suitable for optofluidic devices allowing planar fabrication and velocity independent particle focusing. Simulations are presented and fabrication outlined with evidence that stacked SU8 layers are suitable building blocks. © OSA 2018.
1041 a57203308821 Hueros R.A.R. p350 False Journal 196 Enhanced Detection of Single Viruses On-Chip via Hydrodynamic Focusing Planar optofluidics provide a powerful tool for facilitating chip-scale light-matter interactions. Silicon-based liquid core waveguides have been shown to offer single molecule sensitivity for efficient detection of bioparticles. Recently, a PDMS based planar optofluidic platform was introduced that opens the way to rapid development and prototyping of unique structures, taking advantage of the positive attributes of silicon dioxide-based optofluidics and PDMS based microfluidics. Here, hydrodynamic focusing is integrated into a PDMS based optofluidic chip to enhance the detection of single H1N1 viruses on-chip. Chip-plane focusing is provided by a system of microfluidic channels to force the particles towards a region of high optical collection efficiency. Focusing is demonstrated and enhanced detection is quantified using fluorescent polystyrene beads where the coefficient of variation is found to decrease by a factor of 4 with the addition of hydrodynamic focusing. The mean signal amplitude of fluorescently tagged single H1N1 viruses is found to increase with the addition of focusing by a factor of 1.64. © 1995-2012 IEEE.
1042 a55326143600 Parks J.W. p350 False Journal 196 Enhanced Detection of Single Viruses On-Chip via Hydrodynamic Focusing Planar optofluidics provide a powerful tool for facilitating chip-scale light-matter interactions. Silicon-based liquid core waveguides have been shown to offer single molecule sensitivity for efficient detection of bioparticles. Recently, a PDMS based planar optofluidic platform was introduced that opens the way to rapid development and prototyping of unique structures, taking advantage of the positive attributes of silicon dioxide-based optofluidics and PDMS based microfluidics. Here, hydrodynamic focusing is integrated into a PDMS based optofluidic chip to enhance the detection of single H1N1 viruses on-chip. Chip-plane focusing is provided by a system of microfluidic channels to force the particles towards a region of high optical collection efficiency. Focusing is demonstrated and enhanced detection is quantified using fluorescent polystyrene beads where the coefficient of variation is found to decrease by a factor of 4 with the addition of hydrodynamic focusing. The mean signal amplitude of fluorescently tagged single H1N1 viruses is found to increase with the addition of focusing by a factor of 1.64. © 1995-2012 IEEE.
1042 a55326143600 Parks J.W. p407 False Journal 217 Integration of sample preparation and analysis into an optofluidic chip for multi-target disease detection Detection of molecular biomarkers with high specificity and sensitivity from biological samples requires both sophisticated sample preparation and subsequent analysis. These tasks are often carried out on separate platforms which increases required sample volumes and the risk of errors, sample loss, and contamination. Here, we present an optofluidic platform which combines an optical detection section with single nucleic acid strand sensitivity, and a sample processing unit capable of on-chip, specific extraction and labeling of nucleic acid and protein targets in complex biological matrices. First, on-chip labeling and detection of individual lambda DNA molecules down to concentrations of 8 fM is demonstrated. Subsequently, we demonstrate the simultaneous capture, fluorescence tagging and detection of both Zika specific nucleic acid and NS-1 protein targets in both buffer and human serum. We show that the dual DNA and protein assay allows for successful differentiation and diagnosis of Zika against cross-reacting species like dengue. © The Royal Society of Chemistry 2018.
1042 a55326143600 Parks J.W. p840 False Conference 367 Multimodal multiplexing of single-virus detection using multi-mode interference waveguides Multi-mode interference waveguides are used to implement simultaneous spectral and spatial multiplex fluorescence analysis in liquid-core waveguide channels. A six-times multiplex identification of single influenza viruses is demonstrated with two excitation colors and threechannels. © 2017 OSA.
1043 a57212351859 Goodson M. p353 True Conference 124 Do capstone students really understand the needs of the customer?: Observations on students’ blind spots left by early program curriculum Student capstone teams have varying degrees of success in meeting the expectations of their project sponsors. Keeping sponsors happy is important to these programs in order to ensure continued support from these industry representatives, so finding ways to improve project outcomes is critical. In order to find blind spots that students may have been left with after their first 6-7 weeks of instruction, we conducted structured interviews with students in capstone programs at Brigham Young University and the US Air Force Academy. These interviews were then transcribed, coded, and analyzed for themes that may have been well understood or misunderstood by students. We found that a significant number of students had not understood concepts such as a design being more than a prototype, that sponsors have expectations for the tradeoffs between product cost and performance, or that they need to be thinking about how their designs might be deployed. It was also interesting to note that most students also reported feeling confident in their understanding despite their apparent lack thereof, indicating that these could represent major blind spots for students. We propose that developing methods for teaching these principles early on will help students see more clearly what their end goals need to be, and thus help them be more successful in delivering desirable designs. Copyright © 2019 ASME.
1044 a7404766197 Anderson M. p353 False Conference 124 Do capstone students really understand the needs of the customer?: Observations on students’ blind spots left by early program curriculum Student capstone teams have varying degrees of success in meeting the expectations of their project sponsors. Keeping sponsors happy is important to these programs in order to ensure continued support from these industry representatives, so finding ways to improve project outcomes is critical. In order to find blind spots that students may have been left with after their first 6-7 weeks of instruction, we conducted structured interviews with students in capstone programs at Brigham Young University and the US Air Force Academy. These interviews were then transcribed, coded, and analyzed for themes that may have been well understood or misunderstood by students. We found that a significant number of students had not understood concepts such as a design being more than a prototype, that sponsors have expectations for the tradeoffs between product cost and performance, or that they need to be thinking about how their designs might be deployed. It was also interesting to note that most students also reported feeling confident in their understanding despite their apparent lack thereof, indicating that these could represent major blind spots for students. We propose that developing methods for teaching these principles early on will help students see more clearly what their end goals need to be, and thus help them be more successful in delivering desirable designs. Copyright © 2019 ASME.
1044 a7404766197 Anderson M. p354 False Conference 125 The technology/tactics (TEC/TAC) plot: Explicit representation of user actions in the product design space The initial phases of the design process – including interactions with stakeholders, ideation of concept candidates, and the selection of the best candidates – have a large impact on the success of a project as a whole. They also tend to be the most unstructured portion of the project, and are often marginalized by teams who assume they already understand stakeholder needs and the best solution paths to pursue. Design researchers have developed methods shown to increase the creativity and divergent thinking of the design team during these initial phases of design. Nevertheless, these methods often rely on only a vague or amorphous representation of the design space (the set of all possible concepts the design team could feasibly select to meet the objective of the project). In this paper, we introduce a particular design-space structure that can help teams ideate and evaluate their ideation, thus improving the early phases of the design process. The design space presented here is a vector space with a basis of technology (the physical product people will use) and tactics (the procedure for using the product). Also presented are definitions, principles, and sub-theories that facilitate the creation and use of technology-tactics plots to represent the design space. Considering the design space in this structured way, the design team can gain valuable insights that improve the effectiveness of the initial stages of design, and may yield additional benefits to the design process as a whole, if further developed. Copyright © 2019 ASME.
1045 a57212271159 Stapleton T. p354 True Conference 125 The technology/tactics (TEC/TAC) plot: Explicit representation of user actions in the product design space The initial phases of the design process – including interactions with stakeholders, ideation of concept candidates, and the selection of the best candidates – have a large impact on the success of a project as a whole. They also tend to be the most unstructured portion of the project, and are often marginalized by teams who assume they already understand stakeholder needs and the best solution paths to pursue. Design researchers have developed methods shown to increase the creativity and divergent thinking of the design team during these initial phases of design. Nevertheless, these methods often rely on only a vague or amorphous representation of the design space (the set of all possible concepts the design team could feasibly select to meet the objective of the project). In this paper, we introduce a particular design-space structure that can help teams ideate and evaluate their ideation, thus improving the early phases of the design process. The design space presented here is a vector space with a basis of technology (the physical product people will use) and tactics (the procedure for using the product). Also presented are definitions, principles, and sub-theories that facilitate the creation and use of technology-tactics plots to represent the design space. Considering the design space in this structured way, the design team can gain valuable insights that improve the effectiveness of the initial stages of design, and may yield additional benefits to the design process as a whole, if further developed. Copyright © 2019 ASME.
1046 a57205765859 Owens T. p354 False Conference 125 The technology/tactics (TEC/TAC) plot: Explicit representation of user actions in the product design space The initial phases of the design process – including interactions with stakeholders, ideation of concept candidates, and the selection of the best candidates – have a large impact on the success of a project as a whole. They also tend to be the most unstructured portion of the project, and are often marginalized by teams who assume they already understand stakeholder needs and the best solution paths to pursue. Design researchers have developed methods shown to increase the creativity and divergent thinking of the design team during these initial phases of design. Nevertheless, these methods often rely on only a vague or amorphous representation of the design space (the set of all possible concepts the design team could feasibly select to meet the objective of the project). In this paper, we introduce a particular design-space structure that can help teams ideate and evaluate their ideation, thus improving the early phases of the design process. The design space presented here is a vector space with a basis of technology (the physical product people will use) and tactics (the procedure for using the product). Also presented are definitions, principles, and sub-theories that facilitate the creation and use of technology-tactics plots to represent the design space. Considering the design space in this structured way, the design team can gain valuable insights that improve the effectiveness of the initial stages of design, and may yield additional benefits to the design process as a whole, if further developed. Copyright © 2019 ASME.
1046 a57205765859 Owens T. p360 False Journal 190 A CAD assembly simplification approach with ray casting We present novel methods for the removal of interior bodies from complex assemblies using ray casting. These methods locate and preserve bodies that represent the high-fidelity exterior surface of an assembly while removing all interior bodies that do not contribute to the exterior assembly surface. In so doing we create parts that can accurately be used for assembly packaging and other tasks without sufiering from the ineficiencies that come from working with the full assembly. We further present an analysis of the process on assemblies of known properties and several use cases with simplification results. Finally, we present directions for future research that could enhance this work. © 2019 CAD Solutions, LLC.
1047 a7201511283 Webb B.W. p355 True Journal 197 The spectral line weighted-sum-of-gray-gases (SLW) model for prediction of radiative transfer in molecular gases This review documents the history and theoretical development of the Spectral Line Weighted-sum-of-gray-gases (SLW) model. The SLW model is a so-called global engineering model for prediction of radiation transfer in gaseous media. The model bases the gas radiative properties on local thermodynamic properties (temperature, species concentration, etc.), and has been developed for use with any arbitrary solver of the Radiative Transfer Equation (RTE). This review first presents the fundamental groundwork for the SLW model, followed by the detailed theoretical development of the model with associated publication references. The model was first formulated for isothermal, homogeneous single-component gases. As part of this formulation a new gas property distribution function, the Absorption Line Blackbody Distribution Function (ALBDF) was proposed, and the ALBDF has been generated from detailed spectroscopic databases for H2O, CO2, and CO over a range of gas temperature, mole fraction (where appropriate), and total pressure. The SLW model was then extended to treat non-isothermal, non-homogeneous gases, mixtures of gas species, and model application in scenarios featuring non-gray particulates and/or boundaries. In all of its development the SLW model has been rigorously tested against benchmark line-by-line spectral integration solutions of the RTE using the same spectroscopic database as used in the generation of the ALBDF. Work continues on the refinement of the SLW model, enhancing its accuracy in prediction of radiative transfer. Finally, this review will summarize work-to-date utilizing the SLW model in coupled heat transfer scenarios—comprehensive combustion simulations, combined natural convection and radiation, etc. © 2019 Elsevier Inc.
1047 a7201511283 Webb B.W. p398 False Conference 145 Locally correlated slw model for prediction of gas radiation in non-uniform media Following previous theoretical development based on the assumption of a rank correlated/comonotonic spectrum, the Locally Correlated SLW (LC-SLW) method is outlined. The relationship between the LC-SLW method and the RC-SLW method is established, and their performance in prediction of radiative transfer is compared. Despite the fact that the RC-SLW model demonstrates better overall accuracy, the LC-SLW model generally proves more accurate in regions of higher gas temperature. © Begell House Inc. 2020.
1047 a7201511283 Webb B.W. p399 False Conference 146 Accuracy of engineering methods for radiative transfer in CO2-H2O mixtures at high temperature The aim of the paper is to evaluate a set of recently proposed engineering methods of gas radiation. For this purpose, a 3D stochastic ray tracing code was developed to treat realistic geometries. Model parameters based on the same LBL dataset were constructed for all approximate methods. Comparisons consist of two steps: 1/ a set of rays randomly spread over the unit sphere is chosen and narrow band models are assessed against LBL calculations. The most accurate narrow band method is chosen as the reference, 2/ all models are then compared with the chosen reference. For the cases considered in this paper, it was found that: 1/ the l-distribution approach is more accurate than Ck methods and can be used as the reference; 2/ the RC-SLW model provides very accurate predictions; 3/ the WSGG technique, which is the fastest method considered in this work, provides acceptable estimations, even in highly non-isothermal situations. © Begell House Inc. 2020.
1047 a7201511283 Webb B.W. p400 False Conference 147 Assessment of engineering gas radiative property models in high pressure turbulent jet diffusion flames This article is a part of a more general study which aims to determine the most relevant engineering gas radiative property models to be applied in the simulations of combustion problems. Two versions of the full-spectrum CK (FSCK) model, the Rank-Correlated full-spectrum kdistribution/ Spectral-Line-Weighted-sum-of-gray-gases (RC FSK/SLW) and a new version of the Weighted-Sum-of-Grey-Gases (WSGG) model are compared with the Narrow-Band CK (NBCK) model in four turbulent axisymmetric jet diffusion flames fueled either by hydrogen or methane at atmospheric and higher pressures. As a first step, these comparisons are performed in decoupled radiative heat transfer calculations with the thermal fields being prescribed. The databases and coefficients associated to these different models are determined from a unique Line-By-Line database in order to allow a relevant comparison. Model results suggest that the SLW/FSK methods coupled to the Cai's scheme (JQSRT 141 (2014) 65-92) or the Rank-Correlated spectrum (JQSRT 214 (2018) 120-32) and databases generated from accurate LBL database are the most mature gas radiative property models to be implemented in CFD code dealing with combustion problems involving complex geometry and gas-soot mixtures. © Begell House Inc. 2020.
1047 a7201511283 Webb B.W. p472 False Journal 259 Radiative properties of gases Radiation transfer in high-temperature gas systems is critical in many engineering applications. Understanding the fundamental physical phenomena associated with radiative transfer in these environments is thus critical to predicting the physical phenomena. This chapter seeks to present the fundamental physics of radiative transfer in high-temperature gases and review the viable methods for predicting the associated radiative transfer. The general physical statements of gas radiation are first formulated. It is shown that the principal properties of molecular gases needed for the radiative transfer equation are the gas spectral absorption cross section and the spectral absorption coefficient. Radiation constants and equations are explicitly written in terms of wavenumber for gas radiation. The fundamentals of the physical nature of gas radiation are presented to contextualize the spectral properties - what defines positions, strength, and shape of spectral lines at given temperature and pressure. The chapter provides the information needed to find and to read spectroscopic databases such as HITRAN and HITEMP and how to use the compiled data to assemble the gas absorption spectra for both the gas absorption cross section and the gas absorption coefficient. The principles of narrow band models and global models of gas radiation are formulated. The statistical narrow band model with Malkmus' distribution function of line strength for an array of Lorentz lines is presented, and its application for modeling of radiation transfer in nonuniform media is explained. The wide range of global models of gas radiation starting from gray model and weightedsum- of-gray-gases model and their development into more advanced models such as SLW, ADF, and FSK is described. While more detailed attention is given to the SLW model, its relation to the FSK and ADF models is outlined. Finally, the application of global models for prediction of radiative transfer in nonuniform gaseous medium is presented. © Springer International Publishing AG, part of Springer Nature 2018. All rights reserved.
1047 a7201511283 Webb B.W. p877 False Conference 393 The scaled SLW model of gas radiation in non-uniform media The Scaled SLW model for prediction of radiation transfer in non-uniform gaseous media is presented. Construction of the scaled spectral model is described. The model development yields a scaling coefficient which, unlike previous scaled model approaches, is calculated by explicit expressions in terms of the first and minus first moments of absorption cross-section. The Scaled SLW model complements the previously developed correlated SLW models. The proposed scaled model is suitable for engineering applications in comprehensive heat and mass transfer problems. © 2017, Begell House Inc. All Rights Reserved.
1048 a6602191934 Solovjov V.P. p355 False Journal 197 The spectral line weighted-sum-of-gray-gases (SLW) model for prediction of radiative transfer in molecular gases This review documents the history and theoretical development of the Spectral Line Weighted-sum-of-gray-gases (SLW) model. The SLW model is a so-called global engineering model for prediction of radiation transfer in gaseous media. The model bases the gas radiative properties on local thermodynamic properties (temperature, species concentration, etc.), and has been developed for use with any arbitrary solver of the Radiative Transfer Equation (RTE). This review first presents the fundamental groundwork for the SLW model, followed by the detailed theoretical development of the model with associated publication references. The model was first formulated for isothermal, homogeneous single-component gases. As part of this formulation a new gas property distribution function, the Absorption Line Blackbody Distribution Function (ALBDF) was proposed, and the ALBDF has been generated from detailed spectroscopic databases for H2O, CO2, and CO over a range of gas temperature, mole fraction (where appropriate), and total pressure. The SLW model was then extended to treat non-isothermal, non-homogeneous gases, mixtures of gas species, and model application in scenarios featuring non-gray particulates and/or boundaries. In all of its development the SLW model has been rigorously tested against benchmark line-by-line spectral integration solutions of the RTE using the same spectroscopic database as used in the generation of the ALBDF. Work continues on the refinement of the SLW model, enhancing its accuracy in prediction of radiative transfer. Finally, this review will summarize work-to-date utilizing the SLW model in coupled heat transfer scenarios—comprehensive combustion simulations, combined natural convection and radiation, etc. © 2019 Elsevier Inc.
1048 a6602191934 Solovjov V.P. p398 True Conference 145 Locally correlated slw model for prediction of gas radiation in non-uniform media Following previous theoretical development based on the assumption of a rank correlated/comonotonic spectrum, the Locally Correlated SLW (LC-SLW) method is outlined. The relationship between the LC-SLW method and the RC-SLW method is established, and their performance in prediction of radiative transfer is compared. Despite the fact that the RC-SLW model demonstrates better overall accuracy, the LC-SLW model generally proves more accurate in regions of higher gas temperature. © Begell House Inc. 2020.
1048 a6602191934 Solovjov V.P. p399 False Conference 146 Accuracy of engineering methods for radiative transfer in CO2-H2O mixtures at high temperature The aim of the paper is to evaluate a set of recently proposed engineering methods of gas radiation. For this purpose, a 3D stochastic ray tracing code was developed to treat realistic geometries. Model parameters based on the same LBL dataset were constructed for all approximate methods. Comparisons consist of two steps: 1/ a set of rays randomly spread over the unit sphere is chosen and narrow band models are assessed against LBL calculations. The most accurate narrow band method is chosen as the reference, 2/ all models are then compared with the chosen reference. For the cases considered in this paper, it was found that: 1/ the l-distribution approach is more accurate than Ck methods and can be used as the reference; 2/ the RC-SLW model provides very accurate predictions; 3/ the WSGG technique, which is the fastest method considered in this work, provides acceptable estimations, even in highly non-isothermal situations. © Begell House Inc. 2020.
1048 a6602191934 Solovjov V.P. p400 False Conference 147 Assessment of engineering gas radiative property models in high pressure turbulent jet diffusion flames This article is a part of a more general study which aims to determine the most relevant engineering gas radiative property models to be applied in the simulations of combustion problems. Two versions of the full-spectrum CK (FSCK) model, the Rank-Correlated full-spectrum kdistribution/ Spectral-Line-Weighted-sum-of-gray-gases (RC FSK/SLW) and a new version of the Weighted-Sum-of-Grey-Gases (WSGG) model are compared with the Narrow-Band CK (NBCK) model in four turbulent axisymmetric jet diffusion flames fueled either by hydrogen or methane at atmospheric and higher pressures. As a first step, these comparisons are performed in decoupled radiative heat transfer calculations with the thermal fields being prescribed. The databases and coefficients associated to these different models are determined from a unique Line-By-Line database in order to allow a relevant comparison. Model results suggest that the SLW/FSK methods coupled to the Cai's scheme (JQSRT 141 (2014) 65-92) or the Rank-Correlated spectrum (JQSRT 214 (2018) 120-32) and databases generated from accurate LBL database are the most mature gas radiative property models to be implemented in CFD code dealing with combustion problems involving complex geometry and gas-soot mixtures. © Begell House Inc. 2020.
1048 a6602191934 Solovjov V.P. p472 True Journal 259 Radiative properties of gases Radiation transfer in high-temperature gas systems is critical in many engineering applications. Understanding the fundamental physical phenomena associated with radiative transfer in these environments is thus critical to predicting the physical phenomena. This chapter seeks to present the fundamental physics of radiative transfer in high-temperature gases and review the viable methods for predicting the associated radiative transfer. The general physical statements of gas radiation are first formulated. It is shown that the principal properties of molecular gases needed for the radiative transfer equation are the gas spectral absorption cross section and the spectral absorption coefficient. Radiation constants and equations are explicitly written in terms of wavenumber for gas radiation. The fundamentals of the physical nature of gas radiation are presented to contextualize the spectral properties - what defines positions, strength, and shape of spectral lines at given temperature and pressure. The chapter provides the information needed to find and to read spectroscopic databases such as HITRAN and HITEMP and how to use the compiled data to assemble the gas absorption spectra for both the gas absorption cross section and the gas absorption coefficient. The principles of narrow band models and global models of gas radiation are formulated. The statistical narrow band model with Malkmus' distribution function of line strength for an array of Lorentz lines is presented, and its application for modeling of radiation transfer in nonuniform media is explained. The wide range of global models of gas radiation starting from gray model and weightedsum- of-gray-gases model and their development into more advanced models such as SLW, ADF, and FSK is described. While more detailed attention is given to the SLW model, its relation to the FSK and ADF models is outlined. Finally, the application of global models for prediction of radiative transfer in nonuniform gaseous medium is presented. © Springer International Publishing AG, part of Springer Nature 2018. All rights reserved.
1048 a6602191934 Solovjov V.P. p877 True Conference 393 The scaled SLW model of gas radiation in non-uniform media The Scaled SLW model for prediction of radiation transfer in non-uniform gaseous media is presented. Construction of the scaled spectral model is described. The model development yields a scaling coefficient which, unlike previous scaled model approaches, is calculated by explicit expressions in terms of the first and minus first moments of absorption cross-section. The Scaled SLW model complements the previously developed correlated SLW models. The proposed scaled model is suitable for engineering applications in comprehensive heat and mass transfer problems. © 2017, Begell House Inc. All Rights Reserved.
1049 a57193878725 André F. p355 False Journal 197 The spectral line weighted-sum-of-gray-gases (SLW) model for prediction of radiative transfer in molecular gases This review documents the history and theoretical development of the Spectral Line Weighted-sum-of-gray-gases (SLW) model. The SLW model is a so-called global engineering model for prediction of radiation transfer in gaseous media. The model bases the gas radiative properties on local thermodynamic properties (temperature, species concentration, etc.), and has been developed for use with any arbitrary solver of the Radiative Transfer Equation (RTE). This review first presents the fundamental groundwork for the SLW model, followed by the detailed theoretical development of the model with associated publication references. The model was first formulated for isothermal, homogeneous single-component gases. As part of this formulation a new gas property distribution function, the Absorption Line Blackbody Distribution Function (ALBDF) was proposed, and the ALBDF has been generated from detailed spectroscopic databases for H2O, CO2, and CO over a range of gas temperature, mole fraction (where appropriate), and total pressure. The SLW model was then extended to treat non-isothermal, non-homogeneous gases, mixtures of gas species, and model application in scenarios featuring non-gray particulates and/or boundaries. In all of its development the SLW model has been rigorously tested against benchmark line-by-line spectral integration solutions of the RTE using the same spectroscopic database as used in the generation of the ALBDF. Work continues on the refinement of the SLW model, enhancing its accuracy in prediction of radiative transfer. Finally, this review will summarize work-to-date utilizing the SLW model in coupled heat transfer scenarios—comprehensive combustion simulations, combined natural convection and radiation, etc. © 2019 Elsevier Inc.
1049 a57193878725 André F. p398 False Conference 145 Locally correlated slw model for prediction of gas radiation in non-uniform media Following previous theoretical development based on the assumption of a rank correlated/comonotonic spectrum, the Locally Correlated SLW (LC-SLW) method is outlined. The relationship between the LC-SLW method and the RC-SLW method is established, and their performance in prediction of radiative transfer is compared. Despite the fact that the RC-SLW model demonstrates better overall accuracy, the LC-SLW model generally proves more accurate in regions of higher gas temperature. © Begell House Inc. 2020.
1049 a57193878725 André F. p399 True Conference 146 Accuracy of engineering methods for radiative transfer in CO2-H2O mixtures at high temperature The aim of the paper is to evaluate a set of recently proposed engineering methods of gas radiation. For this purpose, a 3D stochastic ray tracing code was developed to treat realistic geometries. Model parameters based on the same LBL dataset were constructed for all approximate methods. Comparisons consist of two steps: 1/ a set of rays randomly spread over the unit sphere is chosen and narrow band models are assessed against LBL calculations. The most accurate narrow band method is chosen as the reference, 2/ all models are then compared with the chosen reference. For the cases considered in this paper, it was found that: 1/ the l-distribution approach is more accurate than Ck methods and can be used as the reference; 2/ the RC-SLW model provides very accurate predictions; 3/ the WSGG technique, which is the fastest method considered in this work, provides acceptable estimations, even in highly non-isothermal situations. © Begell House Inc. 2020.
1049 a57193878725 André F. p400 False Conference 147 Assessment of engineering gas radiative property models in high pressure turbulent jet diffusion flames This article is a part of a more general study which aims to determine the most relevant engineering gas radiative property models to be applied in the simulations of combustion problems. Two versions of the full-spectrum CK (FSCK) model, the Rank-Correlated full-spectrum kdistribution/ Spectral-Line-Weighted-sum-of-gray-gases (RC FSK/SLW) and a new version of the Weighted-Sum-of-Grey-Gases (WSGG) model are compared with the Narrow-Band CK (NBCK) model in four turbulent axisymmetric jet diffusion flames fueled either by hydrogen or methane at atmospheric and higher pressures. As a first step, these comparisons are performed in decoupled radiative heat transfer calculations with the thermal fields being prescribed. The databases and coefficients associated to these different models are determined from a unique Line-By-Line database in order to allow a relevant comparison. Model results suggest that the SLW/FSK methods coupled to the Cai's scheme (JQSRT 141 (2014) 65-92) or the Rank-Correlated spectrum (JQSRT 214 (2018) 120-32) and databases generated from accurate LBL database are the most mature gas radiative property models to be implemented in CFD code dealing with combustion problems involving complex geometry and gas-soot mixtures. © Begell House Inc. 2020.
1049 a57193878725 André F. p472 False Journal 259 Radiative properties of gases Radiation transfer in high-temperature gas systems is critical in many engineering applications. Understanding the fundamental physical phenomena associated with radiative transfer in these environments is thus critical to predicting the physical phenomena. This chapter seeks to present the fundamental physics of radiative transfer in high-temperature gases and review the viable methods for predicting the associated radiative transfer. The general physical statements of gas radiation are first formulated. It is shown that the principal properties of molecular gases needed for the radiative transfer equation are the gas spectral absorption cross section and the spectral absorption coefficient. Radiation constants and equations are explicitly written in terms of wavenumber for gas radiation. The fundamentals of the physical nature of gas radiation are presented to contextualize the spectral properties - what defines positions, strength, and shape of spectral lines at given temperature and pressure. The chapter provides the information needed to find and to read spectroscopic databases such as HITRAN and HITEMP and how to use the compiled data to assemble the gas absorption spectra for both the gas absorption cross section and the gas absorption coefficient. The principles of narrow band models and global models of gas radiation are formulated. The statistical narrow band model with Malkmus' distribution function of line strength for an array of Lorentz lines is presented, and its application for modeling of radiation transfer in nonuniform media is explained. The wide range of global models of gas radiation starting from gray model and weightedsum- of-gray-gases model and their development into more advanced models such as SLW, ADF, and FSK is described. While more detailed attention is given to the SLW model, its relation to the FSK and ADF models is outlined. Finally, the application of global models for prediction of radiative transfer in nonuniform gaseous medium is presented. © Springer International Publishing AG, part of Springer Nature 2018. All rights reserved.
1049 a57193878725 André F. p877 False Conference 393 The scaled SLW model of gas radiation in non-uniform media The Scaled SLW model for prediction of radiation transfer in non-uniform gaseous media is presented. Construction of the scaled spectral model is described. The model development yields a scaling coefficient which, unlike previous scaled model approaches, is calculated by explicit expressions in terms of the first and minus first moments of absorption cross-section. The Scaled SLW model complements the previously developed correlated SLW models. The proposed scaled model is suitable for engineering applications in comprehensive heat and mass transfer problems. © 2017, Begell House Inc. All Rights Reserved.
1050 a57210949030 Patterson C. p356 False Conference 126 Closed-Loop PID Re-Tuning in a Digital Twin by Re-Playing Past Setpoint and Load Disturbance Data [No abstract available]
1051 a7404901361 Kelly J.D. p356 False Conference 126 Closed-Loop PID Re-Tuning in a Digital Twin by Re-Playing Past Setpoint and Load Disturbance Data [No abstract available]
1052 a57210375461 Ba Q. p357 True Journal 198 Measurements and modeling of fluid flow and thermal processes in an industrial precalciner Precalciner performance is crucial to the production rate and lifespan of cement kiln systems. The gas-solid flow and pulverized coal combustion processes in an industrial precalciner were numerically modeled to understand the flow patterns and thermal processes in the system. The gas and meal flow rates and properties were measured on-site to determine the boundary conditions for the simulations and to validate the models. The upward swirl of the gas flow in the furnace helped disperse the particles and extend their duration in the precalciner. The O2 and CO2 concentration distributions indicated that the coal particles were well dispersed and fully combusted. The calculations showed that the precalciner outlet temperature was too high which reduces the thermal efficiency and may damage the preheater installed just after the precalciner. Finally, an optimized precalciner was proposed to improve the temperature distribution. The present work can be used for improving the design of industrial precalciners. © 2019, Global Digital Central. All rights reserved.
1053 a55861508600 Li X. p357 False Journal 198 Measurements and modeling of fluid flow and thermal processes in an industrial precalciner Precalciner performance is crucial to the production rate and lifespan of cement kiln systems. The gas-solid flow and pulverized coal combustion processes in an industrial precalciner were numerically modeled to understand the flow patterns and thermal processes in the system. The gas and meal flow rates and properties were measured on-site to determine the boundary conditions for the simulations and to validate the models. The upward swirl of the gas flow in the furnace helped disperse the particles and extend their duration in the precalciner. The O2 and CO2 concentration distributions indicated that the coal particles were well dispersed and fully combusted. The calculations showed that the precalciner outlet temperature was too high which reduces the thermal efficiency and may damage the preheater installed just after the precalciner. Finally, an optimized precalciner was proposed to improve the temperature distribution. The present work can be used for improving the design of industrial precalciners. © 2019, Global Digital Central. All rights reserved.
1054 a56484754900 Cheng L. p357 False Journal 198 Measurements and modeling of fluid flow and thermal processes in an industrial precalciner Precalciner performance is crucial to the production rate and lifespan of cement kiln systems. The gas-solid flow and pulverized coal combustion processes in an industrial precalciner were numerically modeled to understand the flow patterns and thermal processes in the system. The gas and meal flow rates and properties were measured on-site to determine the boundary conditions for the simulations and to validate the models. The upward swirl of the gas flow in the furnace helped disperse the particles and extend their duration in the precalciner. The O2 and CO2 concentration distributions indicated that the coal particles were well dispersed and fully combusted. The calculations showed that the precalciner outlet temperature was too high which reduces the thermal efficiency and may damage the preheater installed just after the precalciner. Finally, an optimized precalciner was proposed to improve the temperature distribution. The present work can be used for improving the design of industrial precalciners. © 2019, Global Digital Central. All rights reserved.
1055 a6506942267 Lofthouse V. p358 False Journal 199 Using a Product's Sustainability Space as a Design Exploration Tool Sustainable design is often practiced and assessed through the consideration of three essential areas: economic sustainability, environmental sustainability, and social sustainability. For even the simplest of products, the complexities of these three areas and their tradeoffs cause decision-making transparency to be lost in most practical situations. The existing field of multiobjective optimization offers a natural framework to define and explore a given design space. In this paper, a method for defining a product's sustainability space (defined by economic, environmental, and social sustainability objectives) is outlined and used to explore the tradeoffs within the space, thus offering both the design team and the decision makers a means of better understanding the sustainability tradeoffs. This paper concludes that sustainable product development can indeed benefit from tradeoff characterization using multiobjective optimization techniques - even when using only basic models of sustainability. Interestingly, the unique characteristics of the three essential sustainable development areas lead to an alternative view of some traditional multiobjective optimization concepts, such as weak-Pareto optimality. The sustainable redesign of a machine to drill boreholes for water wells is presented as a practical example for method demonstration and discussion. Copyright © The Author(s) 2019.
1056 a6602562656 Bhamra T. p358 False Journal 199 Using a Product's Sustainability Space as a Design Exploration Tool Sustainable design is often practiced and assessed through the consideration of three essential areas: economic sustainability, environmental sustainability, and social sustainability. For even the simplest of products, the complexities of these three areas and their tradeoffs cause decision-making transparency to be lost in most practical situations. The existing field of multiobjective optimization offers a natural framework to define and explore a given design space. In this paper, a method for defining a product's sustainability space (defined by economic, environmental, and social sustainability objectives) is outlined and used to explore the tradeoffs within the space, thus offering both the design team and the decision makers a means of better understanding the sustainability tradeoffs. This paper concludes that sustainable product development can indeed benefit from tradeoff characterization using multiobjective optimization techniques - even when using only basic models of sustainability. Interestingly, the unique characteristics of the three essential sustainable development areas lead to an alternative view of some traditional multiobjective optimization concepts, such as weak-Pareto optimality. The sustainable redesign of a machine to drill boreholes for water wells is presented as a practical example for method demonstration and discussion. Copyright © The Author(s) 2019.
1057 a57202112010 Downing T. p359 False Journal 200 Broadband antireflective light-blocking layer using nanoparticle suspension in photoresist with high-resolution patterning Background: Many MEMS and optical sensor devices can benefit from layers that block transmission and suppress reflection of light across the visible spectrum. Because these devices can include complicated topography, many existing methods for depositing antireflective layers are difficult, impractical, or unusable. Aim: To create a light-blocking antireflective layer that works well with complicated MEMS and sensor devices, a layer should be made that is cheap, simple, and can be deposited and patterned with high resolution at low temperatures. Approach: Light blocking is achieved using an aluminum layer. Suppressing reflection is achieved by mixing aluminum oxide nanoparticles in photoresist to create a layer that partially absorbs and partially scatters light. Results: The combination of a layer of metal and a layer of nanoparticles and photoresist completely blocks transmission of light and significantly reduces reflections across the visible spectrum, particularly for shorter wavelengths. The layer is also patternable to sizes as small as a few microns with high resolution. Conclusion: By combining a metal layer and a layer of nanoparticles in photoresist, a simple, cheap, and effective light-blocking antireflective layer can be created that is compatible with planar devices with complex topography. © 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).
1057 a57202112010 Downing T. p522 False Journal 262 Antireflective light-blocking layers using a liquid top matte coating Methods exist for the creation of antireflective thin film layers; however, many of these methods depend on the use of high temperatures, harsh chemical etches, or are made with difficult pattern materials, rendering them unusable for many applications. In addition, most methods of light blocking are specifically designed to increase light coupling and absorption in the substrate, making them incompatible with some applications that also require blocking transmission of light. A method of forming a simple, patternable light-blocking layer that drastically reduces both transmission and reflection of light without dependence on processes that could damage underlying structures using a light scattering matte coating over a partially antireflective thin film light-blocking layer is presented. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1058 a57202120923 Anderson S. p359 False Journal 200 Broadband antireflective light-blocking layer using nanoparticle suspension in photoresist with high-resolution patterning Background: Many MEMS and optical sensor devices can benefit from layers that block transmission and suppress reflection of light across the visible spectrum. Because these devices can include complicated topography, many existing methods for depositing antireflective layers are difficult, impractical, or unusable. Aim: To create a light-blocking antireflective layer that works well with complicated MEMS and sensor devices, a layer should be made that is cheap, simple, and can be deposited and patterned with high resolution at low temperatures. Approach: Light blocking is achieved using an aluminum layer. Suppressing reflection is achieved by mixing aluminum oxide nanoparticles in photoresist to create a layer that partially absorbs and partially scatters light. Results: The combination of a layer of metal and a layer of nanoparticles and photoresist completely blocks transmission of light and significantly reduces reflections across the visible spectrum, particularly for shorter wavelengths. The layer is also patternable to sizes as small as a few microns with high resolution. Conclusion: By combining a metal layer and a layer of nanoparticles in photoresist, a simple, cheap, and effective light-blocking antireflective layer can be created that is compatible with planar devices with complex topography. © 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).
1058 a57202120923 Anderson S. p522 False Journal 262 Antireflective light-blocking layers using a liquid top matte coating Methods exist for the creation of antireflective thin film layers; however, many of these methods depend on the use of high temperatures, harsh chemical etches, or are made with difficult pattern materials, rendering them unusable for many applications. In addition, most methods of light blocking are specifically designed to increase light coupling and absorption in the substrate, making them incompatible with some applications that also require blocking transmission of light. A method of forming a simple, patternable light-blocking layer that drastically reduces both transmission and reflection of light without dependence on processes that could damage underlying structures using a light scattering matte coating over a partially antireflective thin film light-blocking layer is presented. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1059 a57193360481 Wright L. p360 True Journal 190 A CAD assembly simplification approach with ray casting We present novel methods for the removal of interior bodies from complex assemblies using ray casting. These methods locate and preserve bodies that represent the high-fidelity exterior surface of an assembly while removing all interior bodies that do not contribute to the exterior assembly surface. In so doing we create parts that can accurately be used for assembly packaging and other tasks without sufiering from the ineficiencies that come from working with the full assembly. We further present an analysis of the process on assemblies of known properties and several use cases with simplification results. Finally, we present directions for future research that could enhance this work. © 2019 CAD Solutions, LLC.
1059 a57193360481 Wright L. p420 False Journal 230 Exploration and evaluation of CAD modeling in virtual reality Virtual reality (VR) technology has experienced a recent surge in popularity over the past few years and is finding more applications beyond entertainment. Three dimensional modeling is an application in which integration with VR technology is still in the development stage. The focus of this research is to evaluate the feasibility for computer-aided design in VR and to identify the best set of features for virtual reality modeling and practices in this new domain. A platform for testing CAD in VR is developed through the integration of CAD software with a game engine and compared against traditional CAD methods through testing. Modeling capabilities included previews, creating solid rectangular prisms and spheres, lock to grid, and cuts of similar shapes. User testing with four different models (i.e. chair, maze, truck, sculpture) and survey responses suggest respectively that design in virtual reality promoted greater creativity in modeling, allowed for a greater feature creation rate, and that a slight majority of test participants preferred modeling in VR compared to traditional CAD applications. © 2018, © 2018 CAD Solutions, LLC.
1059 a57193360481 Wright L. p700 False Journal 339 A multi-user computer-aided design competition: Experimental findings and analysis of team-member dynamics A competition for teams of three students using a prototype multi-user computer-aided design (MUCAD) tool was held to investigate various hypotheses regarding the performance of teams in such a setting. By comparing models from the competition to the same model in a single-user CAD environment, it is seen that use of a MUCAD system can significantly increase the value-added per unit of calendar time for a modeling effort. An investigation was also made into the causes of the performance differences among the various MUCAD teams which participated in the competition. Analysis of the results shows that teams that encouraged effective forms of communication and teams whose members scored similarly on the Purdue Spatial Visualization Test: Visualization of Rotations (PSVT:R) performed better than other teams. Areas of future research in analyzing teams in MUCAD environments are suggested. Copyright © 2017 by ASME.
1060 a57205767010 Haskell M. p360 False Journal 190 A CAD assembly simplification approach with ray casting We present novel methods for the removal of interior bodies from complex assemblies using ray casting. These methods locate and preserve bodies that represent the high-fidelity exterior surface of an assembly while removing all interior bodies that do not contribute to the exterior assembly surface. In so doing we create parts that can accurately be used for assembly packaging and other tasks without sufiering from the ineficiencies that come from working with the full assembly. We further present an analysis of the process on assemblies of known properties and several use cases with simplification results. Finally, we present directions for future research that could enhance this work. © 2019 CAD Solutions, LLC.
1061 a57205762391 Bowman E. p360 False Journal 190 A CAD assembly simplification approach with ray casting We present novel methods for the removal of interior bodies from complex assemblies using ray casting. These methods locate and preserve bodies that represent the high-fidelity exterior surface of an assembly while removing all interior bodies that do not contribute to the exterior assembly surface. In so doing we create parts that can accurately be used for assembly packaging and other tasks without sufiering from the ineficiencies that come from working with the full assembly. We further present an analysis of the process on assemblies of known properties and several use cases with simplification results. Finally, we present directions for future research that could enhance this work. © 2019 CAD Solutions, LLC.
1062 a35435170000 Lingwall B.N. p361 False Journal 201 Overestimation of liquefaction hazard in areas of low to moderate seismicity due to improper characterization of probabilistic seismic loading This study evaluates the impact of characterizing probabilistic ground motions for liquefaction hazard analysis (defined and quantified in this paper as liquefaction triggering and free-field post-liquefaction settlements) in areas of low to moderate seismicity. Both pseudo-probabilistic and probabilistic (i.e., performance-based) methods are assessed and compared. Results of the comparative study suggest that pseudo-probabilistic methods can significantly overestimate liquefaction hazards in areas of low seismicity. Performance-based probabilistic methods are shown to predict between 5.2 cm and 16.5 cm (approximately 36–47%) less post-liquefaction free-field settlement on average than pseudo-probabilistic methods in areas of low seismicity at a return period of 2475 years, and to predict 9 cm to 19.7cm (approximately 96%) less post-liquefaction free-field settlement on average than pseudo-probabilistic methods at a return period of 475 years. Soil site classification is shown to have substantial impact on the estimated liquefaction hazards in areas of low seismicity due to soil amplification, potentially increasing design accelerations by up to 56%. Consequences of inconsistencies regarding design ground motions in current seismic design provisions are also discussed. To avoid potential for overpredicting liquefaction hazards, engineers should apply a performance-based approach when assessing liquefaction triggering and its effects in areas of low to moderate seismicity. © 2018 The Authors
1063 a55665473200 Youd T.L. p361 False Journal 201 Overestimation of liquefaction hazard in areas of low to moderate seismicity due to improper characterization of probabilistic seismic loading This study evaluates the impact of characterizing probabilistic ground motions for liquefaction hazard analysis (defined and quantified in this paper as liquefaction triggering and free-field post-liquefaction settlements) in areas of low to moderate seismicity. Both pseudo-probabilistic and probabilistic (i.e., performance-based) methods are assessed and compared. Results of the comparative study suggest that pseudo-probabilistic methods can significantly overestimate liquefaction hazards in areas of low seismicity. Performance-based probabilistic methods are shown to predict between 5.2 cm and 16.5 cm (approximately 36–47%) less post-liquefaction free-field settlement on average than pseudo-probabilistic methods in areas of low seismicity at a return period of 2475 years, and to predict 9 cm to 19.7cm (approximately 96%) less post-liquefaction free-field settlement on average than pseudo-probabilistic methods at a return period of 475 years. Soil site classification is shown to have substantial impact on the estimated liquefaction hazards in areas of low seismicity due to soil amplification, potentially increasing design accelerations by up to 56%. Consequences of inconsistencies regarding design ground motions in current seismic design provisions are also discussed. To avoid potential for overpredicting liquefaction hazards, engineers should apply a performance-based approach when assessing liquefaction triggering and its effects in areas of low to moderate seismicity. © 2018 The Authors
1063 a55665473200 Youd T.L. p594 False Conference 237 Evaluation and optimization of dynamic cone penetration test (DPT) for assessment of liquefaction in gravelly soils The dynamic cone penetration test (DPT) developed in China has been correlated with liquefaction resistance in gravelly soils based on field performance data from the Mw7.9 Wenchuan, China earthquake. The DPT consists of a 74 mm diameter cone tip driven by a 120 kg hammer with a free fall height of 1 m. To expand the data base, DPT soundings were performed at the Pence Ranch and Larter Ranch sites where gravelly soil liquefied during the 1983 Mw6.9 Borah Peak earthquake. DPT testing was performed using an automatic hammer with the energy specified in the Chinese standard and with an SPT hammer. In general, comparisons suggest that standard energy corrections developed for the SPT can be used for the DPT. The DPT correctly predicted liquefaction and non-liquefaction at these two test sites. Liquefaction resistance from the DPT (30% probability) also correlated reasonably well with that from Becker penetration testing (BPT). Copyright © 2018 Association of State Dam Safety Officials, Inc. All Rights Reserved.
1063 a55665473200 Youd T.L. p838 False Conference 365 Probabilistic Lateral Spread Evaluation for Long, Linear Infrastructure Using Performance-Based Reference Parameter Maps The design of long, linear infrastructure such as pipelines, levees, roads, and canals can be challenging in areas of moderate to high seismicity due to numerous seismic and geologic hazards that can be encountered along proposed alignments. One of the most challenging earthquake-related hazards in the design of large infrastructure is liquefaction-induced lateral spread displacement. This paper presents a new simplified probabilistic approach to estimate lateral spread displacements at targeted return periods across large geographic areas using performance-based lateral spread displacement reference parameter maps and (if available) site-specific geotechnical information. The approach is demonstrated on a hypothetical pipeline extending from Rock Springs, Wyoming, to West Bountiful, Utah, in the United States. Advantages and limitations of the proposed approach are discussed. The results of the demonstrative calculation show how the approach can be used to identify areas where additional geotechnical investigations might be needed, and how probabilistic lateral spread displacements can be easily predicted along numerous proposed alignments of the pipeline once geotechnical subsurface investigation and ground surveys become available. © 2017 ASCE.
1064 a57204677450 Blonquist J. p361 False Journal 201 Overestimation of liquefaction hazard in areas of low to moderate seismicity due to improper characterization of probabilistic seismic loading This study evaluates the impact of characterizing probabilistic ground motions for liquefaction hazard analysis (defined and quantified in this paper as liquefaction triggering and free-field post-liquefaction settlements) in areas of low to moderate seismicity. Both pseudo-probabilistic and probabilistic (i.e., performance-based) methods are assessed and compared. Results of the comparative study suggest that pseudo-probabilistic methods can significantly overestimate liquefaction hazards in areas of low seismicity. Performance-based probabilistic methods are shown to predict between 5.2 cm and 16.5 cm (approximately 36–47%) less post-liquefaction free-field settlement on average than pseudo-probabilistic methods in areas of low seismicity at a return period of 2475 years, and to predict 9 cm to 19.7cm (approximately 96%) less post-liquefaction free-field settlement on average than pseudo-probabilistic methods at a return period of 475 years. Soil site classification is shown to have substantial impact on the estimated liquefaction hazards in areas of low seismicity due to soil amplification, potentially increasing design accelerations by up to 56%. Consequences of inconsistencies regarding design ground motions in current seismic design provisions are also discussed. To avoid potential for overpredicting liquefaction hazards, engineers should apply a performance-based approach when assessing liquefaction triggering and its effects in areas of low to moderate seismicity. © 2018 The Authors
1065 a57204677555 Liang J.H. p361 False Journal 201 Overestimation of liquefaction hazard in areas of low to moderate seismicity due to improper characterization of probabilistic seismic loading This study evaluates the impact of characterizing probabilistic ground motions for liquefaction hazard analysis (defined and quantified in this paper as liquefaction triggering and free-field post-liquefaction settlements) in areas of low to moderate seismicity. Both pseudo-probabilistic and probabilistic (i.e., performance-based) methods are assessed and compared. Results of the comparative study suggest that pseudo-probabilistic methods can significantly overestimate liquefaction hazards in areas of low seismicity. Performance-based probabilistic methods are shown to predict between 5.2 cm and 16.5 cm (approximately 36–47%) less post-liquefaction free-field settlement on average than pseudo-probabilistic methods in areas of low seismicity at a return period of 2475 years, and to predict 9 cm to 19.7cm (approximately 96%) less post-liquefaction free-field settlement on average than pseudo-probabilistic methods at a return period of 475 years. Soil site classification is shown to have substantial impact on the estimated liquefaction hazards in areas of low seismicity due to soil amplification, potentially increasing design accelerations by up to 56%. Consequences of inconsistencies regarding design ground motions in current seismic design provisions are also discussed. To avoid potential for overpredicting liquefaction hazards, engineers should apply a performance-based approach when assessing liquefaction triggering and its effects in areas of low to moderate seismicity. © 2018 The Authors
1066 a57204472177 Rowberry H.C. p362 False Journal 202 Strategies for Removing Common Mode Failures from TMR Designs Deployed on SRAM FPGAs Triple modular redundancy (TMR) with repair has proven to be an effective strategy for mitigating the effects of single-event upsets within the configuration memory of static random access memory field-programmable gate arrays. Applying TMR to the design successfully reduces the design's neutron cross section by 80×. The effectiveness of TMR, however, is limited by the presence of single bits in the configuration memory which cause more than one TMR domain to fail simultaneously. We present three strategies to mitigate against these failures and improve the effectiveness of TMR: incremental routing, incremental placement, and striping. These techniques were tested using both fault injection and a wide spectrum neutron beam with the best technique offering a 400× reduction to the design's sensitive neutron cross section. An analysis from the radiation test shows that no single bits caused failure and that multicell upsets were the main cause of failure for these mitigation strategies. © 1963-2012 IEEE.
1067 a56530707600 Noyce S.G. p363 True Journal 203 High surface-area carbon microcantilevers Microscale porous carbon mechanical resonators were formed using carbon nanotube templated microfabrication. These cantilever resonators exhibited nanoscale porosity resulting in a high surface area to volume ratio which could enable sensitive analyte detection in air. These resonators were shown to be mechanically robust and the porosity could be controllably varied resulting in densities from 102 to 103 kg m-3, with pore diameters on the order of hundreds of nanometers. Cantilevers with lengths ranging from 500 μm to 5 mm were clamped in a fixture for mechanical resonance testing where quality factors from 102 to 103 were observed at atmospheric pressure in air. © 2019 The Royal Society of Chemistry.
1068 a54790496100 Craighead H.G. p363 False Journal 203 High surface-area carbon microcantilevers Microscale porous carbon mechanical resonators were formed using carbon nanotube templated microfabrication. These cantilever resonators exhibited nanoscale porosity resulting in a high surface area to volume ratio which could enable sensitive analyte detection in air. These resonators were shown to be mechanically robust and the porosity could be controllably varied resulting in densities from 102 to 103 kg m-3, with pore diameters on the order of hundreds of nanometers. Cantilevers with lengths ranging from 500 μm to 5 mm were clamped in a fixture for mechanical resonance testing where quality factors from 102 to 103 were observed at atmospheric pressure in air. © 2019 The Royal Society of Chemistry.
1069 a26427694400 Jolly S. p364 True Conference 127 Experimental characterization of leaky-mode spatial light modulators fabricated via direct laser writing We have previously presented a novel spatial light modulator appropriate for use in transparent, flat-panel holographic display applications. Our architecture consists of an anisotropic leaky-mode coupler and integrated Bragg reflection grating as a monolithic device implemented in lithium niobate and is fabricated using direct femtosecond laser writing techniques. In this paper, we present a methodology for the experimental characterization of holographically-reconstructed point spread functions from sample devices. © 2019 SPIE.
1069 a26427694400 Jolly S. p641 True Conference 273 Progress in transparent flat-panel holographic displays enabled by guided-wave acousto-optics We have previously introduced a monolithic, integrated optical platform for transparent, flat-panel holographic displays suitable for near-to-eye displays in augmented reality systems. This platform employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram. In this paper, we depict analysis of three key system attributes that inform and influence the display system performance: 1) single-axis diffraction-driven astigmatism, 2) strobed illumination to enforce acousto-optic grating stationarity, and 3) acousto-optically driven spatial Nyquist rate. Copyright © 2018 SPIE. Downloading of the abstract is permitted for personal use only.
1069 a26427694400 Jolly S. p878 True Conference 394 Near-to-eye electroholography via guided-wave acousto-optics for augmented reality Near-to-eye holographic displays act to directly project wavefronts into a viewer's eye in order to recreate 3-D scenes for augmented or virtual reality applications. Recently, several solutions for near-to-eye electroholography have been proposed based on digital spatial light modulators in conjunction with supporting optics, such as holographic waveguides for light delivery; however, such schemes are limited by the inherent low space-bandwidth product available with current digital SLMs. In this paper, we depict a fully monolithic, integrated optical platform for transparent near-to-eye holographic display requiring no supporting optics. Our solution employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram. © 2017 SPIE.
1070 a57190256209 Datta B. p364 False Conference 127 Experimental characterization of leaky-mode spatial light modulators fabricated via direct laser writing We have previously presented a novel spatial light modulator appropriate for use in transparent, flat-panel holographic display applications. Our architecture consists of an anisotropic leaky-mode coupler and integrated Bragg reflection grating as a monolithic device implemented in lithium niobate and is fabricated using direct femtosecond laser writing techniques. In this paper, we present a methodology for the experimental characterization of holographically-reconstructed point spread functions from sample devices. © 2019 SPIE.
1070 a57190256209 Datta B. p641 False Conference 273 Progress in transparent flat-panel holographic displays enabled by guided-wave acousto-optics We have previously introduced a monolithic, integrated optical platform for transparent, flat-panel holographic displays suitable for near-to-eye displays in augmented reality systems. This platform employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram. In this paper, we depict analysis of three key system attributes that inform and influence the display system performance: 1) single-axis diffraction-driven astigmatism, 2) strobed illumination to enforce acousto-optic grating stationarity, and 3) acousto-optically driven spatial Nyquist rate. Copyright © 2018 SPIE. Downloading of the abstract is permitted for personal use only.
1070 a57190256209 Datta B. p878 False Conference 394 Near-to-eye electroholography via guided-wave acousto-optics for augmented reality Near-to-eye holographic displays act to directly project wavefronts into a viewer's eye in order to recreate 3-D scenes for augmented or virtual reality applications. Recently, several solutions for near-to-eye electroholography have been proposed based on digital spatial light modulators in conjunction with supporting optics, such as holographic waveguides for light delivery; however, such schemes are limited by the inherent low space-bandwidth product available with current digital SLMs. In this paper, we depict a fully monolithic, integrated optical platform for transparent near-to-eye holographic display requiring no supporting optics. Our solution employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram. © 2017 SPIE.
1071 a57191107247 Parthiban V. p364 False Conference 127 Experimental characterization of leaky-mode spatial light modulators fabricated via direct laser writing We have previously presented a novel spatial light modulator appropriate for use in transparent, flat-panel holographic display applications. Our architecture consists of an anisotropic leaky-mode coupler and integrated Bragg reflection grating as a monolithic device implemented in lithium niobate and is fabricated using direct femtosecond laser writing techniques. In this paper, we present a methodology for the experimental characterization of holographically-reconstructed point spread functions from sample devices. © 2019 SPIE.
1072 a55664291100 Michael Bove V. p364 False Conference 127 Experimental characterization of leaky-mode spatial light modulators fabricated via direct laser writing We have previously presented a novel spatial light modulator appropriate for use in transparent, flat-panel holographic display applications. Our architecture consists of an anisotropic leaky-mode coupler and integrated Bragg reflection grating as a monolithic device implemented in lithium niobate and is fabricated using direct femtosecond laser writing techniques. In this paper, we present a methodology for the experimental characterization of holographically-reconstructed point spread functions from sample devices. © 2019 SPIE.
1073 a7202317282 Katayama I. p365 True Conference 128 Multi-timescale pump-probe spectroscopy using time-encoding and time-stretching methods To investigate changes of ultrafast dynamics during irreversible phase change in phase change materials Ge2Sb2Te5, we performed high-repetition-rate singleshot pump-probe spectroscopy using a combination of time-encoding and timestretching methods. By measuring the pump-probe traces while ramping the pump intensity, we observed a clear change in the ultrafast pump-probe dynamics after the phase change. Correlation between the ultrafast dynamics in the femtosecond timescale and the amount of phase change observed in millisecond timescale indicates that accumulation of the excited states in the sample plays an important role in the acceleration of the phase change. The result clearly demonstrates the usefulness of our method, which could be applied to the investigation of multi-timescale dynamics in various irreversible phenomena. Improved signal-to-noise ratio and the variable time-window of the single-shot pumpprobe measurements were also demonstrated using a grating pair and a chirped fiber Bragg grating. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
1073 a7202317282 Katayama I. p388 False Conference 140 High-acquisition-rate single-shot pump-probe measurement using chirped-fiber Bragg gratings Multi-timescale dynamics, from femtoseconds to milliseconds, for irreversible phenomena have been of fundamental importance in understanding mechanisms of chaotic phenomena, electronic bunch evaluation of an accelerator, photoinduced phase transitions, laser ablation, etc. Recently, several groups reported high acquisition rate single-shot methods using chirped-pulse single-shot detections and photonic time-stretching [1-3]. In these works, however, the long fiber with the length of several km was used to temporally stretch the time-encoded spectrum by the group velocity dispersion, but his long distance degrades the signal-to-noise ratio due to propagation losses of the probe pulses through the fiber, thus limiting the observable phenomena. © 2019 IEEE
1074 a57192070840 Kobayashi M. p365 False Conference 128 Multi-timescale pump-probe spectroscopy using time-encoding and time-stretching methods To investigate changes of ultrafast dynamics during irreversible phase change in phase change materials Ge2Sb2Te5, we performed high-repetition-rate singleshot pump-probe spectroscopy using a combination of time-encoding and timestretching methods. By measuring the pump-probe traces while ramping the pump intensity, we observed a clear change in the ultrafast pump-probe dynamics after the phase change. Correlation between the ultrafast dynamics in the femtosecond timescale and the amount of phase change observed in millisecond timescale indicates that accumulation of the excited states in the sample plays an important role in the acceleration of the phase change. The result clearly demonstrates the usefulness of our method, which could be applied to the investigation of multi-timescale dynamics in various irreversible phenomena. Improved signal-to-noise ratio and the variable time-window of the single-shot pumpprobe measurements were also demonstrated using a grating pair and a chirped fiber Bragg grating. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
1074 a57192070840 Kobayashi M. p388 True Conference 140 High-acquisition-rate single-shot pump-probe measurement using chirped-fiber Bragg gratings Multi-timescale dynamics, from femtoseconds to milliseconds, for irreversible phenomena have been of fundamental importance in understanding mechanisms of chaotic phenomena, electronic bunch evaluation of an accelerator, photoinduced phase transitions, laser ablation, etc. Recently, several groups reported high acquisition rate single-shot methods using chirped-pulse single-shot detections and photonic time-stretching [1-3]. In these works, however, the long fiber with the length of several km was used to temporally stretch the time-encoded spectrum by the group velocity dispersion, but his long distance degrades the signal-to-noise ratio due to propagation losses of the probe pulses through the fiber, thus limiting the observable phenomena. © 2019 IEEE
1075 a57201700890 Gubaev K. p366 True Journal 204 Accelerating high-throughput searches for new alloys with active learning of interatomic potentials We propose an approach to materials prediction that uses a machine-learning interatomic potential to approximate quantum-mechanical energies and an active learning algorithm for the automatic selection of an optimal training dataset. Our approach significantly reduces the amount of density functional theory (DFT) calculations needed, resorting to DFT only to produce the training data, while structural optimization is performed using the interatomic potentials. Our approach is not limited to one (or a small number of) lattice types (as is the case for cluster expansion, for example) and can predict structures with lattice types not present in the training dataset. We demonstrate the effectiveness of our algorithm by predicting the convex hull for the following three systems: Cu-Pd, Co-Nb-V, and Al-Ni-Ti. Our method is three to four orders of magnitude faster than conventional high-throughput DFT calculations and explores a wider range of materials space. In all three systems, we found unreported stable structures compared to the AFLOW database. Because our method is much cheaper and explores much more of materials space than high-throughput methods or cluster expansion, and because our interatomic potentials have a systematically improvable accuracy compared to empirical potentials such as embedded atom model, it will have a significant impact in the discovery of new alloy phases, particularly those with three or more components. © 2018
1076 a57195574701 Podryabinkin E.V. p366 False Journal 204 Accelerating high-throughput searches for new alloys with active learning of interatomic potentials We propose an approach to materials prediction that uses a machine-learning interatomic potential to approximate quantum-mechanical energies and an active learning algorithm for the automatic selection of an optimal training dataset. Our approach significantly reduces the amount of density functional theory (DFT) calculations needed, resorting to DFT only to produce the training data, while structural optimization is performed using the interatomic potentials. Our approach is not limited to one (or a small number of) lattice types (as is the case for cluster expansion, for example) and can predict structures with lattice types not present in the training dataset. We demonstrate the effectiveness of our algorithm by predicting the convex hull for the following three systems: Cu-Pd, Co-Nb-V, and Al-Ni-Ti. Our method is three to four orders of magnitude faster than conventional high-throughput DFT calculations and explores a wider range of materials space. In all three systems, we found unreported stable structures compared to the AFLOW database. Because our method is much cheaper and explores much more of materials space than high-throughput methods or cluster expansion, and because our interatomic potentials have a systematically improvable accuracy compared to empirical potentials such as embedded atom model, it will have a significant impact in the discovery of new alloy phases, particularly those with three or more components. © 2018
1077 a57215333932 Khah F.S. p368 True Conference 130 Development and testing of an innovative architectural programming simulation as a precursor to target value design More than half of international construction projects are underperforming. Poorly defined scope of work has been ranked as the one of the highest reasons for poor performance over which owners and construction stakeholders have control. An owner's requirements and expectations are specified during the programming phase of a project and these define a design's scope of work. One focus of Target Value Design (TVD) is making owner's value a primary driver of design by improving project definition during programming-thus optimizing the design phase. While the number of published research articles praising TVD has been increasing, there is a dearth of information regarding the application of architectural programming (AP) to Target Value Design exercises, which engage stakeholders in a design decision making process called Choosing by Advantages (CBA). CBA first requires identification of attributes that are of value to an owner. The purpose of this research was to explore the importance of architectural programming in helping to identify key attributes of value to an owner, and to report on a lean game designed and preliminarily validated by the authors to investigate the accuracy and perception of attribute identification through AP as represented by the game. © 27th Annual Conference of the International Group for Lean Construction, IGLC 2019. All rights reserved.
1078 a34868658300 Rybkowski Z.K. p368 False Conference 130 Development and testing of an innovative architectural programming simulation as a precursor to target value design More than half of international construction projects are underperforming. Poorly defined scope of work has been ranked as the one of the highest reasons for poor performance over which owners and construction stakeholders have control. An owner's requirements and expectations are specified during the programming phase of a project and these define a design's scope of work. One focus of Target Value Design (TVD) is making owner's value a primary driver of design by improving project definition during programming-thus optimizing the design phase. While the number of published research articles praising TVD has been increasing, there is a dearth of information regarding the application of architectural programming (AP) to Target Value Design exercises, which engage stakeholders in a design decision making process called Choosing by Advantages (CBA). CBA first requires identification of attributes that are of value to an owner. The purpose of this research was to explore the importance of architectural programming in helping to identify key attributes of value to an owner, and to report on a lean game designed and preliminarily validated by the authors to investigate the accuracy and perception of attribute identification through AP as represented by the game. © 27th Annual Conference of the International Group for Lean Construction, IGLC 2019. All rights reserved.
1078 a34868658300 Rybkowski Z.K. p832 False Conference 360 Delivery methods and social network analysis of unethical behavior in the construction industry The construction industry accounts for about one-third of gross capital formation and is ranked as one of the most corrupt. It is a multifaceted industry with unregulated transactions in which illicit behavior can be difficult to detect. The effects of corruption go beyond demoralization associated with bribery, it can lead to substandard quality of infrastructure and insufficient funds available for project maintenance. There are a multitude of reasons identified as possible causes for unethical conduct. A few researchers cited corruption as a result of an unethical decision. Prior research concerning corruption in construction has called for several main strategies: enhanced transparency, ethical codes, project governance, and audit and information technology. However, strategies to combat corruption may not be sufficient. This research first presents an overview of unethical conduct in the industry. Then it examines the ethics in the industry followed by types of relationships and their structure which may be conducive to unethical conduct within the framework of different delivery methods. Finally, an argument is made regarding the importance of strength of relationships in curbing unethical conduct.
1079 a57215305002 Ray Pentecost A. p368 False Conference 130 Development and testing of an innovative architectural programming simulation as a precursor to target value design More than half of international construction projects are underperforming. Poorly defined scope of work has been ranked as the one of the highest reasons for poor performance over which owners and construction stakeholders have control. An owner's requirements and expectations are specified during the programming phase of a project and these define a design's scope of work. One focus of Target Value Design (TVD) is making owner's value a primary driver of design by improving project definition during programming-thus optimizing the design phase. While the number of published research articles praising TVD has been increasing, there is a dearth of information regarding the application of architectural programming (AP) to Target Value Design exercises, which engage stakeholders in a design decision making process called Choosing by Advantages (CBA). CBA first requires identification of attributes that are of value to an owner. The purpose of this research was to explore the importance of architectural programming in helping to identify key attributes of value to an owner, and to report on a lean game designed and preliminarily validated by the authors to investigate the accuracy and perception of attribute identification through AP as represented by the game. © 27th Annual Conference of the International Group for Lean Construction, IGLC 2019. All rights reserved.
1080 a7410171017 Smith J.P. p368 False Conference 130 Development and testing of an innovative architectural programming simulation as a precursor to target value design More than half of international construction projects are underperforming. Poorly defined scope of work has been ranked as the one of the highest reasons for poor performance over which owners and construction stakeholders have control. An owner's requirements and expectations are specified during the programming phase of a project and these define a design's scope of work. One focus of Target Value Design (TVD) is making owner's value a primary driver of design by improving project definition during programming-thus optimizing the design phase. While the number of published research articles praising TVD has been increasing, there is a dearth of information regarding the application of architectural programming (AP) to Target Value Design exercises, which engage stakeholders in a design decision making process called Choosing by Advantages (CBA). CBA first requires identification of attributes that are of value to an owner. The purpose of this research was to explore the importance of architectural programming in helping to identify key attributes of value to an owner, and to report on a lean game designed and preliminarily validated by the authors to investigate the accuracy and perception of attribute identification through AP as represented by the game. © 27th Annual Conference of the International Group for Lean Construction, IGLC 2019. All rights reserved.
1080 a7410171017 Smith J.P. p438 False Journal 243 Identification and Prioritization of Critical Subject Matter within Mechanical Systems Curriculum in Construction Management Education In order for students graduating with construction-related undergraduate degrees to provide immediate and effective benefit to their employers, program curricula must accurately reflect the needs of the industry. One area of the typical construction management curriculum that receives a varying level of emphasis and consideration amongst accredited programs is Mechanical Systems. Similarly, the wide range of possible topics and concepts relevant to mechanical systems receive varying levels of attention. The purpose of this research was to identify what mechanical system topics and concepts were perceived by industry partners as being most important for graduating construction students to know. Construction industry professionals were surveyed to determine what topics they believed warranted prioritization in mechanical system courses. Results indicate that topics related to Contract Administration (e.g., plan and specification reading, MEP coordination, submittal review, etc.) and How HVAC Systems Work (e.g., differences between HVAC system types, HVAC equipment, etc.) were comparatively the most important topics for students to have a knowledge of. Instructors of mechanical systems classes should use these findings to determine what major subject areas to focus on, and allocate time to the various specific concepts appropriately within the constraints of their individual program. © 2018, © 2018 Associated Schools of Construction.
1080 a7410171017 Smith J.P. p831 True Conference 359 Implementation of lean practices among finishing contractors in the US Many parties to the construction process have implemented lean construction practices to improve efficiency within their respective scopes of work. Academics have researched a wide range of these applications in an effort to assess barriers, benefits, and other associated impacts. One area of construction that is currently under-represented in lean literature is finishing contractors. The purpose of this paper was to assess lean implementation by finishing contractors in the US. 33% of the sample of contractors specializing in the finishing methods reported implementation of some level of lean practices. For those attempting lean, the most common tool being utilized was Last Planner System. The same group reported that implementation was driven by a desire to improve efficiency by cutting costs and reducing schedules. Non-practicing respondents indicated that the primary barrier to implementation was a lack of knowledge in the area.
1080 a7410171017 Smith J.P. p832 False Conference 360 Delivery methods and social network analysis of unethical behavior in the construction industry The construction industry accounts for about one-third of gross capital formation and is ranked as one of the most corrupt. It is a multifaceted industry with unregulated transactions in which illicit behavior can be difficult to detect. The effects of corruption go beyond demoralization associated with bribery, it can lead to substandard quality of infrastructure and insufficient funds available for project maintenance. There are a multitude of reasons identified as possible causes for unethical conduct. A few researchers cited corruption as a result of an unethical decision. Prior research concerning corruption in construction has called for several main strategies: enhanced transparency, ethical codes, project governance, and audit and information technology. However, strategies to combat corruption may not be sufficient. This research first presents an overview of unethical conduct in the industry. Then it examines the ethics in the industry followed by types of relationships and their structure which may be conducive to unethical conduct within the framework of different delivery methods. Finally, an argument is made regarding the importance of strength of relationships in curbing unethical conduct.
1081 a57215336161 Muir R. p368 False Conference 130 Development and testing of an innovative architectural programming simulation as a precursor to target value design More than half of international construction projects are underperforming. Poorly defined scope of work has been ranked as the one of the highest reasons for poor performance over which owners and construction stakeholders have control. An owner's requirements and expectations are specified during the programming phase of a project and these define a design's scope of work. One focus of Target Value Design (TVD) is making owner's value a primary driver of design by improving project definition during programming-thus optimizing the design phase. While the number of published research articles praising TVD has been increasing, there is a dearth of information regarding the application of architectural programming (AP) to Target Value Design exercises, which engage stakeholders in a design decision making process called Choosing by Advantages (CBA). CBA first requires identification of attributes that are of value to an owner. The purpose of this research was to explore the importance of architectural programming in helping to identify key attributes of value to an owner, and to report on a lean game designed and preliminarily validated by the authors to investigate the accuracy and perception of attribute identification through AP as represented by the game. © 27th Annual Conference of the International Group for Lean Construction, IGLC 2019. All rights reserved.
1082 a57201360985 Terry J.S. p369 True Conference 131 Adaptive control of large-scale soft robot manipulators with unknown payloads The compliance and other nonlinear dynamics of large-scale soft robots makes effective control difficult. This is especially true when working with unknown payloads or when the system dynamics change over time which is likely to happen for soft robots. In this paper, we present a novel method of coupling model reference adaptive control (MRAC) with model predictive control (MPC) for platforms with antagonistic pneumatic actuators. We demonstrate its utility on a fully inflatable, six degreeof-freedom pneumatically actuated soft robot manipulator that is over two meters long. Specifically, we compare control performance with no integral controller, with an integral controller, and with MRAC when running a nominal model predictive controller with significant weight attached to the end effector. © 2019 ASME.
1083 a57212351343 Whitaker J. p369 False Conference 131 Adaptive control of large-scale soft robot manipulators with unknown payloads The compliance and other nonlinear dynamics of large-scale soft robots makes effective control difficult. This is especially true when working with unknown payloads or when the system dynamics change over time which is likely to happen for soft robots. In this paper, we present a novel method of coupling model reference adaptive control (MRAC) with model predictive control (MPC) for platforms with antagonistic pneumatic actuators. We demonstrate its utility on a fully inflatable, six degreeof-freedom pneumatically actuated soft robot manipulator that is over two meters long. Specifically, we compare control performance with no integral controller, with an integral controller, and with MRAC when running a nominal model predictive controller with significant weight attached to the end effector. © 2019 ASME.
1084 a57194859276 Vaughn A.B. p370 False Conference 132 Three-way spectral decompositions of high-performance military aircraft noise High-performance military aircraft noise contains large- and fine-scale turbulent mixing noise and broadband shock-associated noise. A three-way spectral decomposition quantifies the contribution from each noise type in the sound of a tied-down F-35B aircraft on a linear ground-based array spanning 35–152 deg. This large spatial aperture allows for detailed investigation into the spatial variation in broadband shock-associated noise and fine- and large-scale turbulent mixing noise. The spectral models used in the decomposition capture the main features of the measured spectra with three exceptions: 1) that the F-35B engine noise contains multiple spectral peaks in the maximum radiation region, 2) that the nonlinear propagation increases the high-frequency spectral levels, and 3) that the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The F-35B broadband shock-associated noise has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. However, the peak level and width exhibit different trends than laboratory-scale broadband shock-associated noise and those recently reported for the F/A-18E aircraft. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1084 a57194859276 Vaughn A.B. p373 True Conference 134 Crackle-related beamforming of military jet aircraft noise Crackle is a perceptual feature of supersonic jet noise that is related to the presence of acoustic shocks. This study investigates the apparent source locations of events related to crackle for a high-performance military jet aircraft using an event-based, time-domain beamforming method. This method utilizes the cross correlation between adjacent microphones to determine the angle of propagation of an ensemble of shock-related events within the time waveform. This angle of propagation is then traced back towards the source to find the apparent source location. Based on the angle of propagation, derivative skewness, and overall sound pressure level, the microphone pairs along the array can be sorted into six groups. With increasing engine condition, groups related to the presence of crackle tend to shift downstream and broaden, in qualitative agreement with the general aeroacoustic source locations. However, a comparison with near-field acoustical holography shows that the apparent source region of crackle-related events appears upstream of the overall energy at intermediate power but appear to converge at maximum afterburner. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1084 a57194859276 Vaughn A.B. p862 False Conference 383 Level-educed wavepacket representation of Mach 1.8 laboratory-scale jet noise The search for an equivalent acoustic source model for high-speed jet noise has recently focused on wavepacket representations. A wavepacket is defined as a spatially extended source with an axial amplitude distribution that grows, saturates and decays, an axial phase relationship that produces directional noise, and correlation lengths longer than the integral length scales of the turbulent structures. This definition of a wavepacket has the same characteristics as the large-scale turbulent mixing noise; if the turbulent mixing noise can be isolated, the associate equivalent acoustic wavepacket—defined as a pressure fluctuation on a cylinder around the jet nozzle—can be found. An estimate of the frequencydependent, spatial variation in the large-scale turbulent mixing noise comes from a similarity spectra decomposition of the measured autospectral density, which in turn leads to data-educed wavenumber axial spectra associated with the frequency-dependent equivalent wavepackets. This wavepacket eduction technique has been applied to acoustical measurements of an unheated, Mach 1.8 jet in the near and far fields. At both locations, the resulting frequency-dependent, data-educed wavenumber spectra exhibit different types of self-similarity for low and high frequency regimes that become apparent when the axial wavenumber is scaled by the acoustic wavenumber, with a transition band between the two regimes. As expected, the data-educed wavenumber spectra can be used to predict field levels in the dominant radiation lobe. Addition of an uncorrelated source distribution, derived from the similarity spectra decomposition associated with the fine-scale turbulent mixing noise, creates a model that accounts for the sideline levels. This field-prediction ability of the wavepacket-plus-uncorrelated-distribution model is tested using the near and far field measurements. When predicting the field at the other location, the model’s average error is less than 2 dB for St = 0.04-0.25 but increases for larger St because the apparent directivity changes from near to far field, likely due to the frequency dependence of the extended source region. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1085 a15766049500 Swift S.H. p370 False Conference 132 Three-way spectral decompositions of high-performance military aircraft noise High-performance military aircraft noise contains large- and fine-scale turbulent mixing noise and broadband shock-associated noise. A three-way spectral decomposition quantifies the contribution from each noise type in the sound of a tied-down F-35B aircraft on a linear ground-based array spanning 35–152 deg. This large spatial aperture allows for detailed investigation into the spatial variation in broadband shock-associated noise and fine- and large-scale turbulent mixing noise. The spectral models used in the decomposition capture the main features of the measured spectra with three exceptions: 1) that the F-35B engine noise contains multiple spectral peaks in the maximum radiation region, 2) that the nonlinear propagation increases the high-frequency spectral levels, and 3) that the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The F-35B broadband shock-associated noise has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. However, the peak level and width exhibit different trends than laboratory-scale broadband shock-associated noise and those recently reported for the F/A-18E aircraft. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1085 a15766049500 Swift S.H. p373 False Conference 134 Crackle-related beamforming of military jet aircraft noise Crackle is a perceptual feature of supersonic jet noise that is related to the presence of acoustic shocks. This study investigates the apparent source locations of events related to crackle for a high-performance military jet aircraft using an event-based, time-domain beamforming method. This method utilizes the cross correlation between adjacent microphones to determine the angle of propagation of an ensemble of shock-related events within the time waveform. This angle of propagation is then traced back towards the source to find the apparent source location. Based on the angle of propagation, derivative skewness, and overall sound pressure level, the microphone pairs along the array can be sorted into six groups. With increasing engine condition, groups related to the presence of crackle tend to shift downstream and broaden, in qualitative agreement with the general aeroacoustic source locations. However, a comparison with near-field acoustical holography shows that the apparent source region of crackle-related events appears upstream of the overall energy at intermediate power but appear to converge at maximum afterburner. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1085 a15766049500 Swift S.H. p623 True Conference 259 Spatiotemporal correlation analysis of jet noise from a round-nozzle supersonic aircraft Spatiotemporal analysis of noise from a tethered F-35B provides insight into the spatial, spectral and temporal relationships within the sound field. Six engine power conditions ranging from 25% to 150% engine thrust request were measured using a 71-microphone linear ground array located approximately 8 m from the estimated shear layer. Mixing noise trends with engine power for the round-nozzle F-35B are similar to those of a nominally rectangular-nozzle high-performance jet aircraft [Harker et al, AIAA, 2016]. Cross-correlation and coherence measures are used to corroborate and confirm identifications of fine- and large-scale turbulent mixing noise contributions from a concurrent study of the F-35B dataset [Neilsen et al., AIAA, 2018]. The relationships observed between multiple spatiospectral lobes seen in the maximum radiation regions of prior and concurrent high-performance aircraft noise studies [Leete et al., AIAA, 2018] are confirmed and expanded upon. Correlograms help identify how the multiple spatiospectral lobes have different apparent phase speeds across the array, corresponding to different directionality, some components of which also change with engine power. Increased overlap of lobes with increased engine power appears to drive global decreases in field coherence. Finally, the structure of the spatiospectral lobes appears to be more visible in nondimensionalized coherence length than in the spectrum itself. Broadband shock-associated noise (BBSAN) is found in the upstream direction at engine powers of 75% engine thrust request and above. Coherence is also used to separate BBSAN from jet mixing noise because the BBSAN is coherent within the relevant frequency range while adjacent fine-scale mixing noise is not. However, correlation and coherence analyses show that the upstream BBSAN signature is related to sound received in the peak radiation region dominated by the spatiospectral lobes. Possible links between the shock-associated noise and the spatiospectral lobes are discussed. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1085 a15766049500 Swift S.H. p626 False Conference 262 Comparison of noise from high-performance military aircraft for ground run-up and flyover operations While the majority of jet noise analysis takes place with a static jet or aircraft, airbase and community military jet noise exposure happens for the most part when the aircraft is in flight. Comparisons between flyover and ground run-up measurements for high-performance military aircraft have not been previously published. This paper presents comparisons between static ground run-up and flyover measurements for the F-35 operating at 150% Engine Thrust Request. The overall sound pressure levels and spectra are shown for the two scenarios, as well as indicators of nonlinear propagation and shock content, specifically the derivative skewness and average steepening factor. The overall sound pressure level is reduced in the peak radiation direction aft of the aircraft but increased in the forward direction. The peak frequency of the noise is relatively unaffected by flight effects, though the amplitude of each frequency may vary. The increase in level in the forward direction results in shock formation that is absent during ground run-up measurements. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1086 a7202538835 Downing J.M. p370 False Conference 132 Three-way spectral decompositions of high-performance military aircraft noise High-performance military aircraft noise contains large- and fine-scale turbulent mixing noise and broadband shock-associated noise. A three-way spectral decomposition quantifies the contribution from each noise type in the sound of a tied-down F-35B aircraft on a linear ground-based array spanning 35–152 deg. This large spatial aperture allows for detailed investigation into the spatial variation in broadband shock-associated noise and fine- and large-scale turbulent mixing noise. The spectral models used in the decomposition capture the main features of the measured spectra with three exceptions: 1) that the F-35B engine noise contains multiple spectral peaks in the maximum radiation region, 2) that the nonlinear propagation increases the high-frequency spectral levels, and 3) that the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The F-35B broadband shock-associated noise has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. However, the peak level and width exhibit different trends than laboratory-scale broadband shock-associated noise and those recently reported for the F/A-18E aircraft. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1086 a7202538835 Downing J.M. p373 False Conference 134 Crackle-related beamforming of military jet aircraft noise Crackle is a perceptual feature of supersonic jet noise that is related to the presence of acoustic shocks. This study investigates the apparent source locations of events related to crackle for a high-performance military jet aircraft using an event-based, time-domain beamforming method. This method utilizes the cross correlation between adjacent microphones to determine the angle of propagation of an ensemble of shock-related events within the time waveform. This angle of propagation is then traced back towards the source to find the apparent source location. Based on the angle of propagation, derivative skewness, and overall sound pressure level, the microphone pairs along the array can be sorted into six groups. With increasing engine condition, groups related to the presence of crackle tend to shift downstream and broaden, in qualitative agreement with the general aeroacoustic source locations. However, a comparison with near-field acoustical holography shows that the apparent source region of crackle-related events appears upstream of the overall energy at intermediate power but appear to converge at maximum afterburner. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1086 a7202538835 Downing J.M. p623 False Conference 259 Spatiotemporal correlation analysis of jet noise from a round-nozzle supersonic aircraft Spatiotemporal analysis of noise from a tethered F-35B provides insight into the spatial, spectral and temporal relationships within the sound field. Six engine power conditions ranging from 25% to 150% engine thrust request were measured using a 71-microphone linear ground array located approximately 8 m from the estimated shear layer. Mixing noise trends with engine power for the round-nozzle F-35B are similar to those of a nominally rectangular-nozzle high-performance jet aircraft [Harker et al, AIAA, 2016]. Cross-correlation and coherence measures are used to corroborate and confirm identifications of fine- and large-scale turbulent mixing noise contributions from a concurrent study of the F-35B dataset [Neilsen et al., AIAA, 2018]. The relationships observed between multiple spatiospectral lobes seen in the maximum radiation regions of prior and concurrent high-performance aircraft noise studies [Leete et al., AIAA, 2018] are confirmed and expanded upon. Correlograms help identify how the multiple spatiospectral lobes have different apparent phase speeds across the array, corresponding to different directionality, some components of which also change with engine power. Increased overlap of lobes with increased engine power appears to drive global decreases in field coherence. Finally, the structure of the spatiospectral lobes appears to be more visible in nondimensionalized coherence length than in the spectrum itself. Broadband shock-associated noise (BBSAN) is found in the upstream direction at engine powers of 75% engine thrust request and above. Coherence is also used to separate BBSAN from jet mixing noise because the BBSAN is coherent within the relevant frequency range while adjacent fine-scale mixing noise is not. However, correlation and coherence analyses show that the upstream BBSAN signature is related to sound received in the peak radiation region dominated by the spatiospectral lobes. Possible links between the shock-associated noise and the spatiospectral lobes are discussed. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1086 a7202538835 Downing J.M. p626 False Conference 262 Comparison of noise from high-performance military aircraft for ground run-up and flyover operations While the majority of jet noise analysis takes place with a static jet or aircraft, airbase and community military jet noise exposure happens for the most part when the aircraft is in flight. Comparisons between flyover and ground run-up measurements for high-performance military aircraft have not been previously published. This paper presents comparisons between static ground run-up and flyover measurements for the F-35 operating at 150% Engine Thrust Request. The overall sound pressure levels and spectra are shown for the two scenarios, as well as indicators of nonlinear propagation and shock content, specifically the derivative skewness and average steepening factor. The overall sound pressure level is reduced in the peak radiation direction aft of the aircraft but increased in the forward direction. The peak frequency of the noise is relatively unaffected by flight effects, though the amplitude of each frequency may vary. The increase in level in the forward direction results in shock formation that is absent during ground run-up measurements. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1087 a15044701600 James M.M. p370 False Conference 132 Three-way spectral decompositions of high-performance military aircraft noise High-performance military aircraft noise contains large- and fine-scale turbulent mixing noise and broadband shock-associated noise. A three-way spectral decomposition quantifies the contribution from each noise type in the sound of a tied-down F-35B aircraft on a linear ground-based array spanning 35–152 deg. This large spatial aperture allows for detailed investigation into the spatial variation in broadband shock-associated noise and fine- and large-scale turbulent mixing noise. The spectral models used in the decomposition capture the main features of the measured spectra with three exceptions: 1) that the F-35B engine noise contains multiple spectral peaks in the maximum radiation region, 2) that the nonlinear propagation increases the high-frequency spectral levels, and 3) that the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The F-35B broadband shock-associated noise has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. However, the peak level and width exhibit different trends than laboratory-scale broadband shock-associated noise and those recently reported for the F/A-18E aircraft. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation. Copyright © 2019 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1087 a15044701600 James M.M. p373 False Conference 134 Crackle-related beamforming of military jet aircraft noise Crackle is a perceptual feature of supersonic jet noise that is related to the presence of acoustic shocks. This study investigates the apparent source locations of events related to crackle for a high-performance military jet aircraft using an event-based, time-domain beamforming method. This method utilizes the cross correlation between adjacent microphones to determine the angle of propagation of an ensemble of shock-related events within the time waveform. This angle of propagation is then traced back towards the source to find the apparent source location. Based on the angle of propagation, derivative skewness, and overall sound pressure level, the microphone pairs along the array can be sorted into six groups. With increasing engine condition, groups related to the presence of crackle tend to shift downstream and broaden, in qualitative agreement with the general aeroacoustic source locations. However, a comparison with near-field acoustical holography shows that the apparent source region of crackle-related events appears upstream of the overall energy at intermediate power but appear to converge at maximum afterburner. © 2019, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1087 a15044701600 James M.M. p623 False Conference 259 Spatiotemporal correlation analysis of jet noise from a round-nozzle supersonic aircraft Spatiotemporal analysis of noise from a tethered F-35B provides insight into the spatial, spectral and temporal relationships within the sound field. Six engine power conditions ranging from 25% to 150% engine thrust request were measured using a 71-microphone linear ground array located approximately 8 m from the estimated shear layer. Mixing noise trends with engine power for the round-nozzle F-35B are similar to those of a nominally rectangular-nozzle high-performance jet aircraft [Harker et al, AIAA, 2016]. Cross-correlation and coherence measures are used to corroborate and confirm identifications of fine- and large-scale turbulent mixing noise contributions from a concurrent study of the F-35B dataset [Neilsen et al., AIAA, 2018]. The relationships observed between multiple spatiospectral lobes seen in the maximum radiation regions of prior and concurrent high-performance aircraft noise studies [Leete et al., AIAA, 2018] are confirmed and expanded upon. Correlograms help identify how the multiple spatiospectral lobes have different apparent phase speeds across the array, corresponding to different directionality, some components of which also change with engine power. Increased overlap of lobes with increased engine power appears to drive global decreases in field coherence. Finally, the structure of the spatiospectral lobes appears to be more visible in nondimensionalized coherence length than in the spectrum itself. Broadband shock-associated noise (BBSAN) is found in the upstream direction at engine powers of 75% engine thrust request and above. Coherence is also used to separate BBSAN from jet mixing noise because the BBSAN is coherent within the relevant frequency range while adjacent fine-scale mixing noise is not. However, correlation and coherence analyses show that the upstream BBSAN signature is related to sound received in the peak radiation region dominated by the spatiospectral lobes. Possible links between the shock-associated noise and the spatiospectral lobes are discussed. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1087 a15044701600 James M.M. p624 False Conference 260 Dependence of high-performance military aircraft noise on frequency and engine power To further understand the unique characteristics of military aircraft noise, the sound field in the vicinity of a tied-down F-35B was measured for various engine powers, from 25% to 150% Engine Thrust Request (ETR). Synchronous measurements along a linear ground array approximately parallel to the shear layer were used to image the entire field through multisource statistically optimized near-field acoustical holography (M-SONAH). The field in the direction of maximum radiation consists of multiple lobes in the spatiospectral domain, which are manifest as multiple local maxima in space for a fixed frequency or multiple peaks in the spectra at a fixed location. Multiple lobes are observed at non-afterburning and afterburning engine conditions. As frequency increases for a given engine power, lobes appear towards the sideline and shift aft until they disappear beyond the measurement aperture and new lobe(s) take their place. As engine power is increased at a fixed frequency, the forwardmost lobe increases in its relative contribution to the field, which is a major contributing factor to the forward shift in overall directivity with increasing engine power. Field reconstructions and data in the forward direction outside of the region of maximum radiation show the presence of broadband shock-associated noise (BBSAN) for 75% ETR and above. Reconstructions along the nozzle lipline of the jet indicate the BBSAN originates from approximately the same region as the sources for the main radiation direction. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1087 a15044701600 James M.M. p625 False Conference 261 Inclusion of broadband shock-associated noise in spectral decomposition of noise from highperformance military aircraft Attempts to reduce the noise from high-performance military aircraft requires an understanding of the different jet noise generation mechanisms. The primary noise sources originate from interactions between turbulent mixing noise associated with large and finescale turbulent structures and the ambient air. A nonideally expanded jet also contains broadband shock-associated noise. A three-way decomposition of the spectral density measured near a tied-down F-35B quantifies the contribution from each type of noise. The decomposition is performed on noise from a ground-based, linear array of microphones, approximately 8 m from the estimated shear layer, which spanned an angular aperture of 35° to 152° (relative to engine inlet). This large spatial aperture allows for a detailed investigation into the spatial variation in broadband shock-associated noise and fine and large-scale turbulent mixing noise. The spectral decompositions match the measured spectral levels with three main exceptions: 1) the F-35B noise contains multiple spectral peaks in the maximum radiation region, 2) nonlinear propagation increases the high-frequency spectral levels, and 3) the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The main peak of the F-35B broadband shock-associated noise, evident from 35°-70°, has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. The F-35B broadband shockassociated noise peak level and width exhibit different trends than laboratory-scale BBSAN and those recently reported for the F/A-18E [Tam et al., Journal of Sound and Vibration, Vol. 422, 2018, pp. 92-111]. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation from high-performance military aircraft. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1087 a15044701600 James M.M. p626 False Conference 262 Comparison of noise from high-performance military aircraft for ground run-up and flyover operations While the majority of jet noise analysis takes place with a static jet or aircraft, airbase and community military jet noise exposure happens for the most part when the aircraft is in flight. Comparisons between flyover and ground run-up measurements for high-performance military aircraft have not been previously published. This paper presents comparisons between static ground run-up and flyover measurements for the F-35 operating at 150% Engine Thrust Request. The overall sound pressure levels and spectra are shown for the two scenarios, as well as indicators of nonlinear propagation and shock content, specifically the derivative skewness and average steepening factor. The overall sound pressure level is reduced in the peak radiation direction aft of the aircraft but increased in the forward direction. The peak frequency of the noise is relatively unaffected by flight effects, though the amplitude of each frequency may vary. The increase in level in the forward direction results in shock formation that is absent during ground run-up measurements. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1087 a15044701600 James M.M. p861 False Conference 382 Acoustic shock formation in noise propagation during ground run-up operations of military aircraft A distinctive feature of many propagating, high-amplitude jet noise waveforms is the presence of acoustic shocks. Metrics indicative of shock presence, specifically the skewness of the time derivative of the waveform, the average steepening factor, and a new wavelet-based metric called the shock energy fraction (SEF), are used to quantify the strength and prevalence of acoustic shocks within waveforms recorded 10-305 m from a tethered military aircraft. The derivative skewness is more sensitive to the presence of the largest and steepest shocks, while the ASF and SEF tend to emphasize aggregate behavior of the entire waveform. These metrics are applied at engine conditions ranging from 50% to 150% engine thrust request, over a wide range of angles and distances, to assess the growth and decay of shock waves. The responses of these metrics point to significant shock formation occurring through nonlinear propagation out to 76 m from the microphone array reference position. Although these strongest shocks decay, the metrics point to continued nonlinear propagation in the far-field, out to 305 m. Many of these features are accurately characterized using a nonlinear propagation scheme based on the Burgers equation, but this scheme fails to account for multipath interference and significant atmospheric effects over the long propagation distances, resulting in an overestimation of nonlinearity metrics. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1087 a15044701600 James M.M. p863 False Conference 384 Beamforming-based wavepacket model for noise environment predictions of tactical aircraft Jet noise consists of extended, partially correlated sources such that a single-wavepacket source representation is inadequate. A multiple-wavepacket (MWP) model provides an analytical framework for jet-noise-like radiation to simulate jet noise field levels as well as the corresponding spatial coherence properties within the field. Here, a beamforming method with regularization is applied to noise measured by a linear array near a high-performance military aircraft. Beamforming results are decomposed into a reduced-order MWP model and the predicted radiation is validated in terms of level and coherence properties using benchmark measurements. Sound levels and coherence lengths generated by the beamforming results show good agreement with benchmark measurements over a range of frequencies that contribute significantly to the overall radiation. The MWP model is shown to predict full-scale specific features such as multilobe directivity patterns, and the addition of an uncorrelated distribution (UD) model adequately predicts the sideline radiation that is otherwise difficult to reproduce from wavepacket radiation. The MWP model predicted radiation characteristics are an improvement over single-wavepacket models, which do not incorporate spatiotemporal features of the radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1087 a15044701600 James M.M. p865 False Conference 386 Preliminary investigation of multilobe fighter jet noise sources using acoustical holography An understanding of jet noise source mechanisms can facilitate targeted noise reduction efforts. This understanding has been enhanced with acoustic imaging technologies, such as near-field acoustical holography (NAH). In this study, multisource statistically optimized NAH (M-SONAH) was used to image the sound field near a tethered F-35 aircraft at multiple frequencies. A linear microphone array, placed along the ground, spanned the length of the jet exhaust plume. A multisource model of the sound field was included in the algorithm to incorporate the effects of the ground reflection on the measurement. Narrowband reconstructions elucidated fine details of the radiation patterns, such as multilobe radiation patterns (which may supersede “dual-lobe” patterns shown in previous studies), and broadband shock-associated noise. [Work supported by F-35 JPO.] © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1088 a57203579114 Barreto D. p371 False Journal 193 The Sobrado Vallim Rehabilitation Project This paper presents the assessment of the historical two story Sobrado Vallim building located in Bananal, in the state of São Paulo, Brazil. The Sobrado Vallim was built as the house of the local coffee Baron. Since being unoccupied by the family, the building has served as a school and as the City Hall; more recently the building has housed a local community association. The first story is formed by rammed earth walls supporting a wood floor. The walls on the second floor are built with adobe blocks, and several wood columns embedded into the walls support the wood roof trusses. The building has been unoccupied for several years and a temporary shoring system has been designed and installed to prevent possible collapse. The analyses included measuring and defining the building structural elements to determine their capacity. The rammed earth walls compression strength was determined using flatjacks. Samples of the adobe blocks were obtained so that their physical and mechanical properties could be determined through laboratory testing. Thermography was used to assess the wood elements condition. The proposed structural solution was to maintain the shell of the building and construct a steel frame structure within the existing elements. The steel frame would reduce the span and partially support the roof trusses at their mid-length. The ends of the wood trusses would still bear on the existing second floor walls. The proposed solution reduced significantly the loads on the existing elements, allowing the form the building to be maintained. © 2019, RILEM.
1089 a57203573476 Carilho M. p371 False Journal 193 The Sobrado Vallim Rehabilitation Project This paper presents the assessment of the historical two story Sobrado Vallim building located in Bananal, in the state of São Paulo, Brazil. The Sobrado Vallim was built as the house of the local coffee Baron. Since being unoccupied by the family, the building has served as a school and as the City Hall; more recently the building has housed a local community association. The first story is formed by rammed earth walls supporting a wood floor. The walls on the second floor are built with adobe blocks, and several wood columns embedded into the walls support the wood roof trusses. The building has been unoccupied for several years and a temporary shoring system has been designed and installed to prevent possible collapse. The analyses included measuring and defining the building structural elements to determine their capacity. The rammed earth walls compression strength was determined using flatjacks. Samples of the adobe blocks were obtained so that their physical and mechanical properties could be determined through laboratory testing. Thermography was used to assess the wood elements condition. The proposed structural solution was to maintain the shell of the building and construct a steel frame structure within the existing elements. The steel frame would reduce the span and partially support the roof trusses at their mid-length. The ends of the wood trusses would still bear on the existing second floor walls. The proposed solution reduced significantly the loads on the existing elements, allowing the form the building to be maintained. © 2019, RILEM.
1090 a57203570620 Domschke V. p371 False Journal 193 The Sobrado Vallim Rehabilitation Project This paper presents the assessment of the historical two story Sobrado Vallim building located in Bananal, in the state of São Paulo, Brazil. The Sobrado Vallim was built as the house of the local coffee Baron. Since being unoccupied by the family, the building has served as a school and as the City Hall; more recently the building has housed a local community association. The first story is formed by rammed earth walls supporting a wood floor. The walls on the second floor are built with adobe blocks, and several wood columns embedded into the walls support the wood roof trusses. The building has been unoccupied for several years and a temporary shoring system has been designed and installed to prevent possible collapse. The analyses included measuring and defining the building structural elements to determine their capacity. The rammed earth walls compression strength was determined using flatjacks. Samples of the adobe blocks were obtained so that their physical and mechanical properties could be determined through laboratory testing. Thermography was used to assess the wood elements condition. The proposed structural solution was to maintain the shell of the building and construct a steel frame structure within the existing elements. The steel frame would reduce the span and partially support the roof trusses at their mid-length. The ends of the wood trusses would still bear on the existing second floor walls. The proposed solution reduced significantly the loads on the existing elements, allowing the form the building to be maintained. © 2019, RILEM.
1091 a57216989927 Tilahun L.E. p372 False Conference 133 Expanding the far UV range of aluminum-coated mirrors for space-based observations to reflect hydrogen Lyman lines via fluoride multilayers While no solid barrier layer is transparent below ~103nm, simulations show that ~9.5nm LiF on 8.5nm MgF2 on Al could reflect some hydrogen Lyman lines better than a single fluoride layer does. Experiments are promising. © OSA 2019 © 2019 The Author(s)
1092 a57211502145 Gabriel Richardson J. p372 False Conference 133 Expanding the far UV range of aluminum-coated mirrors for space-based observations to reflect hydrogen Lyman lines via fluoride multilayers While no solid barrier layer is transparent below ~103nm, simulations show that ~9.5nm LiF on 8.5nm MgF2 on Al could reflect some hydrogen Lyman lines better than a single fluoride layer does. Experiments are promising. © OSA 2019 © 2019 The Author(s)
1093 a6507803480 Steven Turley R. p372 False Conference 133 Expanding the far UV range of aluminum-coated mirrors for space-based observations to reflect hydrogen Lyman lines via fluoride multilayers While no solid barrier layer is transparent below ~103nm, simulations show that ~9.5nm LiF on 8.5nm MgF2 on Al could reflect some hydrogen Lyman lines better than a single fluoride layer does. Experiments are promising. © OSA 2019 © 2019 The Author(s)
1094 a24330327900 Vance A. p375 True Conference 136 The fog of warnings: How non-essential notifications blur with security warnings Adherence to security warnings continues to be an important problem in information security. Although users may fail to heed a security warning for a variety of reasons, a major contributor is habituation, which is decreased response to repeated stimulation. However, the scope of this problem may actually be much broader than previously thought because of the neurobiological phenomenon of generalization. Whereas habituation describes a diminished response with repetitions of the same stimulus, generalization occurs when habituation to one stimulus carries over to other novel stimuli that are similar in appearance. Generalization has important implications for the domains of usable security and human-computer interaction. Because a basic principle of user interface design is visual consistency, generalization suggests that through exposure to frequent non-security-related notifications (e.g., dialogs, alerts, confirmations, etc.) that share a similar look and feel, users may become deeply habituated to critical security warnings that they have never seen before. Further, with the increasing number of notifications in our lives across a range of mobile, Internet of Things, and computing devices, the accumulated effect of generalization may be substantial. However, this problem has not been empirically examined before. This paper contributes by measuring the impacts of generalization in terms of (1) diminished attention via mouse cursor tracking and (2) users' ability to behaviorally adhere to security warnings. Through an online experiment, we find that: • Habituation to a frequent non-security-related notification does carry over to a one-time security warning. • Generalization of habituation is manifest both in (1) decreased attention to warnings and (2) lower warning adherence behavior. • The carry-over effect, most importantly, is due to generalization, and not fatigue. • The degree that generalization occurs depends on the similarity in look and feel between a notification and warning. These findings open new avenues of research and provide guidance to software developers for creating warnings that are more resistant to the effects of generalization of habituation, thereby improving users' security warning adherence. © is held by the author/owner.
1095 a55634592700 Eargle D. p375 False Conference 136 The fog of warnings: How non-essential notifications blur with security warnings Adherence to security warnings continues to be an important problem in information security. Although users may fail to heed a security warning for a variety of reasons, a major contributor is habituation, which is decreased response to repeated stimulation. However, the scope of this problem may actually be much broader than previously thought because of the neurobiological phenomenon of generalization. Whereas habituation describes a diminished response with repetitions of the same stimulus, generalization occurs when habituation to one stimulus carries over to other novel stimuli that are similar in appearance. Generalization has important implications for the domains of usable security and human-computer interaction. Because a basic principle of user interface design is visual consistency, generalization suggests that through exposure to frequent non-security-related notifications (e.g., dialogs, alerts, confirmations, etc.) that share a similar look and feel, users may become deeply habituated to critical security warnings that they have never seen before. Further, with the increasing number of notifications in our lives across a range of mobile, Internet of Things, and computing devices, the accumulated effect of generalization may be substantial. However, this problem has not been empirically examined before. This paper contributes by measuring the impacts of generalization in terms of (1) diminished attention via mouse cursor tracking and (2) users' ability to behaviorally adhere to security warnings. Through an online experiment, we find that: • Habituation to a frequent non-security-related notification does carry over to a one-time security warning. • Generalization of habituation is manifest both in (1) decreased attention to warnings and (2) lower warning adherence behavior. • The carry-over effect, most importantly, is due to generalization, and not fatigue. • The degree that generalization occurs depends on the similarity in look and feel between a notification and warning. These findings open new avenues of research and provide guidance to software developers for creating warnings that are more resistant to the effects of generalization of habituation, thereby improving users' security warning adherence. © is held by the author/owner.
1096 a36713489900 Jenkins J.L. p375 False Conference 136 The fog of warnings: How non-essential notifications blur with security warnings Adherence to security warnings continues to be an important problem in information security. Although users may fail to heed a security warning for a variety of reasons, a major contributor is habituation, which is decreased response to repeated stimulation. However, the scope of this problem may actually be much broader than previously thought because of the neurobiological phenomenon of generalization. Whereas habituation describes a diminished response with repetitions of the same stimulus, generalization occurs when habituation to one stimulus carries over to other novel stimuli that are similar in appearance. Generalization has important implications for the domains of usable security and human-computer interaction. Because a basic principle of user interface design is visual consistency, generalization suggests that through exposure to frequent non-security-related notifications (e.g., dialogs, alerts, confirmations, etc.) that share a similar look and feel, users may become deeply habituated to critical security warnings that they have never seen before. Further, with the increasing number of notifications in our lives across a range of mobile, Internet of Things, and computing devices, the accumulated effect of generalization may be substantial. However, this problem has not been empirically examined before. This paper contributes by measuring the impacts of generalization in terms of (1) diminished attention via mouse cursor tracking and (2) users' ability to behaviorally adhere to security warnings. Through an online experiment, we find that: • Habituation to a frequent non-security-related notification does carry over to a one-time security warning. • Generalization of habituation is manifest both in (1) decreased attention to warnings and (2) lower warning adherence behavior. • The carry-over effect, most importantly, is due to generalization, and not fatigue. • The degree that generalization occurs depends on the similarity in look and feel between a notification and warning. These findings open new avenues of research and provide guidance to software developers for creating warnings that are more resistant to the effects of generalization of habituation, thereby improving users' security warning adherence. © is held by the author/owner.
1097 a35725132100 Brock Kirwan C. p375 False Conference 136 The fog of warnings: How non-essential notifications blur with security warnings Adherence to security warnings continues to be an important problem in information security. Although users may fail to heed a security warning for a variety of reasons, a major contributor is habituation, which is decreased response to repeated stimulation. However, the scope of this problem may actually be much broader than previously thought because of the neurobiological phenomenon of generalization. Whereas habituation describes a diminished response with repetitions of the same stimulus, generalization occurs when habituation to one stimulus carries over to other novel stimuli that are similar in appearance. Generalization has important implications for the domains of usable security and human-computer interaction. Because a basic principle of user interface design is visual consistency, generalization suggests that through exposure to frequent non-security-related notifications (e.g., dialogs, alerts, confirmations, etc.) that share a similar look and feel, users may become deeply habituated to critical security warnings that they have never seen before. Further, with the increasing number of notifications in our lives across a range of mobile, Internet of Things, and computing devices, the accumulated effect of generalization may be substantial. However, this problem has not been empirically examined before. This paper contributes by measuring the impacts of generalization in terms of (1) diminished attention via mouse cursor tracking and (2) users' ability to behaviorally adhere to security warnings. Through an online experiment, we find that: • Habituation to a frequent non-security-related notification does carry over to a one-time security warning. • Generalization of habituation is manifest both in (1) decreased attention to warnings and (2) lower warning adherence behavior. • The carry-over effect, most importantly, is due to generalization, and not fatigue. • The degree that generalization occurs depends on the similarity in look and feel between a notification and warning. These findings open new avenues of research and provide guidance to software developers for creating warnings that are more resistant to the effects of generalization of habituation, thereby improving users' security warning adherence. © is held by the author/owner.
1098 a36986090000 Anderson B.B. p375 False Conference 136 The fog of warnings: How non-essential notifications blur with security warnings Adherence to security warnings continues to be an important problem in information security. Although users may fail to heed a security warning for a variety of reasons, a major contributor is habituation, which is decreased response to repeated stimulation. However, the scope of this problem may actually be much broader than previously thought because of the neurobiological phenomenon of generalization. Whereas habituation describes a diminished response with repetitions of the same stimulus, generalization occurs when habituation to one stimulus carries over to other novel stimuli that are similar in appearance. Generalization has important implications for the domains of usable security and human-computer interaction. Because a basic principle of user interface design is visual consistency, generalization suggests that through exposure to frequent non-security-related notifications (e.g., dialogs, alerts, confirmations, etc.) that share a similar look and feel, users may become deeply habituated to critical security warnings that they have never seen before. Further, with the increasing number of notifications in our lives across a range of mobile, Internet of Things, and computing devices, the accumulated effect of generalization may be substantial. However, this problem has not been empirically examined before. This paper contributes by measuring the impacts of generalization in terms of (1) diminished attention via mouse cursor tracking and (2) users' ability to behaviorally adhere to security warnings. Through an online experiment, we find that: • Habituation to a frequent non-security-related notification does carry over to a one-time security warning. • Generalization of habituation is manifest both in (1) decreased attention to warnings and (2) lower warning adherence behavior. • The carry-over effect, most importantly, is due to generalization, and not fatigue. • The degree that generalization occurs depends on the similarity in look and feel between a notification and warning. These findings open new avenues of research and provide guidance to software developers for creating warnings that are more resistant to the effects of generalization of habituation, thereby improving users' security warning adherence. © is held by the author/owner.
1099 a57193722976 Nascimento M.R. p376 True Journal 205 Testing and analysis of masonry hollow clay block prisms filled with mortar In some design situations, in construction systems with structural masonry, an increase in the capacity of the walls is required, which can be achieved with the filling of empty cells of masonry blocks with grout. The Brazilian technical standard for clay masonry blocks aiming at attaining greater agility and flexibility in the construction process allows the use of bedding mortar instead of grout to fill the cells of the blocks. In this context, the objective of this study was to evaluate the mechanical behaviour of prisms filled with bedding mortar. Six classes of mortar and one type of clay block with nominal resistance of 6 MPa were studied. The results of the compressive strength of the prisms indicate the viability of using bedding mortar with the same structural function as grout. This article presents also an analytical study to evaluate the mechanical behaviour of clay block prisms filled with mortar. Analyses were conducted using general-purpose, nonlinear finite element software that simulates structural behaviour under different loading scenarios. A three-dimensional model of the prisms was developed using eight-node brick elements for both block and mortar with nonlinear properties assigned to each material. Copyright © 2019 Inderscience Enterprises Ltd.
1100 a7005521036 Roman H.R. p376 False Journal 205 Testing and analysis of masonry hollow clay block prisms filled with mortar In some design situations, in construction systems with structural masonry, an increase in the capacity of the walls is required, which can be achieved with the filling of empty cells of masonry blocks with grout. The Brazilian technical standard for clay masonry blocks aiming at attaining greater agility and flexibility in the construction process allows the use of bedding mortar instead of grout to fill the cells of the blocks. In this context, the objective of this study was to evaluate the mechanical behaviour of prisms filled with bedding mortar. Six classes of mortar and one type of clay block with nominal resistance of 6 MPa were studied. The results of the compressive strength of the prisms indicate the viability of using bedding mortar with the same structural function as grout. This article presents also an analytical study to evaluate the mechanical behaviour of clay block prisms filled with mortar. Analyses were conducted using general-purpose, nonlinear finite element software that simulates structural behaviour under different loading scenarios. A three-dimensional model of the prisms was developed using eight-node brick elements for both block and mortar with nonlinear properties assigned to each material. Copyright © 2019 Inderscience Enterprises Ltd.
1100 a7005521036 Roman H.R. p389 False Journal 212 Numerical analyses of mortar incorporating the variation in Poisson’s ratio with increasing axial load The work presented herein evaluated the influence of compressive strength and confinement on the stress-strain behaviour of axially loaded mortar specimens by means of experimental and numerical analyses. Two mortars were tested, with volume proportions of cement: Lime: Sand of 1:0.5:4 and 1:1:6. From these two specimen heights, 50 and 140mm, with diameter of 45mm, resulting in diameter/height ratios of 1.0 and 0.3, were manufactured. The experimental results indicated that the confinement and strength of the mortar influence its stress-strain behaviour, the larger the confinement, the more, nonlinear the behaviour. In addition, the results indicated that the Poisson’s ratio and tangent modulus of elasticity vary with increasing applied load. Two numerical models were tested using the same finite element mesh, boundary conditions and load. The first model was based on the Total Strain Smeared Crack Model and the second model accounted for the observations from the experimental phase with a nonlinear “elastic phased” analysis, which updates the modulus of elasticity and the Poisson’s ratio at each new phase. The tangent modulus of elasticity was calculated directly from the experimental results while the Poisson’s ratio was approximated using the model proposed by OTTOSEN [16]. The numerical model based on the total strain smeared crack was not able to reproduce the behaviour of the compressed mortar near failure while the phased model presented satisfactory results, even close to failure, when cracking is significant. © 2019, International Masonry Society. All rights reserved.
1100 a7005521036 Roman H.R. p644 False Conference 276 Numerical analyses of mortar incorporating the variation in poisson's ratio with increasing axial load This work evaluated the influence of compressive strength and confinement on the stress-strain behavior of axial loaded mortar specimens by means of experimental and numerical analyses. Two mortars were tested, with volume proportions of cement, lime and sand of 1:0.5:4 and 1:1:6. Two specimen heights, 50 and 140 mm, with diameter of 45 mm, resulting in diameter/height ratios of 1.0 and 0.3, respectively were used. The experimental results indicated that the confinement and strength of the mortar influence its stress-strain behavior: the larger the confinement, the more the non-linear behavior. In addition, the results indicated that the Poisson's ratio and the tangent modulus of elasticity vary with increasing applied load. A numerical model was developed that accounted for the observations from the experimental phase with a nonlinear elastic phased analysis, which updates the modulus of elasticity and the Poisson's ratio at each new phase. The tangent modulus of elasticity was calculated directly from the experimental results while the Poisson's ratio was approximated using the model proposed by Ottosen. The numerical model presented satisfactory results, even close to the failure, when cracking is significant. © 2018 The International Masonry Society (IMS).
1101 a55557218000 Abut F. p377 True Journal 206 A robust ensemble feature selector based on rank aggregation for developing new VO2max prediction models using support vector machines This paper proposes a new ensemble feature selector, called the majority voting feature selector (MVFS), for developing new maximal oxygen uptake (VO2max) prediction models using a support vector machine (SVM). The approach is based on rank aggregation, which meaningfully utilizes the correlation among the relevance ranks of predictor variables given by three state-of-the-art feature selectors: Relief-F, minimum redundancy maximum relevance (mRMR), and maximum likelihood feature selection (MLFS). By applying the SVM combined with MVFS on a self-created dataset containing maximal and submaximal exercise data from 185 college students, several new hybrid VO2max prediction models have been created. To compare the performance of the proposed ensemble approach on prediction of VO2max, SVM-based models with individual combinations of Relief-F, mRMR, and MLFS as well as with other alternative ensemble feature selectors from the literature have also been developed. The results reveal that MVFS outperforms other individual and ensemble feature selectors and yields up to 8.76% increment and 11.15% decrement rates in multiple correlation coefficients (Rs) and root mean square errors (RMSEs), respectively. Furthermore, in addition to reconfirming the relevance of sex, age, and maximal heart rate in predicting VO2max, which were previously reported in the literature, it is revealed that submaximal heart rates and exercise times at 1.5-mile distance are two further discriminative predictors of VO2max. The results have also been compared to those obtained by a general regression neural network and single decision tree combined with MVFS, and it is shown that the SVM exhibits much better performance than other methods for prediction of VO2max. © TÜBİTAK
1101 a55557218000 Abut F. p529 False Conference 190 Predicting the maximum endurance time for left-side bridge exercise using machine learning methods and hybrid data This study was carried out with the intention to create new models to predict the maximum endurance time for the left-side bridge exercise using machine learning methods and hybrid data. Particularly, four different methods including Multilayer Feed-Forward Artificial Neural Network (MFANN), Generalized Regression Neural Network (GRNN), Radial Basis Function Neural Network (RBFNN) and Single Decision Tree (SDT) have been used for model development. The dataset used to create the prediction models includes physiological, exercise and questionnaire data related to individuals who performed the left-side bridge exercise and completed the Perceived Activity Rating (PAR) and Perceived Functional Ability (PFA) questionnaires. To evaluate the performance of the models, two well-known metrics, namely Root Mean Square Error (RMSE) and Multiple Correlation Coefficient (R) have been used, whereas the generalization errors have been assessed using 10-fold cross validation. The best prediction performance among the models has been obtained by using MFANN along with the predictor variables gender, age, body mass index (BMI), the times to reach a rate of perceived exertion values of 7 and 8 (RPE-7 and RPE-8, respectively) and PAR, producing the lowest RMSE and the highest R with 10.61 seconds (s) and 0.92, respectively. © 2017 IEEE.
1102 a7102443026 Akay M.F. p377 False Journal 206 A robust ensemble feature selector based on rank aggregation for developing new VO2max prediction models using support vector machines This paper proposes a new ensemble feature selector, called the majority voting feature selector (MVFS), for developing new maximal oxygen uptake (VO2max) prediction models using a support vector machine (SVM). The approach is based on rank aggregation, which meaningfully utilizes the correlation among the relevance ranks of predictor variables given by three state-of-the-art feature selectors: Relief-F, minimum redundancy maximum relevance (mRMR), and maximum likelihood feature selection (MLFS). By applying the SVM combined with MVFS on a self-created dataset containing maximal and submaximal exercise data from 185 college students, several new hybrid VO2max prediction models have been created. To compare the performance of the proposed ensemble approach on prediction of VO2max, SVM-based models with individual combinations of Relief-F, mRMR, and MLFS as well as with other alternative ensemble feature selectors from the literature have also been developed. The results reveal that MVFS outperforms other individual and ensemble feature selectors and yields up to 8.76% increment and 11.15% decrement rates in multiple correlation coefficients (Rs) and root mean square errors (RMSEs), respectively. Furthermore, in addition to reconfirming the relevance of sex, age, and maximal heart rate in predicting VO2max, which were previously reported in the literature, it is revealed that submaximal heart rates and exercise times at 1.5-mile distance are two further discriminative predictors of VO2max. The results have also been compared to those obtained by a general regression neural network and single decision tree combined with MVFS, and it is shown that the SVM exhibits much better performance than other methods for prediction of VO2max. © TÜBİTAK
1102 a7102443026 Akay M.F. p529 True Conference 190 Predicting the maximum endurance time for left-side bridge exercise using machine learning methods and hybrid data This study was carried out with the intention to create new models to predict the maximum endurance time for the left-side bridge exercise using machine learning methods and hybrid data. Particularly, four different methods including Multilayer Feed-Forward Artificial Neural Network (MFANN), Generalized Regression Neural Network (GRNN), Radial Basis Function Neural Network (RBFNN) and Single Decision Tree (SDT) have been used for model development. The dataset used to create the prediction models includes physiological, exercise and questionnaire data related to individuals who performed the left-side bridge exercise and completed the Perceived Activity Rating (PAR) and Perceived Functional Ability (PFA) questionnaires. To evaluate the performance of the models, two well-known metrics, namely Root Mean Square Error (RMSE) and Multiple Correlation Coefficient (R) have been used, whereas the generalization errors have been assessed using 10-fold cross validation. The best prediction performance among the models has been obtained by using MFANN along with the predictor variables gender, age, body mass index (BMI), the times to reach a rate of perceived exertion values of 7 and 8 (RPE-7 and RPE-8, respectively) and PAR, producing the lowest RMSE and the highest R with 10.61 seconds (s) and 0.92, respectively. © 2017 IEEE.
1103 a7403558004 George J. p377 False Journal 206 A robust ensemble feature selector based on rank aggregation for developing new VO2max prediction models using support vector machines This paper proposes a new ensemble feature selector, called the majority voting feature selector (MVFS), for developing new maximal oxygen uptake (VO2max) prediction models using a support vector machine (SVM). The approach is based on rank aggregation, which meaningfully utilizes the correlation among the relevance ranks of predictor variables given by three state-of-the-art feature selectors: Relief-F, minimum redundancy maximum relevance (mRMR), and maximum likelihood feature selection (MLFS). By applying the SVM combined with MVFS on a self-created dataset containing maximal and submaximal exercise data from 185 college students, several new hybrid VO2max prediction models have been created. To compare the performance of the proposed ensemble approach on prediction of VO2max, SVM-based models with individual combinations of Relief-F, mRMR, and MLFS as well as with other alternative ensemble feature selectors from the literature have also been developed. The results reveal that MVFS outperforms other individual and ensemble feature selectors and yields up to 8.76% increment and 11.15% decrement rates in multiple correlation coefficients (Rs) and root mean square errors (RMSEs), respectively. Furthermore, in addition to reconfirming the relevance of sex, age, and maximal heart rate in predicting VO2max, which were previously reported in the literature, it is revealed that submaximal heart rates and exercise times at 1.5-mile distance are two further discriminative predictors of VO2max. The results have also been compared to those obtained by a general regression neural network and single decision tree combined with MVFS, and it is shown that the SVM exhibits much better performance than other methods for prediction of VO2max. © TÜBİTAK
1103 a7403558004 George J. p529 False Conference 190 Predicting the maximum endurance time for left-side bridge exercise using machine learning methods and hybrid data This study was carried out with the intention to create new models to predict the maximum endurance time for the left-side bridge exercise using machine learning methods and hybrid data. Particularly, four different methods including Multilayer Feed-Forward Artificial Neural Network (MFANN), Generalized Regression Neural Network (GRNN), Radial Basis Function Neural Network (RBFNN) and Single Decision Tree (SDT) have been used for model development. The dataset used to create the prediction models includes physiological, exercise and questionnaire data related to individuals who performed the left-side bridge exercise and completed the Perceived Activity Rating (PAR) and Perceived Functional Ability (PFA) questionnaires. To evaluate the performance of the models, two well-known metrics, namely Root Mean Square Error (RMSE) and Multiple Correlation Coefficient (R) have been used, whereas the generalization errors have been assessed using 10-fold cross validation. The best prediction performance among the models has been obtained by using MFANN along with the predictor variables gender, age, body mass index (BMI), the times to reach a rate of perceived exertion values of 7 and 8 (RPE-7 and RPE-8, respectively) and PAR, producing the lowest RMSE and the highest R with 10.61 seconds (s) and 0.92, respectively. © 2017 IEEE.
1104 a56790117900 Yellowhorse A.D. p380 True Conference 138 Regular 2D and 3D linkage-based origami tessellations Linkage origami is one effective approach for addressing stiffness and accommodating panels of finite size in origami models and tessellations. However, successfully implementing linkage origami in tessellations can be challenging. In this work, multiple theorems are presented that provide criteria for designing origami units or cells that can be assembled into arbitrarily large tessellations. The application of these theorems is demonstrated through examples of tessellations in two and three dimensions. Copyright © 2019 ASME.
1104 a56790117900 Yellowhorse A.D. p446 True Journal 250 Deployable lenticular stiffeners for origami-inspired mechanisms Light-weight origami-inspired mechanisms can provide advantages in deployable space systems and other applications. However, a significant challenge in their design is ensuring that they are sufficiently stiff. Compliant, deployable stiffeners utilizing a profile that approximates the Euler Spiral are proposed as one possible solution. It is shown that a structure with this specific profile, called a lenticular stiffener, permits stiffeners to be flattened using a force applied at their edge. Formulas for calculating the increase in stiffness are developed. Relations needed to design the deployment behavior of the stiffeners are also derived. Finally, advantages of different configurations of stiffeners are evaluated. These results are verified through simulation and experiments. © 2018 Taylor & Francis.
1104 a56790117900 Yellowhorse A.D. p580 True Conference 225 Three approaches for managing stiffness in origami-inspired mechanisms Ensuring that deployable mechanisms are sufficiently rigid is a major challenge due to their large size relative to their mass. This paper examines three basic types of stiffener that can be applied to light, origami-inspired structures to manage their stiffness. These stiffeners are modeled analytically to enable prediction and optimization of their behavior. The results obtained from this analysis are compared to results from a finite-element analysis and experimental data. After verifying these models, the advantages and disadvantages of each stiffener type are considered. This comparison will facilitate stiffener selection for future engineering applications. Copyright © 2018 ASME
1104 a56790117900 Yellowhorse A.D. p817 True Conference 352 Optimization of origami-based tubes for lightweight deployable structures Tubular origami may provide both the needed deployment displacement and sufficient strength to be useful as deployable structures. This paper reviews origami tube-based deployable mechanisms and a structural optimization of FEA models is performed. Symmetric and non-symmetric 4-sided tubes are evaluated. Panel geometries and thicknesses are varied to produce rigidly foldable origami-tube-based mechanisms that are both strong and lightweight. The mechanical properties of these tubes over various deployment lengths are discussed. Three different configurations of this mechanism are compared and the advantages of each are discussed. Copyright © 2017 ASME.
1105 a57193911152 Fernquest S. p382 True Journal 208 Compositional MRI of the Hip: Reproducibility, Effect of Joint Unloading, and Comparison of T2 Relaxometry with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Objective: Our aim was to compare T2 with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the hip and assess the reproducibility and effect of joint unloading on T2 mapping. Design: Ten individuals at high risk of developing hip osteoarthritis (SibKids) underwent contemporaneous T2 mapping and dGEMRIC in the hip (10 hips). Twelve healthy volunteers underwent T2 mapping of both hips (24 hips) at time points 25, 35, 45, and 55 minutes post offloading. Acetabular and femoral cartilage was manually segmented into regions of interest. The relationship between T2 and dGEMRIC values from anatomically corresponding regions of interests was quantified using Pearson’s correlation. The reproducibility of image analysis for T2 and dGEMRIC, and reproducibility of image acquisition for T2, was quantified using the intraclass correlation coefficient (ICC), root mean square coefficient of variance (RMSCoV), smallest detectable difference (SDD), and Bland-Altman plots. The paired t test was used to determine if difference existed in T2 values at different unloading times. Results: T2 values correlated most strongly with dGEMRIC values in diseased cartilage (r = −0.61, P = <0.001). T2 image analysis (segmentation) reproducibility was ICC = 0.96 to 0.98, RMSCoV = 3.5% to 5.2%, and SDD = 2.2 to 3.5 ms. T2 values at 25 minutes unloading were not significantly different to longer unloading times (P = 0.132). SDD for T2 image acquisition reproducibility was 7.1 to 7.4 ms. Conclusions: T2 values in the hip correlate well with dGEMRIC in areas of cartilage damage. T2 shows high reproducibility and values do not change beyond 25 minutes of joint unloading. © The Author(s) 2019.
1105 a57193911152 Fernquest S. p701 False Journal 343 Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip Background Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. Methods Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. Results Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = −0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. Conclusions The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis. © 2017 Osteoarthritis Research Society International
1106 a55780846900 Palmer A. p382 False Journal 208 Compositional MRI of the Hip: Reproducibility, Effect of Joint Unloading, and Comparison of T2 Relaxometry with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Objective: Our aim was to compare T2 with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the hip and assess the reproducibility and effect of joint unloading on T2 mapping. Design: Ten individuals at high risk of developing hip osteoarthritis (SibKids) underwent contemporaneous T2 mapping and dGEMRIC in the hip (10 hips). Twelve healthy volunteers underwent T2 mapping of both hips (24 hips) at time points 25, 35, 45, and 55 minutes post offloading. Acetabular and femoral cartilage was manually segmented into regions of interest. The relationship between T2 and dGEMRIC values from anatomically corresponding regions of interests was quantified using Pearson’s correlation. The reproducibility of image analysis for T2 and dGEMRIC, and reproducibility of image acquisition for T2, was quantified using the intraclass correlation coefficient (ICC), root mean square coefficient of variance (RMSCoV), smallest detectable difference (SDD), and Bland-Altman plots. The paired t test was used to determine if difference existed in T2 values at different unloading times. Results: T2 values correlated most strongly with dGEMRIC values in diseased cartilage (r = −0.61, P = <0.001). T2 image analysis (segmentation) reproducibility was ICC = 0.96 to 0.98, RMSCoV = 3.5% to 5.2%, and SDD = 2.2 to 3.5 ms. T2 values at 25 minutes unloading were not significantly different to longer unloading times (P = 0.132). SDD for T2 image acquisition reproducibility was 7.1 to 7.4 ms. Conclusions: T2 values in the hip correlate well with dGEMRIC in areas of cartilage damage. T2 shows high reproducibility and values do not change beyond 25 minutes of joint unloading. © The Author(s) 2019.
1106 a55780846900 Palmer A. p701 True Journal 343 Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip Background Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. Methods Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. Results Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = −0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. Conclusions The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis. © 2017 Osteoarthritis Research Society International
1107 a57203303999 Gammer B. p382 False Journal 208 Compositional MRI of the Hip: Reproducibility, Effect of Joint Unloading, and Comparison of T2 Relaxometry with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Objective: Our aim was to compare T2 with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the hip and assess the reproducibility and effect of joint unloading on T2 mapping. Design: Ten individuals at high risk of developing hip osteoarthritis (SibKids) underwent contemporaneous T2 mapping and dGEMRIC in the hip (10 hips). Twelve healthy volunteers underwent T2 mapping of both hips (24 hips) at time points 25, 35, 45, and 55 minutes post offloading. Acetabular and femoral cartilage was manually segmented into regions of interest. The relationship between T2 and dGEMRIC values from anatomically corresponding regions of interests was quantified using Pearson’s correlation. The reproducibility of image analysis for T2 and dGEMRIC, and reproducibility of image acquisition for T2, was quantified using the intraclass correlation coefficient (ICC), root mean square coefficient of variance (RMSCoV), smallest detectable difference (SDD), and Bland-Altman plots. The paired t test was used to determine if difference existed in T2 values at different unloading times. Results: T2 values correlated most strongly with dGEMRIC values in diseased cartilage (r = −0.61, P = <0.001). T2 image analysis (segmentation) reproducibility was ICC = 0.96 to 0.98, RMSCoV = 3.5% to 5.2%, and SDD = 2.2 to 3.5 ms. T2 values at 25 minutes unloading were not significantly different to longer unloading times (P = 0.132). SDD for T2 image acquisition reproducibility was 7.1 to 7.4 ms. Conclusions: T2 values in the hip correlate well with dGEMRIC in areas of cartilage damage. T2 shows high reproducibility and values do not change beyond 25 minutes of joint unloading. © The Author(s) 2019.
1108 a57217139231 Hirons E. p382 False Journal 208 Compositional MRI of the Hip: Reproducibility, Effect of Joint Unloading, and Comparison of T2 Relaxometry with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Objective: Our aim was to compare T2 with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the hip and assess the reproducibility and effect of joint unloading on T2 mapping. Design: Ten individuals at high risk of developing hip osteoarthritis (SibKids) underwent contemporaneous T2 mapping and dGEMRIC in the hip (10 hips). Twelve healthy volunteers underwent T2 mapping of both hips (24 hips) at time points 25, 35, 45, and 55 minutes post offloading. Acetabular and femoral cartilage was manually segmented into regions of interest. The relationship between T2 and dGEMRIC values from anatomically corresponding regions of interests was quantified using Pearson’s correlation. The reproducibility of image analysis for T2 and dGEMRIC, and reproducibility of image acquisition for T2, was quantified using the intraclass correlation coefficient (ICC), root mean square coefficient of variance (RMSCoV), smallest detectable difference (SDD), and Bland-Altman plots. The paired t test was used to determine if difference existed in T2 values at different unloading times. Results: T2 values correlated most strongly with dGEMRIC values in diseased cartilage (r = −0.61, P = <0.001). T2 image analysis (segmentation) reproducibility was ICC = 0.96 to 0.98, RMSCoV = 3.5% to 5.2%, and SDD = 2.2 to 3.5 ms. T2 values at 25 minutes unloading were not significantly different to longer unloading times (P = 0.132). SDD for T2 image acquisition reproducibility was 7.1 to 7.4 ms. Conclusions: T2 values in the hip correlate well with dGEMRIC in areas of cartilage damage. T2 shows high reproducibility and values do not change beyond 25 minutes of joint unloading. © The Author(s) 2019.
1109 a14064679200 Kendrick B. p382 False Journal 208 Compositional MRI of the Hip: Reproducibility, Effect of Joint Unloading, and Comparison of T2 Relaxometry with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Objective: Our aim was to compare T2 with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the hip and assess the reproducibility and effect of joint unloading on T2 mapping. Design: Ten individuals at high risk of developing hip osteoarthritis (SibKids) underwent contemporaneous T2 mapping and dGEMRIC in the hip (10 hips). Twelve healthy volunteers underwent T2 mapping of both hips (24 hips) at time points 25, 35, 45, and 55 minutes post offloading. Acetabular and femoral cartilage was manually segmented into regions of interest. The relationship between T2 and dGEMRIC values from anatomically corresponding regions of interests was quantified using Pearson’s correlation. The reproducibility of image analysis for T2 and dGEMRIC, and reproducibility of image acquisition for T2, was quantified using the intraclass correlation coefficient (ICC), root mean square coefficient of variance (RMSCoV), smallest detectable difference (SDD), and Bland-Altman plots. The paired t test was used to determine if difference existed in T2 values at different unloading times. Results: T2 values correlated most strongly with dGEMRIC values in diseased cartilage (r = −0.61, P = <0.001). T2 image analysis (segmentation) reproducibility was ICC = 0.96 to 0.98, RMSCoV = 3.5% to 5.2%, and SDD = 2.2 to 3.5 ms. T2 values at 25 minutes unloading were not significantly different to longer unloading times (P = 0.132). SDD for T2 image acquisition reproducibility was 7.1 to 7.4 ms. Conclusions: T2 values in the hip correlate well with dGEMRIC in areas of cartilage damage. T2 shows high reproducibility and values do not change beyond 25 minutes of joint unloading. © The Author(s) 2019.
1110 a7405891981 Taylor A. p382 False Journal 208 Compositional MRI of the Hip: Reproducibility, Effect of Joint Unloading, and Comparison of T2 Relaxometry with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Objective: Our aim was to compare T2 with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the hip and assess the reproducibility and effect of joint unloading on T2 mapping. Design: Ten individuals at high risk of developing hip osteoarthritis (SibKids) underwent contemporaneous T2 mapping and dGEMRIC in the hip (10 hips). Twelve healthy volunteers underwent T2 mapping of both hips (24 hips) at time points 25, 35, 45, and 55 minutes post offloading. Acetabular and femoral cartilage was manually segmented into regions of interest. The relationship between T2 and dGEMRIC values from anatomically corresponding regions of interests was quantified using Pearson’s correlation. The reproducibility of image analysis for T2 and dGEMRIC, and reproducibility of image acquisition for T2, was quantified using the intraclass correlation coefficient (ICC), root mean square coefficient of variance (RMSCoV), smallest detectable difference (SDD), and Bland-Altman plots. The paired t test was used to determine if difference existed in T2 values at different unloading times. Results: T2 values correlated most strongly with dGEMRIC values in diseased cartilage (r = −0.61, P = <0.001). T2 image analysis (segmentation) reproducibility was ICC = 0.96 to 0.98, RMSCoV = 3.5% to 5.2%, and SDD = 2.2 to 3.5 ms. T2 values at 25 minutes unloading were not significantly different to longer unloading times (P = 0.132). SDD for T2 image acquisition reproducibility was 7.1 to 7.4 ms. Conclusions: T2 values in the hip correlate well with dGEMRIC in areas of cartilage damage. T2 shows high reproducibility and values do not change beyond 25 minutes of joint unloading. © The Author(s) 2019.
1111 a57201739935 De Berker H. p382 False Journal 208 Compositional MRI of the Hip: Reproducibility, Effect of Joint Unloading, and Comparison of T2 Relaxometry with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Objective: Our aim was to compare T2 with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the hip and assess the reproducibility and effect of joint unloading on T2 mapping. Design: Ten individuals at high risk of developing hip osteoarthritis (SibKids) underwent contemporaneous T2 mapping and dGEMRIC in the hip (10 hips). Twelve healthy volunteers underwent T2 mapping of both hips (24 hips) at time points 25, 35, 45, and 55 minutes post offloading. Acetabular and femoral cartilage was manually segmented into regions of interest. The relationship between T2 and dGEMRIC values from anatomically corresponding regions of interests was quantified using Pearson’s correlation. The reproducibility of image analysis for T2 and dGEMRIC, and reproducibility of image acquisition for T2, was quantified using the intraclass correlation coefficient (ICC), root mean square coefficient of variance (RMSCoV), smallest detectable difference (SDD), and Bland-Altman plots. The paired t test was used to determine if difference existed in T2 values at different unloading times. Results: T2 values correlated most strongly with dGEMRIC values in diseased cartilage (r = −0.61, P = <0.001). T2 image analysis (segmentation) reproducibility was ICC = 0.96 to 0.98, RMSCoV = 3.5% to 5.2%, and SDD = 2.2 to 3.5 ms. T2 values at 25 minutes unloading were not significantly different to longer unloading times (P = 0.132). SDD for T2 image acquisition reproducibility was 7.1 to 7.4 ms. Conclusions: T2 values in the hip correlate well with dGEMRIC in areas of cartilage damage. T2 shows high reproducibility and values do not change beyond 25 minutes of joint unloading. © The Author(s) 2019.
1112 a6508339625 Bangerter N. p382 False Journal 208 Compositional MRI of the Hip: Reproducibility, Effect of Joint Unloading, and Comparison of T2 Relaxometry with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Objective: Our aim was to compare T2 with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the hip and assess the reproducibility and effect of joint unloading on T2 mapping. Design: Ten individuals at high risk of developing hip osteoarthritis (SibKids) underwent contemporaneous T2 mapping and dGEMRIC in the hip (10 hips). Twelve healthy volunteers underwent T2 mapping of both hips (24 hips) at time points 25, 35, 45, and 55 minutes post offloading. Acetabular and femoral cartilage was manually segmented into regions of interest. The relationship between T2 and dGEMRIC values from anatomically corresponding regions of interests was quantified using Pearson’s correlation. The reproducibility of image analysis for T2 and dGEMRIC, and reproducibility of image acquisition for T2, was quantified using the intraclass correlation coefficient (ICC), root mean square coefficient of variance (RMSCoV), smallest detectable difference (SDD), and Bland-Altman plots. The paired t test was used to determine if difference existed in T2 values at different unloading times. Results: T2 values correlated most strongly with dGEMRIC values in diseased cartilage (r = −0.61, P = <0.001). T2 image analysis (segmentation) reproducibility was ICC = 0.96 to 0.98, RMSCoV = 3.5% to 5.2%, and SDD = 2.2 to 3.5 ms. T2 values at 25 minutes unloading were not significantly different to longer unloading times (P = 0.132). SDD for T2 image acquisition reproducibility was 7.1 to 7.4 ms. Conclusions: T2 values in the hip correlate well with dGEMRIC in areas of cartilage damage. T2 shows high reproducibility and values do not change beyond 25 minutes of joint unloading. © The Author(s) 2019.
1112 a6508339625 Bangerter N. p701 False Journal 343 Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip Background Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. Methods Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. Results Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = −0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. Conclusions The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis. © 2017 Osteoarthritis Research Society International
1113 a57213262958 Carr A. p382 False Journal 208 Compositional MRI of the Hip: Reproducibility, Effect of Joint Unloading, and Comparison of T2 Relaxometry with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Objective: Our aim was to compare T2 with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the hip and assess the reproducibility and effect of joint unloading on T2 mapping. Design: Ten individuals at high risk of developing hip osteoarthritis (SibKids) underwent contemporaneous T2 mapping and dGEMRIC in the hip (10 hips). Twelve healthy volunteers underwent T2 mapping of both hips (24 hips) at time points 25, 35, 45, and 55 minutes post offloading. Acetabular and femoral cartilage was manually segmented into regions of interest. The relationship between T2 and dGEMRIC values from anatomically corresponding regions of interests was quantified using Pearson’s correlation. The reproducibility of image analysis for T2 and dGEMRIC, and reproducibility of image acquisition for T2, was quantified using the intraclass correlation coefficient (ICC), root mean square coefficient of variance (RMSCoV), smallest detectable difference (SDD), and Bland-Altman plots. The paired t test was used to determine if difference existed in T2 values at different unloading times. Results: T2 values correlated most strongly with dGEMRIC values in diseased cartilage (r = −0.61, P = <0.001). T2 image analysis (segmentation) reproducibility was ICC = 0.96 to 0.98, RMSCoV = 3.5% to 5.2%, and SDD = 2.2 to 3.5 ms. T2 values at 25 minutes unloading were not significantly different to longer unloading times (P = 0.132). SDD for T2 image acquisition reproducibility was 7.1 to 7.4 ms. Conclusions: T2 values in the hip correlate well with dGEMRIC in areas of cartilage damage. T2 shows high reproducibility and values do not change beyond 25 minutes of joint unloading. © The Author(s) 2019.
1113 a57213262958 Carr A. p701 False Journal 343 Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip Background Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. Methods Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. Results Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = −0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. Conclusions The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis. © 2017 Osteoarthritis Research Society International
1114 a6506674242 Glyn-Jones S. p382 False Journal 208 Compositional MRI of the Hip: Reproducibility, Effect of Joint Unloading, and Comparison of T2 Relaxometry with Delayed Gadolinium-Enhanced Magnetic Resonance Imaging of Cartilage Objective: Our aim was to compare T2 with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) in the hip and assess the reproducibility and effect of joint unloading on T2 mapping. Design: Ten individuals at high risk of developing hip osteoarthritis (SibKids) underwent contemporaneous T2 mapping and dGEMRIC in the hip (10 hips). Twelve healthy volunteers underwent T2 mapping of both hips (24 hips) at time points 25, 35, 45, and 55 minutes post offloading. Acetabular and femoral cartilage was manually segmented into regions of interest. The relationship between T2 and dGEMRIC values from anatomically corresponding regions of interests was quantified using Pearson’s correlation. The reproducibility of image analysis for T2 and dGEMRIC, and reproducibility of image acquisition for T2, was quantified using the intraclass correlation coefficient (ICC), root mean square coefficient of variance (RMSCoV), smallest detectable difference (SDD), and Bland-Altman plots. The paired t test was used to determine if difference existed in T2 values at different unloading times. Results: T2 values correlated most strongly with dGEMRIC values in diseased cartilage (r = −0.61, P = <0.001). T2 image analysis (segmentation) reproducibility was ICC = 0.96 to 0.98, RMSCoV = 3.5% to 5.2%, and SDD = 2.2 to 3.5 ms. T2 values at 25 minutes unloading were not significantly different to longer unloading times (P = 0.132). SDD for T2 image acquisition reproducibility was 7.1 to 7.4 ms. Conclusions: T2 values in the hip correlate well with dGEMRIC in areas of cartilage damage. T2 shows high reproducibility and values do not change beyond 25 minutes of joint unloading. © The Author(s) 2019.
1114 a6506674242 Glyn-Jones S. p701 False Journal 343 Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip Background Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. Methods Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. Results Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = −0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. Conclusions The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis. © 2017 Osteoarthritis Research Society International
1115 a57191362366 Zimmerman T.K. p383 False Journal 209 Developable mechanisms on developable surfaces The trend toward smaller mechanism footprints and volumes, while maintaining the ability to perform complex tasks, presents the opportunity for exploration of hypercompact mechanical systems integrated with curved surfaces. Developable surfaces are shapes that a flat sheet can take without tearing or stretching, and they represent a wide range of manufactured surfaces. This work introduces “developable mechanisms” as devices that emerge from or conform to developable surfaces. They are made possible by aligning hinge axes with developable surface ruling lines to enable mobility. Because rigid-link motion depends on the relative orientation of hinge axes and not link geometry, links can take the shape of the corresponding developable surface. Mechanisms are classified by their associated surface type, and these relationships are defined and demonstrated by example. Developable mechanisms show promise for meeting unfilled needs using systems not previously envisioned. © 2019 The Authors, some rights reserved.
1115 a57191362366 Zimmerman T.K. p409 False Journal 219 Regional Stiffness Reduction Using Lamina Emergent Torsional Joints for Flexible Printed Circuit Board Design Flexible printed circuit boards (PCBs) make it possible for engineers to design devices that use space efficiently and can undergo changes in shape and configuration. However, they also suffer from tradeoffs due to nonideal material properties. Here, a method is presented that allows engineers to introduce regions of flexibility in otherwise rigid PCB substrates. This method employs geometric features to reduce local stiffness in the PCB, rather than reducing the global stiffness by material selection. Analytical and finite element models are presented to calculate the maximum stresses caused by deflection. An example device is produced and tested to verify the models. Copyright © 2018 by ASME.
1115 a57191362366 Zimmerman T.K. p455 True Conference 161 Modified Material Properties in Curved Panels Through Lamina Emergent Torsional Joints Compliant joints have a number of advantages that make them suitable for highly constrained design problems. While much work has been done on the design of compliant joints manufactured from planar sheet materials, this work focuses on the design of cylindrically-curved joints. A method for using lamina emergent torsional (LET) joints to increase energy storage efficiency in curved sheet materials is presented. A numerical model is provided for predicting the stiffness and maximum applied moment of a curved LET joint. Predicted curved LET joint stiffnesses and maximum moments are utilized to create shape factors that produce an effective modulus of elasticity and an effective modulus of resilience. For a given case, the effective modulus of elasticity is shown to decrease by about three orders of magnitude while the effective resilience decreases by approximately one order of magnitude. Designers can use this information to tailor materials to fit design requirements or to select alternative materials that were previously unsuited for an application. © 2018 IEEE.
1116 a57194018623 Calvin J.J. p384 True Journal 210 Review of surface water interactions with metal oxide nanoparticles Surface water can affect the properties of metal oxide nanoparticles. Investigations on several systems revealed that nanoparticles have different thermodynamic properties than their bulk counterparts due to adsorbed water on their surfaces. Some thermodynamically metastable phases of bulk metal oxides become stable when reduced to the nanoscale, partially due to interactions between high energy surfaces and surface water. Water adsorption microcalorimetry and high-temperature oxide melt solution calorimetry, low-temperature specific heat calorimetry, and inelastic neutron scattering are used to understand the interactions of surface water with metal oxide nanoparticles. Computational methods, such as molecular dynamics simulations and density functional theory calculations, have been used to study these interactions. Investigations on titania, cassiterite, and alumina illustrate the insights gained by these measurements. The energetics of water on metal oxide surfaces are different from those of either liquid water or hexagonal ice, and there is substantial variation in water interactions on different metal oxide surfaces. Copyright © Materials Research Society 2019.
1117 a57205236255 Rosen P.F. p384 False Journal 210 Review of surface water interactions with metal oxide nanoparticles Surface water can affect the properties of metal oxide nanoparticles. Investigations on several systems revealed that nanoparticles have different thermodynamic properties than their bulk counterparts due to adsorbed water on their surfaces. Some thermodynamically metastable phases of bulk metal oxides become stable when reduced to the nanoscale, partially due to interactions between high energy surfaces and surface water. Water adsorption microcalorimetry and high-temperature oxide melt solution calorimetry, low-temperature specific heat calorimetry, and inelastic neutron scattering are used to understand the interactions of surface water with metal oxide nanoparticles. Computational methods, such as molecular dynamics simulations and density functional theory calculations, have been used to study these interactions. Investigations on titania, cassiterite, and alumina illustrate the insights gained by these measurements. The energetics of water on metal oxide surfaces are different from those of either liquid water or hexagonal ice, and there is substantial variation in water interactions on different metal oxide surfaces. Copyright © Materials Research Society 2019.
1118 a57194101278 Ross N.L. p384 False Journal 210 Review of surface water interactions with metal oxide nanoparticles Surface water can affect the properties of metal oxide nanoparticles. Investigations on several systems revealed that nanoparticles have different thermodynamic properties than their bulk counterparts due to adsorbed water on their surfaces. Some thermodynamically metastable phases of bulk metal oxides become stable when reduced to the nanoscale, partially due to interactions between high energy surfaces and surface water. Water adsorption microcalorimetry and high-temperature oxide melt solution calorimetry, low-temperature specific heat calorimetry, and inelastic neutron scattering are used to understand the interactions of surface water with metal oxide nanoparticles. Computational methods, such as molecular dynamics simulations and density functional theory calculations, have been used to study these interactions. Investigations on titania, cassiterite, and alumina illustrate the insights gained by these measurements. The energetics of water on metal oxide surfaces are different from those of either liquid water or hexagonal ice, and there is substantial variation in water interactions on different metal oxide surfaces. Copyright © Materials Research Society 2019.
1119 a35392647700 Navrotsky A. p384 False Journal 210 Review of surface water interactions with metal oxide nanoparticles Surface water can affect the properties of metal oxide nanoparticles. Investigations on several systems revealed that nanoparticles have different thermodynamic properties than their bulk counterparts due to adsorbed water on their surfaces. Some thermodynamically metastable phases of bulk metal oxides become stable when reduced to the nanoscale, partially due to interactions between high energy surfaces and surface water. Water adsorption microcalorimetry and high-temperature oxide melt solution calorimetry, low-temperature specific heat calorimetry, and inelastic neutron scattering are used to understand the interactions of surface water with metal oxide nanoparticles. Computational methods, such as molecular dynamics simulations and density functional theory calculations, have been used to study these interactions. Investigations on titania, cassiterite, and alumina illustrate the insights gained by these measurements. The energetics of water on metal oxide surfaces are different from those of either liquid water or hexagonal ice, and there is substantial variation in water interactions on different metal oxide surfaces. Copyright © Materials Research Society 2019.
1120 a57204968964 Bohman M. p385 True Journal 202 Microcontroller compiler-assisted software fault tolerance Commercial off-the-shelf microcontrollers can be useful for noncritical processing on spaceborne platforms. These microprocessors can be inexpensive and consume small amounts of power. However, the software running on these processors is vulnerable to radiation upsets. In this paper, we present a fully automated, configurable, software-based tool to increase the reliability of microprocessors in high-radiation environments. This tool consists of a set of open-source LLVM compiler passes to automatically implement software-based mitigation techniques. We duplicate or triplicate computations and insert voting mechanisms into software during the compilation process, allowing for runtime error correction. While the techniques we implement are not novel, previous work has typically been closed source, processor architecture dependent, not automated, and not tested in real high-radiation environments. In contrast, the compiler passes presented in this paper are publicly available, highly customizable, and are platform independent and language independent. We have tested our modified software using both fault injection and through neutron beam radiation on a Texas Instruments MSP430 microcontroller. When tested by a neutron beam, we were able to decrease the cross section of programs by 17-29 × , increasing mean-work-to-failure by 4-7 ×. © 1963-2012 IEEE.
1121 a57205645397 Anderson J. p386 False Journal 202 Selective hardening for neural networks in FPGAs Neural networks are becoming an attractive solution for automatizing vehicles in the automotive, military, and aerospace markets. Thanks to their low-cost, low-power consumption, and flexibility, field-programmable gate arrays (FPGAs) are among the promising devices to implement neural networks. Unfortunately, FPGAs are also known to be susceptible to radiation-induced errors. In this paper, we evaluate the effects of radiation-induced errors in the output correctness of two neural networks [Iris Flower artificial neural network (ANN) and Modified National Institute of Standards and Technology (MNIST) convolutional neural network (CNN)] implemented in static random-access memory-based FPGAs. In particular, we notice that radiation can induce errors that modify the output of the network with or without affecting the neural network's functionality. We call the former critical errors and the latter tolerable errors. Through exhaustive fault injection, we identify the portions of Iris Flower ANN and MNIST CNN implementation on FPGAs that are more likely, once corrupted, to generate a critical or a tolerable error. Based on this analysis, we propose a selective hardening strategy that triplicates only the most vulnerable layers of the neural network. With neutron radiation testing, our selective hardening solution was able to mask 40% of faults with a marginal 8% overhead in one of our tested neural networks. © 1963-2012 IEEE.
1121 a57205645397 Anderson J. p404 True Conference 150 Neutron Radiation Beam Results for the Xilinx UltraScale+ MPSoC The paper summarizes the single-event upset (SEU) results obtained from neutron testing on the UltraScale+ MPSoC ZU9EG device. This complex device contains a large amount of programmable logic and multiple processor cores. Tests were performed on the programmable logic and the processing system simultaneously. Estimates of the single-event upset neutron cross section were obtained for the programmable logic CRAM, BRAM, OCM memory, and cache memories. During the test, no processor crashes or silent data corruptions were observed. In addition, a processor failure cross section was estimated for several software benchmark operating on the various processor cores. Several FPGA CRAM scrubbers were tested including an external JTAG, the Xilinx 'SEM' IP, and the use of the PCAP operating in baremetal. In parallel with these tests, single-event induced high current events were monitored using an external power supply and monitoring scripts. © 2018 IEEE.
1121 a57205645397 Anderson J. p405 False Conference 151 Single-Event Characterization of 16 nm FinFET Xilinx UltraScale+ Devices with Heavy Ion and Neutron Irradiation This study examines the single-event response of Xilinx 16nm FinFET UltraScale+ FPGA and MPSoC device families. Heavy-ion single-event latch-up, single-event upsets in configuration SRAM, BlockRAM™ memories, and flip-flops, and neutron-induced single-event latch-up results are provided. © 2018 IEEE.
1122 a55353164900 Cazzaniga C. p386 False Journal 202 Selective hardening for neural networks in FPGAs Neural networks are becoming an attractive solution for automatizing vehicles in the automotive, military, and aerospace markets. Thanks to their low-cost, low-power consumption, and flexibility, field-programmable gate arrays (FPGAs) are among the promising devices to implement neural networks. Unfortunately, FPGAs are also known to be susceptible to radiation-induced errors. In this paper, we evaluate the effects of radiation-induced errors in the output correctness of two neural networks [Iris Flower artificial neural network (ANN) and Modified National Institute of Standards and Technology (MNIST) convolutional neural network (CNN)] implemented in static random-access memory-based FPGAs. In particular, we notice that radiation can induce errors that modify the output of the network with or without affecting the neural network's functionality. We call the former critical errors and the latter tolerable errors. Through exhaustive fault injection, we identify the portions of Iris Flower ANN and MNIST CNN implementation on FPGAs that are more likely, once corrupted, to generate a critical or a tolerable error. Based on this analysis, we propose a selective hardening strategy that triplicates only the most vulnerable layers of the neural network. With neutron radiation testing, our selective hardening solution was able to mask 40% of faults with a marginal 8% overhead in one of our tested neural networks. © 1963-2012 IEEE.
1123 a7101816954 Frost C. p386 False Journal 202 Selective hardening for neural networks in FPGAs Neural networks are becoming an attractive solution for automatizing vehicles in the automotive, military, and aerospace markets. Thanks to their low-cost, low-power consumption, and flexibility, field-programmable gate arrays (FPGAs) are among the promising devices to implement neural networks. Unfortunately, FPGAs are also known to be susceptible to radiation-induced errors. In this paper, we evaluate the effects of radiation-induced errors in the output correctness of two neural networks [Iris Flower artificial neural network (ANN) and Modified National Institute of Standards and Technology (MNIST) convolutional neural network (CNN)] implemented in static random-access memory-based FPGAs. In particular, we notice that radiation can induce errors that modify the output of the network with or without affecting the neural network's functionality. We call the former critical errors and the latter tolerable errors. Through exhaustive fault injection, we identify the portions of Iris Flower ANN and MNIST CNN implementation on FPGAs that are more likely, once corrupted, to generate a critical or a tolerable error. Based on this analysis, we propose a selective hardening strategy that triplicates only the most vulnerable layers of the neural network. With neutron radiation testing, our selective hardening solution was able to mask 40% of faults with a marginal 8% overhead in one of our tested neural networks. © 1963-2012 IEEE.
1124 a57200527971 Elston E. p387 False Journal 211 Adhesion testing of printed inks while varying the surface treatment of polymer substrates Additive manufacturing with conductive materials enables new approaches to printed electronics that are unachievable by standard electronics manufacturing processes. In particular, electronics can be embedded directly into structural components in nearly arbitrary 3D space. While these methods incorporate many of the same materials, the new processing methods require standard test methods to compare materials, processing conditions, and determine design limits. This work demonstrates a test method to quantitatively measure the adhesion failure of printed inks deposited on a substrate without changing the ink printing conditions. The proposed method is an adaption of single lap shear testing in which the lap joint is created by bonding the second substrate to the ink after curing. It was found that the interfacial shear strengths are independent of the adhesives used to attach cured conductive ink to the second substrate. In addition, chemical surface treatments of flame and plasma and mechanical sand-blasting increase the interfacial shear strengths by ~25% and 80%, respectively, while altering the adhesive failure mode to cohesive failure for most cases. This work also shows extruded substrates with undulated features increase adhesion strength; therefore, in addition to surface treatments, the geometric freedom of additive manufacturing (AM) could be leveraged to design surface features for enhanced adhesion. © 2019, © 2019 Taylor & Francis Group, LLC.
1125 a11440678000 Schrand A. p387 False Journal 211 Adhesion testing of printed inks while varying the surface treatment of polymer substrates Additive manufacturing with conductive materials enables new approaches to printed electronics that are unachievable by standard electronics manufacturing processes. In particular, electronics can be embedded directly into structural components in nearly arbitrary 3D space. While these methods incorporate many of the same materials, the new processing methods require standard test methods to compare materials, processing conditions, and determine design limits. This work demonstrates a test method to quantitatively measure the adhesion failure of printed inks deposited on a substrate without changing the ink printing conditions. The proposed method is an adaption of single lap shear testing in which the lap joint is created by bonding the second substrate to the ink after curing. It was found that the interfacial shear strengths are independent of the adhesives used to attach cured conductive ink to the second substrate. In addition, chemical surface treatments of flame and plasma and mechanical sand-blasting increase the interfacial shear strengths by ~25% and 80%, respectively, while altering the adhesive failure mode to cohesive failure for most cases. This work also shows extruded substrates with undulated features increase adhesion strength; therefore, in addition to surface treatments, the geometric freedom of additive manufacturing (AM) could be leveraged to design surface features for enhanced adhesion. © 2019, © 2019 Taylor & Francis Group, LLC.
1126 a24337245000 Arashida Y. p388 False Conference 140 High-acquisition-rate single-shot pump-probe measurement using chirped-fiber Bragg gratings Multi-timescale dynamics, from femtoseconds to milliseconds, for irreversible phenomena have been of fundamental importance in understanding mechanisms of chaotic phenomena, electronic bunch evaluation of an accelerator, photoinduced phase transitions, laser ablation, etc. Recently, several groups reported high acquisition rate single-shot methods using chirped-pulse single-shot detections and photonic time-stretching [1-3]. In these works, however, the long fiber with the length of several km was used to temporally stretch the time-encoded spectrum by the group velocity dispersion, but his long distance degrades the signal-to-noise ratio due to propagation losses of the probe pulses through the fiber, thus limiting the observable phenomena. © 2019 IEEE
1127 a56023819400 Yamashita G. p388 False Conference 140 High-acquisition-rate single-shot pump-probe measurement using chirped-fiber Bragg gratings Multi-timescale dynamics, from femtoseconds to milliseconds, for irreversible phenomena have been of fundamental importance in understanding mechanisms of chaotic phenomena, electronic bunch evaluation of an accelerator, photoinduced phase transitions, laser ablation, etc. Recently, several groups reported high acquisition rate single-shot methods using chirped-pulse single-shot detections and photonic time-stretching [1-3]. In these works, however, the long fiber with the length of several km was used to temporally stretch the time-encoded spectrum by the group velocity dispersion, but his long distance degrades the signal-to-noise ratio due to propagation losses of the probe pulses through the fiber, thus limiting the observable phenomena. © 2019 IEEE
1128 a10639240900 Matsubara E. p388 False Conference 140 High-acquisition-rate single-shot pump-probe measurement using chirped-fiber Bragg gratings Multi-timescale dynamics, from femtoseconds to milliseconds, for irreversible phenomena have been of fundamental importance in understanding mechanisms of chaotic phenomena, electronic bunch evaluation of an accelerator, photoinduced phase transitions, laser ablation, etc. Recently, several groups reported high acquisition rate single-shot methods using chirped-pulse single-shot detections and photonic time-stretching [1-3]. In these works, however, the long fiber with the length of several km was used to temporally stretch the time-encoded spectrum by the group velocity dispersion, but his long distance degrades the signal-to-noise ratio due to propagation losses of the probe pulses through the fiber, thus limiting the observable phenomena. © 2019 IEEE
1129 a11043349200 Ashida M. p388 False Conference 140 High-acquisition-rate single-shot pump-probe measurement using chirped-fiber Bragg gratings Multi-timescale dynamics, from femtoseconds to milliseconds, for irreversible phenomena have been of fundamental importance in understanding mechanisms of chaotic phenomena, electronic bunch evaluation of an accelerator, photoinduced phase transitions, laser ablation, etc. Recently, several groups reported high acquisition rate single-shot methods using chirped-pulse single-shot detections and photonic time-stretching [1-3]. In these works, however, the long fiber with the length of several km was used to temporally stretch the time-encoded spectrum by the group velocity dispersion, but his long distance degrades the signal-to-noise ratio due to propagation losses of the probe pulses through the fiber, thus limiting the observable phenomena. © 2019 IEEE
1130 a54782837300 Lübeck A. p389 True Journal 212 Numerical analyses of mortar incorporating the variation in Poisson’s ratio with increasing axial load The work presented herein evaluated the influence of compressive strength and confinement on the stress-strain behaviour of axially loaded mortar specimens by means of experimental and numerical analyses. Two mortars were tested, with volume proportions of cement: Lime: Sand of 1:0.5:4 and 1:1:6. From these two specimen heights, 50 and 140mm, with diameter of 45mm, resulting in diameter/height ratios of 1.0 and 0.3, were manufactured. The experimental results indicated that the confinement and strength of the mortar influence its stress-strain behaviour, the larger the confinement, the more, nonlinear the behaviour. In addition, the results indicated that the Poisson’s ratio and tangent modulus of elasticity vary with increasing applied load. Two numerical models were tested using the same finite element mesh, boundary conditions and load. The first model was based on the Total Strain Smeared Crack Model and the second model accounted for the observations from the experimental phase with a nonlinear “elastic phased” analysis, which updates the modulus of elasticity and the Poisson’s ratio at each new phase. The tangent modulus of elasticity was calculated directly from the experimental results while the Poisson’s ratio was approximated using the model proposed by OTTOSEN [16]. The numerical model based on the total strain smeared crack was not able to reproduce the behaviour of the compressed mortar near failure while the phased model presented satisfactory results, even close to failure, when cracking is significant. © 2019, International Masonry Society. All rights reserved.
1130 a54782837300 Lübeck A. p644 True Conference 276 Numerical analyses of mortar incorporating the variation in poisson's ratio with increasing axial load This work evaluated the influence of compressive strength and confinement on the stress-strain behavior of axial loaded mortar specimens by means of experimental and numerical analyses. Two mortars were tested, with volume proportions of cement, lime and sand of 1:0.5:4 and 1:1:6. Two specimen heights, 50 and 140 mm, with diameter of 45 mm, resulting in diameter/height ratios of 1.0 and 0.3, respectively were used. The experimental results indicated that the confinement and strength of the mortar influence its stress-strain behavior: the larger the confinement, the more the non-linear behavior. In addition, the results indicated that the Poisson's ratio and the tangent modulus of elasticity vary with increasing applied load. A numerical model was developed that accounted for the observations from the experimental phase with a nonlinear elastic phased analysis, which updates the modulus of elasticity and the Poisson's ratio at each new phase. The tangent modulus of elasticity was calculated directly from the experimental results while the Poisson's ratio was approximated using the model proposed by Ottosen. The numerical model presented satisfactory results, even close to the failure, when cracking is significant. © 2018 The International Masonry Society (IMS).
1131 a8048702500 Mohamad G. p389 False Journal 212 Numerical analyses of mortar incorporating the variation in Poisson’s ratio with increasing axial load The work presented herein evaluated the influence of compressive strength and confinement on the stress-strain behaviour of axially loaded mortar specimens by means of experimental and numerical analyses. Two mortars were tested, with volume proportions of cement: Lime: Sand of 1:0.5:4 and 1:1:6. From these two specimen heights, 50 and 140mm, with diameter of 45mm, resulting in diameter/height ratios of 1.0 and 0.3, were manufactured. The experimental results indicated that the confinement and strength of the mortar influence its stress-strain behaviour, the larger the confinement, the more, nonlinear the behaviour. In addition, the results indicated that the Poisson’s ratio and tangent modulus of elasticity vary with increasing applied load. Two numerical models were tested using the same finite element mesh, boundary conditions and load. The first model was based on the Total Strain Smeared Crack Model and the second model accounted for the observations from the experimental phase with a nonlinear “elastic phased” analysis, which updates the modulus of elasticity and the Poisson’s ratio at each new phase. The tangent modulus of elasticity was calculated directly from the experimental results while the Poisson’s ratio was approximated using the model proposed by OTTOSEN [16]. The numerical model based on the total strain smeared crack was not able to reproduce the behaviour of the compressed mortar near failure while the phased model presented satisfactory results, even close to failure, when cracking is significant. © 2019, International Masonry Society. All rights reserved.
1131 a8048702500 Mohamad G. p644 False Conference 276 Numerical analyses of mortar incorporating the variation in poisson's ratio with increasing axial load This work evaluated the influence of compressive strength and confinement on the stress-strain behavior of axial loaded mortar specimens by means of experimental and numerical analyses. Two mortars were tested, with volume proportions of cement, lime and sand of 1:0.5:4 and 1:1:6. Two specimen heights, 50 and 140 mm, with diameter of 45 mm, resulting in diameter/height ratios of 1.0 and 0.3, respectively were used. The experimental results indicated that the confinement and strength of the mortar influence its stress-strain behavior: the larger the confinement, the more the non-linear behavior. In addition, the results indicated that the Poisson's ratio and the tangent modulus of elasticity vary with increasing applied load. A numerical model was developed that accounted for the observations from the experimental phase with a nonlinear elastic phased analysis, which updates the modulus of elasticity and the Poisson's ratio at each new phase. The tangent modulus of elasticity was calculated directly from the experimental results while the Poisson's ratio was approximated using the model proposed by Ottosen. The numerical model presented satisfactory results, even close to the failure, when cracking is significant. © 2018 The International Masonry Society (IMS).
1131 a8048702500 Mohamad G. p775 True Journal 382 Strength, behavior, and failure mode of hollow concrete masonry constructed with mortars of different strengths This study reports the failure modes of hollow concrete masonry prisms, taking into account the block and mortar stress-strain behavior. An extensive and detailed experimental program has been conducted on three-block high stack-bonded prisms, built using a combination of one hollow block type and three mortars with different strengths. Based on the results of the experiments, masonry failure was assessed. The main conclusion of this is that the mortar in all cases governs the masonry failure mechanism. The ratio between the masonry and block moduli of elasticity, which can be used as a measure of loss of stiffness, indicates that masonry built with a strong mortar behaves almost as a homogenous material. The typical failure mode observed during testing for this type of masonry was due to tensile stresses developed in the block. A crack developed at and propagated instantly through the block face until reaching the mortar bed joint; the crack then propagated through the head joint causing a localized split at the interface between block and mortar. For masonry built with two different weak mortars, as the stress/strength ratio increased, the ratio between the masonry and mortar moduli of elasticity decreased to 0.32 and 0.55, for the weak and the weaker mortar respectively. The observed failure mode, however, was independent of how weak the mortar was since, for both cases, the masonry failed due to localized mortar crushing. Another conclusion from the study presented herein is that a robust and reliable prediction of the masonry compressive strength requires the use of the nonlinear stress-strain relationship of the component materials. © 2016 Elsevier Ltd
1132 a57207228809 Milani A.S. p389 False Journal 212 Numerical analyses of mortar incorporating the variation in Poisson’s ratio with increasing axial load The work presented herein evaluated the influence of compressive strength and confinement on the stress-strain behaviour of axially loaded mortar specimens by means of experimental and numerical analyses. Two mortars were tested, with volume proportions of cement: Lime: Sand of 1:0.5:4 and 1:1:6. From these two specimen heights, 50 and 140mm, with diameter of 45mm, resulting in diameter/height ratios of 1.0 and 0.3, were manufactured. The experimental results indicated that the confinement and strength of the mortar influence its stress-strain behaviour, the larger the confinement, the more, nonlinear the behaviour. In addition, the results indicated that the Poisson’s ratio and tangent modulus of elasticity vary with increasing applied load. Two numerical models were tested using the same finite element mesh, boundary conditions and load. The first model was based on the Total Strain Smeared Crack Model and the second model accounted for the observations from the experimental phase with a nonlinear “elastic phased” analysis, which updates the modulus of elasticity and the Poisson’s ratio at each new phase. The tangent modulus of elasticity was calculated directly from the experimental results while the Poisson’s ratio was approximated using the model proposed by OTTOSEN [16]. The numerical model based on the total strain smeared crack was not able to reproduce the behaviour of the compressed mortar near failure while the phased model presented satisfactory results, even close to failure, when cracking is significant. © 2019, International Masonry Society. All rights reserved.
1132 a57207228809 Milani A.S. p644 False Conference 276 Numerical analyses of mortar incorporating the variation in poisson's ratio with increasing axial load This work evaluated the influence of compressive strength and confinement on the stress-strain behavior of axial loaded mortar specimens by means of experimental and numerical analyses. Two mortars were tested, with volume proportions of cement, lime and sand of 1:0.5:4 and 1:1:6. Two specimen heights, 50 and 140 mm, with diameter of 45 mm, resulting in diameter/height ratios of 1.0 and 0.3, respectively were used. The experimental results indicated that the confinement and strength of the mortar influence its stress-strain behavior: the larger the confinement, the more the non-linear behavior. In addition, the results indicated that the Poisson's ratio and the tangent modulus of elasticity vary with increasing applied load. A numerical model was developed that accounted for the observations from the experimental phase with a nonlinear elastic phased analysis, which updates the modulus of elasticity and the Poisson's ratio at each new phase. The tangent modulus of elasticity was calculated directly from the experimental results while the Poisson's ratio was approximated using the model proposed by Ottosen. The numerical model presented satisfactory results, even close to the failure, when cracking is significant. © 2018 The International Masonry Society (IMS).
1133 a13411176900 Gou Y. p390 True Journal 213 A design approach to fully compliant multistable mechanisms employing a single bistable mechanism A fully compliant multistable mechanism is a monolithic structure that is capable of staying at multiple positions without power input, and has many applications including switches, valves, positioners. However, it is difficult to design such a mechanism because of the complexities of the multistable behavior, the practical stress limits and the buckling constraints. This paper discusses the design approach for fully compliant multistable mechanisms which employs a single bistable mechanism and several end-effectors connected in series. The force-displacement characteristics of the end-effectors are derived using the pseudo-rigid-body model. The design approach to the fully compliant multistable mechanism is provided to determine the design parameters for the flexible segments considering the critical buckling load and the bending strength. Two design examples are presented to demonstrate the feasibility of the approach. © 2019, © 2019 Taylor & Francis Group, LLC.
1134 a57205595555 Peterson S. p391 True Conference 141 When official systems overload: A framework for finding social media calls for help during evacuations During large-scale disasters it is not uncommon for Public Safety Answering Points (e.g., 9-1-1) to encounter service disruptions or become overloaded due to call volume. As observed in the two past United States hurricane seasons, citizens are increasingly turning to social media whether as a consequence of their inability to reach 9-1-1, or as a preferential means of communications. Relying on past research that has examined social media use in disasters, combined with the practical knowledge of the first-hand disaster response experiences, this paper develops a knowledge-driven framework containing parameters useful in identifying patterns of shared information on social media when citizens need help. This effort explores the feasibility of determining differences, similarities, common themes, and time-specific discoveries of social media calls for help associated with hurricane evacuations. At a future date, validation of this framework will be demonstrated using datasets from multiple disasters. The results will lead to recommendations on how the framework can be modified to make it applicable as a generic disaster-type characterization tool. © 2019 Information Systems for Crisis Response and Management, ISCRAM. All rights reserved.
1135 a9336961600 Stephens K.K. p391 False Conference 141 When official systems overload: A framework for finding social media calls for help during evacuations During large-scale disasters it is not uncommon for Public Safety Answering Points (e.g., 9-1-1) to encounter service disruptions or become overloaded due to call volume. As observed in the two past United States hurricane seasons, citizens are increasingly turning to social media whether as a consequence of their inability to reach 9-1-1, or as a preferential means of communications. Relying on past research that has examined social media use in disasters, combined with the practical knowledge of the first-hand disaster response experiences, this paper develops a knowledge-driven framework containing parameters useful in identifying patterns of shared information on social media when citizens need help. This effort explores the feasibility of determining differences, similarities, common themes, and time-specific discoveries of social media calls for help associated with hurricane evacuations. At a future date, validation of this framework will be demonstrated using datasets from multiple disasters. The results will lead to recommendations on how the framework can be modified to make it applicable as a generic disaster-type characterization tool. © 2019 Information Systems for Crisis Response and Management, ISCRAM. All rights reserved.
1136 a16425686200 Hughes A. p391 False Conference 141 When official systems overload: A framework for finding social media calls for help during evacuations During large-scale disasters it is not uncommon for Public Safety Answering Points (e.g., 9-1-1) to encounter service disruptions or become overloaded due to call volume. As observed in the two past United States hurricane seasons, citizens are increasingly turning to social media whether as a consequence of their inability to reach 9-1-1, or as a preferential means of communications. Relying on past research that has examined social media use in disasters, combined with the practical knowledge of the first-hand disaster response experiences, this paper develops a knowledge-driven framework containing parameters useful in identifying patterns of shared information on social media when citizens need help. This effort explores the feasibility of determining differences, similarities, common themes, and time-specific discoveries of social media calls for help associated with hurricane evacuations. At a future date, validation of this framework will be demonstrated using datasets from multiple disasters. The results will lead to recommendations on how the framework can be modified to make it applicable as a generic disaster-type characterization tool. © 2019 Information Systems for Crisis Response and Management, ISCRAM. All rights reserved.
1136 a16425686200 Hughes A. p395 False Conference 144 Requirements for software to support the use of social media in emergency management: A Delphi study Social Media contain a wealth of information that could improve the situational awareness of Emergency Managers during a crisis, but many barriers stand in the way. These include information overload, making it impossible to deal with the flood of raw posts, and lack of trust in unverified crowdsourced data. The purpose of this project is to build a communications bridge between emergency responders and technologists who can provide the advances needed to realize social media's full potential. We are employing a Delphi study survey design, which is a technique for exploring and developing consensus among a group of experts around a particular topic. Participants include emergency managers and technologists with experience in software to support the use of social media in crisis response, from many countries. The topics of the study are described and preliminary, partial results presented for Round 1 of the study, based on 33 responses. © 2019 Information Systems for Crisis Response and Management, ISCRAM. All rights reserved.
1137 a57217471535 Purohit H. p391 False Conference 141 When official systems overload: A framework for finding social media calls for help during evacuations During large-scale disasters it is not uncommon for Public Safety Answering Points (e.g., 9-1-1) to encounter service disruptions or become overloaded due to call volume. As observed in the two past United States hurricane seasons, citizens are increasingly turning to social media whether as a consequence of their inability to reach 9-1-1, or as a preferential means of communications. Relying on past research that has examined social media use in disasters, combined with the practical knowledge of the first-hand disaster response experiences, this paper develops a knowledge-driven framework containing parameters useful in identifying patterns of shared information on social media when citizens need help. This effort explores the feasibility of determining differences, similarities, common themes, and time-specific discoveries of social media calls for help associated with hurricane evacuations. At a future date, validation of this framework will be demonstrated using datasets from multiple disasters. The results will lead to recommendations on how the framework can be modified to make it applicable as a generic disaster-type characterization tool. © 2019 Information Systems for Crisis Response and Management, ISCRAM. All rights reserved.
1138 a56577741600 Sen U. p392 True Journal 170 Orthogonal liquid-jet impingement on wettability-patterned impermeable substrates Liquid-jet impingement on flat impermeable substrates is important for a multitude of applications ranging from electronic-equipment cooling to fuel atomization and erosion of solid surfaces. On a wettable horizontal surface, where a sufficient downstream liquid depth can be sustained after axisymmetric impingement, the jet forms a thin film on the substrate up to a radial distance where the film height suddenly increases, forming a hydraulic jump. On a superhydrophobic surface, where a downstream liquid depth is not naturally sustained, the thin film expands and breaks up into droplets, which are subsequently ejected in a random fashion outward, as carried by their radial momentum. In the present work, a facile, scalable, wettability-patterning approach is presented for delaying or even eliminating droplet breakup in the case of jet impingement on horizontal superhydrophobic surfaces. Analytical expressions for predicting the hydraulic jump and droplet breakup locations are developed to designate the proper wettability patterns that facilitate alteration and control of the postimpingement liquid behavior. The axisymmetric model is extended to evaluate the radial variation of the competing forces responsible for film breakup, and a design criterion for the effective wettability patterns is proposed. © 2019 American Physical Society.
1139 a55807316700 Chatterjee S. p392 False Journal 170 Orthogonal liquid-jet impingement on wettability-patterned impermeable substrates Liquid-jet impingement on flat impermeable substrates is important for a multitude of applications ranging from electronic-equipment cooling to fuel atomization and erosion of solid surfaces. On a wettable horizontal surface, where a sufficient downstream liquid depth can be sustained after axisymmetric impingement, the jet forms a thin film on the substrate up to a radial distance where the film height suddenly increases, forming a hydraulic jump. On a superhydrophobic surface, where a downstream liquid depth is not naturally sustained, the thin film expands and breaks up into droplets, which are subsequently ejected in a random fashion outward, as carried by their radial momentum. In the present work, a facile, scalable, wettability-patterning approach is presented for delaying or even eliminating droplet breakup in the case of jet impingement on horizontal superhydrophobic surfaces. Analytical expressions for predicting the hydraulic jump and droplet breakup locations are developed to designate the proper wettability patterns that facilitate alteration and control of the postimpingement liquid behavior. The axisymmetric model is extended to evaluate the radial variation of the competing forces responsible for film breakup, and a design criterion for the effective wettability patterns is proposed. © 2019 American Physical Society.
1140 a7102317656 Ganguly R. p392 False Journal 170 Orthogonal liquid-jet impingement on wettability-patterned impermeable substrates Liquid-jet impingement on flat impermeable substrates is important for a multitude of applications ranging from electronic-equipment cooling to fuel atomization and erosion of solid surfaces. On a wettable horizontal surface, where a sufficient downstream liquid depth can be sustained after axisymmetric impingement, the jet forms a thin film on the substrate up to a radial distance where the film height suddenly increases, forming a hydraulic jump. On a superhydrophobic surface, where a downstream liquid depth is not naturally sustained, the thin film expands and breaks up into droplets, which are subsequently ejected in a random fashion outward, as carried by their radial momentum. In the present work, a facile, scalable, wettability-patterning approach is presented for delaying or even eliminating droplet breakup in the case of jet impingement on horizontal superhydrophobic surfaces. Analytical expressions for predicting the hydraulic jump and droplet breakup locations are developed to designate the proper wettability patterns that facilitate alteration and control of the postimpingement liquid behavior. The axisymmetric model is extended to evaluate the radial variation of the competing forces responsible for film breakup, and a design criterion for the effective wettability patterns is proposed. © 2019 American Physical Society.
1141 a57200514682 Yu L. p392 False Journal 170 Orthogonal liquid-jet impingement on wettability-patterned impermeable substrates Liquid-jet impingement on flat impermeable substrates is important for a multitude of applications ranging from electronic-equipment cooling to fuel atomization and erosion of solid surfaces. On a wettable horizontal surface, where a sufficient downstream liquid depth can be sustained after axisymmetric impingement, the jet forms a thin film on the substrate up to a radial distance where the film height suddenly increases, forming a hydraulic jump. On a superhydrophobic surface, where a downstream liquid depth is not naturally sustained, the thin film expands and breaks up into droplets, which are subsequently ejected in a random fashion outward, as carried by their radial momentum. In the present work, a facile, scalable, wettability-patterning approach is presented for delaying or even eliminating droplet breakup in the case of jet impingement on horizontal superhydrophobic surfaces. Analytical expressions for predicting the hydraulic jump and droplet breakup locations are developed to designate the proper wettability patterns that facilitate alteration and control of the postimpingement liquid behavior. The axisymmetric model is extended to evaluate the radial variation of the competing forces responsible for film breakup, and a design criterion for the effective wettability patterns is proposed. © 2019 American Physical Society.
1142 a7003388995 Megaridis C.M. p392 False Journal 170 Orthogonal liquid-jet impingement on wettability-patterned impermeable substrates Liquid-jet impingement on flat impermeable substrates is important for a multitude of applications ranging from electronic-equipment cooling to fuel atomization and erosion of solid surfaces. On a wettable horizontal surface, where a sufficient downstream liquid depth can be sustained after axisymmetric impingement, the jet forms a thin film on the substrate up to a radial distance where the film height suddenly increases, forming a hydraulic jump. On a superhydrophobic surface, where a downstream liquid depth is not naturally sustained, the thin film expands and breaks up into droplets, which are subsequently ejected in a random fashion outward, as carried by their radial momentum. In the present work, a facile, scalable, wettability-patterning approach is presented for delaying or even eliminating droplet breakup in the case of jet impingement on horizontal superhydrophobic surfaces. Analytical expressions for predicting the hydraulic jump and droplet breakup locations are developed to designate the proper wettability patterns that facilitate alteration and control of the postimpingement liquid behavior. The axisymmetric model is extended to evaluate the radial variation of the competing forces responsible for film breakup, and a design criterion for the effective wettability patterns is proposed. © 2019 American Physical Society.
1143 a16229559200 Banik J.A. p393 False Conference 142 Folding approaches for tensioned precision planar shell structures An origami-based engineering approach is applied to the folding design of tensioned precision space structures. Tension is a viable means of stiffening a flat antenna aperture, especially when stowed volume is paramount. Three folding patterns are described, and the design guidelines are developed. Deployment kinematics follow the simplicity of a single-degree-of-freedom mechanism for two of the three patterns. The panels are rigid, and articulations occur along the prescribed lines. These deployment architectures are compatible with storable tubular extendible member booms, articulated trusses, or continuous longeron coilable trusses, all commonly used to deploy spacecraft structures. High areal packaging densities were demonstrated: 1.0 m2∕l for a diamond pattern with a high deployed aspect ratio and 0.5 m2∕l for spiral and serpentine patterns compatible with high and low deployed aspect ratios. A double-layer material hinge method is also presented and used to enable the structures to fold, deploy, and be tensioned to a planar state. Copyright © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1143 a16229559200 Banik J.A. p634 False Conference 269 Folding approaches for tensioned precision planar shell structures An origami-based engineering approach is applied to the folding design of tensioned precision space structures. Tension is a viable means of stiffening a flat antenna aperture especially when stowed volume is paramount. Three folding patterns are introduced and the design guidelines are developed. Deployment kinematics follow the simplicity of a single degree of freedom mechanism for two of the three patterns. The panels are rigid, and articulations occur along the prescribed lines. These deployment architectures are compatible with storable tubular extendible member booms, articulated trusses, or continuous longeron coilable trusses, all commonly used to deploy spacecraft structures. High areal packaging densities were demonstrated: 1.0 m2/L for a diamond pattern with a high deployed aspect ratio and 0.5 m2/L for spiral and serpentine patterns compatible with high and low deployed aspect ratios. A double-layer material hinge method is also presented and used to enable the structures to fold, deploy, and be tensioned to a planar state. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1144 a57207993531 Villa J.M. p394 False Conference 143 Mexico City Basin Effects: Past, Present, and Future Seismic hazard in Mexico City governed by site effects. The M8.1 1985 subduction zone earthquake, which caused significant damage and loss of thousands of lives at 350 km epicentral distance, has become the quintessential example of the role that site effects can play in modifying the amplitude, frequency, and duration of ground shaking; and in aggravating the catastrophic consequences of earthquakes. We here present observations and analyses of the M7.1 September 19, 2017, event that -while triggered by an intraplate rupture at approximately half the epicentral distance of the 1985 event relative to Mexico City -caused severe structural damage to a few tens of buildings located in a relatively narrow zone between the hill and lake zones of the basin, known as the transition zone. We show that the M 7.1 mainshock exposed the vulnerabilities of the pre-1985 building code in the transition zone; but more importantly highlighted the improvement of the 1987 building code revision in terms of the performance of modern high-rise buildings that suffered catastrophic consequences during the 1985 Michoácan earthquake sequence. We next analyze several records collected at stations in the basin over the past 20 years. We highlight the importance of three-dimensional heterogeneity of the basin sediments, the coupling between hydrological setting and site response and their evolution with time, and the energy interaction between the deep basin edge and the shallow clay layers. Results presented are the collective effort of the GEER teams that were deployed to perform post-earthquake reconnaissance in the affected regions of the epicentral area and in Mexico City after the M 7.1 September 19, 2017, earthquake sequence. © 2019 American Society of Civil Engineers.
1145 a56560118600 Ayoubi P. p394 False Conference 143 Mexico City Basin Effects: Past, Present, and Future Seismic hazard in Mexico City governed by site effects. The M8.1 1985 subduction zone earthquake, which caused significant damage and loss of thousands of lives at 350 km epicentral distance, has become the quintessential example of the role that site effects can play in modifying the amplitude, frequency, and duration of ground shaking; and in aggravating the catastrophic consequences of earthquakes. We here present observations and analyses of the M7.1 September 19, 2017, event that -while triggered by an intraplate rupture at approximately half the epicentral distance of the 1985 event relative to Mexico City -caused severe structural damage to a few tens of buildings located in a relatively narrow zone between the hill and lake zones of the basin, known as the transition zone. We show that the M 7.1 mainshock exposed the vulnerabilities of the pre-1985 building code in the transition zone; but more importantly highlighted the improvement of the 1987 building code revision in terms of the performance of modern high-rise buildings that suffered catastrophic consequences during the 1985 Michoácan earthquake sequence. We next analyze several records collected at stations in the basin over the past 20 years. We highlight the importance of three-dimensional heterogeneity of the basin sediments, the coupling between hydrological setting and site response and their evolution with time, and the energy interaction between the deep basin edge and the shallow clay layers. Results presented are the collective effort of the GEER teams that were deployed to perform post-earthquake reconnaissance in the affected regions of the epicentral area and in Mexico City after the M 7.1 September 19, 2017, earthquake sequence. © 2019 American Society of Civil Engineers.
1146 a57214608701 Roxanne Hiltz S. p395 True Conference 144 Requirements for software to support the use of social media in emergency management: A Delphi study Social Media contain a wealth of information that could improve the situational awareness of Emergency Managers during a crisis, but many barriers stand in the way. These include information overload, making it impossible to deal with the flood of raw posts, and lack of trust in unverified crowdsourced data. The purpose of this project is to build a communications bridge between emergency responders and technologists who can provide the advances needed to realize social media's full potential. We are employing a Delphi study survey design, which is a technique for exploring and developing consensus among a group of experts around a particular topic. Participants include emergency managers and technologists with experience in software to support the use of social media in crisis response, from many countries. The topics of the study are described and preliminary, partial results presented for Round 1 of the study, based on 33 responses. © 2019 Information Systems for Crisis Response and Management, ISCRAM. All rights reserved.
1147 a55598006500 Imran M. p395 False Conference 144 Requirements for software to support the use of social media in emergency management: A Delphi study Social Media contain a wealth of information that could improve the situational awareness of Emergency Managers during a crisis, but many barriers stand in the way. These include information overload, making it impossible to deal with the flood of raw posts, and lack of trust in unverified crowdsourced data. The purpose of this project is to build a communications bridge between emergency responders and technologists who can provide the advances needed to realize social media's full potential. We are employing a Delphi study survey design, which is a technique for exploring and developing consensus among a group of experts around a particular topic. Participants include emergency managers and technologists with experience in software to support the use of social media in crisis response, from many countries. The topics of the study are described and preliminary, partial results presented for Round 1 of the study, based on 33 responses. © 2019 Information Systems for Crisis Response and Management, ISCRAM. All rights reserved.
1148 a23668489900 Plotnick L. p395 False Conference 144 Requirements for software to support the use of social media in emergency management: A Delphi study Social Media contain a wealth of information that could improve the situational awareness of Emergency Managers during a crisis, but many barriers stand in the way. These include information overload, making it impossible to deal with the flood of raw posts, and lack of trust in unverified crowdsourced data. The purpose of this project is to build a communications bridge between emergency responders and technologists who can provide the advances needed to realize social media's full potential. We are employing a Delphi study survey design, which is a technique for exploring and developing consensus among a group of experts around a particular topic. Participants include emergency managers and technologists with experience in software to support the use of social media in crisis response, from many countries. The topics of the study are described and preliminary, partial results presented for Round 1 of the study, based on 33 responses. © 2019 Information Systems for Crisis Response and Management, ISCRAM. All rights reserved.
1149 a15848894300 Power R. p395 False Conference 144 Requirements for software to support the use of social media in emergency management: A Delphi study Social Media contain a wealth of information that could improve the situational awareness of Emergency Managers during a crisis, but many barriers stand in the way. These include information overload, making it impossible to deal with the flood of raw posts, and lack of trust in unverified crowdsourced data. The purpose of this project is to build a communications bridge between emergency responders and technologists who can provide the advances needed to realize social media's full potential. We are employing a Delphi study survey design, which is a technique for exploring and developing consensus among a group of experts around a particular topic. Participants include emergency managers and technologists with experience in software to support the use of social media in crisis response, from many countries. The topics of the study are described and preliminary, partial results presented for Round 1 of the study, based on 33 responses. © 2019 Information Systems for Crisis Response and Management, ISCRAM. All rights reserved.
1150 a57209871741 Turoff M. p395 False Conference 144 Requirements for software to support the use of social media in emergency management: A Delphi study Social Media contain a wealth of information that could improve the situational awareness of Emergency Managers during a crisis, but many barriers stand in the way. These include information overload, making it impossible to deal with the flood of raw posts, and lack of trust in unverified crowdsourced data. The purpose of this project is to build a communications bridge between emergency responders and technologists who can provide the advances needed to realize social media's full potential. We are employing a Delphi study survey design, which is a technique for exploring and developing consensus among a group of experts around a particular topic. Participants include emergency managers and technologists with experience in software to support the use of social media in crisis response, from many countries. The topics of the study are described and preliminary, partial results presented for Round 1 of the study, based on 33 responses. © 2019 Information Systems for Crisis Response and Management, ISCRAM. All rights reserved.
1151 a35380198000 Sato Y. p396 False Journal 214 Preface [No abstract available]
1151 a35380198000 Sato Y. p885 False Journal 411 Preface [No abstract available]
1152 a57200723881 Yan D. p396 False Journal 214 Preface [No abstract available]
1152 a57200723881 Yan D. p885 False Journal 411 Preface [No abstract available]
1153 a7401952672 Rodríguez E. p397 True Journal 215 The winds and currents mission concept The Winds and Currents Mission (WaCM) is a proposed approach to meet the need identified by the NRC Decadal Survey for the simultaneous measurements of ocean vector winds and currents. WaCM features a Ka-band pencil-beam Doppler scatterometer able to map ocean winds and currents globally. We review the principles behind the WaCM measurement and the requirements driving the mission. We then present an overview of the WaCM observatory and tie its capabilities to other OceanObs reviews and measurement approaches. © 2019 Rodríguez, Bourassa, Chelton, Farrar, Long, Perkovic-Martin and Samelson.
1154 a35556946600 Bourassa M. p397 False Journal 215 The winds and currents mission concept The Winds and Currents Mission (WaCM) is a proposed approach to meet the need identified by the NRC Decadal Survey for the simultaneous measurements of ocean vector winds and currents. WaCM features a Ka-band pencil-beam Doppler scatterometer able to map ocean winds and currents globally. We review the principles behind the WaCM measurement and the requirements driving the mission. We then present an overview of the WaCM observatory and tie its capabilities to other OceanObs reviews and measurement approaches. © 2019 Rodríguez, Bourassa, Chelton, Farrar, Long, Perkovic-Martin and Samelson.
1155 a7004590414 Chelton D. p397 False Journal 215 The winds and currents mission concept The Winds and Currents Mission (WaCM) is a proposed approach to meet the need identified by the NRC Decadal Survey for the simultaneous measurements of ocean vector winds and currents. WaCM features a Ka-band pencil-beam Doppler scatterometer able to map ocean winds and currents globally. We review the principles behind the WaCM measurement and the requirements driving the mission. We then present an overview of the WaCM observatory and tie its capabilities to other OceanObs reviews and measurement approaches. © 2019 Rodríguez, Bourassa, Chelton, Farrar, Long, Perkovic-Martin and Samelson.
1156 a43261827400 Thomas Farrar J. p397 False Journal 215 The winds and currents mission concept The Winds and Currents Mission (WaCM) is a proposed approach to meet the need identified by the NRC Decadal Survey for the simultaneous measurements of ocean vector winds and currents. WaCM features a Ka-band pencil-beam Doppler scatterometer able to map ocean winds and currents globally. We review the principles behind the WaCM measurement and the requirements driving the mission. We then present an overview of the WaCM observatory and tie its capabilities to other OceanObs reviews and measurement approaches. © 2019 Rodríguez, Bourassa, Chelton, Farrar, Long, Perkovic-Martin and Samelson.
1157 a55428435400 Perkovic-Martin D. p397 False Journal 215 The winds and currents mission concept The Winds and Currents Mission (WaCM) is a proposed approach to meet the need identified by the NRC Decadal Survey for the simultaneous measurements of ocean vector winds and currents. WaCM features a Ka-band pencil-beam Doppler scatterometer able to map ocean winds and currents globally. We review the principles behind the WaCM measurement and the requirements driving the mission. We then present an overview of the WaCM observatory and tie its capabilities to other OceanObs reviews and measurement approaches. © 2019 Rodríguez, Bourassa, Chelton, Farrar, Long, Perkovic-Martin and Samelson.
1158 a7004611313 Samelson R. p397 False Journal 215 The winds and currents mission concept The Winds and Currents Mission (WaCM) is a proposed approach to meet the need identified by the NRC Decadal Survey for the simultaneous measurements of ocean vector winds and currents. WaCM features a Ka-band pencil-beam Doppler scatterometer able to map ocean winds and currents globally. We review the principles behind the WaCM measurement and the requirements driving the mission. We then present an overview of the WaCM observatory and tie its capabilities to other OceanObs reviews and measurement approaches. © 2019 Rodríguez, Bourassa, Chelton, Farrar, Long, Perkovic-Martin and Samelson.
1159 a7004507225 Lemonnier D. p398 False Conference 145 Locally correlated slw model for prediction of gas radiation in non-uniform media Following previous theoretical development based on the assumption of a rank correlated/comonotonic spectrum, the Locally Correlated SLW (LC-SLW) method is outlined. The relationship between the LC-SLW method and the RC-SLW method is established, and their performance in prediction of radiative transfer is compared. Despite the fact that the RC-SLW model demonstrates better overall accuracy, the LC-SLW model generally proves more accurate in regions of higher gas temperature. © Begell House Inc. 2020.
1159 a7004507225 Lemonnier D. p877 False Conference 393 The scaled SLW model of gas radiation in non-uniform media The Scaled SLW model for prediction of radiation transfer in non-uniform gaseous media is presented. Construction of the scaled spectral model is described. The model development yields a scaling coefficient which, unlike previous scaled model approaches, is calculated by explicit expressions in terms of the first and minus first moments of absorption cross-section. The Scaled SLW model complements the previously developed correlated SLW models. The proposed scaled model is suitable for engineering applications in comprehensive heat and mass transfer problems. © 2017, Begell House Inc. All Rights Reserved.
1160 a57193568214 Coelho F. p399 False Conference 146 Accuracy of engineering methods for radiative transfer in CO2-H2O mixtures at high temperature The aim of the paper is to evaluate a set of recently proposed engineering methods of gas radiation. For this purpose, a 3D stochastic ray tracing code was developed to treat realistic geometries. Model parameters based on the same LBL dataset were constructed for all approximate methods. Comparisons consist of two steps: 1/ a set of rays randomly spread over the unit sphere is chosen and narrow band models are assessed against LBL calculations. The most accurate narrow band method is chosen as the reference, 2/ all models are then compared with the chosen reference. For the cases considered in this paper, it was found that: 1/ the l-distribution approach is more accurate than Ck methods and can be used as the reference; 2/ the RC-SLW model provides very accurate predictions; 3/ the WSGG technique, which is the fastest method considered in this work, provides acceptable estimations, even in highly non-isothermal situations. © Begell House Inc. 2020.
1160 a57193568214 Coelho F. p400 False Conference 147 Assessment of engineering gas radiative property models in high pressure turbulent jet diffusion flames This article is a part of a more general study which aims to determine the most relevant engineering gas radiative property models to be applied in the simulations of combustion problems. Two versions of the full-spectrum CK (FSCK) model, the Rank-Correlated full-spectrum kdistribution/ Spectral-Line-Weighted-sum-of-gray-gases (RC FSK/SLW) and a new version of the Weighted-Sum-of-Grey-Gases (WSGG) model are compared with the Narrow-Band CK (NBCK) model in four turbulent axisymmetric jet diffusion flames fueled either by hydrogen or methane at atmospheric and higher pressures. As a first step, these comparisons are performed in decoupled radiative heat transfer calculations with the thermal fields being prescribed. The databases and coefficients associated to these different models are determined from a unique Line-By-Line database in order to allow a relevant comparison. Model results suggest that the SLW/FSK methods coupled to the Cai's scheme (JQSRT 141 (2014) 65-92) or the Rank-Correlated spectrum (JQSRT 214 (2018) 120-32) and databases generated from accurate LBL database are the most mature gas radiative property models to be implemented in CFD code dealing with combustion problems involving complex geometry and gas-soot mixtures. © Begell House Inc. 2020.
1161 a6506341914 Consalvi J.-L. p399 False Conference 146 Accuracy of engineering methods for radiative transfer in CO2-H2O mixtures at high temperature The aim of the paper is to evaluate a set of recently proposed engineering methods of gas radiation. For this purpose, a 3D stochastic ray tracing code was developed to treat realistic geometries. Model parameters based on the same LBL dataset were constructed for all approximate methods. Comparisons consist of two steps: 1/ a set of rays randomly spread over the unit sphere is chosen and narrow band models are assessed against LBL calculations. The most accurate narrow band method is chosen as the reference, 2/ all models are then compared with the chosen reference. For the cases considered in this paper, it was found that: 1/ the l-distribution approach is more accurate than Ck methods and can be used as the reference; 2/ the RC-SLW model provides very accurate predictions; 3/ the WSGG technique, which is the fastest method considered in this work, provides acceptable estimations, even in highly non-isothermal situations. © Begell House Inc. 2020.
1161 a6506341914 Consalvi J.-L. p400 True Conference 147 Assessment of engineering gas radiative property models in high pressure turbulent jet diffusion flames This article is a part of a more general study which aims to determine the most relevant engineering gas radiative property models to be applied in the simulations of combustion problems. Two versions of the full-spectrum CK (FSCK) model, the Rank-Correlated full-spectrum kdistribution/ Spectral-Line-Weighted-sum-of-gray-gases (RC FSK/SLW) and a new version of the Weighted-Sum-of-Grey-Gases (WSGG) model are compared with the Narrow-Band CK (NBCK) model in four turbulent axisymmetric jet diffusion flames fueled either by hydrogen or methane at atmospheric and higher pressures. As a first step, these comparisons are performed in decoupled radiative heat transfer calculations with the thermal fields being prescribed. The databases and coefficients associated to these different models are determined from a unique Line-By-Line database in order to allow a relevant comparison. Model results suggest that the SLW/FSK methods coupled to the Cai's scheme (JQSRT 141 (2014) 65-92) or the Rank-Correlated spectrum (JQSRT 214 (2018) 120-32) and databases generated from accurate LBL database are the most mature gas radiative property models to be implemented in CFD code dealing with combustion problems involving complex geometry and gas-soot mixtures. © Begell House Inc. 2020.
1162 a7005053199 Franca F. p399 False Conference 146 Accuracy of engineering methods for radiative transfer in CO2-H2O mixtures at high temperature The aim of the paper is to evaluate a set of recently proposed engineering methods of gas radiation. For this purpose, a 3D stochastic ray tracing code was developed to treat realistic geometries. Model parameters based on the same LBL dataset were constructed for all approximate methods. Comparisons consist of two steps: 1/ a set of rays randomly spread over the unit sphere is chosen and narrow band models are assessed against LBL calculations. The most accurate narrow band method is chosen as the reference, 2/ all models are then compared with the chosen reference. For the cases considered in this paper, it was found that: 1/ the l-distribution approach is more accurate than Ck methods and can be used as the reference; 2/ the RC-SLW model provides very accurate predictions; 3/ the WSGG technique, which is the fastest method considered in this work, provides acceptable estimations, even in highly non-isothermal situations. © Begell House Inc. 2020.
1162 a7005053199 Franca F. p400 False Conference 147 Assessment of engineering gas radiative property models in high pressure turbulent jet diffusion flames This article is a part of a more general study which aims to determine the most relevant engineering gas radiative property models to be applied in the simulations of combustion problems. Two versions of the full-spectrum CK (FSCK) model, the Rank-Correlated full-spectrum kdistribution/ Spectral-Line-Weighted-sum-of-gray-gases (RC FSK/SLW) and a new version of the Weighted-Sum-of-Grey-Gases (WSGG) model are compared with the Narrow-Band CK (NBCK) model in four turbulent axisymmetric jet diffusion flames fueled either by hydrogen or methane at atmospheric and higher pressures. As a first step, these comparisons are performed in decoupled radiative heat transfer calculations with the thermal fields being prescribed. The databases and coefficients associated to these different models are determined from a unique Line-By-Line database in order to allow a relevant comparison. Model results suggest that the SLW/FSK methods coupled to the Cai's scheme (JQSRT 141 (2014) 65-92) or the Rank-Correlated spectrum (JQSRT 214 (2018) 120-32) and databases generated from accurate LBL database are the most mature gas radiative property models to be implemented in CFD code dealing with combustion problems involving complex geometry and gas-soot mixtures. © Begell House Inc. 2020.
1163 a55671352500 Galtier M. p399 False Conference 146 Accuracy of engineering methods for radiative transfer in CO2-H2O mixtures at high temperature The aim of the paper is to evaluate a set of recently proposed engineering methods of gas radiation. For this purpose, a 3D stochastic ray tracing code was developed to treat realistic geometries. Model parameters based on the same LBL dataset were constructed for all approximate methods. Comparisons consist of two steps: 1/ a set of rays randomly spread over the unit sphere is chosen and narrow band models are assessed against LBL calculations. The most accurate narrow band method is chosen as the reference, 2/ all models are then compared with the chosen reference. For the cases considered in this paper, it was found that: 1/ the l-distribution approach is more accurate than Ck methods and can be used as the reference; 2/ the RC-SLW model provides very accurate predictions; 3/ the WSGG technique, which is the fastest method considered in this work, provides acceptable estimations, even in highly non-isothermal situations. © Begell House Inc. 2020.
1163 a55671352500 Galtier M. p400 False Conference 147 Assessment of engineering gas radiative property models in high pressure turbulent jet diffusion flames This article is a part of a more general study which aims to determine the most relevant engineering gas radiative property models to be applied in the simulations of combustion problems. Two versions of the full-spectrum CK (FSCK) model, the Rank-Correlated full-spectrum kdistribution/ Spectral-Line-Weighted-sum-of-gray-gases (RC FSK/SLW) and a new version of the Weighted-Sum-of-Grey-Gases (WSGG) model are compared with the Narrow-Band CK (NBCK) model in four turbulent axisymmetric jet diffusion flames fueled either by hydrogen or methane at atmospheric and higher pressures. As a first step, these comparisons are performed in decoupled radiative heat transfer calculations with the thermal fields being prescribed. The databases and coefficients associated to these different models are determined from a unique Line-By-Line database in order to allow a relevant comparison. Model results suggest that the SLW/FSK methods coupled to the Cai's scheme (JQSRT 141 (2014) 65-92) or the Rank-Correlated spectrum (JQSRT 214 (2018) 120-32) and databases generated from accurate LBL database are the most mature gas radiative property models to be implemented in CFD code dealing with combustion problems involving complex geometry and gas-soot mixtures. © Begell House Inc. 2020.
1164 a22952048100 Nmira F. p399 False Conference 146 Accuracy of engineering methods for radiative transfer in CO2-H2O mixtures at high temperature The aim of the paper is to evaluate a set of recently proposed engineering methods of gas radiation. For this purpose, a 3D stochastic ray tracing code was developed to treat realistic geometries. Model parameters based on the same LBL dataset were constructed for all approximate methods. Comparisons consist of two steps: 1/ a set of rays randomly spread over the unit sphere is chosen and narrow band models are assessed against LBL calculations. The most accurate narrow band method is chosen as the reference, 2/ all models are then compared with the chosen reference. For the cases considered in this paper, it was found that: 1/ the l-distribution approach is more accurate than Ck methods and can be used as the reference; 2/ the RC-SLW model provides very accurate predictions; 3/ the WSGG technique, which is the fastest method considered in this work, provides acceptable estimations, even in highly non-isothermal situations. © Begell House Inc. 2020.
1164 a22952048100 Nmira F. p400 False Conference 147 Assessment of engineering gas radiative property models in high pressure turbulent jet diffusion flames This article is a part of a more general study which aims to determine the most relevant engineering gas radiative property models to be applied in the simulations of combustion problems. Two versions of the full-spectrum CK (FSCK) model, the Rank-Correlated full-spectrum kdistribution/ Spectral-Line-Weighted-sum-of-gray-gases (RC FSK/SLW) and a new version of the Weighted-Sum-of-Grey-Gases (WSGG) model are compared with the Narrow-Band CK (NBCK) model in four turbulent axisymmetric jet diffusion flames fueled either by hydrogen or methane at atmospheric and higher pressures. As a first step, these comparisons are performed in decoupled radiative heat transfer calculations with the thermal fields being prescribed. The databases and coefficients associated to these different models are determined from a unique Line-By-Line database in order to allow a relevant comparison. Model results suggest that the SLW/FSK methods coupled to the Cai's scheme (JQSRT 141 (2014) 65-92) or the Rank-Correlated spectrum (JQSRT 214 (2018) 120-32) and databases generated from accurate LBL database are the most mature gas radiative property models to be implemented in CFD code dealing with combustion problems involving complex geometry and gas-soot mixtures. © Begell House Inc. 2020.
1165 a6507447149 Pastusek P. p401 True Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1166 a23012428800 Payette G. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1167 a56642521500 Shor R. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1168 a24780432200 Cayeux E. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1169 a55233755100 Aarsnes U.J. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1170 a7801636116 Menand S. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1171 a7101973402 Macpherson J. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1172 a35368447500 Gandikota R. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1173 a7801530241 Behounek M. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1174 a56689651300 Harmer R. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1175 a7005786977 Detournay E. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1176 a7801609389 Illerhaus R. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1177 a55922401500 Liu Y. p401 False Conference 148 Creating open source models, test cases, and data for oilfield drilling challenges The drilling industry has substantially improved performance based on knowledge from physics-based, statistical, and empirical models of components and systems. However, most models and source code have been recreated multiple times, which requires significant effort and energy with little additional benefit or step-wise improvements. The authors propose that it is time to form a coalition of industry and academic leaders to support an open source effort for drilling, to encourage the reuse of continuously improving models and coding efforts. The vision for this guiding coalition is to 1) set up a repository for source code, data, benchmarks, and documentation, 2) encourage good coding practices, 3) review and comment on the models and data submitted, 4) test, use and improve the code, 5) propose and collect anonymized real data, 6) attract talent and support to the effort, and 7) mentor those getting started. Those interested to add their time and talent to the cause may publish their results through peer-reviewed literature. Several online meetings are planned to create this coalition, establish a charter, and layout the guiding principles. Multiple support avenues are proposed to sustain the effort such as: annual user group meetings, create a SPE Technical Section, and initiating a Joint Industry Program (JIP). The Open Porous Media Initiative is just one example of how this could be organized and maintained. As a starting point, this paper reviews existing published drilling models and highlights the similarities and differences for commonly used drillstring hydraulics, dynamics, directional, and bit-rock interaction models. The key requirements for re-usability of the models and code are: 1) The model itself must be available as open source, well documented with the objective and expected outcomes, include commented code, and shared in a publicly available repository which can be updated, 2) A user's guide must include how to run the core software, how to extend software capabilities, i.e., plug in new features or elements, 3) Include a "theory" manual to explain the fundamental principles, the base equations, any assumptions, and the known limitations, 4) Data examples and formatting requirements to cover a diversity of drilling operations, and 5) Test cases to benchmark the performance and output of different proposed models. In May 2018 at "The 4th International Colloquium on Non-linear dynamics and control of deep drilling systems," the keynote question was, "Is it time to start using open source models?" The answer is "yes". Modeling the drilling process is done to help drill a round, ledge free hole, without patterns, with minimum vibration, minimum unplanned dog legs, that reaches all geological targets, in one run per section, and in the least time possible. An open source repository for drilling will speed up the rate of learning and automation efforts to achieve this goal throughout the entire well execution workflow, including planning, BHA design, real-time operations, and post well analysis. Copyright 2019, SPE/IADC International Drilling Conference and Exhibition.
1178 a57191525048 Allender E.J. p402 True Journal 216 Traverses for the ISECG-GER design reference mission for humans on the lunar surface This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts. © 2018 COSPAR
1179 a41262329300 Orgel C. p402 False Journal 216 Traverses for the ISECG-GER design reference mission for humans on the lunar surface This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts. © 2018 COSPAR
1180 a57203758421 Almeida N.V. p402 False Journal 216 Traverses for the ISECG-GER design reference mission for humans on the lunar surface This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts. © 2018 COSPAR
1181 a57203801188 Cook J. p402 False Journal 216 Traverses for the ISECG-GER design reference mission for humans on the lunar surface This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts. © 2018 COSPAR
1182 a57203805526 Ende J.J. p402 False Journal 216 Traverses for the ISECG-GER design reference mission for humans on the lunar surface This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts. © 2018 COSPAR
1183 a57202763603 Kamps O. p402 False Journal 216 Traverses for the ISECG-GER design reference mission for humans on the lunar surface This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts. © 2018 COSPAR
1184 a56116155300 Mazrouei S. p402 False Journal 216 Traverses for the ISECG-GER design reference mission for humans on the lunar surface This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts. © 2018 COSPAR
1185 a57203801050 Slezak T.J. p402 False Journal 216 Traverses for the ISECG-GER design reference mission for humans on the lunar surface This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts. © 2018 COSPAR
1186 a57199854443 Soini A.-J. p402 False Journal 216 Traverses for the ISECG-GER design reference mission for humans on the lunar surface This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts. © 2018 COSPAR
1187 a56979909000 Kring D.A. p402 False Journal 216 Traverses for the ISECG-GER design reference mission for humans on the lunar surface This study explores the Design Reference Mission (DRM) architecture developed by Hufenbach et al. (2015) as a prelude to the release of the 2018 Global Exploration Roadmap (GER) developed by the International Space Exploration Coordination Group (ISECG). The focus of this study is the exploration of the south polar region of the Moon, a region that has not been visited by any human missions, yet exhibits a multitude of scientifically important locations – the investigation of which will address long standing questions in lunar research. This DRM architecture involves five landing sites (Malapert massif, South Pole/Shackleton crater, Schrödinger basin, Antoniadi crater, and the South Pole-Aitken basin center), to be visited in sequential years by crew, beginning in 2028. Two Lunar Electric Rovers (LER) are proposed to be tele-robotically operated between sites to rendez-vous with crew at the time of the next landing. With engineering parameters in mind we explore the feasibility of tele-robotic operation of these LERs between lunar landing sites, and identify potential high interest sampling locations en-route. Additionally, in-depth sample collection and return traverses are identified for each individual landing site across key geologic terrains that also detail crew Extra-Vehicular Activity (EVA). Exploration at and between landing sites is designed to address a suite of National Research Council (2007) scientific concepts. © 2018 COSPAR
1188 a57205650285 Leavitt J.C. p404 False Conference 150 Neutron Radiation Beam Results for the Xilinx UltraScale+ MPSoC The paper summarizes the single-event upset (SEU) results obtained from neutron testing on the UltraScale+ MPSoC ZU9EG device. This complex device contains a large amount of programmable logic and multiple processor cores. Tests were performed on the programmable logic and the processing system simultaneously. Estimates of the single-event upset neutron cross section were obtained for the programmable logic CRAM, BRAM, OCM memory, and cache memories. During the test, no processor crashes or silent data corruptions were observed. In addition, a processor failure cross section was estimated for several software benchmark operating on the various processor cores. Several FPGA CRAM scrubbers were tested including an external JTAG, the Xilinx 'SEM' IP, and the use of the PCAP operating in baremetal. In parallel with these tests, single-event induced high current events were monitored using an external power supply and monitoring scripts. © 2018 IEEE.
1189 a56698926600 Lee D.S. p405 True Conference 151 Single-Event Characterization of 16 nm FinFET Xilinx UltraScale+ Devices with Heavy Ion and Neutron Irradiation This study examines the single-event response of Xilinx 16nm FinFET UltraScale+ FPGA and MPSoC device families. Heavy-ion single-event latch-up, single-event upsets in configuration SRAM, BlockRAM™ memories, and flip-flops, and neutron-induced single-event latch-up results are provided. © 2018 IEEE.
1190 a55627591500 King M. p405 False Conference 151 Single-Event Characterization of 16 nm FinFET Xilinx UltraScale+ Devices with Heavy Ion and Neutron Irradiation This study examines the single-event response of Xilinx 16nm FinFET UltraScale+ FPGA and MPSoC device families. Heavy-ion single-event latch-up, single-event upsets in configuration SRAM, BlockRAM™ memories, and flip-flops, and neutron-induced single-event latch-up results are provided. © 2018 IEEE.
1191 a57205652485 Evans W. p405 False Conference 151 Single-Event Characterization of 16 nm FinFET Xilinx UltraScale+ Devices with Heavy Ion and Neutron Irradiation This study examines the single-event response of Xilinx 16nm FinFET UltraScale+ FPGA and MPSoC device families. Heavy-ion single-event latch-up, single-event upsets in configuration SRAM, BlockRAM™ memories, and flip-flops, and neutron-induced single-event latch-up results are provided. © 2018 IEEE.
1192 a57193683516 Rice W. p405 False Conference 151 Single-Event Characterization of 16 nm FinFET Xilinx UltraScale+ Devices with Heavy Ion and Neutron Irradiation This study examines the single-event response of Xilinx 16nm FinFET UltraScale+ FPGA and MPSoC device families. Heavy-ion single-event latch-up, single-event upsets in configuration SRAM, BlockRAM™ memories, and flip-flops, and neutron-induced single-event latch-up results are provided. © 2018 IEEE.
1193 a57202192401 Kim K.M. p408 True Journal 218 Evaluating Safety Impacts of Access Management Alternatives with the Surrogate Safety Assessment Model In a traditional safety impact analysis, it is necessary to have crash data on existing roadway conditions and a few years must pass before accumulating additional crash data to evaluate the safety impact of an improvement. This is a time-consuming approach and there remains uncertainty in the crash data integrity. The surrogate safety assessment model (SSAM) was developed for resolving these issues. With SSAM, a conflict analysis is performed in a simulated environment. A planned improvement alternative is modeled and no physical installation of the alternative is needed. This study evaluated if SSAM can be used to assess the safety of a highway segment in terms of the number and type of conflicts and to compare the safety effects of multiple access management alternatives. An evaluation of the effect of converting a two-way left-turn lane (TWLTL) into a raised median on a section of an urban street was performed using SSAM working on VISSIM simulation’s trajectory files. The analysis showed that a raised median would be much safer than a TWLTL median for the same level of traffic volume, with approximately 32 to 50 percent reduction in the number of crossing conflicts. The analysis showed that about 34,000 to 38,000 veh/day would be the demand level where the median conversion is recommended for the four-lane study section. The study concluded that the combination of a simulation software program with SSAM could be a viable surrogate analysis approach for evaluating and comparing the safety effects of multiple access management alternatives. © National Academy of Sciences: Transportation Research Board 2018.
1194 a57203191415 Russell B.D. p409 False Journal 219 Regional Stiffness Reduction Using Lamina Emergent Torsional Joints for Flexible Printed Circuit Board Design Flexible printed circuit boards (PCBs) make it possible for engineers to design devices that use space efficiently and can undergo changes in shape and configuration. However, they also suffer from tradeoffs due to nonideal material properties. Here, a method is presented that allows engineers to introduce regions of flexibility in otherwise rigid PCB substrates. This method employs geometric features to reduce local stiffness in the PCB, rather than reducing the global stiffness by material selection. Analytical and finite element models are presented to calculate the maximum stresses caused by deflection. An example device is produced and tested to verify the models. Copyright © 2018 by ASME.
1195 a57203142381 Emerson P. p410 False Journal 220 Influence of microstructure geometry on pool boiling at superhydrophobic surfaces Periodically patterned superhydrophobic surfaces with rectangular rib and circular post arrays were utilized as heat transfer surfaces in a boiling apparatus with the water pool undergoing saturated pool boiling. The surface microstructures were geometrically defined by cavity fraction (the ratio of projected cavity area to surface area), pitch (the center to center distance between microfeatures), and feature height. Surface heat flux and surface superheat, the difference between the heated surface and the pool saturation temperature, were measured for each surface. Ten different micropatterned surfaces with post or rib geometries were considered with cavity fraction varying from 0.5 to 0.98, pitch varying from 8 to 40 μm, and microfeature height at 4 μm or 15 μm. The surface heat flux was measured across a range of surface superheats spanning 2–38 K. It is demonstrated for the first time that the transition from nucleate boiling to film boiling on rib patterned surfaces depends strongly on the cavity fraction. Increasing the microstructure height from 4 μm to 15 μm modestly increases the transition temperature. Nucleate boiling is more suppressed on post patterned surfaces than on rib patterned surfaces. Further, the rib structured surfaces exhibit a sudden transition from nucleate to film boiling while the post structured surfaces exhibit a gradual transition, with the vapor film growing slowly across the surface. Once stable film boiling is reached, the surface microstructure negligibly influences the heat flux for all surfaces. © 2018 Elsevier Ltd
1196 a57204916397 Duffy C. p411 True Journal 221 Feasibility of induced pluripotent stem cell therapies for treatment of type 1 diabetes Despite their potential for treating type 1 diabetes (T1D), induced pluripotent stem cells (iPSCs) have not yet been used successfully in the clinic. In this article, advances in iPSC therapies are reviewed and compared with current methods of treating T1D. Encapsulation of iPSCs is being pursued to address such safety concerns as the possibility of immune rejection or teratoma formation, and provide for retrievability. Issues of material selection, cell differentiation, size of islet aggregates, sites of implantation, animal models, and vascularization are also being addressed. Clinical trials are being conducted to test a variety of new devices with the hope of providing additional therapies for T1D. This review of iPSCs to treat T1D provides a current assessment of the challenges and potential for this proposed new therapy. © Copyright 2018, Mary Ann Liebert, Inc., publishers 2018.
1197 a57204916190 Prugue C. p411 False Journal 221 Feasibility of induced pluripotent stem cell therapies for treatment of type 1 diabetes Despite their potential for treating type 1 diabetes (T1D), induced pluripotent stem cells (iPSCs) have not yet been used successfully in the clinic. In this article, advances in iPSC therapies are reviewed and compared with current methods of treating T1D. Encapsulation of iPSCs is being pursued to address such safety concerns as the possibility of immune rejection or teratoma formation, and provide for retrievability. Issues of material selection, cell differentiation, size of islet aggregates, sites of implantation, animal models, and vascularization are also being addressed. Clinical trials are being conducted to test a variety of new devices with the hope of providing additional therapies for T1D. This review of iPSCs to treat T1D provides a current assessment of the challenges and potential for this proposed new therapy. © Copyright 2018, Mary Ann Liebert, Inc., publishers 2018.
1198 a57204910117 Glew R. p411 False Journal 221 Feasibility of induced pluripotent stem cell therapies for treatment of type 1 diabetes Despite their potential for treating type 1 diabetes (T1D), induced pluripotent stem cells (iPSCs) have not yet been used successfully in the clinic. In this article, advances in iPSC therapies are reviewed and compared with current methods of treating T1D. Encapsulation of iPSCs is being pursued to address such safety concerns as the possibility of immune rejection or teratoma formation, and provide for retrievability. Issues of material selection, cell differentiation, size of islet aggregates, sites of implantation, animal models, and vascularization are also being addressed. Clinical trials are being conducted to test a variety of new devices with the hope of providing additional therapies for T1D. This review of iPSCs to treat T1D provides a current assessment of the challenges and potential for this proposed new therapy. © Copyright 2018, Mary Ann Liebert, Inc., publishers 2018.
1199 a57198809206 Smith T. p411 False Journal 221 Feasibility of induced pluripotent stem cell therapies for treatment of type 1 diabetes Despite their potential for treating type 1 diabetes (T1D), induced pluripotent stem cells (iPSCs) have not yet been used successfully in the clinic. In this article, advances in iPSC therapies are reviewed and compared with current methods of treating T1D. Encapsulation of iPSCs is being pursued to address such safety concerns as the possibility of immune rejection or teratoma formation, and provide for retrievability. Issues of material selection, cell differentiation, size of islet aggregates, sites of implantation, animal models, and vascularization are also being addressed. Clinical trials are being conducted to test a variety of new devices with the hope of providing additional therapies for T1D. This review of iPSCs to treat T1D provides a current assessment of the challenges and potential for this proposed new therapy. © Copyright 2018, Mary Ann Liebert, Inc., publishers 2018.
1200 a57204925116 Howell C. p411 False Journal 221 Feasibility of induced pluripotent stem cell therapies for treatment of type 1 diabetes Despite their potential for treating type 1 diabetes (T1D), induced pluripotent stem cells (iPSCs) have not yet been used successfully in the clinic. In this article, advances in iPSC therapies are reviewed and compared with current methods of treating T1D. Encapsulation of iPSCs is being pursued to address such safety concerns as the possibility of immune rejection or teratoma formation, and provide for retrievability. Issues of material selection, cell differentiation, size of islet aggregates, sites of implantation, animal models, and vascularization are also being addressed. Clinical trials are being conducted to test a variety of new devices with the hope of providing additional therapies for T1D. This review of iPSCs to treat T1D provides a current assessment of the challenges and potential for this proposed new therapy. © Copyright 2018, Mary Ann Liebert, Inc., publishers 2018.
1201 a57204911023 Choi G. p411 False Journal 221 Feasibility of induced pluripotent stem cell therapies for treatment of type 1 diabetes Despite their potential for treating type 1 diabetes (T1D), induced pluripotent stem cells (iPSCs) have not yet been used successfully in the clinic. In this article, advances in iPSC therapies are reviewed and compared with current methods of treating T1D. Encapsulation of iPSCs is being pursued to address such safety concerns as the possibility of immune rejection or teratoma formation, and provide for retrievability. Issues of material selection, cell differentiation, size of islet aggregates, sites of implantation, animal models, and vascularization are also being addressed. Clinical trials are being conducted to test a variety of new devices with the hope of providing additional therapies for T1D. This review of iPSCs to treat T1D provides a current assessment of the challenges and potential for this proposed new therapy. © Copyright 2018, Mary Ann Liebert, Inc., publishers 2018.
1202 a55303499100 Bowen L. p412 False Journal 222 A model for multi-input mechanical advantage in origami-based mechanisms Mechanical advantage is traditionally defined for single-input and single-output rigidbody mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origamibased mechanisms are capable of offering unique solutions to engineering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi-input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. © 2018 by ASME.
1203 a56577817900 Wilcox E. p412 False Journal 222 A model for multi-input mechanical advantage in origami-based mechanisms Mechanical advantage is traditionally defined for single-input and single-output rigidbody mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origamibased mechanisms are capable of offering unique solutions to engineering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi-input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. © 2018 by ASME.
1204 a57189623841 Shrager A. p412 False Journal 222 A model for multi-input mechanical advantage in origami-based mechanisms Mechanical advantage is traditionally defined for single-input and single-output rigidbody mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origamibased mechanisms are capable of offering unique solutions to engineering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi-input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. © 2018 by ASME.
1205 a7003678761 Frecker M.I. p412 False Journal 222 A model for multi-input mechanical advantage in origami-based mechanisms Mechanical advantage is traditionally defined for single-input and single-output rigidbody mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origamibased mechanisms are capable of offering unique solutions to engineering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi-input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. © 2018 by ASME.
1206 a6602997992 von Lockette P. p412 False Journal 222 A model for multi-input mechanical advantage in origami-based mechanisms Mechanical advantage is traditionally defined for single-input and single-output rigidbody mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origamibased mechanisms are capable of offering unique solutions to engineering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi-input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. © 2018 by ASME.
1207 a7202539045 Simpson T.W. p412 False Journal 222 A model for multi-input mechanical advantage in origami-based mechanisms Mechanical advantage is traditionally defined for single-input and single-output rigidbody mechanisms. A generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms, would prove useful in predicting complex mechanism behavior. While origamibased mechanisms are capable of offering unique solutions to engineering problems, the design process of such mechanisms is complicated by the interaction of motion and forces. This paper presents a model of the mechanical advantage for multi-input compliant mechanisms and explores how modifying the parameters of a model affects their behavior. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. © 2018 by ASME.
1208 a55710750200 Temple K. p414 False Journal 224 Spectrum allocations: The aeronautical telemetry story in the USA Aeronautical telemetry encompasses all the technologies necessary to successfully monitor airborne test articles, such as fixed and rotary wing aircraft, missiles, and drones. Aeronautical telemetry is primarily focused on the final stages of development when the test article performs the maneuvers required to operate in its deployed environment. Necessarily, the test article is 'in the air' while the flight test engineers who monitor its performance are 'on the ground.' The key enabling resource for aeronautical telemetry is spectrum: bandwidth is needed to transmit the measurements from the test article to the ground so flight test engineers can monitor the test, the safety of which is paramount. © 1986-2012 IEEE.
1208 a55710750200 Temple K. p712 False Journal 350 Space-Time Coding for Aeronautical Telemetry: Part II - Decoder and System Performance This paper describes the use of Alamouti-encoded-shaped offset QPSK version TG (SOQPSK-TG) to solve the two-antenna problem in aeronautical telemetry. The Alamouti space-time block code is used to encode the phase states in the complex exponential representation of SOQPSK-TG. Because SOQPSK-TG possesses memory, the Alamouti decoder is a sequence estimator. Maximum likelihood and least squares sequence decoders are derived. To reduce the number of states, the eight-waveform cross-correlated trellis-coded quadrature modulation (XTCQM) approximate representation of SOQPSK-TG is used. A prototype decoder based on the least squares decoder and the estimators described in Part I and operating at a data rate of 10 Mb/s was tested in the laboratory in test flights at the Air Force Test Center, Edwards AFB. The test flights demonstrate that Alamouti-encoded SOQPSK-TG, as described in this paper, using the least squares decoder based on the estimators described in Part I solves the two antenna problem in aeronautical telemetry. © 2017 IEEE.
1208 a55710750200 Temple K. p886 False Conference 398 A summary of data-aided equalizer experiments at edwards AFB This paper summarizes the analysis of bit error rate data captured during flight tests designed to compare data-aided equalizers with SOQPSK-TG to unequalized and currently available blind, adaptive equalizers with SOQPSK-TG. The number of bit errors, on a second-by-second basis, are analyzed. The results are different for each test point. Given the uncertain behavior of the preamble detector for the data-aided equalizer and the differing channel conditions between the data-aided equalizer channel and the conventional serial streaming telemetry channel, we are unable to draw any firm comparative conclusions.
1209 a6508087756 Chalfant T. p414 False Journal 224 Spectrum allocations: The aeronautical telemetry story in the USA Aeronautical telemetry encompasses all the technologies necessary to successfully monitor airborne test articles, such as fixed and rotary wing aircraft, missiles, and drones. Aeronautical telemetry is primarily focused on the final stages of development when the test article performs the maneuvers required to operate in its deployed environment. Necessarily, the test article is 'in the air' while the flight test engineers who monitor its performance are 'on the ground.' The key enabling resource for aeronautical telemetry is spectrum: bandwidth is needed to transmit the measurements from the test article to the ground so flight test engineers can monitor the test, the safety of which is paramount. © 1986-2012 IEEE.
1210 a57207110219 Ernst D. p414 False Journal 224 Spectrum allocations: The aeronautical telemetry story in the USA Aeronautical telemetry encompasses all the technologies necessary to successfully monitor airborne test articles, such as fixed and rotary wing aircraft, missiles, and drones. Aeronautical telemetry is primarily focused on the final stages of development when the test article performs the maneuvers required to operate in its deployed environment. Necessarily, the test article is 'in the air' while the flight test engineers who monitor its performance are 'on the ground.' The key enabling resource for aeronautical telemetry is spectrum: bandwidth is needed to transmit the measurements from the test article to the ground so flight test engineers can monitor the test, the safety of which is paramount. © 1986-2012 IEEE.
1211 a57214580514 Kahn C. p414 False Journal 224 Spectrum allocations: The aeronautical telemetry story in the USA Aeronautical telemetry encompasses all the technologies necessary to successfully monitor airborne test articles, such as fixed and rotary wing aircraft, missiles, and drones. Aeronautical telemetry is primarily focused on the final stages of development when the test article performs the maneuvers required to operate in its deployed environment. Necessarily, the test article is 'in the air' while the flight test engineers who monitor its performance are 'on the ground.' The key enabling resource for aeronautical telemetry is spectrum: bandwidth is needed to transmit the measurements from the test article to the ground so flight test engineers can monitor the test, the safety of which is paramount. © 1986-2012 IEEE.
1212 a57204110218 McGhin R.F. III p415 True Journal 225 Submerged hydraulic jump remediation at low-head dams: Partial width deflector design Low-head dams are capable of creating dangerous countercurrents just downstream from the structure. These dangerous countercurrents are known as submerged hydraulic jumps and are responsible for hundreds of fatalities at numerous low-head dams across the United States. The countercurrent creates high upstream-directed surface velocities across the width of the channel, making it nearly impossible for a trapped individual to escape. This submerged jump can occur for a range of upstream and downstream conditions. A multiple partial width deflector design for the downstream side of the dam was tested in the laboratory to determine effectiveness in completely or partially eliminating the submerged hydraulic jump. The results demonstrate that a dramatic reduction in upstream-directed surface velocities over a wide range of headwater and tailwater conditions is possible. The dam modification is relatively inexpensive, simple to install, and designed such that an individual will likely escape the submerged jump without severe injury or harm. The design is ready for prototype testing. © 2018 American Society of Civil Engineers.
1213 a56549581200 Kern E. p415 False Journal 225 Submerged hydraulic jump remediation at low-head dams: Partial width deflector design Low-head dams are capable of creating dangerous countercurrents just downstream from the structure. These dangerous countercurrents are known as submerged hydraulic jumps and are responsible for hundreds of fatalities at numerous low-head dams across the United States. The countercurrent creates high upstream-directed surface velocities across the width of the channel, making it nearly impossible for a trapped individual to escape. This submerged jump can occur for a range of upstream and downstream conditions. A multiple partial width deflector design for the downstream side of the dam was tested in the laboratory to determine effectiveness in completely or partially eliminating the submerged hydraulic jump. The results demonstrate that a dramatic reduction in upstream-directed surface velocities over a wide range of headwater and tailwater conditions is possible. The dam modification is relatively inexpensive, simple to install, and designed such that an individual will likely escape the submerged jump without severe injury or harm. The design is ready for prototype testing. © 2018 American Society of Civil Engineers.
1214 a55259726700 Jensen J.L. p416 True Journal 226 Investigating Strategies for Pre-Class Content Learning in a Flipped Classroom In a flipped classroom model, learning of basic content is shifted before class while in-class time is used for concept application. Empirical and controlled research studies are lacking on the best strategies to provide the necessary pre-class content instruction. In this study, we tested three methods of pre-class content learning—interactive online tutorials, video lectures, and textbook-style readings—while holding the content and the in-class application activities constant. Identical introductory, non-majors biology classes were manipulated at both a public, open-enrollment institution and a private, highly selective institution. We found that video lectures offer a small advantage to overall student learning over interactive tutorials or textbook-style readings. Although our two populations differed in their ability to effectively learn from pre-class activities, through a student-centered flipped classroom approach, students at both institutions demonstrated equal learning gains by the final assessment. Potential reasons for some observed differences are suggested. © 2018, The Author(s).
1215 a55256673100 Holt E.A. p416 False Journal 226 Investigating Strategies for Pre-Class Content Learning in a Flipped Classroom In a flipped classroom model, learning of basic content is shifted before class while in-class time is used for concept application. Empirical and controlled research studies are lacking on the best strategies to provide the necessary pre-class content instruction. In this study, we tested three methods of pre-class content learning—interactive online tutorials, video lectures, and textbook-style readings—while holding the content and the in-class application activities constant. Identical introductory, non-majors biology classes were manipulated at both a public, open-enrollment institution and a private, highly selective institution. We found that video lectures offer a small advantage to overall student learning over interactive tutorials or textbook-style readings. Although our two populations differed in their ability to effectively learn from pre-class activities, through a student-centered flipped classroom approach, students at both institutions demonstrated equal learning gains by the final assessment. Potential reasons for some observed differences are suggested. © 2018, The Author(s).
1216 a57202609763 Sowards J.B. p416 False Journal 226 Investigating Strategies for Pre-Class Content Learning in a Flipped Classroom In a flipped classroom model, learning of basic content is shifted before class while in-class time is used for concept application. Empirical and controlled research studies are lacking on the best strategies to provide the necessary pre-class content instruction. In this study, we tested three methods of pre-class content learning—interactive online tutorials, video lectures, and textbook-style readings—while holding the content and the in-class application activities constant. Identical introductory, non-majors biology classes were manipulated at both a public, open-enrollment institution and a private, highly selective institution. We found that video lectures offer a small advantage to overall student learning over interactive tutorials or textbook-style readings. Although our two populations differed in their ability to effectively learn from pre-class activities, through a student-centered flipped classroom approach, students at both institutions demonstrated equal learning gains by the final assessment. Potential reasons for some observed differences are suggested. © 2018, The Author(s).
1217 a6508265156 Heath Ogden T. p416 False Journal 226 Investigating Strategies for Pre-Class Content Learning in a Flipped Classroom In a flipped classroom model, learning of basic content is shifted before class while in-class time is used for concept application. Empirical and controlled research studies are lacking on the best strategies to provide the necessary pre-class content instruction. In this study, we tested three methods of pre-class content learning—interactive online tutorials, video lectures, and textbook-style readings—while holding the content and the in-class application activities constant. Identical introductory, non-majors biology classes were manipulated at both a public, open-enrollment institution and a private, highly selective institution. We found that video lectures offer a small advantage to overall student learning over interactive tutorials or textbook-style readings. Although our two populations differed in their ability to effectively learn from pre-class activities, through a student-centered flipped classroom approach, students at both institutions demonstrated equal learning gains by the final assessment. Potential reasons for some observed differences are suggested. © 2018, The Author(s).
1218 a56433927200 West R.E. p416 False Journal 226 Investigating Strategies for Pre-Class Content Learning in a Flipped Classroom In a flipped classroom model, learning of basic content is shifted before class while in-class time is used for concept application. Empirical and controlled research studies are lacking on the best strategies to provide the necessary pre-class content instruction. In this study, we tested three methods of pre-class content learning—interactive online tutorials, video lectures, and textbook-style readings—while holding the content and the in-class application activities constant. Identical introductory, non-majors biology classes were manipulated at both a public, open-enrollment institution and a private, highly selective institution. We found that video lectures offer a small advantage to overall student learning over interactive tutorials or textbook-style readings. Although our two populations differed in their ability to effectively learn from pre-class activities, through a student-centered flipped classroom approach, students at both institutions demonstrated equal learning gains by the final assessment. Potential reasons for some observed differences are suggested. © 2018, The Author(s).
1218 a56433927200 West R.E. p695 False Journal 338 The need, development, and validation of the innovation test instrument This study discusses the need, development, and validation of the Innovation Test Instrument (ITI). This article outlines how the researchers identified the content domain of the assessment and created test items. Then, it describes initial validation testing of the instrument. The findings suggest that the ITI is a good first step in creating an innovation assessment because it is more inclusive of both divergent and convergent thinking. In comparison, past innovation assessments have only assessed either divergence or convergence. The ITI still needs further validation and improvement to make strong claims about its ability to determine the effectiveness of an innovation course. © 2017, Virginia Polytechnic Institute. All rights reserved.
1219 a7404022739 Cox J.J. p417 True Journal 227 Simulated Microstructural and Compositional Evolution of U-Pu-Zr Alloys Using the Potts-Phase Field Modeling Technique U-Pu-Zr alloys are considered ideal metallic fuels for experimental breeder reactors because of their superior material properties and potential for increased burnup performance. However, significant constituent redistribution has been observed in these alloys when irradiated, or subject to a thermal gradient, resulting in inhomogeneity of both composition and phase, which, in turn, alters the fuel performance. The hybrid Potts-phase field method is reformulated for ternary alloys in a thermal gradient and utilized to simulate and predict constituent redistribution and phase transformations in the U-Pu-Zr nuclear fuel system. Simulated evolution profiles for the U-16Pu-23Zr (at. pct) alloy show concentric zones that are compared with published experimental results; discrepancies in zone size are attributed to thermal profile differences and assumptions related to the diffusivity values used. Twenty-one alloys, over the entire ternary compositional spectrum, are also simulated to investigate the effects of alloy composition on constituent redistribution and phase transformations. The U-40Pu-20Zr (at. pct) alloy shows the most potential for compositional uniformity and phase homogeneity, throughout a thermal gradient, while remaining in the compositional range of feasible alloys. © 2018, The Minerals, Metals & Materials Society and ASM International.
1220 a7003352704 Tikare V. p417 False Journal 227 Simulated Microstructural and Compositional Evolution of U-Pu-Zr Alloys Using the Potts-Phase Field Modeling Technique U-Pu-Zr alloys are considered ideal metallic fuels for experimental breeder reactors because of their superior material properties and potential for increased burnup performance. However, significant constituent redistribution has been observed in these alloys when irradiated, or subject to a thermal gradient, resulting in inhomogeneity of both composition and phase, which, in turn, alters the fuel performance. The hybrid Potts-phase field method is reformulated for ternary alloys in a thermal gradient and utilized to simulate and predict constituent redistribution and phase transformations in the U-Pu-Zr nuclear fuel system. Simulated evolution profiles for the U-16Pu-23Zr (at. pct) alloy show concentric zones that are compared with published experimental results; discrepancies in zone size are attributed to thermal profile differences and assumptions related to the diffusivity values used. Twenty-one alloys, over the entire ternary compositional spectrum, are also simulated to investigate the effects of alloy composition on constituent redistribution and phase transformations. The U-40Pu-20Zr (at. pct) alloy shows the most potential for compositional uniformity and phase homogeneity, throughout a thermal gradient, while remaining in the compositional range of feasible alloys. © 2018, The Minerals, Metals & Materials Society and ASM International.
1221 a7102280128 Kurata M. p417 False Journal 227 Simulated Microstructural and Compositional Evolution of U-Pu-Zr Alloys Using the Potts-Phase Field Modeling Technique U-Pu-Zr alloys are considered ideal metallic fuels for experimental breeder reactors because of their superior material properties and potential for increased burnup performance. However, significant constituent redistribution has been observed in these alloys when irradiated, or subject to a thermal gradient, resulting in inhomogeneity of both composition and phase, which, in turn, alters the fuel performance. The hybrid Potts-phase field method is reformulated for ternary alloys in a thermal gradient and utilized to simulate and predict constituent redistribution and phase transformations in the U-Pu-Zr nuclear fuel system. Simulated evolution profiles for the U-16Pu-23Zr (at. pct) alloy show concentric zones that are compared with published experimental results; discrepancies in zone size are attributed to thermal profile differences and assumptions related to the diffusivity values used. Twenty-one alloys, over the entire ternary compositional spectrum, are also simulated to investigate the effects of alloy composition on constituent redistribution and phase transformations. The U-40Pu-20Zr (at. pct) alloy shows the most potential for compositional uniformity and phase homogeneity, throughout a thermal gradient, while remaining in the compositional range of feasible alloys. © 2018, The Minerals, Metals & Materials Society and ASM International.
1222 a34976725300 Haut T. p418 False Journal 228 The effect of two distinct fast time scales in the rotating, stratified Boussinesq equations: variations from quasi-geostrophy Inspired by the use of fast singular limits in time-parallel numerical methods for a single fast frequency, we consider the limiting, nonlinear dynamics for a system of partial differential equations when two fast, distinct time scales are present. First-order slow equations are derived via the method of multiple time scales when the two small parameters are related by a rational power. We find that the resultant system depends only on the relationship of the two fast time scales, i.e. which fast time is fastest? Using the theory of cancellation of fast oscillations, we show that with the appropriate assumptions on the nonlinear operator of the full system, this reduced slow system is exactly that which the solution will converge to if each asymptotic limit is considered sequentially. The same result is also obtained via the method of renormalization. The specific example of the rotating, stratified Boussinesq equations is explored in detail, indicating that the most common distinguished limit of this system—quasi-geostrophy, is not the only limiting asymptotic system. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1223 a6602423274 Wingate B.A. p418 False Journal 228 The effect of two distinct fast time scales in the rotating, stratified Boussinesq equations: variations from quasi-geostrophy Inspired by the use of fast singular limits in time-parallel numerical methods for a single fast frequency, we consider the limiting, nonlinear dynamics for a system of partial differential equations when two fast, distinct time scales are present. First-order slow equations are derived via the method of multiple time scales when the two small parameters are related by a rational power. We find that the resultant system depends only on the relationship of the two fast time scales, i.e. which fast time is fastest? Using the theory of cancellation of fast oscillations, we show that with the appropriate assumptions on the nonlinear operator of the full system, this reduced slow system is exactly that which the solution will converge to if each asymptotic limit is considered sequentially. The same result is also obtained via the method of renormalization. The specific example of the rotating, stratified Boussinesq equations is explored in detail, indicating that the most common distinguished limit of this system—quasi-geostrophy, is not the only limiting asymptotic system. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1224 a57198044407 Huang X. p419 True Journal 229 A cost-effective approach to realization of the efficient methane chemical-looping combustion by using coal fly ash as a support for oxygen carrier Developing highly reactive, durable and low-cost oxygen carrier (OC) is the key to the advancement of the chemical looping combustion (CLC) technology that is regarded as the most energy-efficient way for the capture of CO2 emitted from fossil fuel combustion. In this study, the byproduct from coal power plant, coal fly ash (FA) was utilized as the support for Cu-based OC in methane CLC. Its performance was investigated with a thermogravimetric analyzer and a lab-scale fixed bed reactor. The results showed the FA is better as a support of OC than the most commonly used Al2O3 in anti-carbon deposition and thus beneficial to the importance of the stability of FA supported OCs. Among all the tested OCs, the Cu-based OC synthesized with FA support and impregnation method demonstrated the best performance, with CH4 conversion of 94–100% and CO2 selectivity of 91–94% in ten cycles at 800–850 °C, and minor deactivation. The characterization of the fresh and spent OCs revealed that the FA support itself could provide 1.0–2.9 wt% active oxygen for fuel combustion, which is enabled by the iron oxide in FA. In addition, the distribution of Cu on the FA support became more uniform on spent OC than on the fresh one. Also, the partially irreversible CuO decomposition into Cu2O during cyclic tests was the main reason for the deactivation of OC. Thus, Use of FA as an OC support is conducive to both development of cost-effective CLC and an environmental-friendly utilization of waste FA. © 2018 Elsevier Ltd
1225 a55736791400 Wang X. p419 False Journal 229 A cost-effective approach to realization of the efficient methane chemical-looping combustion by using coal fly ash as a support for oxygen carrier Developing highly reactive, durable and low-cost oxygen carrier (OC) is the key to the advancement of the chemical looping combustion (CLC) technology that is regarded as the most energy-efficient way for the capture of CO2 emitted from fossil fuel combustion. In this study, the byproduct from coal power plant, coal fly ash (FA) was utilized as the support for Cu-based OC in methane CLC. Its performance was investigated with a thermogravimetric analyzer and a lab-scale fixed bed reactor. The results showed the FA is better as a support of OC than the most commonly used Al2O3 in anti-carbon deposition and thus beneficial to the importance of the stability of FA supported OCs. Among all the tested OCs, the Cu-based OC synthesized with FA support and impregnation method demonstrated the best performance, with CH4 conversion of 94–100% and CO2 selectivity of 91–94% in ten cycles at 800–850 °C, and minor deactivation. The characterization of the fresh and spent OCs revealed that the FA support itself could provide 1.0–2.9 wt% active oxygen for fuel combustion, which is enabled by the iron oxide in FA. In addition, the distribution of Cu on the FA support became more uniform on spent OC than on the fresh one. Also, the partially irreversible CuO decomposition into Cu2O during cyclic tests was the main reason for the deactivation of OC. Thus, Use of FA as an OC support is conducive to both development of cost-effective CLC and an environmental-friendly utilization of waste FA. © 2018 Elsevier Ltd
1226 a7601492574 Wang Y. p419 False Journal 229 A cost-effective approach to realization of the efficient methane chemical-looping combustion by using coal fly ash as a support for oxygen carrier Developing highly reactive, durable and low-cost oxygen carrier (OC) is the key to the advancement of the chemical looping combustion (CLC) technology that is regarded as the most energy-efficient way for the capture of CO2 emitted from fossil fuel combustion. In this study, the byproduct from coal power plant, coal fly ash (FA) was utilized as the support for Cu-based OC in methane CLC. Its performance was investigated with a thermogravimetric analyzer and a lab-scale fixed bed reactor. The results showed the FA is better as a support of OC than the most commonly used Al2O3 in anti-carbon deposition and thus beneficial to the importance of the stability of FA supported OCs. Among all the tested OCs, the Cu-based OC synthesized with FA support and impregnation method demonstrated the best performance, with CH4 conversion of 94–100% and CO2 selectivity of 91–94% in ten cycles at 800–850 °C, and minor deactivation. The characterization of the fresh and spent OCs revealed that the FA support itself could provide 1.0–2.9 wt% active oxygen for fuel combustion, which is enabled by the iron oxide in FA. In addition, the distribution of Cu on the FA support became more uniform on spent OC than on the fresh one. Also, the partially irreversible CuO decomposition into Cu2O during cyclic tests was the main reason for the deactivation of OC. Thus, Use of FA as an OC support is conducive to both development of cost-effective CLC and an environmental-friendly utilization of waste FA. © 2018 Elsevier Ltd
1227 a57203572325 Zhu Y. p419 False Journal 229 A cost-effective approach to realization of the efficient methane chemical-looping combustion by using coal fly ash as a support for oxygen carrier Developing highly reactive, durable and low-cost oxygen carrier (OC) is the key to the advancement of the chemical looping combustion (CLC) technology that is regarded as the most energy-efficient way for the capture of CO2 emitted from fossil fuel combustion. In this study, the byproduct from coal power plant, coal fly ash (FA) was utilized as the support for Cu-based OC in methane CLC. Its performance was investigated with a thermogravimetric analyzer and a lab-scale fixed bed reactor. The results showed the FA is better as a support of OC than the most commonly used Al2O3 in anti-carbon deposition and thus beneficial to the importance of the stability of FA supported OCs. Among all the tested OCs, the Cu-based OC synthesized with FA support and impregnation method demonstrated the best performance, with CH4 conversion of 94–100% and CO2 selectivity of 91–94% in ten cycles at 800–850 °C, and minor deactivation. The characterization of the fresh and spent OCs revealed that the FA support itself could provide 1.0–2.9 wt% active oxygen for fuel combustion, which is enabled by the iron oxide in FA. In addition, the distribution of Cu on the FA support became more uniform on spent OC than on the fresh one. Also, the partially irreversible CuO decomposition into Cu2O during cyclic tests was the main reason for the deactivation of OC. Thus, Use of FA as an OC support is conducive to both development of cost-effective CLC and an environmental-friendly utilization of waste FA. © 2018 Elsevier Ltd
1228 a57201742316 Feeman S.M. p420 True Journal 230 Exploration and evaluation of CAD modeling in virtual reality Virtual reality (VR) technology has experienced a recent surge in popularity over the past few years and is finding more applications beyond entertainment. Three dimensional modeling is an application in which integration with VR technology is still in the development stage. The focus of this research is to evaluate the feasibility for computer-aided design in VR and to identify the best set of features for virtual reality modeling and practices in this new domain. A platform for testing CAD in VR is developed through the integration of CAD software with a game engine and compared against traditional CAD methods through testing. Modeling capabilities included previews, creating solid rectangular prisms and spheres, lock to grid, and cuts of similar shapes. User testing with four different models (i.e. chair, maze, truck, sculpture) and survey responses suggest respectively that design in virtual reality promoted greater creativity in modeling, allowed for a greater feature creation rate, and that a slight majority of test participants preferred modeling in VR compared to traditional CAD applications. © 2018, © 2018 CAD Solutions, LLC.
1229 a56463982900 Clavijo C.E. p422 True Journal 232 Thermally induced atomization during droplet impingement on superheated hydrophobic and superhydrophobic surfaces This paper presents on thermally induced atomization dynamics during liquid water droplet impingement on superheated hydrophobic and superhydrophobic surfaces. Circular micropillars 4 μm in height with varying center-to-center distances (pitch) of 8 μm, 12 μm and 16 μm, are used to create the superhydrophobic surfaces. The range of surface temperatures explored is 110°C&lt;Ts&lt;337°C. An image processing algorithm was developed to quantify the temporal behavior of thermally induced atomization captured via high-speed photography. Results show thermally induced atomization is initially absent (&lt;1 ms following impact) on all surfaces. The amount of ejected droplets later during droplet spreading is determined as a function of surface structuring and temperature. Atomization ceases when the surface has cooled sufficiently (2.5–4 ms depending on the surface). The maximum amount of atomization for a given scenario is highly dependent on surface temperature and surface microstructure characteristics. At low surface temperatures, atomization increases with increasing surface temperature; however at high surface temperatures atomization decreases with increasing surface temperature. This rise and fall behavior is tantamount to the classical relationship between heat flux and surface temperature for pool boiling. Both droplet impingement and pool boiling depend on vapor bubble formation dynamics and the stability of the so-called Leidenfrost vapor film, which is impacted by surface wettability. Results also show that small surface pitch causes a high atomization intensity, indicating that not all superhydrophobic surfaces sustain Leidenfrost-like behavior at all excess temperatures. © 2018 Elsevier Ltd
1229 a56463982900 Clavijo C.E. p825 True Journal 394 Hydrodynamics of droplet impingement on hot surfaces of varying wettability This work presents on the hydrodynamics of water droplet impingement on superheated solid surfaces across the entire wettability spectrum: superhydrophilic, hydrophilic, hydrophobic and superhydrophobic. While a large body of work exists on droplet impingement on hydrophilic and superhydrophilic surfaces, impingement on the latter two has been largely neglected and the present results show that dynamics are dramatically different. Experiments ranging in surface temperature from 125°C to 415°C and Weber numbers from 10 to 225 were performed and analyzed using high-speed imaging. Some of the most striking differences are as follows. While atomization is always present for impingement on the hydrophilic and superhydrophilic surfaces at temperatures below the Leidenfrost point, atomization is absent at low Weber numbers and at low excess surface temperatures on the hydrophobic surface. At high surface temperatures, the attraction of vapor bubbles on the hydrophobic surface allows a vapor blanket to form more readily thus leading to Leidenfrost behavior at a much lower temperature than classically observed on a hydrophilic surface. One of the most interesting phenomenon that will be discussed includes what will be described as a “pseudo-Leidenfrost” state for impingement on the superhydrophobic surface. Because water can be suspended at the peaks of the roughness on a superhydrophobic interface, vapor escapes from underneath the droplet thus mimicking Leidenfrost behavior for all excess temperatures. This results in minimal atomization for superhydrophobic impingement over the entire regime explored. Finally, maximum spread diameters for Leidenfrost impingement are tabulated as a function of the Weber number for all surfaces and are shown to be larger on the smooth surfaces than on the textured ones indicating that droplet spreading at the Leidenfrost point is not independent of surface type as previously supposed. © 2016 Elsevier Ltd
1230 a55764401200 Stevens K. p422 False Journal 232 Thermally induced atomization during droplet impingement on superheated hydrophobic and superhydrophobic surfaces This paper presents on thermally induced atomization dynamics during liquid water droplet impingement on superheated hydrophobic and superhydrophobic surfaces. Circular micropillars 4 μm in height with varying center-to-center distances (pitch) of 8 μm, 12 μm and 16 μm, are used to create the superhydrophobic surfaces. The range of surface temperatures explored is 110°C&lt;Ts&lt;337°C. An image processing algorithm was developed to quantify the temporal behavior of thermally induced atomization captured via high-speed photography. Results show thermally induced atomization is initially absent (&lt;1 ms following impact) on all surfaces. The amount of ejected droplets later during droplet spreading is determined as a function of surface structuring and temperature. Atomization ceases when the surface has cooled sufficiently (2.5–4 ms depending on the surface). The maximum amount of atomization for a given scenario is highly dependent on surface temperature and surface microstructure characteristics. At low surface temperatures, atomization increases with increasing surface temperature; however at high surface temperatures atomization decreases with increasing surface temperature. This rise and fall behavior is tantamount to the classical relationship between heat flux and surface temperature for pool boiling. Both droplet impingement and pool boiling depend on vapor bubble formation dynamics and the stability of the so-called Leidenfrost vapor film, which is impacted by surface wettability. Results also show that small surface pitch causes a high atomization intensity, indicating that not all superhydrophobic surfaces sustain Leidenfrost-like behavior at all excess temperatures. © 2018 Elsevier Ltd
1230 a55764401200 Stevens K. p822 True Journal 392 Two-phase flow pressure drop in superhydrophobic channels Superhydrophobic surfaces have been shown to reduce drag in single-phase channel flow; however, little work has been done to characterize their drag-reducing ability found in two-phase flows. Adiabatic, air-water mixtures were used to explore the influence of hydrophobicity on two-phase flows and the hydrodynamics which might be present in flow condensation environments. Pressure drop measurements in a rectangular channel with one superhydrophobic wall (cross-section approximately 0.37 × 10 mm) and three transparent hydrophilic walls were obtained. Data for air/water mixtures with superficial Reynolds numbers ranging from 22–215 and 55–220, respectively, were obtained for superhydrophobic surfaces with three different cavity fractions. Agreement between experimentally obtained two-phase pressure drop data and correlations in the literature for conventional smooth control surfaces was better than 20 percent, which is within the accuracy of the correlations. The data reveal a reduction in the pressure drop for two-phase flow in a channel with a single superhydrophobic wall compared to a control scenario. The observed reduction is approximately 10 percent greater than the reduction that is observed for single-phase flow (relative to a classical channel). © 2017 Elsevier Ltd
1231 a6602549459 Chahal J.S. p423 True Journal 233 Carlitz–Wan conjecture for permutation polynomials and Weill bound for curves over finite fields The Carlitz–Wan conjecture, which is now a theorem, asserts that for any positive integer n, there is a constant Cn such that if q is any prime power &gt;Cn with GCD(n,q−1)&gt;1, then there is no permutation polynomial of degree n over the finite field with q elements. From the work of von zur Gathen, it is known that one can take Cn=n4. On the other hand, a conjecture of Mullen, which asserts essentially that one can take Cn=n(n−2) has been shown to be false. In this paper, we use a precise version of Weil bound for the number of points of affine algebraic curves over finite fields to obtain a refinement of the result of von zur Gathen where n4 is replaced by a sharper bound. As a corollary, we show that Mullen's conjecture holds in the affirmative if n(n−2) is replaced by n2(n−2)2. © 2018 Elsevier Inc.
1232 a6602123531 Ghorpade S.R. p423 False Journal 233 Carlitz–Wan conjecture for permutation polynomials and Weill bound for curves over finite fields The Carlitz–Wan conjecture, which is now a theorem, asserts that for any positive integer n, there is a constant Cn such that if q is any prime power &gt;Cn with GCD(n,q−1)&gt;1, then there is no permutation polynomial of degree n over the finite field with q elements. From the work of von zur Gathen, it is known that one can take Cn=n4. On the other hand, a conjecture of Mullen, which asserts essentially that one can take Cn=n(n−2) has been shown to be false. In this paper, we use a precise version of Weil bound for the number of points of affine algebraic curves over finite fields to obtain a refinement of the result of von zur Gathen where n4 is replaced by a sharper bound. As a corollary, we show that Mullen's conjecture holds in the affirmative if n(n−2) is replaced by n2(n−2)2. © 2018 Elsevier Inc.
1233 a57193089338 Frank I.W. p424 False Journal 234 Error correction in structured optical receivers Quantum green machines using integrated optics may enable better communication in photon-starved environments, but fabrication inconsistencies induce unpredictable internal phase errors, making them difficult to construct. We describe and experimentally demonstrate a new method to compensate for arbitrary phase errors by deriving a convex error space and implementing an algorithm to learn a unique codebook of codewords corresponding to each matrix. © 1995-2012 IEEE.
1234 a57201086222 Desrochers C. p425 True Journal 235 Column axial load effects on the performance of skewed SMF RBS connections The selection of an appropriate seismic steel system (braced frame, moment frame, shear wall, etc.) is often influenced by architectural considerations. Moment frame configurations offer the most architectural flexibility, but are somewhat limited by a lack of guidance in the AISC seismic provisions regarding the use of non-orthogonal (skewed) beam-column connections. A recent study investigating laterally skewed moment frame connections indicates adequate seismic performance; however, it was observed that skewed connections increase the potential for column twist and column flange yielding. It is unclear how larger column axial loads present in medium-to-high-rise structures will affect the performance of skewed special moment frame connections. This study investigates the effects of column axial loads on skewed special moment frame connections containing reduced beam sections (RBSs). Detailed finite element analyses are used for all investigations, and several beam-column connection configurations are considered, representing: 3 beam-column geometries (shallow, medium and deep columns); 4 levels of skew at the beam-to-column connection; and 4 levels of applied column axial load. Results indicate that for axial loads less than 50% of the column axial capacity, there is little effect on connection rotation capacity. Beam-skew angle is the main contributor to resulting column twist. With the exception of the deep column geometries that experienced local flange buckling at 50% ΦPn axial load, increased column axial loads have little effect on resulting column flange yielding in skewed RBS moment connections. © 2018 Elsevier Ltd
1235 a26634282400 Prinz G.S. p425 False Journal 235 Column axial load effects on the performance of skewed SMF RBS connections The selection of an appropriate seismic steel system (braced frame, moment frame, shear wall, etc.) is often influenced by architectural considerations. Moment frame configurations offer the most architectural flexibility, but are somewhat limited by a lack of guidance in the AISC seismic provisions regarding the use of non-orthogonal (skewed) beam-column connections. A recent study investigating laterally skewed moment frame connections indicates adequate seismic performance; however, it was observed that skewed connections increase the potential for column twist and column flange yielding. It is unclear how larger column axial loads present in medium-to-high-rise structures will affect the performance of skewed special moment frame connections. This study investigates the effects of column axial loads on skewed special moment frame connections containing reduced beam sections (RBSs). Detailed finite element analyses are used for all investigations, and several beam-column connection configurations are considered, representing: 3 beam-column geometries (shallow, medium and deep columns); 4 levels of skew at the beam-to-column connection; and 4 levels of applied column axial load. Results indicate that for axial loads less than 50% of the column axial capacity, there is little effect on connection rotation capacity. Beam-skew angle is the main contributor to resulting column twist. With the exception of the deep column geometries that experienced local flange buckling at 50% ΦPn axial load, increased column axial loads have little effect on resulting column flange yielding in skewed RBS moment connections. © 2018 Elsevier Ltd
1236 a57204595191 Shah D. p426 True Journal 236 Tutorial on interpreting x-ray photoelectron spectroscopy survey spectra: Questions and answers on spectra from the atomic layer deposition of Al2O3 on silicon X-ray photoelectron spectroscopy (XPS) has become the most widely used method for chemically analyzing surfaces. In XPS, photoelectrons are generated by irradiating a surface with x rays. As the importance and popularity of XPS have grown, it has drawn users without significant XPS experience, and incorrect and incomplete interpretations of XPS spectra regularly appear in the literature. This tutorial is designed as a tool to guide less experienced users in analyzing XPS survey spectra. Here, the authors examine a series of XPS survey spectra collected during the atomic layer deposition (ALD) of Al2O3 from trimethylaluminum and water precursors. Prior to this, brief explanations of XPS and ALD are presented. This tutorial is structured as a series of questions and answers that the interested reader may choose to engage in. The XPS spectra are scrutinized to extract information about the elements present in the film, the presence of contamination, and the nature of the film growth process. The questions and answers in this tutorial address important fundamental issues common to the interpretation of many XPS survey spectra in the context of ALD. © 2018 Author(s).
1237 a57204607180 Patel D.I. p426 False Journal 236 Tutorial on interpreting x-ray photoelectron spectroscopy survey spectra: Questions and answers on spectra from the atomic layer deposition of Al2O3 on silicon X-ray photoelectron spectroscopy (XPS) has become the most widely used method for chemically analyzing surfaces. In XPS, photoelectrons are generated by irradiating a surface with x rays. As the importance and popularity of XPS have grown, it has drawn users without significant XPS experience, and incorrect and incomplete interpretations of XPS spectra regularly appear in the literature. This tutorial is designed as a tool to guide less experienced users in analyzing XPS survey spectra. Here, the authors examine a series of XPS survey spectra collected during the atomic layer deposition (ALD) of Al2O3 from trimethylaluminum and water precursors. Prior to this, brief explanations of XPS and ALD are presented. This tutorial is structured as a series of questions and answers that the interested reader may choose to engage in. The XPS spectra are scrutinized to extract information about the elements present in the film, the presence of contamination, and the nature of the film growth process. The questions and answers in this tutorial address important fundamental issues common to the interpretation of many XPS survey spectra in the context of ALD. © 2018 Author(s).
1238 a56226072000 Roychowdhury T. p426 False Journal 236 Tutorial on interpreting x-ray photoelectron spectroscopy survey spectra: Questions and answers on spectra from the atomic layer deposition of Al2O3 on silicon X-ray photoelectron spectroscopy (XPS) has become the most widely used method for chemically analyzing surfaces. In XPS, photoelectrons are generated by irradiating a surface with x rays. As the importance and popularity of XPS have grown, it has drawn users without significant XPS experience, and incorrect and incomplete interpretations of XPS spectra regularly appear in the literature. This tutorial is designed as a tool to guide less experienced users in analyzing XPS survey spectra. Here, the authors examine a series of XPS survey spectra collected during the atomic layer deposition (ALD) of Al2O3 from trimethylaluminum and water precursors. Prior to this, brief explanations of XPS and ALD are presented. This tutorial is structured as a series of questions and answers that the interested reader may choose to engage in. The XPS spectra are scrutinized to extract information about the elements present in the film, the presence of contamination, and the nature of the film growth process. The questions and answers in this tutorial address important fundamental issues common to the interpretation of many XPS survey spectra in the context of ALD. © 2018 Author(s).
1239 a7003631423 Rayner G.B. p426 False Journal 236 Tutorial on interpreting x-ray photoelectron spectroscopy survey spectra: Questions and answers on spectra from the atomic layer deposition of Al2O3 on silicon X-ray photoelectron spectroscopy (XPS) has become the most widely used method for chemically analyzing surfaces. In XPS, photoelectrons are generated by irradiating a surface with x rays. As the importance and popularity of XPS have grown, it has drawn users without significant XPS experience, and incorrect and incomplete interpretations of XPS spectra regularly appear in the literature. This tutorial is designed as a tool to guide less experienced users in analyzing XPS survey spectra. Here, the authors examine a series of XPS survey spectra collected during the atomic layer deposition (ALD) of Al2O3 from trimethylaluminum and water precursors. Prior to this, brief explanations of XPS and ALD are presented. This tutorial is structured as a series of questions and answers that the interested reader may choose to engage in. The XPS spectra are scrutinized to extract information about the elements present in the film, the presence of contamination, and the nature of the film growth process. The questions and answers in this tutorial address important fundamental issues common to the interpretation of many XPS survey spectra in the context of ALD. © 2018 Author(s).
1240 a57204596520 O’Toole N. p426 False Journal 236 Tutorial on interpreting x-ray photoelectron spectroscopy survey spectra: Questions and answers on spectra from the atomic layer deposition of Al2O3 on silicon X-ray photoelectron spectroscopy (XPS) has become the most widely used method for chemically analyzing surfaces. In XPS, photoelectrons are generated by irradiating a surface with x rays. As the importance and popularity of XPS have grown, it has drawn users without significant XPS experience, and incorrect and incomplete interpretations of XPS spectra regularly appear in the literature. This tutorial is designed as a tool to guide less experienced users in analyzing XPS survey spectra. Here, the authors examine a series of XPS survey spectra collected during the atomic layer deposition (ALD) of Al2O3 from trimethylaluminum and water precursors. Prior to this, brief explanations of XPS and ALD are presented. This tutorial is structured as a series of questions and answers that the interested reader may choose to engage in. The XPS spectra are scrutinized to extract information about the elements present in the film, the presence of contamination, and the nature of the film growth process. The questions and answers in this tutorial address important fundamental issues common to the interpretation of many XPS survey spectra in the context of ALD. © 2018 Author(s).
1241 a7103236401 Baer D.R. p426 False Journal 236 Tutorial on interpreting x-ray photoelectron spectroscopy survey spectra: Questions and answers on spectra from the atomic layer deposition of Al2O3 on silicon X-ray photoelectron spectroscopy (XPS) has become the most widely used method for chemically analyzing surfaces. In XPS, photoelectrons are generated by irradiating a surface with x rays. As the importance and popularity of XPS have grown, it has drawn users without significant XPS experience, and incorrect and incomplete interpretations of XPS spectra regularly appear in the literature. This tutorial is designed as a tool to guide less experienced users in analyzing XPS survey spectra. Here, the authors examine a series of XPS survey spectra collected during the atomic layer deposition (ALD) of Al2O3 from trimethylaluminum and water precursors. Prior to this, brief explanations of XPS and ALD are presented. This tutorial is structured as a series of questions and answers that the interested reader may choose to engage in. The XPS spectra are scrutinized to extract information about the elements present in the film, the presence of contamination, and the nature of the film growth process. The questions and answers in this tutorial address important fundamental issues common to the interpretation of many XPS survey spectra in the context of ALD. © 2018 Author(s).
1242 a57195264521 Loiseau J. p427 True Conference 153 FleCSPH: A parallel and distributed smoothed particle hydrodynamics framework based on FleCSI FleCSPH1 is a complement of the FleCSI framework, focusing on tree data structures with support for binary, quad and octrees. The framework provides parallel, distributed and accelerated tree construction and search in the context of multi-physics problems. FleCSI2 is a compile-Time configurable framework designed to support multi-physics applications and is developed and maintained by the Los Alamos National Laboratory. FleCSI provides domain scientists with a set of data structures and tools to target parallel and distributed architectures on current and future supercomputers, including the ongoing 2020 target to support the first Exascale supercomputers. Our work on FleCSPH is based on a specific method that emphasizes different walls in HPC called Smoothed Particle Hydrodynamics (SPH). This method can be efficiently solved using binary, quad and octrees while providing irregularities in terms of computation and communications. This paper is decomposed as follows: The introduction describes the SPH method and the reasons that makes it a good test case for the FleCSPH framework. We give more details on the FleCSI framework; The second part is dedicated to the tree data structure itself and the choices we made for the domain decomposition, the tree construction and search. We also describe our distribution strategies and their reliability to the FleCSI model; The third part describes our test cases and the current results of the application. The test cases are the Sod shock tube, the Sedov blast and 2D/3D fluid flows. © 2018 IEEE.
1243 a57204829124 Lim H. p427 False Conference 153 FleCSPH: A parallel and distributed smoothed particle hydrodynamics framework based on FleCSI FleCSPH1 is a complement of the FleCSI framework, focusing on tree data structures with support for binary, quad and octrees. The framework provides parallel, distributed and accelerated tree construction and search in the context of multi-physics problems. FleCSI2 is a compile-Time configurable framework designed to support multi-physics applications and is developed and maintained by the Los Alamos National Laboratory. FleCSI provides domain scientists with a set of data structures and tools to target parallel and distributed architectures on current and future supercomputers, including the ongoing 2020 target to support the first Exascale supercomputers. Our work on FleCSPH is based on a specific method that emphasizes different walls in HPC called Smoothed Particle Hydrodynamics (SPH). This method can be efficiently solved using binary, quad and octrees while providing irregularities in terms of computation and communications. This paper is decomposed as follows: The introduction describes the SPH method and the reasons that makes it a good test case for the FleCSPH framework. We give more details on the FleCSI framework; The second part is dedicated to the tree data structure itself and the choices we made for the domain decomposition, the tree construction and search. We also describe our distribution strategies and their reliability to the FleCSI model; The third part describes our test cases and the current results of the application. The test cases are the Sod shock tube, the Sedov blast and 2D/3D fluid flows. © 2018 IEEE.
1244 a35239803700 Bergen B.K. p427 False Conference 153 FleCSPH: A parallel and distributed smoothed particle hydrodynamics framework based on FleCSI FleCSPH1 is a complement of the FleCSI framework, focusing on tree data structures with support for binary, quad and octrees. The framework provides parallel, distributed and accelerated tree construction and search in the context of multi-physics problems. FleCSI2 is a compile-Time configurable framework designed to support multi-physics applications and is developed and maintained by the Los Alamos National Laboratory. FleCSI provides domain scientists with a set of data structures and tools to target parallel and distributed architectures on current and future supercomputers, including the ongoing 2020 target to support the first Exascale supercomputers. Our work on FleCSPH is based on a specific method that emphasizes different walls in HPC called Smoothed Particle Hydrodynamics (SPH). This method can be efficiently solved using binary, quad and octrees while providing irregularities in terms of computation and communications. This paper is decomposed as follows: The introduction describes the SPH method and the reasons that makes it a good test case for the FleCSPH framework. We give more details on the FleCSI framework; The second part is dedicated to the tree data structure itself and the choices we made for the domain decomposition, the tree construction and search. We also describe our distribution strategies and their reliability to the FleCSI model; The third part describes our test cases and the current results of the application. The test cases are the Sod shock tube, the Sedov blast and 2D/3D fluid flows. © 2018 IEEE.
1245 a37086141200 Moss N.D. p427 False Conference 153 FleCSPH: A parallel and distributed smoothed particle hydrodynamics framework based on FleCSI FleCSPH1 is a complement of the FleCSI framework, focusing on tree data structures with support for binary, quad and octrees. The framework provides parallel, distributed and accelerated tree construction and search in the context of multi-physics problems. FleCSI2 is a compile-Time configurable framework designed to support multi-physics applications and is developed and maintained by the Los Alamos National Laboratory. FleCSI provides domain scientists with a set of data structures and tools to target parallel and distributed architectures on current and future supercomputers, including the ongoing 2020 target to support the first Exascale supercomputers. Our work on FleCSPH is based on a specific method that emphasizes different walls in HPC called Smoothed Particle Hydrodynamics (SPH). This method can be efficiently solved using binary, quad and octrees while providing irregularities in terms of computation and communications. This paper is decomposed as follows: The introduction describes the SPH method and the reasons that makes it a good test case for the FleCSPH framework. We give more details on the FleCSI framework; The second part is dedicated to the tree data structure itself and the choices we made for the domain decomposition, the tree construction and search. We also describe our distribution strategies and their reliability to the FleCSI model; The third part describes our test cases and the current results of the application. The test cases are the Sod shock tube, the Sedov blast and 2D/3D fluid flows. © 2018 IEEE.
1246 a8329346700 Alin F. p427 False Conference 153 FleCSPH: A parallel and distributed smoothed particle hydrodynamics framework based on FleCSI FleCSPH1 is a complement of the FleCSI framework, focusing on tree data structures with support for binary, quad and octrees. The framework provides parallel, distributed and accelerated tree construction and search in the context of multi-physics problems. FleCSI2 is a compile-Time configurable framework designed to support multi-physics applications and is developed and maintained by the Los Alamos National Laboratory. FleCSI provides domain scientists with a set of data structures and tools to target parallel and distributed architectures on current and future supercomputers, including the ongoing 2020 target to support the first Exascale supercomputers. Our work on FleCSPH is based on a specific method that emphasizes different walls in HPC called Smoothed Particle Hydrodynamics (SPH). This method can be efficiently solved using binary, quad and octrees while providing irregularities in terms of computation and communications. This paper is decomposed as follows: The introduction describes the SPH method and the reasons that makes it a good test case for the FleCSPH framework. We give more details on the FleCSI framework; The second part is dedicated to the tree data structure itself and the choices we made for the domain decomposition, the tree construction and search. We also describe our distribution strategies and their reliability to the FleCSI model; The third part describes our test cases and the current results of the application. The test cases are the Sod shock tube, the Sedov blast and 2D/3D fluid flows. © 2018 IEEE.
1247 a55369699900 Ni Q. p428 True Journal 237 Controlling normal stiffness in droplet-based linear bearings While capillary forces are negligible relative to gravity at the macroscale, they provide adequate force to effectively manipulate millimeter to micro meter objects. The fluidic actuation can be accomplished using droplets that also act as bearings. While rotary droplet bearings have been previously demonstrated, this paper addresses the positioning accuracy of a droplet-based bearing consisting of a droplet between a moving plate and a stationary substrate with constrained wetting region under a normal load. Key wetting cases are analyzed using both closed form analytical approximations and numerical simulations. The vertical force and stiffness characteristics are analyzed in relation to the wetting boundaries of the supporting surface. Case studies of different wetting boundaries are presented and summarized. Design strategies are presented for maximizing load carrying capability and stiffness. These results show that controlled wetting and opposing droplet configurations can create much higher stiffness fluidic bearings than simple droplets. © 2018 by the authors.
1248 a57204830739 Hastings A. p429 True Conference 154 Using physical and functional comparisons to assure 3rd-party IP for modern FPGAs In modern FPGA design, 3rd-party IP is commonly used to reduce costs and time-to-market. However, the complexity of IP and associated CAD tools makes it easier for attackers to maliciously tamper with the IP (i.e. insert Hardware Trojans) in ways that are hard to detect. This work proposes techniques that allows a user to incorporate trusted 3rd-party IP into a design and verify that the incorporation occurs tamper-free. We present comparative results from utilizing this framework across a benchmark suite of 22 designs. We show that the approach reliably detects tampering without giving any false positives. © 2018 IEEE.
1249 a57204825465 Jensen S. p429 False Conference 154 Using physical and functional comparisons to assure 3rd-party IP for modern FPGAs In modern FPGA design, 3rd-party IP is commonly used to reduce costs and time-to-market. However, the complexity of IP and associated CAD tools makes it easier for attackers to maliciously tamper with the IP (i.e. insert Hardware Trojans) in ways that are hard to detect. This work proposes techniques that allows a user to incorporate trusted 3rd-party IP into a design and verify that the incorporation occurs tamper-free. We present comparative results from utilizing this framework across a benchmark suite of 22 designs. We show that the approach reliably detects tampering without giving any false positives. © 2018 IEEE.
1250 a7006372151 Hutchings B. p429 False Conference 154 Using physical and functional comparisons to assure 3rd-party IP for modern FPGAs In modern FPGA design, 3rd-party IP is commonly used to reduce costs and time-to-market. However, the complexity of IP and associated CAD tools makes it easier for attackers to maliciously tamper with the IP (i.e. insert Hardware Trojans) in ways that are hard to detect. This work proposes techniques that allows a user to incorporate trusted 3rd-party IP into a design and verify that the incorporation occurs tamper-free. We present comparative results from utilizing this framework across a benchmark suite of 22 designs. We show that the approach reliably detects tampering without giving any false positives. © 2018 IEEE.
1250 a7006372151 Hutchings B. p489 False Conference 181 Designing a sustainable large-scale project-based learning (PBL) experience for juniors in electrical and computer engineering This paper presents a large-scale Project-Based Learning (PBL) curriculum that can handle 200 students per year without requiring an undue commitment of faculty or teaching-assistant time. The following strategies were used to attain the student benefits of the PBL curriculum while accommodating a large number of students and while keeping the faculty and teaching-assistant commitments to reasonable levels. (1) A top-level hardware/software specification of the system (laser-tag) is provided to the students. (2) Students must test their software and hardware using both their own methods and with provided test software and hardware fixtures. (3) How-to and demonstration videos are provided via a dedicated youTube channel. (4) Students implement the system by completing a series of scheduled milestones. (5) The same PBL project is completed every year. This large scale PBL curriculum is conducted during the junior year and has been in place for several years in the Electrical and Computer Engineering Department. © American Society for Engineering Education, 2018.
1250 a7006372151 Hutchings B. p736 True Conference 317 Project-based learning curriculum for the junior year based on building a laser tag system [No abstract available]
1251 a57203192064 Davis B.R. p430 False Journal 238 Reengineering cell-free protein synthesis as a biosensor: Biosensing with transcription, translation, and protein-folding Biosensors highjack and reengineer biological systems for highly specific detection of diverse molecules. However, many traditional biosensor devices have slow response times and high operating costs and require specialized training and immobile lab equipment. In an effort to address these limitations, researchers have begun using cell-free protein synthesis (CFPS) systems as biosensors. CFPS-based systems provide the advantages of speed, portability, and robustness at a relatively low cost. Here, we review CFPS-based biosensors according to the three fundamental stages of CFPS: transcription, translation, and protein folding. © 2018 Elsevier B.V.
1252 a57203188827 Ford H. p430 False Journal 238 Reengineering cell-free protein synthesis as a biosensor: Biosensing with transcription, translation, and protein-folding Biosensors highjack and reengineer biological systems for highly specific detection of diverse molecules. However, many traditional biosensor devices have slow response times and high operating costs and require specialized training and immobile lab equipment. In an effort to address these limitations, researchers have begun using cell-free protein synthesis (CFPS) systems as biosensors. CFPS-based systems provide the advantages of speed, portability, and robustness at a relatively low cost. Here, we review CFPS-based biosensors according to the three fundamental stages of CFPS: transcription, translation, and protein folding. © 2018 Elsevier B.V.
1253 a55619678900 Safdarnejad S.M. p431 True Journal 239 Performance comparison of low temperature and chemical absorption carbon capture processes in response to dynamic electricity demand and price profiles Current projections to the year 2050 reveal that fossil fuels will remain the main source of energy generation. To achieve the target limits of carbon dioxide emission, set by national and international policies, carbon capture will play a key role. Modeling and optimization of various carbon capture technologies such as pre-combustion, oxy-fuel, and post-combustion, when integrated with coal-fired power plants, have been researched extensively in literature. Research on the integration of power generation with capture technologies regarding comparisons between the different schemes in response to dynamic inputs is lacking. This work provides a comparison between a low temperature carbon capture and a chemical absorption process in response to a dynamic electricity demand and price profile and in the presence of an intermittent wind power supply. The objective in this work is to meet the overall electricity demand of residential users and the carbon capture process while the total operating cost associated with the integrated system of power generation and carbon capture is minimized. This comparison includes scenarios with and without energy storage associated with each capture technology. It is observed that in both integrated systems, with and without energy storage, the overall electricity demanded by the capture process and residential users is supplied by a combination of coal and wind power. For the case without energy storage, the total operating cost and energy demand of the low temperature carbon capture, based on a similar amount of captured carbon dioxide, are 4.3% and 20.5% less than that of chemical absorption, respectively. For the scenario with energy storage, the low temperature carbon capture requires 32.34% less energy to capture similar amounts of carbon dioxide while incurring 9.09% less overall operational cost. © 2018 Elsevier Ltd
1254 a57202852104 Barnwell N.V. p432 False Journal 240 Flexural strength and stiffness of block-out connections for steel columns In many steel buildings, the columns are attached to the foundation through a block-out in the slab-on-grade that is later filled with unreinforced concrete. Engineers typically neglect the block-out concrete in design, effectively treating block-out connections as exposed connections with pinned behavior. Quantifying the flexural strength and stiffness of block-out connections is helpful for determining moment demands on foundations and may lead to more economical connections at the base of steel moment frames. Eight experimental specimens (two-thirds scale) were subjected to lateral loads to investigate the effects of column size, block-out thickness, and load orientation on connection flexural strength and stiffness. The observed flexural strengths were 1.4–2.7 times greater than those calculated neglecting the block-out concrete, because the block-out concrete effectively thickened and expanded the column base plate. A simple method was developed that predicted the flexural strength of the block-out connections to within 10 percent. The effective flexural stiffness at the base of the columns that were tested could be reasonably estimated using a model that combines the theory of beams on elastic foundations with a base rotational spring. © 2018
1255 a57202852946 Tryon J.E. p432 False Journal 240 Flexural strength and stiffness of block-out connections for steel columns In many steel buildings, the columns are attached to the foundation through a block-out in the slab-on-grade that is later filled with unreinforced concrete. Engineers typically neglect the block-out concrete in design, effectively treating block-out connections as exposed connections with pinned behavior. Quantifying the flexural strength and stiffness of block-out connections is helpful for determining moment demands on foundations and may lead to more economical connections at the base of steel moment frames. Eight experimental specimens (two-thirds scale) were subjected to lateral loads to investigate the effects of column size, block-out thickness, and load orientation on connection flexural strength and stiffness. The observed flexural strengths were 1.4–2.7 times greater than those calculated neglecting the block-out concrete, because the block-out concrete effectively thickened and expanded the column base plate. A simple method was developed that predicted the flexural strength of the block-out connections to within 10 percent. The effective flexural stiffness at the base of the columns that were tested could be reasonably estimated using a model that combines the theory of beams on elastic foundations with a base rotational spring. © 2018
1256 a57202860730 Sadler A.L. p432 False Journal 240 Flexural strength and stiffness of block-out connections for steel columns In many steel buildings, the columns are attached to the foundation through a block-out in the slab-on-grade that is later filled with unreinforced concrete. Engineers typically neglect the block-out concrete in design, effectively treating block-out connections as exposed connections with pinned behavior. Quantifying the flexural strength and stiffness of block-out connections is helpful for determining moment demands on foundations and may lead to more economical connections at the base of steel moment frames. Eight experimental specimens (two-thirds scale) were subjected to lateral loads to investigate the effects of column size, block-out thickness, and load orientation on connection flexural strength and stiffness. The observed flexural strengths were 1.4–2.7 times greater than those calculated neglecting the block-out concrete, because the block-out concrete effectively thickened and expanded the column base plate. A simple method was developed that predicted the flexural strength of the block-out connections to within 10 percent. The effective flexural stiffness at the base of the columns that were tested could be reasonably estimated using a model that combines the theory of beams on elastic foundations with a base rotational spring. © 2018
1257 a56701619800 Ding S. p433 True Journal 241 CIP2A immunosensor comprised of vertically-aligned carbon nanotube interdigitated electrodes towards point-of-care oral cancer screening Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered significant attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDEs were functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—an oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant label-free immunosensor was capable of detecting CIP2A across a wide linear sensing range (1−100 pg/mL) with a detection limit of 0.24 pg/mL within saliva supernatant—a range that is more sensitive than the corresponding CIP2A enzyme linked immunosorbent assay (ELISA). These results help pave the way for rapid cancer screening tests at the point-of-care (POC) such as for the early-stage diagnosis of oral cancer at a dentist's office. © 2018 Elsevier B.V.
1258 a8369472600 Das S.R. p433 False Journal 241 CIP2A immunosensor comprised of vertically-aligned carbon nanotube interdigitated electrodes towards point-of-care oral cancer screening Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered significant attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDEs were functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—an oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant label-free immunosensor was capable of detecting CIP2A across a wide linear sensing range (1−100 pg/mL) with a detection limit of 0.24 pg/mL within saliva supernatant—a range that is more sensitive than the corresponding CIP2A enzyme linked immunosorbent assay (ELISA). These results help pave the way for rapid cancer screening tests at the point-of-care (POC) such as for the early-stage diagnosis of oral cancer at a dentist's office. © 2018 Elsevier B.V.
1259 a57193322440 Brownlee B.J. p433 False Journal 241 CIP2A immunosensor comprised of vertically-aligned carbon nanotube interdigitated electrodes towards point-of-care oral cancer screening Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered significant attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDEs were functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—an oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant label-free immunosensor was capable of detecting CIP2A across a wide linear sensing range (1−100 pg/mL) with a detection limit of 0.24 pg/mL within saliva supernatant—a range that is more sensitive than the corresponding CIP2A enzyme linked immunosorbent assay (ELISA). These results help pave the way for rapid cancer screening tests at the point-of-care (POC) such as for the early-stage diagnosis of oral cancer at a dentist's office. © 2018 Elsevier B.V.
1259 a57193322440 Brownlee B.J. p858 True Journal 401 Improving sensitivity of electrochemical sensors with convective transport in free-standing, carbon nanotube structures High-aspect-ratio, porous membrane of vertically-aligned carbon nanotubes (CNTs) were developed through a templated microfabrication approach for electrochemical sensing. Nanostructured platinum (Pt) catalyst was deposited onto the CNTs with a facile, electroless deposition method, resulting in a Pt-nanowire-coated, CNT sensor (PN-CNT). Convective mass transfer enhancement was shown to improve PN-CNT sensor performance in the non‐enzymatic, amperometric sensing of hydrogen peroxide (H2O2). In particular, convective enhancement was achieved through the use of high surface area to fluid volume structures and concentration boundary layer confinement in a channel. Stir speed and sensor orientation especially influenced the measured current in stirred environments for sensors with through-channel diameters of 16 μm. Through-flow sensing produced drastically higher signals than stirred sensing with over 90% of the H2O2being oxidized as it passed through the PN-CNT sensor, even for low concentrations in the range of 50 nM to 500 μM. This effective utilization of the analyte in detection demonstrates the utility of exploiting convection in electrochemical sensing. For through‐flow at 100 μL s−1, a sensitivity of 24,300 μA mM−1 cm−2was achieved based on the frontal projected area (871 μA mM−1cm−2based on the nominal microchannel surface area), with a 0.03 μM limit of detection and a linear sensing range of 0.03–500 μM. © 2017 Elsevier B.V.
1260 a56376235200 Parate K. p433 False Journal 241 CIP2A immunosensor comprised of vertically-aligned carbon nanotube interdigitated electrodes towards point-of-care oral cancer screening Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered significant attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDEs were functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—an oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant label-free immunosensor was capable of detecting CIP2A across a wide linear sensing range (1−100 pg/mL) with a detection limit of 0.24 pg/mL within saliva supernatant—a range that is more sensitive than the corresponding CIP2A enzyme linked immunosorbent assay (ELISA). These results help pave the way for rapid cancer screening tests at the point-of-care (POC) such as for the early-stage diagnosis of oral cancer at a dentist's office. © 2018 Elsevier B.V.
1261 a57202237979 Davis T.M. p433 False Journal 241 CIP2A immunosensor comprised of vertically-aligned carbon nanotube interdigitated electrodes towards point-of-care oral cancer screening Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered significant attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDEs were functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—an oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant label-free immunosensor was capable of detecting CIP2A across a wide linear sensing range (1−100 pg/mL) with a detection limit of 0.24 pg/mL within saliva supernatant—a range that is more sensitive than the corresponding CIP2A enzyme linked immunosorbent assay (ELISA). These results help pave the way for rapid cancer screening tests at the point-of-care (POC) such as for the early-stage diagnosis of oral cancer at a dentist's office. © 2018 Elsevier B.V.
1262 a56702333100 Stromberg L.R. p433 False Journal 241 CIP2A immunosensor comprised of vertically-aligned carbon nanotube interdigitated electrodes towards point-of-care oral cancer screening Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered significant attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDEs were functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—an oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant label-free immunosensor was capable of detecting CIP2A across a wide linear sensing range (1−100 pg/mL) with a detection limit of 0.24 pg/mL within saliva supernatant—a range that is more sensitive than the corresponding CIP2A enzyme linked immunosorbent assay (ELISA). These results help pave the way for rapid cancer screening tests at the point-of-care (POC) such as for the early-stage diagnosis of oral cancer at a dentist's office. © 2018 Elsevier B.V.
1263 a7401994123 Chan E.K.L. p433 False Journal 241 CIP2A immunosensor comprised of vertically-aligned carbon nanotube interdigitated electrodes towards point-of-care oral cancer screening Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered significant attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDEs were functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—an oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant label-free immunosensor was capable of detecting CIP2A across a wide linear sensing range (1−100 pg/mL) with a detection limit of 0.24 pg/mL within saliva supernatant—a range that is more sensitive than the corresponding CIP2A enzyme linked immunosorbent assay (ELISA). These results help pave the way for rapid cancer screening tests at the point-of-care (POC) such as for the early-stage diagnosis of oral cancer at a dentist's office. © 2018 Elsevier B.V.
1264 a35336731800 Katz J. p433 False Journal 241 CIP2A immunosensor comprised of vertically-aligned carbon nanotube interdigitated electrodes towards point-of-care oral cancer screening Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered significant attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDEs were functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—an oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant label-free immunosensor was capable of detecting CIP2A across a wide linear sensing range (1−100 pg/mL) with a detection limit of 0.24 pg/mL within saliva supernatant—a range that is more sensitive than the corresponding CIP2A enzyme linked immunosorbent assay (ELISA). These results help pave the way for rapid cancer screening tests at the point-of-care (POC) such as for the early-stage diagnosis of oral cancer at a dentist's office. © 2018 Elsevier B.V.
1265 a23388379100 Claussen J.C. p433 False Journal 241 CIP2A immunosensor comprised of vertically-aligned carbon nanotube interdigitated electrodes towards point-of-care oral cancer screening Vertically aligned carbon nanotube array (VANTA) coatings have recently garnered significant attention due in part to their unique material properties including light absorption, chemical inertness, and electrical conductivity. Herein we report the first use of VANTAs grown via chemical vapor deposition in a 2D interdigitated electrode (IDE) footprint with a high height-to-width aspect ratio (3:1 or 75:25 µm). The VANTA-IDEs were functionalized with an antibody (Ab) specific to the human cancerous inhibitor PP2A (CIP2A)—an oncoprotein that is associated with a variety of malignancies such as oral, breast, and multiple myeloma cancers. The resultant label-free immunosensor was capable of detecting CIP2A across a wide linear sensing range (1−100 pg/mL) with a detection limit of 0.24 pg/mL within saliva supernatant—a range that is more sensitive than the corresponding CIP2A enzyme linked immunosorbent assay (ELISA). These results help pave the way for rapid cancer screening tests at the point-of-care (POC) such as for the early-stage diagnosis of oral cancer at a dentist's office. © 2018 Elsevier B.V.
1265 a23388379100 Claussen J.C. p858 False Journal 401 Improving sensitivity of electrochemical sensors with convective transport in free-standing, carbon nanotube structures High-aspect-ratio, porous membrane of vertically-aligned carbon nanotubes (CNTs) were developed through a templated microfabrication approach for electrochemical sensing. Nanostructured platinum (Pt) catalyst was deposited onto the CNTs with a facile, electroless deposition method, resulting in a Pt-nanowire-coated, CNT sensor (PN-CNT). Convective mass transfer enhancement was shown to improve PN-CNT sensor performance in the non‐enzymatic, amperometric sensing of hydrogen peroxide (H2O2). In particular, convective enhancement was achieved through the use of high surface area to fluid volume structures and concentration boundary layer confinement in a channel. Stir speed and sensor orientation especially influenced the measured current in stirred environments for sensors with through-channel diameters of 16 μm. Through-flow sensing produced drastically higher signals than stirred sensing with over 90% of the H2O2being oxidized as it passed through the PN-CNT sensor, even for low concentrations in the range of 50 nM to 500 μM. This effective utilization of the analyte in detection demonstrates the utility of exploiting convection in electrochemical sensing. For through‐flow at 100 μL s−1, a sensitivity of 24,300 μA mM−1 cm−2was achieved based on the frontal projected area (871 μA mM−1cm−2based on the nominal microchannel surface area), with a 0.03 μM limit of detection and a linear sensing range of 0.03–500 μM. © 2017 Elsevier B.V.
1266 a57204695840 Larmore G. p434 True Conference 155 Active Topology Inference in Store, Code, and Forward Networks This paper presents a technique for active topology inference in store, code, and forward networks. Many techniques exist for topology inference and are well suited for storeand- forward and cut-through switching; however, these simpler techniques fail to capitalize on the flexibility of recoding afforded by store, code, and forward networks. This is in contrast to network coding, which recodes the data whenever possible and consequently achieves the maximum flow (and minimum cut) of throughput across a network. The technique herein utilizes a single probe message between a single source and potentially many destination nodes to achieve deterministic topology inference. © 2018 IEEE.
1267 a57204695450 Perrinsy E. p435 False Conference 156 On peak-to-average power ratio optimization for coded APSK The symmetric information rate is used to define the relationship between the APSK constellation parameters, the code rate, and the average and peak Eb=N0. Minimizing the average Eb=N0 reproduces the DVB-S2 constellation parameters for 16- And 32-APSK. Minimizing the peak Eb=N0 produces DVB-S2 constellation parameters for 16- And 32-APSK that minimize the peak-to-average power ratio. The peak-to-average power ratio gains are less than 1 dB, but when used on coded systems with very steep decoded bit error probability vs. Eb=N0 curves, the gains can be significant. © 2018 IEEE.
1268 a56490084100 Boyce P. p436 True Conference 157 Cryptanalysis of Lempel-Ziv Compressed and Encrypted Text: The Statistics of Compression Modern secure communication systems typically follow a pattern at the transmitter of first compression encoding followed by encryption, and then additional encoders to mitigate the effects of channel noise, etc. One of the purposes of the compression algorithm is to remove statistical information about the plaintext, so as to render the ciphertext impervious to statistical attacks. It is well known, however, that in practice there is no such thing as a universal compression algorithm; thus, some statistical information about the plaintext tends to survive the compression process. In this paper, we consider Lempel-Ziv Welch compression and analyze its effectiveness in removing statistical information from English plaintext. Specifically, we present several techniques for exploiting the structure of the compression algorithm to launch a successful statistical attack on compressed and encrypted data. All attacks are ciphertext only, and one of them relies on linear programming. Although our attacks indicate that an eavesdropper may require additional ciphertext to carry out a successful attack if compression is used, the specific adaptive nature of the Lempel-Ziv compression technique leaves its own statistics on the message, which can be exploited by an attacker. © 2018 IEEE.
1269 a57204693186 Harrisony W.K. p436 False Conference 157 Cryptanalysis of Lempel-Ziv Compressed and Encrypted Text: The Statistics of Compression Modern secure communication systems typically follow a pattern at the transmitter of first compression encoding followed by encryption, and then additional encoders to mitigate the effects of channel noise, etc. One of the purposes of the compression algorithm is to remove statistical information about the plaintext, so as to render the ciphertext impervious to statistical attacks. It is well known, however, that in practice there is no such thing as a universal compression algorithm; thus, some statistical information about the plaintext tends to survive the compression process. In this paper, we consider Lempel-Ziv Welch compression and analyze its effectiveness in removing statistical information from English plaintext. Specifically, we present several techniques for exploiting the structure of the compression algorithm to launch a successful statistical attack on compressed and encrypted data. All attacks are ciphertext only, and one of them relies on linear programming. Although our attacks indicate that an eavesdropper may require additional ciphertext to carry out a successful attack if compression is used, the specific adaptive nature of the Lempel-Ziv compression technique leaves its own statistics on the message, which can be exploited by an attacker. © 2018 IEEE.
1270 a57188711588 Henrie A. p437 True Journal 242 Erratum: Hardware and software improvements to a low-cost horizontal parallax holographic video monitor (Applied Optics (2018) 57 (A122-A133) DOI: 10.1364/AO.57.00A122) In [1], the trademarked term "HoloMonitor," which belongs to Phase Holographic Imaging PHI AB, was removed. The article was corrected online on 10 September 2018. © 2018 Optical Society of America.
1270 a57188711588 Henrie A. p571 True Journal 242 Hardware and software improvements to a low-cost horizontal parallax holographic video monitor Displays capable of true holographic video have been prohibitively expensive and difficult to build. With this paper, we present a suite of modularized hardware components and software tools needed to build a HoloMonitor with basic “hacker-space” equipment, highlighting improvements that have enabled the total materials cost to fall to $820, well below that of other holographic displays. It is our hope that the current level of simplicity, development, design flexibility, and documentation will enable the lay engineer, programmer, and scientist to relatively easily replicate, modify, and build upon our designs, bringing true holographic video to the masses. © 2017 Optical Society of America.
1271 a57200118672 Codling J.R. p437 False Journal 242 Erratum: Hardware and software improvements to a low-cost horizontal parallax holographic video monitor (Applied Optics (2018) 57 (A122-A133) DOI: 10.1364/AO.57.00A122) In [1], the trademarked term "HoloMonitor," which belongs to Phase Holographic Imaging PHI AB, was removed. The article was corrected online on 10 September 2018. © 2018 Optical Society of America.
1271 a57200118672 Codling J.R. p571 False Journal 242 Hardware and software improvements to a low-cost horizontal parallax holographic video monitor Displays capable of true holographic video have been prohibitively expensive and difficult to build. With this paper, we present a suite of modularized hardware components and software tools needed to build a HoloMonitor with basic “hacker-space” equipment, highlighting improvements that have enabled the total materials cost to fall to $820, well below that of other holographic displays. It is our hope that the current level of simplicity, development, design flexibility, and documentation will enable the lay engineer, programmer, and scientist to relatively easily replicate, modify, and build upon our designs, bringing true holographic video to the masses. © 2017 Optical Society of America.
1272 a57164754700 Gneiting S. p437 False Journal 242 Erratum: Hardware and software improvements to a low-cost horizontal parallax holographic video monitor (Applied Optics (2018) 57 (A122-A133) DOI: 10.1364/AO.57.00A122) In [1], the trademarked term "HoloMonitor," which belongs to Phase Holographic Imaging PHI AB, was removed. The article was corrected online on 10 September 2018. © 2018 Optical Society of America.
1272 a57164754700 Gneiting S. p562 False Conference 211 Progress on photophoretic trap displays We review the fundamentals photophoretic trap displays and discuss the possibility of creating occlusion capable image points. Anisotropic scattering is observed independently in single and double point traps. © 2018 The Author(s).
1272 a57164754700 Gneiting S. p571 False Journal 242 Hardware and software improvements to a low-cost horizontal parallax holographic video monitor Displays capable of true holographic video have been prohibitively expensive and difficult to build. With this paper, we present a suite of modularized hardware components and software tools needed to build a HoloMonitor with basic “hacker-space” equipment, highlighting improvements that have enabled the total materials cost to fall to $820, well below that of other holographic displays. It is our hope that the current level of simplicity, development, design flexibility, and documentation will enable the lay engineer, programmer, and scientist to relatively easily replicate, modify, and build upon our designs, bringing true holographic video to the masses. © 2017 Optical Society of America.
1273 a57200117120 Christensen J.B. p437 False Journal 242 Erratum: Hardware and software improvements to a low-cost horizontal parallax holographic video monitor (Applied Optics (2018) 57 (A122-A133) DOI: 10.1364/AO.57.00A122) In [1], the trademarked term "HoloMonitor," which belongs to Phase Holographic Imaging PHI AB, was removed. The article was corrected online on 10 September 2018. © 2018 Optical Society of America.
1273 a57200117120 Christensen J.B. p571 False Journal 242 Hardware and software improvements to a low-cost horizontal parallax holographic video monitor Displays capable of true holographic video have been prohibitively expensive and difficult to build. With this paper, we present a suite of modularized hardware components and software tools needed to build a HoloMonitor with basic “hacker-space” equipment, highlighting improvements that have enabled the total materials cost to fall to $820, well below that of other holographic displays. It is our hope that the current level of simplicity, development, design flexibility, and documentation will enable the lay engineer, programmer, and scientist to relatively easily replicate, modify, and build upon our designs, bringing true holographic video to the masses. © 2017 Optical Society of America.
1274 a57200121629 Burdette M.J. p437 False Journal 242 Erratum: Hardware and software improvements to a low-cost horizontal parallax holographic video monitor (Applied Optics (2018) 57 (A122-A133) DOI: 10.1364/AO.57.00A122) In [1], the trademarked term "HoloMonitor," which belongs to Phase Holographic Imaging PHI AB, was removed. The article was corrected online on 10 September 2018. © 2018 Optical Society of America.
1274 a57200121629 Burdette M.J. p571 False Journal 242 Hardware and software improvements to a low-cost horizontal parallax holographic video monitor Displays capable of true holographic video have been prohibitively expensive and difficult to build. With this paper, we present a suite of modularized hardware components and software tools needed to build a HoloMonitor with basic “hacker-space” equipment, highlighting improvements that have enabled the total materials cost to fall to $820, well below that of other holographic displays. It is our hope that the current level of simplicity, development, design flexibility, and documentation will enable the lay engineer, programmer, and scientist to relatively easily replicate, modify, and build upon our designs, bringing true holographic video to the masses. © 2017 Optical Society of America.
1275 a55523036500 Burgett J.M. p438 True Journal 243 Identification and Prioritization of Critical Subject Matter within Mechanical Systems Curriculum in Construction Management Education In order for students graduating with construction-related undergraduate degrees to provide immediate and effective benefit to their employers, program curricula must accurately reflect the needs of the industry. One area of the typical construction management curriculum that receives a varying level of emphasis and consideration amongst accredited programs is Mechanical Systems. Similarly, the wide range of possible topics and concepts relevant to mechanical systems receive varying levels of attention. The purpose of this research was to identify what mechanical system topics and concepts were perceived by industry partners as being most important for graduating construction students to know. Construction industry professionals were surveyed to determine what topics they believed warranted prioritization in mechanical system courses. Results indicate that topics related to Contract Administration (e.g., plan and specification reading, MEP coordination, submittal review, etc.) and How HVAC Systems Work (e.g., differences between HVAC system types, HVAC equipment, etc.) were comparatively the most important topics for students to have a knowledge of. Instructors of mechanical systems classes should use these findings to determine what major subject areas to focus on, and allocate time to the various specific concepts appropriately within the constraints of their individual program. © 2018, © 2018 Associated Schools of Construction.
1276 a56287595000 Perrenoud A. p438 False Journal 243 Identification and Prioritization of Critical Subject Matter within Mechanical Systems Curriculum in Construction Management Education In order for students graduating with construction-related undergraduate degrees to provide immediate and effective benefit to their employers, program curricula must accurately reflect the needs of the industry. One area of the typical construction management curriculum that receives a varying level of emphasis and consideration amongst accredited programs is Mechanical Systems. Similarly, the wide range of possible topics and concepts relevant to mechanical systems receive varying levels of attention. The purpose of this research was to identify what mechanical system topics and concepts were perceived by industry partners as being most important for graduating construction students to know. Construction industry professionals were surveyed to determine what topics they believed warranted prioritization in mechanical system courses. Results indicate that topics related to Contract Administration (e.g., plan and specification reading, MEP coordination, submittal review, etc.) and How HVAC Systems Work (e.g., differences between HVAC system types, HVAC equipment, etc.) were comparatively the most important topics for students to have a knowledge of. Instructors of mechanical systems classes should use these findings to determine what major subject areas to focus on, and allocate time to the various specific concepts appropriately within the constraints of their individual program. © 2018, © 2018 Associated Schools of Construction.
1277 a56426567600 Schinn S.-M. p439 False Journal 244 The emerging impact of cell-free chemical biosynthesis Biomanufacturing has emerged as a promising alternative to chemocatalysis for green, renewable, complex synthesis of biofuels, medicines, and fine chemicals. Cell-free chemical biosynthesis offers additional advantages over in vivo production, enabling plug-and-play assembly of separately produced enzymes into an optimal cascade, versatile reaction conditions, and direct access to the reaction environment. In order for these advantages to be realized on the larger scale of industry, strategies are needed to reduce costs of biocatalyst generation, improve biocatalyst stability, and enable economically sustainable continuous cascade operation. Here we overview the advantages and remaining challenges of applying cell-free chemical biosynthesis for commodity production, and discuss recent advances in cascade engineering, enzyme immobilization, and enzyme encapsulation which constitute important steps towards addressing these challenges. © 2017
1278 a57200181918 Long E.A. p439 False Journal 244 The emerging impact of cell-free chemical biosynthesis Biomanufacturing has emerged as a promising alternative to chemocatalysis for green, renewable, complex synthesis of biofuels, medicines, and fine chemicals. Cell-free chemical biosynthesis offers additional advantages over in vivo production, enabling plug-and-play assembly of separately produced enzymes into an optimal cascade, versatile reaction conditions, and direct access to the reaction environment. In order for these advantages to be realized on the larger scale of industry, strategies are needed to reduce costs of biocatalyst generation, improve biocatalyst stability, and enable economically sustainable continuous cascade operation. Here we overview the advantages and remaining challenges of applying cell-free chemical biosynthesis for commodity production, and discuss recent advances in cascade engineering, enzyme immobilization, and enzyme encapsulation which constitute important steps towards addressing these challenges. © 2017
1279 a16197655400 Hess B.C. p440 False Journal 245 Efficiency of Generalized Regular k-point grids Most DFT practitioners use regular grids (Monkhorst-Pack, MP) for integrations in the Brillouin zone. Although regular grids are the natural choice and easy to generate, more general grids whose generating vectors are not merely integer divisions of the reciprocal lattice vectors, are usually more efficient (Wisesa et al., 2016). We demonstrate the efficiency of generalized regular (GR) grids compared to Monkhorst-Pack (MP) and simultaneously commensurate (SC) grids. In the case of metals, for total energy accuracies of one meV/atom, GR grids are 60% faster on average than MP grids and 20% faster than SC grids. GR grids also have greater freedom in choosing the k-point density, enabling the practitioner to achieve a target accuracy with the minimum computational cost. © 2018 Elsevier B.V.
1280 a56703039000 Loney D.A. p441 True Journal 246 Rapid Operational Access and Maneuver Support platform for military logistics and operation planning in water environments Logistical and combat operations in riverine, estuarine, and coastal environments remain a key military focus due to limited maneuverability, imperfect knowledge, and rapidly changing constraints. Vessel operation in water environments can be enhanced by routing algorithms that integrate mission parameters with environmental data and vessel specifications. These algorithms must update predetermined routes in a timely manner as parameters and specifications change. The US Army Engineer Research and Development Center Coastal and Hydraulics Laboratory is developing the capability for military planners to rapidly optimize vessel routes in water environments by extending capabilities of the Rapid Operational Access and Maneuver Support (ROAMS) modeling platform. The ROAMS platform allows users to rapidly generate models of a water environment in limited-information conditions, utilizing the Adaptive Hydraulics and STeady-state spectral WAVE computational engines for the base two-dimensional hydrodynamics and waves, respectively. Routing capabilities are built on path search and penalty-barrier optimization to automatically produce routes that account for temporally changing environmental variables and vessel maneuverability. This work outlines the components of the ROAMS routing package and presents a case study using ROAMS in a northeastern American metropolitan area. Benefits and limitations of the ROAMS routing platform are discussed and future improvements are suggested. © The Author(s) 2018.
1281 a39362193900 Pevey K.C. p441 False Journal 246 Rapid Operational Access and Maneuver Support platform for military logistics and operation planning in water environments Logistical and combat operations in riverine, estuarine, and coastal environments remain a key military focus due to limited maneuverability, imperfect knowledge, and rapidly changing constraints. Vessel operation in water environments can be enhanced by routing algorithms that integrate mission parameters with environmental data and vessel specifications. These algorithms must update predetermined routes in a timely manner as parameters and specifications change. The US Army Engineer Research and Development Center Coastal and Hydraulics Laboratory is developing the capability for military planners to rapidly optimize vessel routes in water environments by extending capabilities of the Rapid Operational Access and Maneuver Support (ROAMS) modeling platform. The ROAMS platform allows users to rapidly generate models of a water environment in limited-information conditions, utilizing the Adaptive Hydraulics and STeady-state spectral WAVE computational engines for the base two-dimensional hydrodynamics and waves, respectively. Routing capabilities are built on path search and penalty-barrier optimization to automatically produce routes that account for temporally changing environmental variables and vessel maneuverability. This work outlines the components of the ROAMS routing package and presents a case study using ROAMS in a northeastern American metropolitan area. Benefits and limitations of the ROAMS routing platform are discussed and future improvements are suggested. © The Author(s) 2018.
1282 a57197749025 McAlpin J.T. p441 False Journal 246 Rapid Operational Access and Maneuver Support platform for military logistics and operation planning in water environments Logistical and combat operations in riverine, estuarine, and coastal environments remain a key military focus due to limited maneuverability, imperfect knowledge, and rapidly changing constraints. Vessel operation in water environments can be enhanced by routing algorithms that integrate mission parameters with environmental data and vessel specifications. These algorithms must update predetermined routes in a timely manner as parameters and specifications change. The US Army Engineer Research and Development Center Coastal and Hydraulics Laboratory is developing the capability for military planners to rapidly optimize vessel routes in water environments by extending capabilities of the Rapid Operational Access and Maneuver Support (ROAMS) modeling platform. The ROAMS platform allows users to rapidly generate models of a water environment in limited-information conditions, utilizing the Adaptive Hydraulics and STeady-state spectral WAVE computational engines for the base two-dimensional hydrodynamics and waves, respectively. Routing capabilities are built on path search and penalty-barrier optimization to automatically produce routes that account for temporally changing environmental variables and vessel maneuverability. This work outlines the components of the ROAMS routing package and presents a case study using ROAMS in a northeastern American metropolitan area. Benefits and limitations of the ROAMS routing platform are discussed and future improvements are suggested. © The Author(s) 2018.
1283 a57201022887 Nelsen B.W. p441 False Journal 246 Rapid Operational Access and Maneuver Support platform for military logistics and operation planning in water environments Logistical and combat operations in riverine, estuarine, and coastal environments remain a key military focus due to limited maneuverability, imperfect knowledge, and rapidly changing constraints. Vessel operation in water environments can be enhanced by routing algorithms that integrate mission parameters with environmental data and vessel specifications. These algorithms must update predetermined routes in a timely manner as parameters and specifications change. The US Army Engineer Research and Development Center Coastal and Hydraulics Laboratory is developing the capability for military planners to rapidly optimize vessel routes in water environments by extending capabilities of the Rapid Operational Access and Maneuver Support (ROAMS) modeling platform. The ROAMS platform allows users to rapidly generate models of a water environment in limited-information conditions, utilizing the Adaptive Hydraulics and STeady-state spectral WAVE computational engines for the base two-dimensional hydrodynamics and waves, respectively. Routing capabilities are built on path search and penalty-barrier optimization to automatically produce routes that account for temporally changing environmental variables and vessel maneuverability. This work outlines the components of the ROAMS routing package and presents a case study using ROAMS in a northeastern American metropolitan area. Benefits and limitations of the ROAMS routing platform are discussed and future improvements are suggested. © The Author(s) 2018.
1284 a57217564448 Hargis B.H. p441 False Journal 246 Rapid Operational Access and Maneuver Support platform for military logistics and operation planning in water environments Logistical and combat operations in riverine, estuarine, and coastal environments remain a key military focus due to limited maneuverability, imperfect knowledge, and rapidly changing constraints. Vessel operation in water environments can be enhanced by routing algorithms that integrate mission parameters with environmental data and vessel specifications. These algorithms must update predetermined routes in a timely manner as parameters and specifications change. The US Army Engineer Research and Development Center Coastal and Hydraulics Laboratory is developing the capability for military planners to rapidly optimize vessel routes in water environments by extending capabilities of the Rapid Operational Access and Maneuver Support (ROAMS) modeling platform. The ROAMS platform allows users to rapidly generate models of a water environment in limited-information conditions, utilizing the Adaptive Hydraulics and STeady-state spectral WAVE computational engines for the base two-dimensional hydrodynamics and waves, respectively. Routing capabilities are built on path search and penalty-barrier optimization to automatically produce routes that account for temporally changing environmental variables and vessel maneuverability. This work outlines the components of the ROAMS routing package and presents a case study using ROAMS in a northeastern American metropolitan area. Benefits and limitations of the ROAMS routing platform are discussed and future improvements are suggested. © The Author(s) 2018.
1285 a57213462935 Peterson J.R. p442 False Journal 247 Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1285 a57213462935 Peterson J.R. p757 False Journal 369 Tuning Ferritin's band gap through mixed metal oxide nanoparticle formation This study uses the formation of a mixed metal oxide inside ferritin to tune the band gap energy of the ferritin mineral. The mixed metal oxide is composed of both Co and Mn, and is formed by reacting aqueous Co2+ with MnO4in the presence of apoferritin. Altering the ratio between the two reactants allowed for controlled tuning of the band gap energies. All minerals formed were indirect band gap materials, with indirect band gap energies ranging from 0.52 to 1.30 eV. The direct transitions were also measured, with energy values ranging from 2.71 to 3.11 eV. Tuning the band gap energies of these samples changes the wavelengths absorbed by each mineral, increasing ferritin's potential in solar-energy harvesting. Additionally, the success of using MnO4 in ferritin mineral formation opens the possibility for new mixed metal oxide cores inside ferritin. © 2017 IOP Publishing Ltd.
1285 a57213462935 Peterson J.R. p758 False Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
1286 a57205507684 Perego A. p442 False Journal 247 Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1287 a57205503531 Shelley M. p442 False Journal 247 Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1288 a57194047397 Olsen C.R. p442 False Journal 247 Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1288 a57194047397 Olsen C.R. p757 True Journal 369 Tuning Ferritin's band gap through mixed metal oxide nanoparticle formation This study uses the formation of a mixed metal oxide inside ferritin to tune the band gap energy of the ferritin mineral. The mixed metal oxide is composed of both Co and Mn, and is formed by reacting aqueous Co2+ with MnO4in the presence of apoferritin. Altering the ratio between the two reactants allowed for controlled tuning of the band gap energies. All minerals formed were indirect band gap materials, with indirect band gap energies ranging from 0.52 to 1.30 eV. The direct transitions were also measured, with energy values ranging from 2.71 to 3.11 eV. Tuning the band gap energies of these samples changes the wavelengths absorbed by each mineral, increasing ferritin's potential in solar-energy harvesting. Additionally, the success of using MnO4 in ferritin mineral formation opens the possibility for new mixed metal oxide cores inside ferritin. © 2017 IOP Publishing Ltd.
1288 a57194047397 Olsen C.R. p758 True Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
1289 a57205500882 Perez L.D. p442 False Journal 247 Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1290 a57205505883 Hogg H.L. p442 False Journal 247 Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1291 a57212277009 Watt R.K. p442 False Journal 247 Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1291 a57212277009 Watt R.K. p757 False Journal 369 Tuning Ferritin's band gap through mixed metal oxide nanoparticle formation This study uses the formation of a mixed metal oxide inside ferritin to tune the band gap energy of the ferritin mineral. The mixed metal oxide is composed of both Co and Mn, and is formed by reacting aqueous Co2+ with MnO4in the presence of apoferritin. Altering the ratio between the two reactants allowed for controlled tuning of the band gap energies. All minerals formed were indirect band gap materials, with indirect band gap energies ranging from 0.52 to 1.30 eV. The direct transitions were also measured, with energy values ranging from 2.71 to 3.11 eV. Tuning the band gap energies of these samples changes the wavelengths absorbed by each mineral, increasing ferritin's potential in solar-energy harvesting. Additionally, the success of using MnO4 in ferritin mineral formation opens the possibility for new mixed metal oxide cores inside ferritin. © 2017 IOP Publishing Ltd.
1291 a57212277009 Watt R.K. p758 False Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
1292 a35587077000 Colton J.S. p442 False Journal 247 Lead sulfide quantum dots inside ferritin: synthesis and application to photovoltaics We present a new water phase synthesis method for lead sulfide colloidal quantum dots, and test their applicability for use in photovoltaics. The quantum dots are synthesized inside ferritin protein shells (PbS-FTN). Our synthesis method is simpler than what has previously been reported for PbS-FTN quantum dots, namely we demonstrate that the synthesizing reaction can be run in an aerobic environment and with a Pb:S ratio of 1:1. Protection from photocorrosion is demonstrated by comparing the time evolution of photoluminescence from PbS-FTN with that of non-ferritin PbS quantum dots. In the photovoltaic testing, we use a dye-sensitized solar cell scheme with PbS-FTN as the dye and test several methods to adsorb PbS-FTN to the mesoporous TiO2 layer which is coated on the solar cell anodes. The highest performing cell shows an efficiency of 0.29% using the drop casting method. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1292 a35587077000 Colton J.S. p757 False Journal 369 Tuning Ferritin's band gap through mixed metal oxide nanoparticle formation This study uses the formation of a mixed metal oxide inside ferritin to tune the band gap energy of the ferritin mineral. The mixed metal oxide is composed of both Co and Mn, and is formed by reacting aqueous Co2+ with MnO4in the presence of apoferritin. Altering the ratio between the two reactants allowed for controlled tuning of the band gap energies. All minerals formed were indirect band gap materials, with indirect band gap energies ranging from 0.52 to 1.30 eV. The direct transitions were also measured, with energy values ranging from 2.71 to 3.11 eV. Tuning the band gap energies of these samples changes the wavelengths absorbed by each mineral, increasing ferritin's potential in solar-energy harvesting. Additionally, the success of using MnO4 in ferritin mineral formation opens the possibility for new mixed metal oxide cores inside ferritin. © 2017 IOP Publishing Ltd.
1292 a35587077000 Colton J.S. p758 False Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
1293 a57190849274 Jiang Z. p443 False Journal 222 A pseudo-static model for dynamic analysis on frequency domain of distributed compliant mechanisms This paper presents a pseudo-static modeling methodology for dynamic analysis of distributed compliant mechanisms to provide accurate and efficient solutions. First, a dynamic stiffness matrix of the flexible beam is deduced, which has the same definition and a similar form as the traditional static compliance/stiffness matrix but is frequency dependent. Second, the pseudo-static modeling procedure for the dynamic analysis is implemented in a statics-similar way based on D'alembert's principle. Then, all the kinematic, static and dynamic performances of compliant mechanisms can be analyzed based on the pseudo-static model. The superiority of the proposed method is that when it is used for the dynamic modeling of compliant mechanisms, the traditional dynamic modeling procedures, such as calculation of the elastic and kinetic energies as well as using Lagrange's equation, are avoided and the dynamic modeling is converted to a staticssimilar problem. Comparison of the proposed method with an elastic-beam-based model in previous literature and finite element analysis for an exemplary XY precision positioning stage reveals its high accuracy and easy operation. © 2018 by ASME.
1294 a55235047300 Poornejad N. p444 True Journal 248 Corrigendum: Efficient decellularization of whole porcine kidneys improves reseeded cell behavior (Biomedical Materials (Bristol) (2016) 11 (025003) DOI: 10.1088/1748-6041/11/2/025003) The above manuscript describes our efforts to improve the process for recellularization of porcine kidneys. We obtained what we believed to be an immortalized cell line of human renal cortical tubular epithelium (RCTE) cells from the Feinberg School of Medicine, Northwestern University to conduct our reseeding experiments. The RCTE cells that were provided to us were later discovered to actually be Madin-Darby Canine Kidney (MDCK) epithelial cells. Despite being of canine origin, MDCK cells are a distal tubule epithelial cell line that behave similarly to human RCTE cells. The conclusions regarding reseeding as reported in our paper are still sound, as described in the following. © 2018 IOP Publishing Ltd.
1294 a55235047300 Poornejad N. p805 True Journal 391 Re-epithelialization of whole porcine kidneys with renal epithelial cells Decellularized porcine kidneys were recellularized with renal epithelial cells by three methods: perfusion through the vasculature under high pressure, perfusion through the ureter under high pressure, or perfusion through the ureter under moderate vacuum. Histology, scanning electron microscopy, confocal microscopy, and magnetic resonance imaging were used to assess vasculature preservation and the distribution of cells throughout the kidneys. Cells were detected in the magnetic resonance imaging by labeling them with iron oxide. Perfusion of cells through the ureter under moderate vacuum (40 mmHg) produced the most uniform distribution of cells throughout the kidneys. © 2017, © The Author(s) 2017.
1295 a56515354700 Momtahan N. p444 False Journal 248 Corrigendum: Efficient decellularization of whole porcine kidneys improves reseeded cell behavior (Biomedical Materials (Bristol) (2016) 11 (025003) DOI: 10.1088/1748-6041/11/2/025003) The above manuscript describes our efforts to improve the process for recellularization of porcine kidneys. We obtained what we believed to be an immortalized cell line of human renal cortical tubular epithelium (RCTE) cells from the Feinberg School of Medicine, Northwestern University to conduct our reseeding experiments. The RCTE cells that were provided to us were later discovered to actually be Madin-Darby Canine Kidney (MDCK) epithelial cells. Despite being of canine origin, MDCK cells are a distal tubule epithelial cell line that behave similarly to human RCTE cells. The conclusions regarding reseeding as reported in our paper are still sound, as described in the following. © 2018 IOP Publishing Ltd.
1296 a57194105863 Salehi A.S.M. p444 False Journal 248 Corrigendum: Efficient decellularization of whole porcine kidneys improves reseeded cell behavior (Biomedical Materials (Bristol) (2016) 11 (025003) DOI: 10.1088/1748-6041/11/2/025003) The above manuscript describes our efforts to improve the process for recellularization of porcine kidneys. We obtained what we believed to be an immortalized cell line of human renal cortical tubular epithelium (RCTE) cells from the Feinberg School of Medicine, Northwestern University to conduct our reseeding experiments. The RCTE cells that were provided to us were later discovered to actually be Madin-Darby Canine Kidney (MDCK) epithelial cells. Despite being of canine origin, MDCK cells are a distal tubule epithelial cell line that behave similarly to human RCTE cells. The conclusions regarding reseeding as reported in our paper are still sound, as described in the following. © 2018 IOP Publishing Ltd.
1297 a56921113900 Scott D.R. p444 False Journal 248 Corrigendum: Efficient decellularization of whole porcine kidneys improves reseeded cell behavior (Biomedical Materials (Bristol) (2016) 11 (025003) DOI: 10.1088/1748-6041/11/2/025003) The above manuscript describes our efforts to improve the process for recellularization of porcine kidneys. We obtained what we believed to be an immortalized cell line of human renal cortical tubular epithelium (RCTE) cells from the Feinberg School of Medicine, Northwestern University to conduct our reseeding experiments. The RCTE cells that were provided to us were later discovered to actually be Madin-Darby Canine Kidney (MDCK) epithelial cells. Despite being of canine origin, MDCK cells are a distal tubule epithelial cell line that behave similarly to human RCTE cells. The conclusions regarding reseeding as reported in our paper are still sound, as described in the following. © 2018 IOP Publishing Ltd.
1298 a57044630300 Fronk C.A. p444 False Journal 248 Corrigendum: Efficient decellularization of whole porcine kidneys improves reseeded cell behavior (Biomedical Materials (Bristol) (2016) 11 (025003) DOI: 10.1088/1748-6041/11/2/025003) The above manuscript describes our efforts to improve the process for recellularization of porcine kidneys. We obtained what we believed to be an immortalized cell line of human renal cortical tubular epithelium (RCTE) cells from the Feinberg School of Medicine, Northwestern University to conduct our reseeding experiments. The RCTE cells that were provided to us were later discovered to actually be Madin-Darby Canine Kidney (MDCK) epithelial cells. Despite being of canine origin, MDCK cells are a distal tubule epithelial cell line that behave similarly to human RCTE cells. The conclusions regarding reseeding as reported in our paper are still sound, as described in the following. © 2018 IOP Publishing Ltd.
1299 a7005654753 Roeder B.L. p444 False Journal 248 Corrigendum: Efficient decellularization of whole porcine kidneys improves reseeded cell behavior (Biomedical Materials (Bristol) (2016) 11 (025003) DOI: 10.1088/1748-6041/11/2/025003) The above manuscript describes our efforts to improve the process for recellularization of porcine kidneys. We obtained what we believed to be an immortalized cell line of human renal cortical tubular epithelium (RCTE) cells from the Feinberg School of Medicine, Northwestern University to conduct our reseeding experiments. The RCTE cells that were provided to us were later discovered to actually be Madin-Darby Canine Kidney (MDCK) epithelial cells. Despite being of canine origin, MDCK cells are a distal tubule epithelial cell line that behave similarly to human RCTE cells. The conclusions regarding reseeding as reported in our paper are still sound, as described in the following. © 2018 IOP Publishing Ltd.
1299 a7005654753 Roeder B.L. p805 False Journal 391 Re-epithelialization of whole porcine kidneys with renal epithelial cells Decellularized porcine kidneys were recellularized with renal epithelial cells by three methods: perfusion through the vasculature under high pressure, perfusion through the ureter under high pressure, or perfusion through the ureter under moderate vacuum. Histology, scanning electron microscopy, confocal microscopy, and magnetic resonance imaging were used to assess vasculature preservation and the distribution of cells throughout the kidneys. Cells were detected in the magnetic resonance imaging by labeling them with iron oxide. Perfusion of cells through the ureter under moderate vacuum (40 mmHg) produced the most uniform distribution of cells throughout the kidneys. © 2017, © The Author(s) 2017.
1300 a56701050600 Reynolds P.R. p444 False Journal 248 Corrigendum: Efficient decellularization of whole porcine kidneys improves reseeded cell behavior (Biomedical Materials (Bristol) (2016) 11 (025003) DOI: 10.1088/1748-6041/11/2/025003) The above manuscript describes our efforts to improve the process for recellularization of porcine kidneys. We obtained what we believed to be an immortalized cell line of human renal cortical tubular epithelium (RCTE) cells from the Feinberg School of Medicine, Northwestern University to conduct our reseeding experiments. The RCTE cells that were provided to us were later discovered to actually be Madin-Darby Canine Kidney (MDCK) epithelial cells. Despite being of canine origin, MDCK cells are a distal tubule epithelial cell line that behave similarly to human RCTE cells. The conclusions regarding reseeding as reported in our paper are still sound, as described in the following. © 2018 IOP Publishing Ltd.
1300 a56701050600 Reynolds P.R. p805 False Journal 391 Re-epithelialization of whole porcine kidneys with renal epithelial cells Decellularized porcine kidneys were recellularized with renal epithelial cells by three methods: perfusion through the vasculature under high pressure, perfusion through the ureter under high pressure, or perfusion through the ureter under moderate vacuum. Histology, scanning electron microscopy, confocal microscopy, and magnetic resonance imaging were used to assess vasculature preservation and the distribution of cells throughout the kidneys. Cells were detected in the magnetic resonance imaging by labeling them with iron oxide. Perfusion of cells through the ureter under moderate vacuum (40 mmHg) produced the most uniform distribution of cells throughout the kidneys. © 2017, © The Author(s) 2017.
1301 a57203184524 Cramer J. p445 True Journal 249 Effect of strain path on forming limits and retained austenite transformation in Q&P 1180 steel Forming limits and retained austenite (RA) transformation in Q&P 1180 steel are quantified as a function of plastic strain levels for three different strain paths. In-plane uniaxial tension testing was performed in a standard test frame, while limiting dome height tooling was employed for out-of-plane biaxial and plane strain tension experiments. Sheet specimens were tested incrementally for each strain path, and the RA content at each level of strain was measured using electron backscatter diffraction (EBSD). The biaxial tension strain path resulted in the greatest effective strain prior to necking at 0.355, compared to 0.123 for plane strain and 0.142 for uniaxial tension. EBSD measurements for various levels of plastic strain reveal a clear dependence of RA rate of transformation on strain path for the three linear strain paths that were employed in this work. Thinning strains appear to provide a slightly better correlation to RA transformation than effective strain levels, where biaxial tension achieved the greatest level just prior to necking, followed by plane-strain tension, and then uniaxial tension. © 2018 Elsevier B.V.
1302 a57201465968 Adams D. p445 False Journal 249 Effect of strain path on forming limits and retained austenite transformation in Q&P 1180 steel Forming limits and retained austenite (RA) transformation in Q&P 1180 steel are quantified as a function of plastic strain levels for three different strain paths. In-plane uniaxial tension testing was performed in a standard test frame, while limiting dome height tooling was employed for out-of-plane biaxial and plane strain tension experiments. Sheet specimens were tested incrementally for each strain path, and the RA content at each level of strain was measured using electron backscatter diffraction (EBSD). The biaxial tension strain path resulted in the greatest effective strain prior to necking at 0.355, compared to 0.123 for plane strain and 0.142 for uniaxial tension. EBSD measurements for various levels of plastic strain reveal a clear dependence of RA rate of transformation on strain path for the three linear strain paths that were employed in this work. Thinning strains appear to provide a slightly better correlation to RA transformation than effective strain levels, where biaxial tension achieved the greatest level just prior to necking, followed by plane-strain tension, and then uniaxial tension. © 2018 Elsevier B.V.
1303 a56248395300 Brown T. p445 False Journal 249 Effect of strain path on forming limits and retained austenite transformation in Q&P 1180 steel Forming limits and retained austenite (RA) transformation in Q&P 1180 steel are quantified as a function of plastic strain levels for three different strain paths. In-plane uniaxial tension testing was performed in a standard test frame, while limiting dome height tooling was employed for out-of-plane biaxial and plane strain tension experiments. Sheet specimens were tested incrementally for each strain path, and the RA content at each level of strain was measured using electron backscatter diffraction (EBSD). The biaxial tension strain path resulted in the greatest effective strain prior to necking at 0.355, compared to 0.123 for plane strain and 0.142 for uniaxial tension. EBSD measurements for various levels of plastic strain reveal a clear dependence of RA rate of transformation on strain path for the three linear strain paths that were employed in this work. Thinning strains appear to provide a slightly better correlation to RA transformation than effective strain levels, where biaxial tension achieved the greatest level just prior to necking, followed by plane-strain tension, and then uniaxial tension. © 2018 Elsevier B.V.
1304 a57203180153 Misha R. p445 False Journal 249 Effect of strain path on forming limits and retained austenite transformation in Q&P 1180 steel Forming limits and retained austenite (RA) transformation in Q&P 1180 steel are quantified as a function of plastic strain levels for three different strain paths. In-plane uniaxial tension testing was performed in a standard test frame, while limiting dome height tooling was employed for out-of-plane biaxial and plane strain tension experiments. Sheet specimens were tested incrementally for each strain path, and the RA content at each level of strain was measured using electron backscatter diffraction (EBSD). The biaxial tension strain path resulted in the greatest effective strain prior to necking at 0.355, compared to 0.123 for plane strain and 0.142 for uniaxial tension. EBSD measurements for various levels of plastic strain reveal a clear dependence of RA rate of transformation on strain path for the three linear strain paths that were employed in this work. Thinning strains appear to provide a slightly better correlation to RA transformation than effective strain levels, where biaxial tension achieved the greatest level just prior to necking, followed by plane-strain tension, and then uniaxial tension. © 2018 Elsevier B.V.
1305 a7005486887 Sachdev A. p445 False Journal 249 Effect of strain path on forming limits and retained austenite transformation in Q&P 1180 steel Forming limits and retained austenite (RA) transformation in Q&P 1180 steel are quantified as a function of plastic strain levels for three different strain paths. In-plane uniaxial tension testing was performed in a standard test frame, while limiting dome height tooling was employed for out-of-plane biaxial and plane strain tension experiments. Sheet specimens were tested incrementally for each strain path, and the RA content at each level of strain was measured using electron backscatter diffraction (EBSD). The biaxial tension strain path resulted in the greatest effective strain prior to necking at 0.355, compared to 0.123 for plane strain and 0.142 for uniaxial tension. EBSD measurements for various levels of plastic strain reveal a clear dependence of RA rate of transformation on strain path for the three linear strain paths that were employed in this work. Thinning strains appear to provide a slightly better correlation to RA transformation than effective strain levels, where biaxial tension achieved the greatest level just prior to necking, followed by plane-strain tension, and then uniaxial tension. © 2018 Elsevier B.V.
1306 a34874038200 Wright G.A. p447 True Journal 251 Engineering attitudes: an investigation of the effect of literature on student attitudes toward engineering The growth of STEM career occupations is outpacing the college enrollment of STEM students in the United States. There have been many research projects investigating this issue. There has not however been a study which investigated the impact non-fiction literature has on student interest in studying STEM (specifically engineering) content. The purpose of this study was to investigate the change of student attitudes toward engineering after reading literature involving non-fiction engineering centric narratives. The study used a modified version of the PATT (Pupils Attitudes Towards Technology) called the TEAS (Technology and Engineering Attitudes Scale) to measure student attitude change. The students were high-school aged students in the United States (ages: 15–17) who were enrolled in an English Literature course. The students completed the TEAS before and after reading and studying two engineering and technology centric non-fiction books (The Boy Who Harnessed The Wind and October Sky). The data revealed that student attitude after reading and studying the two books did not statistically change. © 2017, Springer Science+Business Media B.V.
1306 a34874038200 Wright G.A. p483 True Conference 175 Increasing student construction interest by engaging elementary students in an inquiry-based 3D modelling after school program This study was part of a two-year funded grant investigating how to increase student interest and consequent enrollment in construction education. The specifics of this aspect of the study involved a grass-roots movement where construction education was introduced to elementary students (grades 4 - 6). The research model involved giving the students a construction interest inventory and career placement inventory pre-and post-participation in an after-school 3D modeling construction centric curriculum. The curriculum introduced students to the construction fields by giving the students weekly snapshots into construction careers, and also required the students to learn about floor and elevation plans. Students were then taught and expected to design a 3D computer model of a home using Minecraft and Sketchup. The students were provided 4 different models to choose from. The course used a competition based pedagogy where the best home designs were awarded prizes. The results show that student interest after this single intervention (1 semester in length) increased student interest in careers associated to construction. © American Society for Engineering Education, 2018.
1306 a34874038200 Wright G.A. p695 False Journal 338 The need, development, and validation of the innovation test instrument This study discusses the need, development, and validation of the Innovation Test Instrument (ITI). This article outlines how the researchers identified the content domain of the assessment and created test items. Then, it describes initial validation testing of the instrument. The findings suggest that the ITI is a good first step in creating an innovation assessment because it is more inclusive of both divergent and convergent thinking. In comparison, past innovation assessments have only assessed either divergence or convergence. The ITI still needs further validation and improvement to make strong claims about its ability to determine the effectiveness of an innovation course. © 2017, Virginia Polytechnic Institute. All rights reserved.
1307 a57201366662 Collins N.S. p448 False Journal 252 Total hemispherical apparent radiative properties of the infinite V-groove with specular reflection Multiple reflections in a cavity geometry augment the emission and absorption of the cavity opening relative to a flat surface in a phenomenon known as the cavity effect. The extent of the cavity effect is quantified using apparent absorptivity and apparent emissivity. Analysis of complicated thermal systems is simplified through application of apparent radiative properties to cavity geometries. The apparent radiative properties of a specularly-reflecting, gray, isothermal V-groove have been derived analytically, but these results have not been validated experimentally or numerically. Additionally, the model for apparent absorptivity of an infinite V-groove subjected to partial illumination in the presence of collimated irradiation is not available. In this work, the following existing models for a specularly-reflecting V-groove are collected into a single source: (1) the apparent absorptivity of a diffusely irradiated V-groove, (2) the apparent emissivity of an isothermal V-groove and (3) the apparent absorptivity of a V-groove subject to collimated irradiation with full-illumination. Further, a new analytical model is developed to predict the apparent absorptivity of an infinite V-groove subject to collimated irradiation with partial-illumination. A custom, Monte Carlo ray tracing solver is used to predict the apparent radiative properties for all cases as a means of numerical verification by comparing the ray tracing data with the results from the new model in this work and the previously existing models. For diffuse irradiation, the analytical model and ray tracing data show excellent agreement with an average discrepancy of 4.4 × 10−4, verifying the diffuse-irradiation analytical model. Similar agreement is found for collimated irradiation, where the full and partial illumination models indicate average discrepancies of 4.9 × 10−4 and 4.6 × 10−4 when compared with ray tracing data. © 2018 Elsevier Ltd
1307 a57201366662 Collins N.S. p589 False Journal 305 Total hemispherical apparent radiative properties of the infinite V-Groove with diffuse reflection [No abstract available]
1308 a57201358872 Farnsworth M.S. p448 False Journal 252 Total hemispherical apparent radiative properties of the infinite V-groove with specular reflection Multiple reflections in a cavity geometry augment the emission and absorption of the cavity opening relative to a flat surface in a phenomenon known as the cavity effect. The extent of the cavity effect is quantified using apparent absorptivity and apparent emissivity. Analysis of complicated thermal systems is simplified through application of apparent radiative properties to cavity geometries. The apparent radiative properties of a specularly-reflecting, gray, isothermal V-groove have been derived analytically, but these results have not been validated experimentally or numerically. Additionally, the model for apparent absorptivity of an infinite V-groove subjected to partial illumination in the presence of collimated irradiation is not available. In this work, the following existing models for a specularly-reflecting V-groove are collected into a single source: (1) the apparent absorptivity of a diffusely irradiated V-groove, (2) the apparent emissivity of an isothermal V-groove and (3) the apparent absorptivity of a V-groove subject to collimated irradiation with full-illumination. Further, a new analytical model is developed to predict the apparent absorptivity of an infinite V-groove subject to collimated irradiation with partial-illumination. A custom, Monte Carlo ray tracing solver is used to predict the apparent radiative properties for all cases as a means of numerical verification by comparing the ray tracing data with the results from the new model in this work and the previously existing models. For diffuse irradiation, the analytical model and ray tracing data show excellent agreement with an average discrepancy of 4.4 × 10−4, verifying the diffuse-irradiation analytical model. Similar agreement is found for collimated irradiation, where the full and partial illumination models indicate average discrepancies of 4.9 × 10−4 and 4.6 × 10−4 when compared with ray tracing data. © 2018 Elsevier Ltd
1308 a57201358872 Farnsworth M.S. p589 False Journal 305 Total hemispherical apparent radiative properties of the infinite V-Groove with diffuse reflection [No abstract available]
1309 a7202006620 Shen T.-C. p449 True Journal 253 Synthesis of high-specific volume carbon nanotube structures for gas-phase applications A novel and efficient gas-phase method has been developed for synthesizing carbon nanotube (CNT) structures with very high specific volume, high surface area and high porosity. The resulting material has potential application as a catalyst and adsorbent support for gas-phase chemical processes and has several advantages over the conventional liquid-phase approach that involves multiple steps and takes many hours to days resulting in a dense mat of CNTs. Multi-walled CNTs were initially nucleated and grown on alumina nanoparticles using a liquid precursor of ferrocene dissolved in xylene. The CNT seeds were extended using ethylene as the gas precursor. Forces generated by CNT growth separated the alumina support clusters to result in a porous entangled structure with a 60 times gain in weight and a 1300 times gain in volume, compared to the original alumina particles. Effects of ferrocene injection rate, alumina particle sizes, and CNT growth parameters on the volume of the structure were analyzed and it was determined that high ferrocene input, moderate temperatures, and small alumina particles all favor the synthesis of high-volume CNT structures. © 2018 Elsevier B.V.
1310 a57194679331 Anderson C.M. p449 False Journal 253 Synthesis of high-specific volume carbon nanotube structures for gas-phase applications A novel and efficient gas-phase method has been developed for synthesizing carbon nanotube (CNT) structures with very high specific volume, high surface area and high porosity. The resulting material has potential application as a catalyst and adsorbent support for gas-phase chemical processes and has several advantages over the conventional liquid-phase approach that involves multiple steps and takes many hours to days resulting in a dense mat of CNTs. Multi-walled CNTs were initially nucleated and grown on alumina nanoparticles using a liquid precursor of ferrocene dissolved in xylene. The CNT seeds were extended using ethylene as the gas precursor. Forces generated by CNT growth separated the alumina support clusters to result in a porous entangled structure with a 60 times gain in weight and a 1300 times gain in volume, compared to the original alumina particles. Effects of ferrocene injection rate, alumina particle sizes, and CNT growth parameters on the volume of the structure were analyzed and it was determined that high ferrocene input, moderate temperatures, and small alumina particles all favor the synthesis of high-volume CNT structures. © 2018 Elsevier B.V.
1311 a57194686620 Thompson S.K. p449 False Journal 253 Synthesis of high-specific volume carbon nanotube structures for gas-phase applications A novel and efficient gas-phase method has been developed for synthesizing carbon nanotube (CNT) structures with very high specific volume, high surface area and high porosity. The resulting material has potential application as a catalyst and adsorbent support for gas-phase chemical processes and has several advantages over the conventional liquid-phase approach that involves multiple steps and takes many hours to days resulting in a dense mat of CNTs. Multi-walled CNTs were initially nucleated and grown on alumina nanoparticles using a liquid precursor of ferrocene dissolved in xylene. The CNT seeds were extended using ethylene as the gas precursor. Forces generated by CNT growth separated the alumina support clusters to result in a porous entangled structure with a 60 times gain in weight and a 1300 times gain in volume, compared to the original alumina particles. Effects of ferrocene injection rate, alumina particle sizes, and CNT growth parameters on the volume of the structure were analyzed and it was determined that high ferrocene input, moderate temperatures, and small alumina particles all favor the synthesis of high-volume CNT structures. © 2018 Elsevier B.V.
1312 a35791260000 Whitty K.J. p449 False Journal 253 Synthesis of high-specific volume carbon nanotube structures for gas-phase applications A novel and efficient gas-phase method has been developed for synthesizing carbon nanotube (CNT) structures with very high specific volume, high surface area and high porosity. The resulting material has potential application as a catalyst and adsorbent support for gas-phase chemical processes and has several advantages over the conventional liquid-phase approach that involves multiple steps and takes many hours to days resulting in a dense mat of CNTs. Multi-walled CNTs were initially nucleated and grown on alumina nanoparticles using a liquid precursor of ferrocene dissolved in xylene. The CNT seeds were extended using ethylene as the gas precursor. Forces generated by CNT growth separated the alumina support clusters to result in a porous entangled structure with a 60 times gain in weight and a 1300 times gain in volume, compared to the original alumina particles. Effects of ferrocene injection rate, alumina particle sizes, and CNT growth parameters on the volume of the structure were analyzed and it was determined that high ferrocene input, moderate temperatures, and small alumina particles all favor the synthesis of high-volume CNT structures. © 2018 Elsevier B.V.
1313 a57198333909 Roy J. p450 True Journal 254 Natural frequencies of piled raft foundation including superstructure effect Dynamic characteristics of piled raft foundation system plays an important role in the safety of high-rise buildings subjected to seismic loadings though the analytical study considering the effect of both foundation and superstructure is very few in literature. The present study first proposes an exact analytical solution for piled raft foundation subjected to harmonic excitation and resting on an elastic Winkler foundation to obtain its natural radial frequency. After successful validation through available centrifuge test results, a series of parametric study has been carried out investigating the influence of various geometrical and geotechnical parameters of the foundation and the soils respectively. It is observed that the pile length and the pile diameter has significant effect on the natural radial frequency of the foundation system whereas soil density and spacing between piles have minimal effect. The importance of stiffness of the superstructure is also considered in the proposed methodology. It is found that the natural radial frequency of piled raft foundation including superstructure stiffness decreases by 12% to 28% when compared with the computation of the natural radial frequency excluding effect of superstructure stiffness. Hence, this study provides a new analytical methodology to obtain the dynamics characteristics of piled raft foundation considering the superstructure effect which can be used for the design. © 2018 Elsevier Ltd
1314 a56666222000 Kumar A. p450 False Journal 254 Natural frequencies of piled raft foundation including superstructure effect Dynamic characteristics of piled raft foundation system plays an important role in the safety of high-rise buildings subjected to seismic loadings though the analytical study considering the effect of both foundation and superstructure is very few in literature. The present study first proposes an exact analytical solution for piled raft foundation subjected to harmonic excitation and resting on an elastic Winkler foundation to obtain its natural radial frequency. After successful validation through available centrifuge test results, a series of parametric study has been carried out investigating the influence of various geometrical and geotechnical parameters of the foundation and the soils respectively. It is observed that the pile length and the pile diameter has significant effect on the natural radial frequency of the foundation system whereas soil density and spacing between piles have minimal effect. The importance of stiffness of the superstructure is also considered in the proposed methodology. It is found that the natural radial frequency of piled raft foundation including superstructure stiffness decreases by 12% to 28% when compared with the computation of the natural radial frequency excluding effect of superstructure stiffness. Hence, this study provides a new analytical methodology to obtain the dynamics characteristics of piled raft foundation considering the superstructure effect which can be used for the design. © 2018 Elsevier Ltd
1315 a7103392045 Choudhury D. p450 False Journal 254 Natural frequencies of piled raft foundation including superstructure effect Dynamic characteristics of piled raft foundation system plays an important role in the safety of high-rise buildings subjected to seismic loadings though the analytical study considering the effect of both foundation and superstructure is very few in literature. The present study first proposes an exact analytical solution for piled raft foundation subjected to harmonic excitation and resting on an elastic Winkler foundation to obtain its natural radial frequency. After successful validation through available centrifuge test results, a series of parametric study has been carried out investigating the influence of various geometrical and geotechnical parameters of the foundation and the soils respectively. It is observed that the pile length and the pile diameter has significant effect on the natural radial frequency of the foundation system whereas soil density and spacing between piles have minimal effect. The importance of stiffness of the superstructure is also considered in the proposed methodology. It is found that the natural radial frequency of piled raft foundation including superstructure stiffness decreases by 12% to 28% when compared with the computation of the natural radial frequency excluding effect of superstructure stiffness. Hence, this study provides a new analytical methodology to obtain the dynamics characteristics of piled raft foundation considering the superstructure effect which can be used for the design. © 2018 Elsevier Ltd
1316 a56009607700 Chanda A. p451 True Journal 255 Biomechanical modeling of prosthetic mesh and human tissue surrogate interaction Surgical repair of hernia and prolapse with prosthetic meshes are well-known to cause pain, infection, hernia recurrence, and mesh contraction and failures. In literature, mesh failure mechanics have been studied with uniaxial, biaxial, and cyclic load testing of dry and wet meshes. Also, extensive experimental studies have been conducted on surrogates, such as non-human primates and rodents, to understand the effect of mesh stiffness, pore size, and knitting patterns on mesh biocompatibility. However, the mechanical properties of such animal tissue surrogates are widely different from human tissues. Therefore, to date, mechanics of the interaction between mesh and human tissues is poorly understood. This work addresses this gap in literature by experimentally and computationally modeling the biomechanical behavior of mesh, sutured to human tissue phantom under tension. A commercially available mesh (Prolene®) was sutured to vaginal tissue phantom material and tested at different uniaxial strains and strain rates. Global and local stresses at the tissue phantom, suture, and mesh were analyzed. The results of this study provide important insights into the mechanics of prosthetic mesh failure and will be indispensable for better mesh design in the future. © 2018 by the authors.
1316 a56009607700 Chanda A. p539 True Journal 298 Computational Modeling of Wound Suture: A Review Suturing is an acquired skill which is based on a surgeon's experience. To date, no two sutures are the same with respect to the type of knot, tension, or suture material. With advancement in medical technologies, robotic suturing is becoming more and more important to operate on complex and difficult to reach internal surgical sites. While it is very difficult to translate a surgeon's suturing expertise to an automated environment, computational models could be employed to estimate baseline suture force requirements for a given wound shape, size, and suture material, which could be subsequently processed by a robot. In the literature, there have been few attempts to characterize wound closure and suture mechanics using simple two- and three-dimensional computational models. Single and multiple skin layers (epidermis, dermis, and hypodermis) and tissues with different wound geometries and sizes have been simulated under simple wound flap displacements to estimate suture force requirements. Also, recently, sutures were modeled to simulate a realistic wound closure via suture pulling, and skin prestress effect due to the natural tension of skin was incorporated in a few models to understand its effects on wound closure mechanics. An extensive review of this literature on computational modeling of wound suture would provide valuable insights into the areas in which further research work is required. Discussion of various computational challenges in modeling sutures in a numerical environment will help in better understanding the roadblocks and the required advancements in suture modeling. © 2008-2011 IEEE.
1317 a57200525944 Ruchti T. p451 False Journal 255 Biomechanical modeling of prosthetic mesh and human tissue surrogate interaction Surgical repair of hernia and prolapse with prosthetic meshes are well-known to cause pain, infection, hernia recurrence, and mesh contraction and failures. In literature, mesh failure mechanics have been studied with uniaxial, biaxial, and cyclic load testing of dry and wet meshes. Also, extensive experimental studies have been conducted on surrogates, such as non-human primates and rodents, to understand the effect of mesh stiffness, pore size, and knitting patterns on mesh biocompatibility. However, the mechanical properties of such animal tissue surrogates are widely different from human tissues. Therefore, to date, mechanics of the interaction between mesh and human tissues is poorly understood. This work addresses this gap in literature by experimentally and computationally modeling the biomechanical behavior of mesh, sutured to human tissue phantom under tension. A commercially available mesh (Prolene®) was sutured to vaginal tissue phantom material and tested at different uniaxial strains and strain rates. Global and local stresses at the tissue phantom, suture, and mesh were analyzed. The results of this study provide important insights into the mechanics of prosthetic mesh failure and will be indispensable for better mesh design in the future. © 2018 by the authors.
1317 a57200525944 Ruchti T. p539 False Journal 298 Computational Modeling of Wound Suture: A Review Suturing is an acquired skill which is based on a surgeon's experience. To date, no two sutures are the same with respect to the type of knot, tension, or suture material. With advancement in medical technologies, robotic suturing is becoming more and more important to operate on complex and difficult to reach internal surgical sites. While it is very difficult to translate a surgeon's suturing expertise to an automated environment, computational models could be employed to estimate baseline suture force requirements for a given wound shape, size, and suture material, which could be subsequently processed by a robot. In the literature, there have been few attempts to characterize wound closure and suture mechanics using simple two- and three-dimensional computational models. Single and multiple skin layers (epidermis, dermis, and hypodermis) and tissues with different wound geometries and sizes have been simulated under simple wound flap displacements to estimate suture force requirements. Also, recently, sutures were modeled to simulate a realistic wound closure via suture pulling, and skin prestress effect due to the natural tension of skin was incorporated in a few models to understand its effects on wound closure mechanics. An extensive review of this literature on computational modeling of wound suture would provide valuable insights into the areas in which further research work is required. Discussion of various computational challenges in modeling sutures in a numerical environment will help in better understanding the roadblocks and the required advancements in suture modeling. © 2008-2011 IEEE.
1318 a57214792802 Upchurch W. p451 False Journal 255 Biomechanical modeling of prosthetic mesh and human tissue surrogate interaction Surgical repair of hernia and prolapse with prosthetic meshes are well-known to cause pain, infection, hernia recurrence, and mesh contraction and failures. In literature, mesh failure mechanics have been studied with uniaxial, biaxial, and cyclic load testing of dry and wet meshes. Also, extensive experimental studies have been conducted on surrogates, such as non-human primates and rodents, to understand the effect of mesh stiffness, pore size, and knitting patterns on mesh biocompatibility. However, the mechanical properties of such animal tissue surrogates are widely different from human tissues. Therefore, to date, mechanics of the interaction between mesh and human tissues is poorly understood. This work addresses this gap in literature by experimentally and computationally modeling the biomechanical behavior of mesh, sutured to human tissue phantom under tension. A commercially available mesh (Prolene®) was sutured to vaginal tissue phantom material and tested at different uniaxial strains and strain rates. Global and local stresses at the tissue phantom, suture, and mesh were analyzed. The results of this study provide important insights into the mechanics of prosthetic mesh failure and will be indispensable for better mesh design in the future. © 2018 by the authors.
1319 a57216486642 Lee J.H. p452 True Conference 158 Autonomous target following with monocular camera on UAS using Recursive-RANSAC tracker This paper presents a vision-based target tracking and following system using a monocular camera on an Unmanned Aerial System (UAS). The R-RANSAC tracker tracks multiple moving objects in the camera field of view and the proposed controller is capable of following a particular target selected by a user while keeping the target in the center of the image. The main contribution of this paper is that multiple objects can be tracked without imposing restrictions such as color, shape, etc. Also, the hardware test shows that the system is able to follow a target autonomously in a real-world outdoor environment. The proposed algorithm is validated on a 3DR X-8 multirotor platform using a downward facing camera. © 2018 IEEE.
1320 a57203661089 Millard J.D. p452 False Conference 158 Autonomous target following with monocular camera on UAS using Recursive-RANSAC tracker This paper presents a vision-based target tracking and following system using a monocular camera on an Unmanned Aerial System (UAS). The R-RANSAC tracker tracks multiple moving objects in the camera field of view and the proposed controller is capable of following a particular target selected by a user while keeping the target in the center of the image. The main contribution of this paper is that multiple objects can be tracked without imposing restrictions such as color, shape, etc. Also, the hardware test shows that the system is able to follow a target autonomously in a real-world outdoor environment. The proposed algorithm is validated on a 3DR X-8 multirotor platform using a downward facing camera. © 2018 IEEE.
1320 a57203661089 Millard J.D. p460 True Conference 165 Improved Track Continuity in Multi Target Tracking by Fusing Multiple Input Sources Reliable track continuity is an important characteristic of multiple target tracking (MTT) algorithms. In the specific case of tracking multiple ground targets from an aerial platform, challenges arise due to realistic operating environments such as imperfections in the measurement source. Some popular visual detection techniques include Kanade-Lucas-Tomasi (KLT)-based motion detection, difference imaging, and object feature matching. Each of these algorithmic detectors has fundamental limitations in regard to providing consistent measurements. In this paper we present a scalable detection framework that leverages multiple measurement sources. We also present the recursive random sample consensus (R-RANSAC) algorithm in a data fusion architecture that can simultaneously accommodate multiple measurement sources. We demonstrate robust track continuity using post-processed flight data and show real-time computational performance. © 2018 AACC.
1321 a57203982016 Bean M. p454 False Conference 160 Zipper Tube Reinforcement to Mitigate Flexible Shaft Buckling The Zipper Tube Reinforcement (ZTR) is a novel support system developed to mitigate buckling in thin flexible devices used in robotic surgery. The ZTR was inspired by a construction technique called a Buckling Restrained Braced Frame (BRBF) and deployable booms for space applications. It utilizes a zipper function to allow a rolled sheet to deploy into a variable-length tube and stow in a small volume spooled on a mandrel. The tube envelops the device and allows it to support a much higher compressive load before buckling failure through the insertion stroke. The ZTR also enables the possibility of smaller, more flexible devices due to its design for continuous support and could find application in other fields. © 2018 IEEE.
1322 a57203992542 Wood D. p454 False Conference 160 Zipper Tube Reinforcement to Mitigate Flexible Shaft Buckling The Zipper Tube Reinforcement (ZTR) is a novel support system developed to mitigate buckling in thin flexible devices used in robotic surgery. The ZTR was inspired by a construction technique called a Buckling Restrained Braced Frame (BRBF) and deployable booms for space applications. It utilizes a zipper function to allow a rolled sheet to deploy into a variable-length tube and stow in a small volume spooled on a mandrel. The tube envelops the device and allows it to support a much higher compressive load before buckling failure through the insertion stroke. The ZTR also enables the possibility of smaller, more flexible devices due to its design for continuous support and could find application in other fields. © 2018 IEEE.
1323 a57203980122 Frandsen D. p455 False Conference 161 Modified Material Properties in Curved Panels Through Lamina Emergent Torsional Joints Compliant joints have a number of advantages that make them suitable for highly constrained design problems. While much work has been done on the design of compliant joints manufactured from planar sheet materials, this work focuses on the design of cylindrically-curved joints. A method for using lamina emergent torsional (LET) joints to increase energy storage efficiency in curved sheet materials is presented. A numerical model is provided for predicting the stiffness and maximum applied moment of a curved LET joint. Predicted curved LET joint stiffnesses and maximum moments are utilized to create shape factors that produce an effective modulus of elasticity and an effective modulus of resilience. For a given case, the effective modulus of elasticity is shown to decrease by about three orders of magnitude while the effective resilience decreases by approximately one order of magnitude. Designers can use this information to tailor materials to fit design requirements or to select alternative materials that were previously unsuited for an application. © 2018 IEEE.
1324 a57203980107 Burrow D. p455 False Conference 161 Modified Material Properties in Curved Panels Through Lamina Emergent Torsional Joints Compliant joints have a number of advantages that make them suitable for highly constrained design problems. While much work has been done on the design of compliant joints manufactured from planar sheet materials, this work focuses on the design of cylindrically-curved joints. A method for using lamina emergent torsional (LET) joints to increase energy storage efficiency in curved sheet materials is presented. A numerical model is provided for predicting the stiffness and maximum applied moment of a curved LET joint. Predicted curved LET joint stiffnesses and maximum moments are utilized to create shape factors that produce an effective modulus of elasticity and an effective modulus of resilience. For a given case, the effective modulus of elasticity is shown to decrease by about three orders of magnitude while the effective resilience decreases by approximately one order of magnitude. Designers can use this information to tailor materials to fit design requirements or to select alternative materials that were previously unsuited for an application. © 2018 IEEE.
1325 a57204553875 Jensen T.D. p458 True Conference 164 The PepSeq Pipeline: Software for Antimicrobial Motif Discovery in Randomly-Generated Peptide Libraries Bacteria with resistance genes are becoming ever more common, and new methods of discovering antibiotics are being developed. One of these new methods involves researchers creating random peptides and testing their antimicrobial activity. Developing antibiotics from these peptides requires understanding which sequence motifs will be toxic to bacteria. To determine if the toxic peptides of a randomly-generated peptide library can be uniquely classified based solely on sequence motifs, we created the PepSeq Pipeline: a new software that utilizes a Random Forest algorithm to extract motifs from a peptide library. We found that this pipeline can accurately classify 56% of the toxic peptides in the peptide library using motifs extracted from the model. Testing on simulated data with less noise, we could classify up to 94% of the toxic peptides. The pipeline extracted significant toxic motifs in every library that was tested, but its ability to classify all toxic peptides depended on the number of motifs in the library. Once extracted, these motifs can be used both to understand the biology behind why certain peptides are toxic and to create novel antibiotics. The code and data used in this analysis can be found at https://github.com/tjense25/pep-seq-pipeline. © 2018 ACM.
1326 a57204546854 Bresciano K.A. p458 False Conference 164 The PepSeq Pipeline: Software for Antimicrobial Motif Discovery in Randomly-Generated Peptide Libraries Bacteria with resistance genes are becoming ever more common, and new methods of discovering antibiotics are being developed. One of these new methods involves researchers creating random peptides and testing their antimicrobial activity. Developing antibiotics from these peptides requires understanding which sequence motifs will be toxic to bacteria. To determine if the toxic peptides of a randomly-generated peptide library can be uniquely classified based solely on sequence motifs, we created the PepSeq Pipeline: a new software that utilizes a Random Forest algorithm to extract motifs from a peptide library. We found that this pipeline can accurately classify 56% of the toxic peptides in the peptide library using motifs extracted from the model. Testing on simulated data with less noise, we could classify up to 94% of the toxic peptides. The pipeline extracted significant toxic motifs in every library that was tested, but its ability to classify all toxic peptides depended on the number of motifs in the library. Once extracted, these motifs can be used both to understand the biology behind why certain peptides are toxic and to create novel antibiotics. The code and data used in this analysis can be found at https://github.com/tjense25/pep-seq-pipeline. © 2018 ACM.
1327 a57204555914 Dallon E. p458 False Conference 164 The PepSeq Pipeline: Software for Antimicrobial Motif Discovery in Randomly-Generated Peptide Libraries Bacteria with resistance genes are becoming ever more common, and new methods of discovering antibiotics are being developed. One of these new methods involves researchers creating random peptides and testing their antimicrobial activity. Developing antibiotics from these peptides requires understanding which sequence motifs will be toxic to bacteria. To determine if the toxic peptides of a randomly-generated peptide library can be uniquely classified based solely on sequence motifs, we created the PepSeq Pipeline: a new software that utilizes a Random Forest algorithm to extract motifs from a peptide library. We found that this pipeline can accurately classify 56% of the toxic peptides in the peptide library using motifs extracted from the model. Testing on simulated data with less noise, we could classify up to 94% of the toxic peptides. The pipeline extracted significant toxic motifs in every library that was tested, but its ability to classify all toxic peptides depended on the number of motifs in the library. Once extracted, these motifs can be used both to understand the biology behind why certain peptides are toxic and to create novel antibiotics. The code and data used in this analysis can be found at https://github.com/tjense25/pep-seq-pipeline. © 2018 ACM.
1328 a57204555396 Stewart E. p458 False Conference 164 The PepSeq Pipeline: Software for Antimicrobial Motif Discovery in Randomly-Generated Peptide Libraries Bacteria with resistance genes are becoming ever more common, and new methods of discovering antibiotics are being developed. One of these new methods involves researchers creating random peptides and testing their antimicrobial activity. Developing antibiotics from these peptides requires understanding which sequence motifs will be toxic to bacteria. To determine if the toxic peptides of a randomly-generated peptide library can be uniquely classified based solely on sequence motifs, we created the PepSeq Pipeline: a new software that utilizes a Random Forest algorithm to extract motifs from a peptide library. We found that this pipeline can accurately classify 56% of the toxic peptides in the peptide library using motifs extracted from the model. Testing on simulated data with less noise, we could classify up to 94% of the toxic peptides. The pipeline extracted significant toxic motifs in every library that was tested, but its ability to classify all toxic peptides depended on the number of motifs in the library. Once extracted, these motifs can be used both to understand the biology behind why certain peptides are toxic and to create novel antibiotics. The code and data used in this analysis can be found at https://github.com/tjense25/pep-seq-pipeline. © 2018 ACM.
1329 a6507235629 Griffitts J. p458 False Conference 164 The PepSeq Pipeline: Software for Antimicrobial Motif Discovery in Randomly-Generated Peptide Libraries Bacteria with resistance genes are becoming ever more common, and new methods of discovering antibiotics are being developed. One of these new methods involves researchers creating random peptides and testing their antimicrobial activity. Developing antibiotics from these peptides requires understanding which sequence motifs will be toxic to bacteria. To determine if the toxic peptides of a randomly-generated peptide library can be uniquely classified based solely on sequence motifs, we created the PepSeq Pipeline: a new software that utilizes a Random Forest algorithm to extract motifs from a peptide library. We found that this pipeline can accurately classify 56% of the toxic peptides in the peptide library using motifs extracted from the model. Testing on simulated data with less noise, we could classify up to 94% of the toxic peptides. The pipeline extracted significant toxic motifs in every library that was tested, but its ability to classify all toxic peptides depended on the number of motifs in the library. Once extracted, these motifs can be used both to understand the biology behind why certain peptides are toxic and to create novel antibiotics. The code and data used in this analysis can be found at https://github.com/tjense25/pep-seq-pipeline. © 2018 ACM.
1330 a57195398251 McMurray J. p459 False Journal 256 Buried Rib SiO2 Multimode Interference Waveguides for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used to create wavelength-dependent spot patterns which enables simultaneous analyte detection on a single optofluidic chip, useful for disease diagnostics. The fidelity of such multi-spot patterns is important for high sensitivity and accurate target identification. Buried rib structures have been incorporated into these SiO2-based waveguides to improve environmental stability. Through experiments and simulation, this letter explores design parameters for a buried MMI rib waveguide based on anti-resonant reflecting optical waveguides in order to produce high-fidelity spot patterns. Optimal rib heights and widths are reported in the context of available microfabrication etch technology and performance for an optimized biosensor is shown. © 1989-2012 IEEE.
1330 a57195398251 McMurray J. p502 False Journal 273 Optimized ARROW-Based MMI Waveguides for High Fidelity Excitation Patterns for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used for multiplexing and de-multiplexing optical signals. High fidelity, wavelength dependent multi-spot patterns from MMI waveguides are useful for sensitive and simultaneous identification of multiple targets in multiplexed fluorescence optofluidic biosensors. Through experiments and simulation, this paper explores design parameters for an MMI rib anti-resonant reflecting optical waveguide in order to produce high fidelity spot patterns at the liquid core biomarker excitation region. Width and etch depth of the single excitation rib waveguide used to excite the MMI waveguide are especially critical because they determine the size of the input optical mode which is imaged at the MMI waveguide's output. To increase optical throughput into the MMI waveguide when light is coupled in from an optical fiber, tapers in the waveguide width can be used for better mode matching. © 2012 IEEE.
1330 a57195398251 McMurray J. p607 False Conference 245 High fidelity MMI excitation patterns for optofluidic multiplexing High fidelity interference patterns from multimode interference waveguides are needed for multiplexed optofluidic biosensors. Spot pattern fidelity can be optimized by careful design of the single-mode waveguides used to excite the multimode waveguides. © OSA 2018.
1330 a57195398251 McMurray J. p706 False Journal 347 Optofluidic lab-on-a-chip fluorescence sensor using integrated buried ARROW (bARROW) waveguides Optofluidic, lab-on-a-chip fluorescence sensors were fabricated using buried anti-resonant reflecting optical waveguides (bARROWs). The bARROWs are impervious to the negative water absorption effects that typically occur in waveguides made using hygroscopic, plasma-enhanced chemical vapor deposition (PECVD) oxides. These sensors were used to detect fluorescent microbeads and had an average signal-to-noise ratio (SNR) that was 81.3% higher than that of single-oxide ARROW fluorescence sensors. While the single-oxide ARROW sensors were annealed at 300 ◦ C to drive moisture out of the waveguides, the bARROW sensors required no annealing process to obtain a high SNR. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.
1331 a57201484423 Olsen M. p459 False Journal 256 Buried Rib SiO2 Multimode Interference Waveguides for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used to create wavelength-dependent spot patterns which enables simultaneous analyte detection on a single optofluidic chip, useful for disease diagnostics. The fidelity of such multi-spot patterns is important for high sensitivity and accurate target identification. Buried rib structures have been incorporated into these SiO2-based waveguides to improve environmental stability. Through experiments and simulation, this letter explores design parameters for a buried MMI rib waveguide based on anti-resonant reflecting optical waveguides in order to produce high-fidelity spot patterns. Optimal rib heights and widths are reported in the context of available microfabrication etch technology and performance for an optimized biosensor is shown. © 1989-2012 IEEE.
1331 a57201484423 Olsen M. p502 False Journal 273 Optimized ARROW-Based MMI Waveguides for High Fidelity Excitation Patterns for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used for multiplexing and de-multiplexing optical signals. High fidelity, wavelength dependent multi-spot patterns from MMI waveguides are useful for sensitive and simultaneous identification of multiple targets in multiplexed fluorescence optofluidic biosensors. Through experiments and simulation, this paper explores design parameters for an MMI rib anti-resonant reflecting optical waveguide in order to produce high fidelity spot patterns at the liquid core biomarker excitation region. Width and etch depth of the single excitation rib waveguide used to excite the MMI waveguide are especially critical because they determine the size of the input optical mode which is imaged at the MMI waveguide's output. To increase optical throughput into the MMI waveguide when light is coupled in from an optical fiber, tapers in the waveguide width can be used for better mode matching. © 2012 IEEE.
1331 a57201484423 Olsen M. p607 False Conference 245 High fidelity MMI excitation patterns for optofluidic multiplexing High fidelity interference patterns from multimode interference waveguides are needed for multiplexed optofluidic biosensors. Spot pattern fidelity can be optimized by careful design of the single-mode waveguides used to excite the multimode waveguides. © OSA 2018.
1332 a57194155925 Orfila M. p459 False Journal 256 Buried Rib SiO2 Multimode Interference Waveguides for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used to create wavelength-dependent spot patterns which enables simultaneous analyte detection on a single optofluidic chip, useful for disease diagnostics. The fidelity of such multi-spot patterns is important for high sensitivity and accurate target identification. Buried rib structures have been incorporated into these SiO2-based waveguides to improve environmental stability. Through experiments and simulation, this letter explores design parameters for a buried MMI rib waveguide based on anti-resonant reflecting optical waveguides in order to produce high-fidelity spot patterns. Optimal rib heights and widths are reported in the context of available microfabrication etch technology and performance for an optimized biosensor is shown. © 1989-2012 IEEE.
1332 a57194155925 Orfila M. p502 False Journal 273 Optimized ARROW-Based MMI Waveguides for High Fidelity Excitation Patterns for Optofluidic Multiplexing Multimode interference (MMI) waveguides can be used for multiplexing and de-multiplexing optical signals. High fidelity, wavelength dependent multi-spot patterns from MMI waveguides are useful for sensitive and simultaneous identification of multiple targets in multiplexed fluorescence optofluidic biosensors. Through experiments and simulation, this paper explores design parameters for an MMI rib anti-resonant reflecting optical waveguide in order to produce high fidelity spot patterns at the liquid core biomarker excitation region. Width and etch depth of the single excitation rib waveguide used to excite the MMI waveguide are especially critical because they determine the size of the input optical mode which is imaged at the MMI waveguide's output. To increase optical throughput into the MMI waveguide when light is coupled in from an optical fiber, tapers in the waveguide width can be used for better mode matching. © 2012 IEEE.
1332 a57194155925 Orfila M. p607 False Conference 245 High fidelity MMI excitation patterns for optofluidic multiplexing High fidelity interference patterns from multimode interference waveguides are needed for multiplexed optofluidic biosensors. Spot pattern fidelity can be optimized by careful design of the single-mode waveguides used to excite the multimode waveguides. © OSA 2018.
1332 a57194155925 Orfila M. p749 False Journal 363 Mitigating Water Absorption in Waveguides Made from Unannealed PECVD SiO2 Water absorption was studied in two types of waveguides made from unannealed plasma enhanced chemical vapor deposition (PECVD) SiO2. Standard rib anti-resonant reflecting optical waveguides (ARROWs) were fabricated with thin films of different intrinsic stress and indices of refraction. Buried ARROWs (bARROWs) with low and high refractive index differences between the core and cladding regions were also fabricated from the same types of PECVD films. All waveguides were subjected to a heated, high humidity environment and their optical throughput was tested over time. Due to water absorption in the SiO2 films, the optical throughput of all of the ARROWs decreased with time spent in the wet environment. The ARROWs with the lowest stress SiO2 had the slowest rate of throughput change. High index difference bARROWs showed no decrease in optical throughput after 40 days in the wet environment and are presented as a solution for environmentally stable waveguides made from unannealed PECVD SiO2. © 2017 IEEE.
1332 a57194155925 Orfila M. p839 False Conference 366 Preserving optical confinement in unannealed PECVD SiO2 waveguides Rib and buried channel waveguides (BCWs) made of unannealed PECVD SiO2 were studied after exposure to high humidity. Low stressed rib waveguides had lower optical throughput change, while high index difference BCWs were practically unaffected. © 2017 OSA.
1333 a35792700800 Yeung E. p462 False Conference 167 A Class of Logistic Functions for Approximating State-Inclusive Koopman Operators An outstanding challenge in nonlinear systems theory is identification or learning of a given nonlinear system's Koopman operator directly from data or models. Advances in extended dynamic mode decomposition approaches and machine learning methods have enabled data-driven discovery of Koopman operators, for both continuous and discrete-time systems. Since Koopman operators are often infinite-dimensional, they are approximated in practice using finite-dimensional systems. The fidelity and convergence of a given finite-dimensional Koopman approximation is a subject of ongoing research. In this paper we introduce a class of Koopman observable functions that confer an approximate closure property on their corresponding finite-dimensional approximations of the Koopman operator. We derive error bounds for the fidelity of this class of observable functions, as well as identify two key learning parameters which can be used to tune performance. We illustrate our approach on two classical nonlinear system models: the Van Der Pol oscillator and the bistable toggle switch. © 2018 AACC.
1333 a35792700800 Yeung E. p888 False Journal 413 A minimal realization technique for the dynamical structure function of a class of LTI systems The dynamical structure function of a linear time invariant (LTI) system reveals causal dependencies among manifest variables without specifying any particular relationships among the unmeasured states of the system. As such, it is a useful representation for complex networks where a coarse description of global system structure is desired without detailing the intricacies of a full state realization. In this paper, we consider the problem of finding a minimal state realization for a given dynamical structure function. Interestingly, some dynamical structure functions require uncontrollable modes in their state realizations to deliver the desired input-output behavior while respecting a specified system structure. As a result, the minimal order necessary to realize a particular dynamical structure function may be greater than that necessary to realize its associated transfer function. Although finding a minimal realization for a given dynamical structure function is difficult in general, we present a straightforward procedure here that works for a simplified class of systems. © 2014 IEEE.
1334 a39062086200 Salva K.T. p463 False Conference 168 Extending Motion Detection to Track Stopped Objects in Visual Multi-Target Tracking Various solutions to visual multi-target tracking have been proposed, but many of them are not capable of running in real time from a moving camera on an unmanned aerial vehicle (UAV). We present a tracker that runs in real time and tracks multiple objects while accounting for camera motion on a UAV. Our algorithm is capable of processing over 10 frames per second on a 1280x720 video sequence. We utilize Recursive-RANSAC, an efficient algorithm for tracking multiple objects in clutter. Our work combines motion detection with optical flow and feature matching to allow stationary objects to be tracked. We use a feature prioritization algorithm to reduce computational complexity and spatial redundancy. We also present a ghost track reduction method which prevents tracking non-existent objects when true objects are no longer visible. We demonstrate the performance of our tracker on a moving camera video sequence. Video results are available at https://youtu.be/6bXjKb-6qY. © 2018 AACC.
1335 a55658283500 Lund J. p464 True Conference 169 Movie recommendations using the deep learning approach Recommendation systems are an important part of suggesting items especially in streaming services. For streaming movie services like Netflix, recommendation systems are essential for helping users find new movies to enjoy. In this paper, we propose a deep learning approach based on autoencoders to produce a collaborative filtering system which predicts movie ratings for a user based on a large database of ratings from other users. Using the MovieLens dataset, we explore the use of deep learning to predict users' ratings on new movies, thereby enabling movie recommendations. To verify the novelty and accuracy of our deep learning approach, we compare our approach to standard collaborative filtering techniques: k-nearest-neighbor and matrix-factorization. The experimental results show that our recommendation system outperforms a user-based neighborhood baseline both in terms of root mean squared error on predicted ratings and in a survey in which users judge between recommendations from both systems. © 2018 IEEE.
1336 a57203575128 Baskota A. p465 True Conference 170 A graduate school recommendation system using the multi-class support vector machine and KNN approaches With the advancement in technology and increased demand on skilled workers these days, education becomes a stepping stone in securing jobs with long-term perspective. As competition for admission into higher education increases, it becomes even more important for applicants to find graduate schools that fit their requirements and expectation. Selecting appropriate schools to apply, however, is a time-consuming process, especially when looking for schools at graduate level due to the various factors in decision making imposed by the schools and applicants. In this paper, we propose a recommendation system that suggests appealing graduate programs to students based on the Support Vector Machine and K-Nearest Neighbor approaches. As graduate programs make decisions based on applicants' qualification, our recommender considers user's personal data and data of various graduate programs obtained from online education portals to make suggestions. We conduct an empirical study using data of current graduate schools and former graduate school applicants, and the performance evaluation validates the merit of our suggestions. © 2018 IEEE.
1337 a56897186700 Lansinger V.B. p467 False Journal 228 One-dimensional turbulence modeling for cylindrical and spherical flows: model formulation and application The one-dimensional turbulence (ODT) model resolves a full range of time and length scales and is computationally efficient. ODT has been applied to a wide range of complex multi-scale flows, such as turbulent combustion. Previous ODT comparisons to experimental data have focused mainly on planar flows. Applications to cylindrical flows, such as round jets, have been based on rough analogies, e.g., by exploiting the fortuitous consistency of the similarity scalings of temporally developing planar jets and spatially developing round jets. To obtain a more systematic treatment, a new formulation of the ODT model in cylindrical and spherical coordinates is presented here. The model is written in terms of a geometric factor so that planar, cylindrical, and spherical configurations are represented in the same way. Temporal and spatial versions of the model are presented. A Lagrangian finite-volume implementation is used with a dynamically adaptive mesh. The adaptive mesh facilitates the implementation of cylindrical and spherical versions of the triplet map, which is used to model turbulent advection (eddy events) in the one-dimensional flow coordinate. In cylindrical and spherical coordinates, geometric stretching of the three triplet map images occurs due to the radial dependence of volume, with the stretching being strongest near the centerline. Two triplet map variants, TMA and TMB, are presented. In TMA, the three map images have the same volume, but different radial segment lengths. In TMB, the three map images have the same radial segment lengths, but different segment volumes. Cylindrical results are presented for temporal pipe flow, a spatial nonreacting jet, and a spatial nonreacting jet flame. These results compare very well to direct numerical simulation for the pipe flow, and to experimental data for the jets. The nonreacting jet treatment overpredicts velocity fluctuations near the centerline, due to the geometric stretching of the triplet maps and its effect on the eddy event rate distribution. TMB performs better than TMA. A hybrid planar-TMB (PTMB) approach is also presented, which further improves the results. TMA, TMB, and PTMB are nearly identical in the pipe flow where the key dynamics occur near the wall away from the centerline. The jet flame illustrates effects of variable density and viscosity, including dilatational effects. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1337 a56897186700 Lansinger V.B. p621 False Conference 257 Simplified modeling for soot formation from solid fuels Modeling soot formed from solid complex fuels such as coal or biomass is difficult and rare in the combustion community. Previously a detailed model was developed for soot formation depicting the soot particle size distribution using the method of moments with interpolative closure. This model is both accurate and complex. Computational expense of this model may be beyond many large-scale simulations. As a result, a simplified version of this detailed model has been developed. This simplified model makes two easy assumptions to drastically reduce the complexity of modeling soot formation. First assumption is that soot particles and soot precursors within a computational domain are assumed to be mono-dispersed, meaning all particles are the same size. This reduces the number of resolved terms to model both soot precursors and soot particles to three resolved terms rather than the 10+ terms required by the previously developed model. Second assumption is that all particles are spherical. While the simplified model is computationally less expensive, these two assumptions come with a cost in accuracy. Presented is both the development of this simplified model along with comparative simulations where the complex and simple models are ran. From these simulations, researchers and developers can justify which model may be used in their respective systems. © 2018 Western States Section/Combustion Institute. All rights reserved.
1338 a57197726868 Medina J. p467 False Journal 228 One-dimensional turbulence modeling for cylindrical and spherical flows: model formulation and application The one-dimensional turbulence (ODT) model resolves a full range of time and length scales and is computationally efficient. ODT has been applied to a wide range of complex multi-scale flows, such as turbulent combustion. Previous ODT comparisons to experimental data have focused mainly on planar flows. Applications to cylindrical flows, such as round jets, have been based on rough analogies, e.g., by exploiting the fortuitous consistency of the similarity scalings of temporally developing planar jets and spatially developing round jets. To obtain a more systematic treatment, a new formulation of the ODT model in cylindrical and spherical coordinates is presented here. The model is written in terms of a geometric factor so that planar, cylindrical, and spherical configurations are represented in the same way. Temporal and spatial versions of the model are presented. A Lagrangian finite-volume implementation is used with a dynamically adaptive mesh. The adaptive mesh facilitates the implementation of cylindrical and spherical versions of the triplet map, which is used to model turbulent advection (eddy events) in the one-dimensional flow coordinate. In cylindrical and spherical coordinates, geometric stretching of the three triplet map images occurs due to the radial dependence of volume, with the stretching being strongest near the centerline. Two triplet map variants, TMA and TMB, are presented. In TMA, the three map images have the same volume, but different radial segment lengths. In TMB, the three map images have the same radial segment lengths, but different segment volumes. Cylindrical results are presented for temporal pipe flow, a spatial nonreacting jet, and a spatial nonreacting jet flame. These results compare very well to direct numerical simulation for the pipe flow, and to experimental data for the jets. The nonreacting jet treatment overpredicts velocity fluctuations near the centerline, due to the geometric stretching of the triplet maps and its effect on the eddy event rate distribution. TMB performs better than TMA. A hybrid planar-TMB (PTMB) approach is also presented, which further improves the results. TMA, TMB, and PTMB are nearly identical in the pipe flow where the key dynamics occur near the wall away from the centerline. The jet flame illustrates effects of variable density and viscosity, including dilatational effects. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1339 a56261172000 Klein M. p467 False Journal 228 One-dimensional turbulence modeling for cylindrical and spherical flows: model formulation and application The one-dimensional turbulence (ODT) model resolves a full range of time and length scales and is computationally efficient. ODT has been applied to a wide range of complex multi-scale flows, such as turbulent combustion. Previous ODT comparisons to experimental data have focused mainly on planar flows. Applications to cylindrical flows, such as round jets, have been based on rough analogies, e.g., by exploiting the fortuitous consistency of the similarity scalings of temporally developing planar jets and spatially developing round jets. To obtain a more systematic treatment, a new formulation of the ODT model in cylindrical and spherical coordinates is presented here. The model is written in terms of a geometric factor so that planar, cylindrical, and spherical configurations are represented in the same way. Temporal and spatial versions of the model are presented. A Lagrangian finite-volume implementation is used with a dynamically adaptive mesh. The adaptive mesh facilitates the implementation of cylindrical and spherical versions of the triplet map, which is used to model turbulent advection (eddy events) in the one-dimensional flow coordinate. In cylindrical and spherical coordinates, geometric stretching of the three triplet map images occurs due to the radial dependence of volume, with the stretching being strongest near the centerline. Two triplet map variants, TMA and TMB, are presented. In TMA, the three map images have the same volume, but different radial segment lengths. In TMB, the three map images have the same radial segment lengths, but different segment volumes. Cylindrical results are presented for temporal pipe flow, a spatial nonreacting jet, and a spatial nonreacting jet flame. These results compare very well to direct numerical simulation for the pipe flow, and to experimental data for the jets. The nonreacting jet treatment overpredicts velocity fluctuations near the centerline, due to the geometric stretching of the triplet maps and its effect on the eddy event rate distribution. TMB performs better than TMA. A hybrid planar-TMB (PTMB) approach is also presented, which further improves the results. TMA, TMB, and PTMB are nearly identical in the pipe flow where the key dynamics occur near the wall away from the centerline. The jet flame illustrates effects of variable density and viscosity, including dilatational effects. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
1340 a57203731804 Johnson M.H. p469 True Conference 171 A Rateless Approach to Physical-Layer Security A majority of coding constructions for physical-layer security are based on linear block codes and their cosets. One issue with these codes is that they require knowledge of channel state information (CSI) for both the friendly party and the eavesdropper in the wiretap channel prior to constructing the code. In this paper, we present a framework for rateless physical-layer security codes over the wiretap channel by introducing both fixed and adaptive variants of rateless security coding schemes. These techniques can be used to reduce the requirements on CSI prior to code construction, because the codes will either adapt to the operating parameters of the legitimate user's channel on the fly and/or target a maximum allowable probability of intercept (POI) at the eavesdropper. All channels in play are packet erasure channels (PECs), as these channels are quite pervasive in most real-world network applications. We further present the details of an actual implementation of rateless physical-layer security coding over a Wi-Fi network. © 2018 IEEE.
1341 a57203372448 Rendon G.T. p470 True Conference 172 Nested QPSK Encoding for Information Theoretic Security This paper proposes a method to provide secrecy for digital communications with arbitrarily large quadrature amplitude modulation (QAM) constellations for transmission over a Gaussian fading wiretap channel. This is accomplished by breaking the constellation down into nested quadrature phase-shift keying (QPSK) symbols and randomizing the assignment between message bits and modulated symbols using channel state information (CSI). If enough random bits can be generated from CSI it becomes possible to uniquely map an arbitrary message to any symbol in the large QAM constellation. The proposed method can thereby provide perfect secrecy while maintaining high reliability by exclusively assigning minimum-distance-mapped constellations through the randomization for use by the legitimate decoder. © 2018 IEEE.
1342 a57203247682 Reynolds J. p471 True Conference 173 A Tale of Two Studies: The Best and Worst of YubiKey Usability Two-factor authentication (2FA) significantly improves the security of password-based authentication. Recently, there has been increased interest in Universal 2nd Factor (U2F) security keys-small hardware devices that require users to press a button on the security key to authenticate. To examine the usability of security keys in non-enterprise usage, we conducted two user studies of the YubiKey, a popular line of U2F security keys. The first study tasked 31 participants with configuring a Windows, Google, and Facebook account to authenticate using a YubiKey. This study revealed problems with setup instructions and workflow including users locking themselves out of their operating system or thinking they had successfully enabled 2FA when they had not. In contrast, the second study had 25 participants use a YubiKey in their daily lives over a period of four weeks, revealing that participants generally enjoyed the experience. Conducting both a laboratory and longitudinal study yielded insights into the usability of security keys that would not have been evident from either study in isolation. Based on our analysis, we recommend standardizing the setup process, enabling verification of success, allowing shared accounts, integrating with operating systems, and preventing lockouts. © 2018 IEEE.
1342 a57203247682 Reynolds J. p793 False Conference 330 TrustBase: An architecture to repair and strengthen certificate-based authentication The current state of certificate-based authentication is messy, with broken authentication in applications and proxies, along with serious flaws in the CA system. To solve these problems, we design TrustBase, an architecture that provides certificate-based authentication as an operating system service, with system administrator control over authentication policy. TrustBase transparently enforces best practices for certificate validation on all applications, while also providing a variety of authentication services to strengthen the CA system. We describe a research prototype of TrustBase for Linux, which uses a loadable kernel module to intercept traffic in the socket layer, then consults a userspace policy engine to evaluate certificate validity using a variety of plugins. We evaluate the security of TrustBase, including a threat analysis, application coverage, and hardening of the Linux prototype. We also describe prototypes of TrustBase for Android and Windows, illustrating the generality of our approach. We show that TrustBase has negligible overhead and universal compatibility with applications. We demonstrate its utility by describing eight authentication services that extend CA hardening to all applications. © 2017 by The USENIX Association. All Rights Reserved.
1343 a57202927332 Witzeman J.S. p473 True Journal 260 The Future of R&D Leadership: Wider changes in the culture and the market will drive changes in the practice of R&D leadership. Overview: The environment in which industrial R&D operates is continuing to evolve, at a pace that seems to be ever increasing. Within the enduring elements of R&D leadership—management of staff and content creation and dissemination, among others—significant changes in practice are emerging or can be expected to emerge over the next few years. These changes, their impact on R&D leadership, and a vision of what R&D leadership will need to be in the future are the focus of this article. © 2018, © 2018, Innovation Research Interchange. Published by Taylor & Francis. All rights reserved.
1344 a7202608915 Henderson P. p473 False Journal 260 The Future of R&D Leadership: Wider changes in the culture and the market will drive changes in the practice of R&D leadership. Overview: The environment in which industrial R&D operates is continuing to evolve, at a pace that seems to be ever increasing. Within the enduring elements of R&D leadership—management of staff and content creation and dissemination, among others—significant changes in practice are emerging or can be expected to emerge over the next few years. These changes, their impact on R&D leadership, and a vision of what R&D leadership will need to be in the future are the focus of this article. © 2018, © 2018, Innovation Research Interchange. Published by Taylor & Francis. All rights reserved.
1345 a57202921889 Welling A.G. p473 False Journal 260 The Future of R&D Leadership: Wider changes in the culture and the market will drive changes in the practice of R&D leadership. Overview: The environment in which industrial R&D operates is continuing to evolve, at a pace that seems to be ever increasing. Within the enduring elements of R&D leadership—management of staff and content creation and dissemination, among others—significant changes in practice are emerging or can be expected to emerge over the next few years. These changes, their impact on R&D leadership, and a vision of what R&D leadership will need to be in the future are the focus of this article. © 2018, © 2018, Innovation Research Interchange. Published by Taylor & Francis. All rights reserved.
1346 a7801604567 Cosner R. p473 False Journal 260 The Future of R&D Leadership: Wider changes in the culture and the market will drive changes in the practice of R&D leadership. Overview: The environment in which industrial R&D operates is continuing to evolve, at a pace that seems to be ever increasing. Within the enduring elements of R&D leadership—management of staff and content creation and dissemination, among others—significant changes in practice are emerging or can be expected to emerge over the next few years. These changes, their impact on R&D leadership, and a vision of what R&D leadership will need to be in the future are the focus of this article. © 2018, © 2018, Innovation Research Interchange. Published by Taylor & Francis. All rights reserved.
1347 a54581173100 Kimmons R. p474 True Journal 261 Mining social media divides: an analysis of K-12 U.S. School uses of Twitter This study utilizes public data mining to explore participation divides of all available K-12 institutional Twitter accounts in the U.S. (n = 8275 accounts, n = 9,216,853 tweets). Results indicated that U.S. schools used Twitter to broadcast information on a variety of topics in a unidirectional manner and that hashtags included a variety of intended purposes, including affinity spaces, education topics, emotive language, and events. Those schools in wealthier, more populated areas were more likely to use Twitter, with wealthy, suburban schools being the most likely to use it and poor, rural schools being the least likely. Furthermore, factors such as charter school status and urbanity influenced the content of school tweets on key issues, with schools in more populated areas tweeting more about coding and college than schools in less populated areas and charter schools tweeting more about college and the politicized educational issue of common core than non-charters. These results reveal participation differences between schools based upon demographics and provides a basis for conducting future large-scale work on publicly available artifacts, such as school tweets, that may be meaningfully used as education research data. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
1348 a57202810627 Carpenter J.P. p474 False Journal 261 Mining social media divides: an analysis of K-12 U.S. School uses of Twitter This study utilizes public data mining to explore participation divides of all available K-12 institutional Twitter accounts in the U.S. (n = 8275 accounts, n = 9,216,853 tweets). Results indicated that U.S. schools used Twitter to broadcast information on a variety of topics in a unidirectional manner and that hashtags included a variety of intended purposes, including affinity spaces, education topics, emotive language, and events. Those schools in wealthier, more populated areas were more likely to use Twitter, with wealthy, suburban schools being the most likely to use it and poor, rural schools being the least likely. Furthermore, factors such as charter school status and urbanity influenced the content of school tweets on key issues, with schools in more populated areas tweeting more about coding and college than schools in less populated areas and charter schools tweeting more about college and the politicized educational issue of common core than non-charters. These results reveal participation differences between schools based upon demographics and provides a basis for conducting future large-scale work on publicly available artifacts, such as school tweets, that may be meaningfully used as education research data. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
1349 a18042644100 Veletsianos G. p474 False Journal 261 Mining social media divides: an analysis of K-12 U.S. School uses of Twitter This study utilizes public data mining to explore participation divides of all available K-12 institutional Twitter accounts in the U.S. (n = 8275 accounts, n = 9,216,853 tweets). Results indicated that U.S. schools used Twitter to broadcast information on a variety of topics in a unidirectional manner and that hashtags included a variety of intended purposes, including affinity spaces, education topics, emotive language, and events. Those schools in wealthier, more populated areas were more likely to use Twitter, with wealthy, suburban schools being the most likely to use it and poor, rural schools being the least likely. Furthermore, factors such as charter school status and urbanity influenced the content of school tweets on key issues, with schools in more populated areas tweeting more about coding and college than schools in less populated areas and charter schools tweeting more about college and the politicized educational issue of common core than non-charters. These results reveal participation differences between schools based upon demographics and provides a basis for conducting future large-scale work on publicly available artifacts, such as school tweets, that may be meaningfully used as education research data. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
1350 a55943223600 Krutka D.G. p474 False Journal 261 Mining social media divides: an analysis of K-12 U.S. School uses of Twitter This study utilizes public data mining to explore participation divides of all available K-12 institutional Twitter accounts in the U.S. (n = 8275 accounts, n = 9,216,853 tweets). Results indicated that U.S. schools used Twitter to broadcast information on a variety of topics in a unidirectional manner and that hashtags included a variety of intended purposes, including affinity spaces, education topics, emotive language, and events. Those schools in wealthier, more populated areas were more likely to use Twitter, with wealthy, suburban schools being the most likely to use it and poor, rural schools being the least likely. Furthermore, factors such as charter school status and urbanity influenced the content of school tweets on key issues, with schools in more populated areas tweeting more about coding and college than schools in less populated areas and charter schools tweeting more about college and the politicized educational issue of common core than non-charters. These results reveal participation differences between schools based upon demographics and provides a basis for conducting future large-scale work on publicly available artifacts, such as school tweets, that may be meaningfully used as education research data. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.
1351 a57204434337 Galan A.M. p475 True Journal 262 Design and characterization of a package-less hybrid PDMS-CMOS-FR4 contact-imaging system for microfluidic integration We demonstrate a hybrid "package-less" polydimethylsiloxane (PDMS)-complementary metal-oxide-semiconductor (CMOS)-FR4 system for contact imaging. The system embeds the CMOS image sensor directly in a PDMS layer instead of the standard chip package to support microfluidic structures much larger and more complex than those in prior art. The CMOS/PDMS layer is self-aligned to form a continuous, flat surface to provide structural support for upper microfluidic layers. The system consists of five layers of PDMS implementing fluid channels, valves, chambers, and inlets/outlets. A custom CMOS image sensor with integrated signal conditioning circuits directly captures light from sample fluid for high optical collection efficiency. Owing to the flexibility afforded by the integration process, the system demonstrates, for the first time, integrated valves in contact imaging. Moreover, we present the first direct comparison of the optical performance of a CMOS image sensor and a photomultiplier tube (PMT) in identical contact-imaging conditions. Measurements show that our CMOS sensor achieves 17 dB better signal-to-noise ratio (SNR) compared with a commercial PMT across a broad range of integration times, with a maximum SNR of 47 dB. Chemiluminescent testing successfully shows signal detection for different analyte concentrations and integration times. The contact-imaging system demonstrates a detection limit of 25 μM of a 9,10-diphenylanthracene-based solution. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1352 a56556056000 Hinton D. p477 True Journal 225 Comparison of calibrated empirical and semi-empirical methods for bedload transport rate prediction in gravel bed streams The performance of seven sediment transport equations for bedload transport is compared using almost 2,600 of more than 8,000 measurements from a recent compilation. Named equations tested include the Meyer-Peter Muller, Barry, Pagosa good condition, Wilcock, Parker (both calibrated and uncalibrated), Recking, and that of Elhakeem and Imran. The purpose of the tests was to evaluate the performance of several empirical and semiempirical formulae using a single calibration point relative to three uncalibrated equations. The seven equations were included because they either have a calibration procedure already developed, are used frequently in practice, are historically foundational in the field, or have recently been proposed. Results are expressed in the root mean square error of the logarithms (RMSEL) and the relative mean error (RME) and show that the Pagosa good and Barry equations best predict bedload sediment transport (RMSEL of 0.02 and 0.02, respectively). The Pagosa good equation requires a data point for bankfull discharge and the corresponding bedload transport. The uncalibrated Recking (2013) equation resulted in lower errors than two of the calibrated formulae (Wilcock 2001 and Parker 1990) and was not far behind the calibrated Elhakeem and Imran (2016) formula. The Meyer-Peter Muller and uncalibrated Parker (1990) equations performed the worst (RMSEL of up to 0.85 and 0.86, respectively). The results herein demonstrate: (1) empirical formulae were more successful at predicting bedload transport than semiempirical alternatives, (2) a single calibration point significantly improves the predictive accuracy of any formula, and (3) calibration cannot compensate for all the shortcomings of a model. © 2018 American Society of Civil Engineers.
1352 a56556056000 Hinton D. p783 True Journal 387 Comprehensive and quality-controlled bedload transport database The processes involved in bed-load sediment transport are complex and difficult to quantify. Field measurements provide insight and a chance to improve predictive methods. A comprehensive database is described that contains more than 15,000 observations from nearly 500 data sets of bed-load sediment transport. Observations are compiled from published sources, author responses to queries, and personal visits to offices. Each entry has been checked twice for accuracy against the original data and converted to a common set of units. The database contains sections for sample descriptions, discharge and transport data, channel and bankfull characteristics, surface and subsurface grain size distributions, and, where possible, stream classification descriptors. Discharges range from far below to several times bankfull values. The database is freely available to the public and may be accessed via direct download and through WaterML based web services from the BYU World Water Data Sediment Transport Database portal at http://worldwater.byu.edu/app/index.php/sediment. The intent of this database is to provide useful data to researchers as they continue to investigate bed-load transport processes. Data can be added to the database by contacting the authors. © 2016 American Society of Civil Engineers.
1353 a57196465311 Cope M. p477 False Journal 225 Comparison of calibrated empirical and semi-empirical methods for bedload transport rate prediction in gravel bed streams The performance of seven sediment transport equations for bedload transport is compared using almost 2,600 of more than 8,000 measurements from a recent compilation. Named equations tested include the Meyer-Peter Muller, Barry, Pagosa good condition, Wilcock, Parker (both calibrated and uncalibrated), Recking, and that of Elhakeem and Imran. The purpose of the tests was to evaluate the performance of several empirical and semiempirical formulae using a single calibration point relative to three uncalibrated equations. The seven equations were included because they either have a calibration procedure already developed, are used frequently in practice, are historically foundational in the field, or have recently been proposed. Results are expressed in the root mean square error of the logarithms (RMSEL) and the relative mean error (RME) and show that the Pagosa good and Barry equations best predict bedload sediment transport (RMSEL of 0.02 and 0.02, respectively). The Pagosa good equation requires a data point for bankfull discharge and the corresponding bedload transport. The uncalibrated Recking (2013) equation resulted in lower errors than two of the calibrated formulae (Wilcock 2001 and Parker 1990) and was not far behind the calibrated Elhakeem and Imran (2016) formula. The Meyer-Peter Muller and uncalibrated Parker (1990) equations performed the worst (RMSEL of up to 0.85 and 0.86, respectively). The results herein demonstrate: (1) empirical formulae were more successful at predicting bedload transport than semiempirical alternatives, (2) a single calibration point significantly improves the predictive accuracy of any formula, and (3) calibration cannot compensate for all the shortcomings of a model. © 2018 American Society of Civil Engineers.
1354 a56740595400 Villanueva I. p478 True Journal 264 A Multimodal Exploration of Engineering Students' Emotions and Electrodermal Activity in Design Activities Background: This exploratory study uses multimodal approaches to explore undergraduate student engagement via topic emotions and electrodermal activity (EDA) in different engineering design method activities and with different instructional delivery formats (e.g., lecture vs. active learning). Purpose/Hypothesis: The goal of this research is to improve our understanding of how students respond, via engagement, to their engineering design activities during class. This study hypothesizes that students would experience no self-reported mean changes in topic emotions from their preassessment scores for each engineering design topic and instructional format nor would electrodermal activities (EDA) associate to these topic emotions throughout the design activities. Design/Method: Eighty-eight freshmen engineering students completed online pretopic and posttopic emotions surveys for five engineering design activities. A subset of 14–18 participants, the focal point of this study, wore an EDA sensor while completing the surveys and participating in these sessions. Results: Preliminary findings suggest that EDA increased for individual and collaborative active learning activities compared to lectures. No significant changes in EDA were found between individual and collaborative active learning activities. Moderate negative correlations were found between EDA and negative topic emotions in the first engineering design activity but not across the rest. At the end of the semester, active learning activities showed higher effect sizes indicating a re-enforcement of students' engagement in the engineering design method activities. Conclusion: This study provides initial results showing how multimodal approaches can help researchers understand students' closer-to-real-time engagement in engineering design topics and instructional delivery formats. © 2018 ASEE
1354 a56740595400 Villanueva I. p603 False Journal 308 An investigation of self-efficacy and topic emotions in entry-level engineering design learning activities Little is known about the impact self-efficacy and topic emotions have on novice engineering students when first exposed to an engineering design course. Freshman students may have difficulties regulating their emotions when exposed to new or complex topics such as engineering design. Consequently, they may become frustrated or discouraged as the semester progresses that can lead to feelings of hopelessness and anxiety. In contrast, novice students may experience feelings of hope and interest that may foster positive learning outcomes in engineering design. The authors explored freshmen engineering students’ (n = 58) levels of self-efficacy and topic emotions while participating on a freshmen-level engineering and graphics design course. Our findings suggests that while positive and negative topic emotions are inversely related, both seem to be associated with self-efficacy. Further, topic emotions appear to mediate self-efficacy as topic emotions such as curiosity, happiness, and interest were reported by engineering students during engineering design activities. Self-efficacy increased over the course of the semester for these freshman engineering design students. © 2019 TEMPUS Publications.
1354 a56740595400 Villanueva I. p636 True Journal 309 Puzzling the pieces: Conceptual blocks of engineering student ideas in a service learning project At its core, engineering and similar disciplines rely strongly on technical innovation to design and develop creative solutions to complex problems. However, for novice engineering students, conceptualizing engineering design activities is not an easy task. To do so, they must overcome cognitive blocks to facilitate unique and adequate engineering design solutions. This effect may be compounded when engineering design projects centered around service learning are introduced. The intent of this study was to explore if and what types of conceptual blocks may be present among novice engineering students when design heuristic cues are provided in the classroom. Findings suggest that using classroom interventions around design heuristic, students had a difficult time "shaking off" their conceptual blocks to the design solution. Primarily, communicative and perceptual blocks were found to predominate among novice engineering student groups. © 2018 TEMPUS Publications.
1355 a56662711400 Campbell B.D. p478 False Journal 264 A Multimodal Exploration of Engineering Students' Emotions and Electrodermal Activity in Design Activities Background: This exploratory study uses multimodal approaches to explore undergraduate student engagement via topic emotions and electrodermal activity (EDA) in different engineering design method activities and with different instructional delivery formats (e.g., lecture vs. active learning). Purpose/Hypothesis: The goal of this research is to improve our understanding of how students respond, via engagement, to their engineering design activities during class. This study hypothesizes that students would experience no self-reported mean changes in topic emotions from their preassessment scores for each engineering design topic and instructional format nor would electrodermal activities (EDA) associate to these topic emotions throughout the design activities. Design/Method: Eighty-eight freshmen engineering students completed online pretopic and posttopic emotions surveys for five engineering design activities. A subset of 14–18 participants, the focal point of this study, wore an EDA sensor while completing the surveys and participating in these sessions. Results: Preliminary findings suggest that EDA increased for individual and collaborative active learning activities compared to lectures. No significant changes in EDA were found between individual and collaborative active learning activities. Moderate negative correlations were found between EDA and negative topic emotions in the first engineering design activity but not across the rest. At the end of the semester, active learning activities showed higher effect sizes indicating a re-enforcement of students' engagement in the engineering design method activities. Conclusion: This study provides initial results showing how multimodal approaches can help researchers understand students' closer-to-real-time engagement in engineering design topics and instructional delivery formats. © 2018 ASEE
1355 a56662711400 Campbell B.D. p603 False Journal 308 An investigation of self-efficacy and topic emotions in entry-level engineering design learning activities Little is known about the impact self-efficacy and topic emotions have on novice engineering students when first exposed to an engineering design course. Freshman students may have difficulties regulating their emotions when exposed to new or complex topics such as engineering design. Consequently, they may become frustrated or discouraged as the semester progresses that can lead to feelings of hopelessness and anxiety. In contrast, novice students may experience feelings of hope and interest that may foster positive learning outcomes in engineering design. The authors explored freshmen engineering students’ (n = 58) levels of self-efficacy and topic emotions while participating on a freshmen-level engineering and graphics design course. Our findings suggests that while positive and negative topic emotions are inversely related, both seem to be associated with self-efficacy. Further, topic emotions appear to mediate self-efficacy as topic emotions such as curiosity, happiness, and interest were reported by engineering students during engineering design activities. Self-efficacy increased over the course of the semester for these freshman engineering design students. © 2019 TEMPUS Publications.
1355 a56662711400 Campbell B.D. p636 False Journal 309 Puzzling the pieces: Conceptual blocks of engineering student ideas in a service learning project At its core, engineering and similar disciplines rely strongly on technical innovation to design and develop creative solutions to complex problems. However, for novice engineering students, conceptualizing engineering design activities is not an easy task. To do so, they must overcome cognitive blocks to facilitate unique and adequate engineering design solutions. This effect may be compounded when engineering design projects centered around service learning are introduced. The intent of this study was to explore if and what types of conceptual blocks may be present among novice engineering students when design heuristic cues are provided in the classroom. Findings suggest that using classroom interventions around design heuristic, students had a difficult time "shaking off" their conceptual blocks to the design solution. Primarily, communicative and perceptual blocks were found to predominate among novice engineering student groups. © 2018 TEMPUS Publications.
1356 a56741048000 Raikes A.C. p478 False Journal 264 A Multimodal Exploration of Engineering Students' Emotions and Electrodermal Activity in Design Activities Background: This exploratory study uses multimodal approaches to explore undergraduate student engagement via topic emotions and electrodermal activity (EDA) in different engineering design method activities and with different instructional delivery formats (e.g., lecture vs. active learning). Purpose/Hypothesis: The goal of this research is to improve our understanding of how students respond, via engagement, to their engineering design activities during class. This study hypothesizes that students would experience no self-reported mean changes in topic emotions from their preassessment scores for each engineering design topic and instructional format nor would electrodermal activities (EDA) associate to these topic emotions throughout the design activities. Design/Method: Eighty-eight freshmen engineering students completed online pretopic and posttopic emotions surveys for five engineering design activities. A subset of 14–18 participants, the focal point of this study, wore an EDA sensor while completing the surveys and participating in these sessions. Results: Preliminary findings suggest that EDA increased for individual and collaborative active learning activities compared to lectures. No significant changes in EDA were found between individual and collaborative active learning activities. Moderate negative correlations were found between EDA and negative topic emotions in the first engineering design activity but not across the rest. At the end of the semester, active learning activities showed higher effect sizes indicating a re-enforcement of students' engagement in the engineering design method activities. Conclusion: This study provides initial results showing how multimodal approaches can help researchers understand students' closer-to-real-time engagement in engineering design topics and instructional delivery formats. © 2018 ASEE
1357 a56149906900 Jones S.H. p478 False Journal 264 A Multimodal Exploration of Engineering Students' Emotions and Electrodermal Activity in Design Activities Background: This exploratory study uses multimodal approaches to explore undergraduate student engagement via topic emotions and electrodermal activity (EDA) in different engineering design method activities and with different instructional delivery formats (e.g., lecture vs. active learning). Purpose/Hypothesis: The goal of this research is to improve our understanding of how students respond, via engagement, to their engineering design activities during class. This study hypothesizes that students would experience no self-reported mean changes in topic emotions from their preassessment scores for each engineering design topic and instructional format nor would electrodermal activities (EDA) associate to these topic emotions throughout the design activities. Design/Method: Eighty-eight freshmen engineering students completed online pretopic and posttopic emotions surveys for five engineering design activities. A subset of 14–18 participants, the focal point of this study, wore an EDA sensor while completing the surveys and participating in these sessions. Results: Preliminary findings suggest that EDA increased for individual and collaborative active learning activities compared to lectures. No significant changes in EDA were found between individual and collaborative active learning activities. Moderate negative correlations were found between EDA and negative topic emotions in the first engineering design activity but not across the rest. At the end of the semester, active learning activities showed higher effect sizes indicating a re-enforcement of students' engagement in the engineering design method activities. Conclusion: This study provides initial results showing how multimodal approaches can help researchers understand students' closer-to-real-time engagement in engineering design topics and instructional delivery formats. © 2018 ASEE
1357 a56149906900 Jones S.H. p603 True Journal 308 An investigation of self-efficacy and topic emotions in entry-level engineering design learning activities Little is known about the impact self-efficacy and topic emotions have on novice engineering students when first exposed to an engineering design course. Freshman students may have difficulties regulating their emotions when exposed to new or complex topics such as engineering design. Consequently, they may become frustrated or discouraged as the semester progresses that can lead to feelings of hopelessness and anxiety. In contrast, novice students may experience feelings of hope and interest that may foster positive learning outcomes in engineering design. The authors explored freshmen engineering students’ (n = 58) levels of self-efficacy and topic emotions while participating on a freshmen-level engineering and graphics design course. Our findings suggests that while positive and negative topic emotions are inversely related, both seem to be associated with self-efficacy. Further, topic emotions appear to mediate self-efficacy as topic emotions such as curiosity, happiness, and interest were reported by engineering students during engineering design activities. Self-efficacy increased over the course of the semester for these freshman engineering design students. © 2019 TEMPUS Publications.
1357 a56149906900 Jones S.H. p636 False Journal 309 Puzzling the pieces: Conceptual blocks of engineering student ideas in a service learning project At its core, engineering and similar disciplines rely strongly on technical innovation to design and develop creative solutions to complex problems. However, for novice engineering students, conceptualizing engineering design activities is not an easy task. To do so, they must overcome cognitive blocks to facilitate unique and adequate engineering design solutions. This effect may be compounded when engineering design projects centered around service learning are introduced. The intent of this study was to explore if and what types of conceptual blocks may be present among novice engineering students when design heuristic cues are provided in the classroom. Findings suggest that using classroom interventions around design heuristic, students had a difficult time "shaking off" their conceptual blocks to the design solution. Primarily, communicative and perceptual blocks were found to predominate among novice engineering student groups. © 2018 TEMPUS Publications.
1358 a6603615600 Putney L.G. p478 False Journal 264 A Multimodal Exploration of Engineering Students' Emotions and Electrodermal Activity in Design Activities Background: This exploratory study uses multimodal approaches to explore undergraduate student engagement via topic emotions and electrodermal activity (EDA) in different engineering design method activities and with different instructional delivery formats (e.g., lecture vs. active learning). Purpose/Hypothesis: The goal of this research is to improve our understanding of how students respond, via engagement, to their engineering design activities during class. This study hypothesizes that students would experience no self-reported mean changes in topic emotions from their preassessment scores for each engineering design topic and instructional format nor would electrodermal activities (EDA) associate to these topic emotions throughout the design activities. Design/Method: Eighty-eight freshmen engineering students completed online pretopic and posttopic emotions surveys for five engineering design activities. A subset of 14–18 participants, the focal point of this study, wore an EDA sensor while completing the surveys and participating in these sessions. Results: Preliminary findings suggest that EDA increased for individual and collaborative active learning activities compared to lectures. No significant changes in EDA were found between individual and collaborative active learning activities. Moderate negative correlations were found between EDA and negative topic emotions in the first engineering design activity but not across the rest. At the end of the semester, active learning activities showed higher effect sizes indicating a re-enforcement of students' engagement in the engineering design method activities. Conclusion: This study provides initial results showing how multimodal approaches can help researchers understand students' closer-to-real-time engagement in engineering design topics and instructional delivery formats. © 2018 ASEE
1359 a57189843306 Zeng M. p479 False Journal 265 Kinetostatic modeling of complex compliant mechanisms with serial-parallel substructures: A semi-analytical matrix displacement method Kinetostatic analysis of compliant mechanisms are crucial at the early stage of design, and it can be difficult and laborsome for complex configurations with distributed compliance. In this paper, a kinetostatic modeling method for flexure-hinge-based compliant mechanisms with hybrid serial-parallel substructures is presented to provide accurate and concise solutions by combining the matrix displacement method with the transfer matrix method. The transition between the elemental stiffness matrix and the transfer matrix of flexure hinges/flexible beams is straightforward, enabling the condensation of a hybrid serial-parallel substructure into one equivalent two-node element simple. A general kinetostatic model of the whole compliant mechanisms is first established based on the equilibrium equation of the nodal force. Then, a condensed two-port mechanical network representing the input/output force-displacement relations of single-degree-of-freedom (DOF) compliant mechanisms and the Jacobian matrix for multi-DOF compliant mechanisms are respectively built. Comparison of the proposed method with the compliance matrix method in previous literature, finite element analysis and experiment for three exemplary mechanisms reveals good prediction accuracy, suggesting its feasibility for fast performance evaluation and parameter optimization at the initial stage of design. © 2018 Elsevier Ltd
1360 a56078900600 Holler B.J. p480 True Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1361 a15081035500 Milam S.N. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1362 a7402814790 Bauer J.M. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1363 a7101806481 Alcock C. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1364 a15318992700 Bannister M.T. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1365 a6601908712 Bjoraker G.L. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1366 a8077103900 Bodewits D. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1367 a6602183163 Bosh A.S. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1368 a7004295901 Buie M.W. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1369 a7004640341 Farnham T.L. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1370 a35772366400 Haghighipour N. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1371 a8390181000 Hardersen P.S. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1372 a23004910700 Harris A.W. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1373 a7003793778 Hirata C.M. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1374 a8578022500 Hsieh H.H. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1375 a9241584700 Kelley M.S.P. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1376 a15842178900 Knight M.M. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1377 a10939408000 Kramer E.A. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1378 a54789941300 Longobardo A. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1379 a7006650428 Nixon C.A. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1380 a7006817766 Palomba E. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1381 a25937446600 Protopapa S. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1382 a55895275900 Quick L.C. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1383 a16043716000 Ragozzine D. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1384 a12647140500 Reddy V. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1385 a7402364894 Rhodes J.D. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1386 a7004387103 Rivkin A.S. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1387 a8891726500 Sarid G. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1388 a57192430052 Sickafoose A.A. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1389 a7401892754 Simon A.A. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1390 a23020214400 Thomas C.A. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1391 a6603882082 Trilling D.E. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1392 a7402396019 West R.A. p480 False Journal 266 Solar system science with the Wide-Field Infrared Survey Telescope We present a community-led assessment of the solar system investigations achievable with NASA's next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0 μ m and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28 deg2 field-of-view Wide Field Instrument. Potential groundbreaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1393 a57031532300 Beauchamp M.J. p481 True Journal 237 3D printed microfluidic features using dose control in X, Y, and Z dimensions Interest has grown in recent years to leverage the possibilities offered by three-dimensional (3D) printing, such as rapid iterative changes; the ability to more fully use 3D device volume; and ease of fabrication, especially as it relates to the creation of complex microfluidic devices. A major shortcoming of most commercially available 3D printers is that their resolution is not sufficient to produce features that are truly microfluidic (&lt; 100 × 100 μm2). Here, we test a custom 3D printer for making ~30 μm scale positive and negative surface features, as well as positive and negative features within internal voids (i.e., microfluidic channels). We found that optical dosage control is essential for creating the smallest microfluidic features (~30 μm wide for ridges, ~20 μm wide for trenches), and that this resolution was achieved for a number of different exposure approaches. Additionally, we printed various microfluidic particle traps, showed capture of 25 μm diameter polymer beads, and iteratively improved the trap design. The rapid feedback allowed by 3D printing, as well as the ability to carefully control optical exposure conditions, should lead to new innovations in the types and sizes of devices that can be created for microfluidics. © 2018 by the authors.
1394 a57203305966 Goettel C. p482 True Conference 174 A cognitive approach to predicting academic success in computing [No abstract available]
1395 a55171433700 Weidman J.E. p483 False Conference 175 Increasing student construction interest by engaging elementary students in an inquiry-based 3D modelling after school program This study was part of a two-year funded grant investigating how to increase student interest and consequent enrollment in construction education. The specifics of this aspect of the study involved a grass-roots movement where construction education was introduced to elementary students (grades 4 - 6). The research model involved giving the students a construction interest inventory and career placement inventory pre-and post-participation in an after-school 3D modeling construction centric curriculum. The curriculum introduced students to the construction fields by giving the students weekly snapshots into construction careers, and also required the students to learn about floor and elevation plans. Students were then taught and expected to design a 3D computer model of a home using Minecraft and Sketchup. The students were provided 4 different models to choose from. The course used a competition based pedagogy where the best home designs were awarded prizes. The results show that student interest after this single intervention (1 semester in length) increased student interest in careers associated to construction. © American Society for Engineering Education, 2018.
1395 a55171433700 Weidman J.E. p684 False Journal 330 Use of Personality Profile Assessments in the U.S. Commercial Construction Industry Employee turnover is a continuing challenge in the construction industry with negative effects on construction companies. Other industries have begun using personality profile assessments as a tool for reducing employee turnover, and more specifically in their hiring, promoting, team building, and leadership development processes. However, it was unknown if this trend was effecting the construction industry. The purpose of this research was to determine if and how U.S. commercial construction companies utilize personality profiles in their employee retention processes. A survey was randomly sent to 235 of the top 400 commercial construction companies in the United States to determine if these companies were using assessments, and if it had any effect on the turnover within these companies. Interviews were conducted over the phone with human resources representatives from these companies, and responses were sorted into similar themes and ideas using qualitative pattern coding techniques. Of the 78 responding companies, one-third were using employee personality profiles within their business practices. This article reports the experiences and general attitudes for both the companies that do and do not utilize personality profiles. The results of this research provides strong evidence that using personality profile assessments can help construction companies reduce employee turnover. © 2017 Associated Schools of Construction.
1395 a55171433700 Weidman J.E. p685 True Journal 331 Simulations in Construction and Engineering Management Education to Explore Professional Challenges Experiential learning opportunities in construction management courses allow students to explore principles and theories through direct, lived experiences that help them develop understandings of professional concepts foundational to their future work. This article examines the results of a multiple-case study that examines a simulation called marshmallow dodgeball conducted in an undergraduate project management course, designed to help students consider ethical and professional dilemmas that parallel those in the field. A thematic analysis of student reflections on the simulation shows students learned about dealing with ethical issues in the field, the role of teamwork, the importance of job skills and specialization, and communication on the job site. © 2017 American Society of Civil Engineers.
1395 a55171433700 Weidman J.E. p726 False Journal 355 Strategies employed and lessons learned by commercial construction companies during economic recession and recovery The purpose of this research was to identify strategies used and lessons learned by western U.S. commercial construction companies during the great recession (2007-2009). The experience gained by companies who weather an economic downturn must be absorbed into the corporate structure in a meaningful way if that knowledge is to be accessible for future recessions. This study focused on identifying and better understanding the specific approaches that commercial construction companies employed to weather the great recession and the corresponding lessons learned. A stratified purposeful sampling survey was conducted across 15 different commercial construction companies and included 57 participants in various management roles. This paper provides a comprehensive list of 124 different strategies or lessons learned across six principal categories: (1) contracting, (2) risk management, (3) cost-control, (4) human resources, (5) financial, and (6) investment related responses. This paper also provides recommendations for commercial construction companies to consider during various economic cycles on the basis of the lessons learned during this recession and recovery. © 2017 American Society of Civil Engineers.
1395 a55171433700 Weidman J.E. p732 True Conference 313 Experiential learning: Using small-scale projects to teach project complexities and relationship roles in construction Experiential learning opportunities give students the ability to understand the implications of principles and theories learned in the classroom through lived experiences. This article examines the use of a construction project simulation activity to teach project management principles in an undergraduate construction management course. After a description of the experiential learning theory and relevant literature examining experiential learning simulations in education, it provides an overview of the methods used to create the experience of small-scale design-bidbuild project simulation in a project management course. Around 240 undergraduates students at the junior or senior level participated as designated contractual players in the project and went through the project from inception to completion over the course of 5 weeks. Finally, it offers a brief discussion of the implications of the findings for construction management and engineering education. Specifically, it discusses that simulated projects possess the potential to provide unique learning opportunities particularly, designed experiences triggering different emotions within the structures of the traditional classroom. © American Society for Engineering Education, 2017.
1396 a57193603847 Bateman T.C. p484 False Conference 176 Outreach potential of displaying research artifacts in art museums This paper explores how displaying engineering research artifacts in art museums can facilitate expanded outreach opportunities. A combination of visual art and innovative engineering offers an unusual opportunity to engage a wide spectrum of society. To evaluate the potential, faculty and students collaborated with the Brigham Young University Museum of Art to create a museum exhibition that connected the art of origami to engineering, math, science, and product design. A framework is introduced that includes the creation of a museum exhibition; and once the initial investment is made to create the central exhibition, the results are efficiently used to extend outreach efforts through first-generation products (coincident with the exhibition) and then through second-generation products (after the exhibition). The paper describes a detailed example of this framework and provides evidence to support the concept that displaying research artifacts in an art museum can expand research opportunities. Products from the exhibition that provided expanded outreach opportunities include the following: an exhibit catalog originally created for the gift shop that was expanded for publication with a national publisher; a tablet/smart phone app that includes origami instructions followed by related engineering activities, which has had broad use beyond the museum activity room; a video that was prepared for museum patrons but has since been made available to larger audiences; materials created for hands-on museum activities that were used for outreach activities after the exhibition; and leverage for industry visits that led to additional applications and research projects. This paper describes the museum exhibition, the first- and second-generation products, the impact of each product, and the benefits and pitfalls of using a museum exhibition to extend outreach impact. © American Society for Engineering Education, 2018.
1396 a57193603847 Bateman T.C. p487 False Conference 179 Assessment of a global engineering outreach course [No abstract available]
1396 a57193603847 Bateman T.C. p734 False Conference 315 Sustainable water filters in southern Peru [No abstract available]
1396 a57193603847 Bateman T.C. p735 False Conference 316 Global humanitarian-based projects: A documentation strategy for strengthening project sustainability [No abstract available]
1397 a57203309361 Palma L. p484 False Conference 176 Outreach potential of displaying research artifacts in art museums This paper explores how displaying engineering research artifacts in art museums can facilitate expanded outreach opportunities. A combination of visual art and innovative engineering offers an unusual opportunity to engage a wide spectrum of society. To evaluate the potential, faculty and students collaborated with the Brigham Young University Museum of Art to create a museum exhibition that connected the art of origami to engineering, math, science, and product design. A framework is introduced that includes the creation of a museum exhibition; and once the initial investment is made to create the central exhibition, the results are efficiently used to extend outreach efforts through first-generation products (coincident with the exhibition) and then through second-generation products (after the exhibition). The paper describes a detailed example of this framework and provides evidence to support the concept that displaying research artifacts in an art museum can expand research opportunities. Products from the exhibition that provided expanded outreach opportunities include the following: an exhibit catalog originally created for the gift shop that was expanded for publication with a national publisher; a tablet/smart phone app that includes origami instructions followed by related engineering activities, which has had broad use beyond the museum activity room; a video that was prepared for museum patrons but has since been made available to larger audiences; materials created for hands-on museum activities that were used for outreach activities after the exhibition; and leverage for industry visits that led to additional applications and research projects. This paper describes the museum exhibition, the first- and second-generation products, the impact of each product, and the benefits and pitfalls of using a museum exhibition to extend outreach impact. © American Society for Engineering Education, 2018.
1398 a35191151900 Ward C.J. p487 False Conference 179 Assessment of a global engineering outreach course [No abstract available]
1399 a26427435500 Warnick G.M. p488 True Conference 180 Understanding engineering and technology student perceptions: Barriers to study abroad participation [No abstract available]
1399 a26427435500 Warnick G.M. p491 False Conference 183 A longitudinal study of social and ethical responsibility among undergraduate engineering students: Comparing baseline and midpoint survey results In addition to developing technically competent engineers, engineering programs aim to prepare students to be professionally and ethically responsible. Universities have sought to integrate ethics instruction into their curricula through a variety of learning experiences. However, there is a lack of research on foundational understandings of social and ethical responsibility among engineering students, including how their perceptions change over time and following participation in specific types of learning experiences. This study uses a longitudinal mixed-methods study design, collecting and analyzing quantitative and qualitative data from engineering students over the course of their four years as undergraduate students. This paper reports insights gained by a repeat survey of student perceptions of ethics and social responsibility. Our analysis compares student responses (n=319) to a survey administered during their first year of college and again in their junior year (approximately fifth-semester), including variations based on student affiliations and demographics (e.g., comparisons among universities, genders, importance of religion, and other relevant factors) and learning experiences (e.g., service-learning programs, ethics courses, extracurricular organizations, etc.). These mid-point findings contribute to our understandings of the trajectories of students' perceptions and perspectives and are beginning to reveal some specific experiences and contexts that are having the largest measurable impacts on the participating students. © American Society for Engineering Education, 2018.
1399 a26427435500 Warnick G.M. p730 False Conference 311 Student perceptions and attitudes towards a required vs. An optional course in leadership For almost ten years, the majority of students in the College of Engineering and Technology at Brigham Young University have been required to take a sophomore level leadership foundations course focused on leadership principles, ethics, and global issues. The course is part of an overall leadership framework whereby students are introduced to the importance of leadership as freshmen, learn foundational leadership principles as sophomores, and practice these principles as juniors and seniors. The leadership foundations course is required for graduation by 7 of 10 programs within the College of Engineering and Technology. Students external to the college also participate in the course as it fulfills two general education requirements for graduation. As a result, the college teaches approximately 12 sections each academic year averaging 60-80 students per section. Approximately 10-15% of student course participants are external to the college. In this paper a survey is presented of 163 students initially enrolled in the leadership foundations course regarding their perceptions and attitudes towards leadership. Results include a comparison of students who are required to take the course and those for whom it is optional. No statistically significant difference was observed between the two groups of students except for their expectation regarding workload. The engineering and technology students expected the leadership foundations course to be easier, relative to their other classes, than the nonengineering and technology group. In general, both sets of students had high expectations for the course and expressed positive attitudes towards learning about leadership. For example, students in both groups indicated they felt learning about leadership was somewhat more important than learning the skills of their discipline. © American Society for Engineering Education, 2017.
1399 a26427435500 Warnick G.M. p738 False Conference 319 Investigating engineering students' understandings of social and ethical responsibility: Coding framework and initial findings [No abstract available]
1400 a57203301406 Call M.S. p488 False Conference 180 Understanding engineering and technology student perceptions: Barriers to study abroad participation [No abstract available]
1401 a36602439100 Davies R. p488 False Conference 180 Understanding engineering and technology student perceptions: Barriers to study abroad participation [No abstract available]
1401 a36602439100 Davies R. p491 False Conference 183 A longitudinal study of social and ethical responsibility among undergraduate engineering students: Comparing baseline and midpoint survey results In addition to developing technically competent engineers, engineering programs aim to prepare students to be professionally and ethically responsible. Universities have sought to integrate ethics instruction into their curricula through a variety of learning experiences. However, there is a lack of research on foundational understandings of social and ethical responsibility among engineering students, including how their perceptions change over time and following participation in specific types of learning experiences. This study uses a longitudinal mixed-methods study design, collecting and analyzing quantitative and qualitative data from engineering students over the course of their four years as undergraduate students. This paper reports insights gained by a repeat survey of student perceptions of ethics and social responsibility. Our analysis compares student responses (n=319) to a survey administered during their first year of college and again in their junior year (approximately fifth-semester), including variations based on student affiliations and demographics (e.g., comparisons among universities, genders, importance of religion, and other relevant factors) and learning experiences (e.g., service-learning programs, ethics courses, extracurricular organizations, etc.). These mid-point findings contribute to our understandings of the trajectories of students' perceptions and perspectives and are beginning to reveal some specific experiences and contexts that are having the largest measurable impacts on the participating students. © American Society for Engineering Education, 2018.
1401 a36602439100 Davies R. p730 False Conference 311 Student perceptions and attitudes towards a required vs. An optional course in leadership For almost ten years, the majority of students in the College of Engineering and Technology at Brigham Young University have been required to take a sophomore level leadership foundations course focused on leadership principles, ethics, and global issues. The course is part of an overall leadership framework whereby students are introduced to the importance of leadership as freshmen, learn foundational leadership principles as sophomores, and practice these principles as juniors and seniors. The leadership foundations course is required for graduation by 7 of 10 programs within the College of Engineering and Technology. Students external to the college also participate in the course as it fulfills two general education requirements for graduation. As a result, the college teaches approximately 12 sections each academic year averaging 60-80 students per section. Approximately 10-15% of student course participants are external to the college. In this paper a survey is presented of 163 students initially enrolled in the leadership foundations course regarding their perceptions and attitudes towards leadership. Results include a comparison of students who are required to take the course and those for whom it is optional. No statistically significant difference was observed between the two groups of students except for their expectation regarding workload. The engineering and technology students expected the leadership foundations course to be easier, relative to their other classes, than the nonengineering and technology group. In general, both sets of students had high expectations for the course and expressed positive attitudes towards learning about leadership. For example, students in both groups indicated they felt learning about leadership was somewhat more important than learning the skills of their discipline. © American Society for Engineering Education, 2017.
1402 a23096760600 Zephirin T. p490 False Conference 182 Investigating influences on first-year engineering students' views of ethics and social responsibility According to current ABET accreditation requirements, engineering students need to become aware of the social contexts of engineering and develop ethical and professional responsibilities during their undergraduate training. Concerns also persist about the moral and ethical commitments of engineers once they enter the workplace, as underscored by a number of recent ethics scandals involving engineers and technology. The education of ethically adept engineers therefore remains a pertinent issue for the engineering education community. Yet there remains relatively little research on how students' prior experiences shape their ethical perspectives. Specifically, there is a lack of understanding of the role of pre-college and early college experiences and other influences in shaping first-year engineering students' views on ethics. This paper reports select results from an NSF-funded project aiming to address some of these gaps in the literature. This longitudinal study was conducted across four universities and focused on the ethical development of undergraduate engineering students. Preliminary analysis of interviews from the first phase of this study identified a number of major themes in the data set, two of which are important to highlight here: 1) influences on students' ethical perspectives (e.g., academic curricular, extracurricular activities, family, etc.) and 2) learned outcomes, defined as insights, learning, or realizations related to ethics, morality, and values. Deeper investigation of the relationship between specific influences and students' insights related to ethics can provide a better understanding of first-year engineering students' baseline ethical development. The goal of this paper is to characterize what specific ethical lessons are gained through various types of experiences, as well as to glean how this learning and growth occurs. Data for this study was drawn from 66 interview transcripts and consisted of sections coded simultaneously for influences and learned outcomes. The cross-coded data were analyzed using a thematic analysis approach. The types of influences impacting students' ethical learning, and exemplars of how students report their lived experiences and ethical realizations, are discussed through the lens of what they learned and the mechanisms through which they gained these understandings. Our analysis suggests that several pre-college (e.g., extracurricular activities, service/volunteer roles and social experiences) and early college experiences (e.g., academic courses, part-time employment) play a critical role in shaping students' ethical perspectives. We more specifically present our findings organized around eight types of experiences and influences, which are in turn related to three categories of learned outcomes and three types of learning mechanisms. As we discuss in more detail below, the results of this study will likely be of interest to engineering educators, policymakers, and researchers with an interest in administering and studying high-impact ethics interventions for undergraduate engineering students. More specifically, our results underscore the importance of being more aware of how students' background perspectives and experiences likely play important roles in enabling or disabling their further ethical development. © American Society for Engineering Education, 2018.
1403 a57203306132 Kim M.D. p490 False Conference 182 Investigating influences on first-year engineering students' views of ethics and social responsibility According to current ABET accreditation requirements, engineering students need to become aware of the social contexts of engineering and develop ethical and professional responsibilities during their undergraduate training. Concerns also persist about the moral and ethical commitments of engineers once they enter the workplace, as underscored by a number of recent ethics scandals involving engineers and technology. The education of ethically adept engineers therefore remains a pertinent issue for the engineering education community. Yet there remains relatively little research on how students' prior experiences shape their ethical perspectives. Specifically, there is a lack of understanding of the role of pre-college and early college experiences and other influences in shaping first-year engineering students' views on ethics. This paper reports select results from an NSF-funded project aiming to address some of these gaps in the literature. This longitudinal study was conducted across four universities and focused on the ethical development of undergraduate engineering students. Preliminary analysis of interviews from the first phase of this study identified a number of major themes in the data set, two of which are important to highlight here: 1) influences on students' ethical perspectives (e.g., academic curricular, extracurricular activities, family, etc.) and 2) learned outcomes, defined as insights, learning, or realizations related to ethics, morality, and values. Deeper investigation of the relationship between specific influences and students' insights related to ethics can provide a better understanding of first-year engineering students' baseline ethical development. The goal of this paper is to characterize what specific ethical lessons are gained through various types of experiences, as well as to glean how this learning and growth occurs. Data for this study was drawn from 66 interview transcripts and consisted of sections coded simultaneously for influences and learned outcomes. The cross-coded data were analyzed using a thematic analysis approach. The types of influences impacting students' ethical learning, and exemplars of how students report their lived experiences and ethical realizations, are discussed through the lens of what they learned and the mechanisms through which they gained these understandings. Our analysis suggests that several pre-college (e.g., extracurricular activities, service/volunteer roles and social experiences) and early college experiences (e.g., academic courses, part-time employment) play a critical role in shaping students' ethical perspectives. We more specifically present our findings organized around eight types of experiences and influences, which are in turn related to three categories of learned outcomes and three types of learning mechanisms. As we discuss in more detail below, the results of this study will likely be of interest to engineering educators, policymakers, and researchers with an interest in administering and studying high-impact ethics interventions for undergraduate engineering students. More specifically, our results underscore the importance of being more aware of how students' background perspectives and experiences likely play important roles in enabling or disabling their further ethical development. © American Society for Engineering Education, 2018.
1404 a57190808464 Katz A. p490 False Conference 182 Investigating influences on first-year engineering students' views of ethics and social responsibility According to current ABET accreditation requirements, engineering students need to become aware of the social contexts of engineering and develop ethical and professional responsibilities during their undergraduate training. Concerns also persist about the moral and ethical commitments of engineers once they enter the workplace, as underscored by a number of recent ethics scandals involving engineers and technology. The education of ethically adept engineers therefore remains a pertinent issue for the engineering education community. Yet there remains relatively little research on how students' prior experiences shape their ethical perspectives. Specifically, there is a lack of understanding of the role of pre-college and early college experiences and other influences in shaping first-year engineering students' views on ethics. This paper reports select results from an NSF-funded project aiming to address some of these gaps in the literature. This longitudinal study was conducted across four universities and focused on the ethical development of undergraduate engineering students. Preliminary analysis of interviews from the first phase of this study identified a number of major themes in the data set, two of which are important to highlight here: 1) influences on students' ethical perspectives (e.g., academic curricular, extracurricular activities, family, etc.) and 2) learned outcomes, defined as insights, learning, or realizations related to ethics, morality, and values. Deeper investigation of the relationship between specific influences and students' insights related to ethics can provide a better understanding of first-year engineering students' baseline ethical development. The goal of this paper is to characterize what specific ethical lessons are gained through various types of experiences, as well as to glean how this learning and growth occurs. Data for this study was drawn from 66 interview transcripts and consisted of sections coded simultaneously for influences and learned outcomes. The cross-coded data were analyzed using a thematic analysis approach. The types of influences impacting students' ethical learning, and exemplars of how students report their lived experiences and ethical realizations, are discussed through the lens of what they learned and the mechanisms through which they gained these understandings. Our analysis suggests that several pre-college (e.g., extracurricular activities, service/volunteer roles and social experiences) and early college experiences (e.g., academic courses, part-time employment) play a critical role in shaping students' ethical perspectives. We more specifically present our findings organized around eight types of experiences and influences, which are in turn related to three categories of learned outcomes and three types of learning mechanisms. As we discuss in more detail below, the results of this study will likely be of interest to engineering educators, policymakers, and researchers with an interest in administering and studying high-impact ethics interventions for undergraduate engineering students. More specifically, our results underscore the importance of being more aware of how students' background perspectives and experiences likely play important roles in enabling or disabling their further ethical development. © American Society for Engineering Education, 2018.
1405 a6507028828 Zoltowski C.B. p491 False Conference 183 A longitudinal study of social and ethical responsibility among undergraduate engineering students: Comparing baseline and midpoint survey results In addition to developing technically competent engineers, engineering programs aim to prepare students to be professionally and ethically responsible. Universities have sought to integrate ethics instruction into their curricula through a variety of learning experiences. However, there is a lack of research on foundational understandings of social and ethical responsibility among engineering students, including how their perceptions change over time and following participation in specific types of learning experiences. This study uses a longitudinal mixed-methods study design, collecting and analyzing quantitative and qualitative data from engineering students over the course of their four years as undergraduate students. This paper reports insights gained by a repeat survey of student perceptions of ethics and social responsibility. Our analysis compares student responses (n=319) to a survey administered during their first year of college and again in their junior year (approximately fifth-semester), including variations based on student affiliations and demographics (e.g., comparisons among universities, genders, importance of religion, and other relevant factors) and learning experiences (e.g., service-learning programs, ethics courses, extracurricular organizations, etc.). These mid-point findings contribute to our understandings of the trajectories of students' perceptions and perspectives and are beginning to reveal some specific experiences and contexts that are having the largest measurable impacts on the participating students. © American Society for Engineering Education, 2018.
1405 a6507028828 Zoltowski C.B. p738 False Conference 319 Investigating engineering students' understandings of social and ethical responsibility: Coding framework and initial findings [No abstract available]
1406 a6701460244 Frezza S.T. p493 True Conference 185 Crafting the future of computing education in CC2020: A workshop A consortium of national and international computing and engineering organizations are currently developing a new set of curricular resources titled Computing Curricula 2020 (CC2020). This project, based on its predecessor CC2005, aims to reflect the state-of-the-art in computing education and practice as well as provide insights into the future of the computing educational field for the 2020s and beyond. This workshop provides an overview of the CC2005 and related reports and links them to the transition into the CC2020 project. It also provides participants with a unique opportunity to collaborate with members of the CC2020 task force and contribute to the development of the resources the project will deliver. The workshop authors and participants will engage in activities to help define how Computing is defined within the project and discuss how to extend its influence in global undergraduate computing education for the future. The authors anticipate full audience involvement and participation in formulating this vision. © American Society for Engineering Education, 2018.
1407 a6602928070 Pears A.N. p493 False Conference 185 Crafting the future of computing education in CC2020: A workshop A consortium of national and international computing and engineering organizations are currently developing a new set of curricular resources titled Computing Curricula 2020 (CC2020). This project, based on its predecessor CC2005, aims to reflect the state-of-the-art in computing education and practice as well as provide insights into the future of the computing educational field for the 2020s and beyond. This workshop provides an overview of the CC2005 and related reports and links them to the transition into the CC2020 project. It also provides participants with a unique opportunity to collaborate with members of the CC2020 task force and contribute to the development of the resources the project will deliver. The workshop authors and participants will engage in activities to help define how Computing is defined within the project and discuss how to extend its influence in global undergraduate computing education for the future. The authors anticipate full audience involvement and participation in formulating this vision. © American Society for Engineering Education, 2018.
1408 a23479472600 Exter M. p493 False Conference 185 Crafting the future of computing education in CC2020: A workshop A consortium of national and international computing and engineering organizations are currently developing a new set of curricular resources titled Computing Curricula 2020 (CC2020). This project, based on its predecessor CC2005, aims to reflect the state-of-the-art in computing education and practice as well as provide insights into the future of the computing educational field for the 2020s and beyond. This workshop provides an overview of the CC2005 and related reports and links them to the transition into the CC2020 project. It also provides participants with a unique opportunity to collaborate with members of the CC2020 task force and contribute to the development of the resources the project will deliver. The workshop authors and participants will engage in activities to help define how Computing is defined within the project and discuss how to extend its influence in global undergraduate computing education for the future. The authors anticipate full audience involvement and participation in formulating this vision. © American Society for Engineering Education, 2018.
1409 a7404006200 Wright S.I. p494 True Journal 267 Preface [No abstract available]
1410 a57202800731 Nowell M.W. p494 False Journal 267 Preface [No abstract available]
1411 a14833931300 Cluff S. p495 True Conference 186 Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lath Martensitic Steel The study of post-transformation microstructures and their properties can be greatly enhanced by studying their dependence on the grain boundary content of parent microstructures. Recent work has extended the crystallographic reconstruction of parent austenite in steels to include the reconstruction of special boundaries, such as annealing twins. These reconstructions present unique challenges, as twinned austenite grains share a subset of possible daughter variant orientations. This gives rise to regions of ambiguity in a reconstruction. A technique for the reconstruction of twin boundaries is presented here that is capable of reconstructing 60° <1 1 1> twins, even in the case where twin regions are comprised entirely of variants that are common between the twin and the parent. This technique is demonstrated in the reconstruction of lath martensitic steels. The reconstruction method utilizes a delayed decision-making approach, where a chosen orientation relationship is used to define all possible groupings of daughter grains into possible parents before divisive decisions are made. These overlapping, inclusive groupings (called clusters) are compared to each other individually using their calculated parent austenite orientations and the topographical nature of the overlapping region. These comparisons are used to uncover possible locations of twin boundaries present in the parent austenite. This technique can be applied to future studies on the dependence of post-transformation microstructures on the special grain boundary content of parent microstructures. © 2018 Institute of Physics Publishing. All rights reserved.
1412 a36667397700 Song R. p495 False Conference 186 Crystallographic Reconstruction of Parent Austenite Twin Boundaries in a Lath Martensitic Steel The study of post-transformation microstructures and their properties can be greatly enhanced by studying their dependence on the grain boundary content of parent microstructures. Recent work has extended the crystallographic reconstruction of parent austenite in steels to include the reconstruction of special boundaries, such as annealing twins. These reconstructions present unique challenges, as twinned austenite grains share a subset of possible daughter variant orientations. This gives rise to regions of ambiguity in a reconstruction. A technique for the reconstruction of twin boundaries is presented here that is capable of reconstructing 60° <1 1 1> twins, even in the case where twin regions are comprised entirely of variants that are common between the twin and the parent. This technique is demonstrated in the reconstruction of lath martensitic steels. The reconstruction method utilizes a delayed decision-making approach, where a chosen orientation relationship is used to define all possible groupings of daughter grains into possible parents before divisive decisions are made. These overlapping, inclusive groupings (called clusters) are compared to each other individually using their calculated parent austenite orientations and the topographical nature of the overlapping region. These comparisons are used to uncover possible locations of twin boundaries present in the parent austenite. This technique can be applied to future studies on the dependence of post-transformation microstructures on the special grain boundary content of parent microstructures. © 2018 Institute of Physics Publishing. All rights reserved.
1413 a57200118442 Whitehead N. p498 True Journal 269 Direct Measurement of High-Gain and Complementary Charge-Steering Amplifiers This brief presents direct measurement of two novel dynamic amplifiers utilizing the 'charge-steering' topology. Employing a delayed clocking scheme, a four-stage charge-steering amplifier achieves the highest gain of any reported charge-steering topology. A complementary charge-steering amplifier exploits both charging and discharging cycles to double the throughput while reducing power consumption by 22%. Fabricated in 180-nm technology, this brief presents, for the first time, direct measurement results of charge-steering amplifiers, including gain, noise, linearity, common-mode response, and power supply rejection ratio. © 2004-2012 IEEE.
1414 a57202289360 Wood Chiang S.-H. p498 False Journal 269 Direct Measurement of High-Gain and Complementary Charge-Steering Amplifiers This brief presents direct measurement of two novel dynamic amplifiers utilizing the 'charge-steering' topology. Employing a delayed clocking scheme, a four-stage charge-steering amplifier achieves the highest gain of any reported charge-steering topology. A complementary charge-steering amplifier exploits both charging and discharging cycles to double the throughput while reducing power consumption by 22%. Fabricated in 180-nm technology, this brief presents, for the first time, direct measurement results of charge-steering amplifiers, including gain, noise, linearity, common-mode response, and power supply rejection ratio. © 2004-2012 IEEE.
1415 a57202322450 Qian Z. p505 True Journal 276 Inverse piezoresistive nanocomposite sensors for identifying human sitting posture Sitting posture is the position in which one holds his/her body upright against gravity while sitting. Poor sitting posture is regarded as an aggravating factor for various diseases. In this paper, we present an inverse piezoresistive nanocomposite sensor, and related deciphering neural network, as a new tool to identify human sitting postures accurately. As a low power consumption device, the proposed tool has simple structure, and is easy to use. The strain gauge is attached to the back of the user to acquire sitting data. A three-layer BP neural network is employed to distinguish normal sitting posture, slight hunchback and severe hunchback according to the acquired data. Experimental results show that our method is both realizable and effective, achieving 98.75% posture identification accuracy. This successful application of inverse piezoresistive nanocomposite sensors reveals that the method could potentially be used for monitoring of diverse physiological parameters in the future. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
1416 a57202323019 Wan J. p505 False Journal 276 Inverse piezoresistive nanocomposite sensors for identifying human sitting posture Sitting posture is the position in which one holds his/her body upright against gravity while sitting. Poor sitting posture is regarded as an aggravating factor for various diseases. In this paper, we present an inverse piezoresistive nanocomposite sensor, and related deciphering neural network, as a new tool to identify human sitting postures accurately. As a low power consumption device, the proposed tool has simple structure, and is easy to use. The strain gauge is attached to the back of the user to acquire sitting data. A three-layer BP neural network is employed to distinguish normal sitting posture, slight hunchback and severe hunchback according to the acquired data. Experimental results show that our method is both realizable and effective, achieving 98.75% posture identification accuracy. This successful application of inverse piezoresistive nanocomposite sensors reveals that the method could potentially be used for monitoring of diverse physiological parameters in the future. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
1417 a56795914000 Liu W. p505 False Journal 276 Inverse piezoresistive nanocomposite sensors for identifying human sitting posture Sitting posture is the position in which one holds his/her body upright against gravity while sitting. Poor sitting posture is regarded as an aggravating factor for various diseases. In this paper, we present an inverse piezoresistive nanocomposite sensor, and related deciphering neural network, as a new tool to identify human sitting postures accurately. As a low power consumption device, the proposed tool has simple structure, and is easy to use. The strain gauge is attached to the back of the user to acquire sitting data. A three-layer BP neural network is employed to distinguish normal sitting posture, slight hunchback and severe hunchback according to the acquired data. Experimental results show that our method is both realizable and effective, achieving 98.75% posture identification accuracy. This successful application of inverse piezoresistive nanocomposite sensors reveals that the method could potentially be used for monitoring of diverse physiological parameters in the future. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
1418 a57202321033 Li X. p505 False Journal 276 Inverse piezoresistive nanocomposite sensors for identifying human sitting posture Sitting posture is the position in which one holds his/her body upright against gravity while sitting. Poor sitting posture is regarded as an aggravating factor for various diseases. In this paper, we present an inverse piezoresistive nanocomposite sensor, and related deciphering neural network, as a new tool to identify human sitting postures accurately. As a low power consumption device, the proposed tool has simple structure, and is easy to use. The strain gauge is attached to the back of the user to acquire sitting data. A three-layer BP neural network is employed to distinguish normal sitting posture, slight hunchback and severe hunchback according to the acquired data. Experimental results show that our method is both realizable and effective, achieving 98.75% posture identification accuracy. This successful application of inverse piezoresistive nanocomposite sensors reveals that the method could potentially be used for monitoring of diverse physiological parameters in the future. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
1419 a57202319101 Baradoy D. p505 False Journal 276 Inverse piezoresistive nanocomposite sensors for identifying human sitting posture Sitting posture is the position in which one holds his/her body upright against gravity while sitting. Poor sitting posture is regarded as an aggravating factor for various diseases. In this paper, we present an inverse piezoresistive nanocomposite sensor, and related deciphering neural network, as a new tool to identify human sitting postures accurately. As a low power consumption device, the proposed tool has simple structure, and is easy to use. The strain gauge is attached to the back of the user to acquire sitting data. A three-layer BP neural network is employed to distinguish normal sitting posture, slight hunchback and severe hunchback according to the acquired data. Experimental results show that our method is both realizable and effective, achieving 98.75% posture identification accuracy. This successful application of inverse piezoresistive nanocomposite sensors reveals that the method could potentially be used for monitoring of diverse physiological parameters in the future. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
1420 a23003484200 Clarke K.D. p506 True Journal 277 Shaping and Forming of Advanced High Strength Steels [No abstract available]
1420 a23003484200 Clarke K.D. p754 True Journal 361 Behavior of Sheet Metal Under Multiaxial Deformation Paths [No abstract available]
1421 a26321508500 Coughlin D.R. p506 False Journal 277 Shaping and Forming of Advanced High Strength Steels [No abstract available]
1421 a26321508500 Coughlin D.R. p754 False Journal 361 Behavior of Sheet Metal Under Multiaxial Deformation Paths [No abstract available]
1422 a7003587356 Carsley J.E. p506 False Journal 277 Shaping and Forming of Advanced High Strength Steels [No abstract available]
1422 a7003587356 Carsley J.E. p754 False Journal 361 Behavior of Sheet Metal Under Multiaxial Deformation Paths [No abstract available]
1422 a7003587356 Carsley J.E. p756 False Journal 361 Microstructure Correlation with Formability for Biaxial Stretching of Magnesium Alloy AZ31B at Mildly Elevated Temperatures Magnesium AZ31B sheets of 2 mm thickness were stretch formed with a 101.6-mm-diameter punch at temperatures from 25°C to 150°C, in 25°C increments. Surface strains were measured with a digital image correlation method. The punch height versus load curve was found to be the same for temperatures of 25°C and for 50°C, whereas at 75°C and above, the load for a given punch height started to decrease, indicating a potential change in deformation mechanism. Electron backscatter diffraction was used to quantify features of the microstructure in the tested specimens. In particular, the gradual decrease in twinning activity as a result of easier thermally activated slip with increasing temperatures is quantified across this range. Moreover, twin activity was found to predominantly involve the formation of {10 1 ¯ 1 } compression twins that rapidly transform to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
1422 a7003587356 Carsley J.E. p884 False Conference 397 Formability of magnesium alloy AZ31B from room temperature to 125, °C under biaxial tension Magnesium AZ31B sheets of 2, mm thickness were stretch formed using a 101.6, mm diameter punch at room temperature and subsequent increments from 25 to 125, °C. Surface strains were measured using a digital image correlation method in order to ensure that biaxial stretching was achieved. The punch height versus load curve was found to be the same for temperatures of 25 and for 50, °C, while at 75, °C the load for a given punch height was less. This difference seems to indicate a change in deformation mechanism between 50 and 75, °C. Electron Backscatter Diffraction (EBSD) was used to quantify features of the microstructure in the as-received and the strained specimens. Rather than a sudden transition from twinning to slip at low temperatures, it appears that twinning gradually decreases and slip activity increases as temperatures rise across the range from 25 to 125, °C. This confirms recent predictions found in the literature. The twin activity predominantly involves the formation of compression twins which rapidly transform further to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
1423 a56457856600 Poon T.C. p507 False Journal 278 Volumetric displays [No abstract available]
1424 a16315369500 Gao H. p507 False Journal 278 Volumetric displays [No abstract available]
1425 a6507336034 Kvavle J. p507 False Journal 278 Volumetric displays [No abstract available]
1426 a56532087700 Qaderi K. p507 False Journal 278 Volumetric displays [No abstract available]
1426 a56532087700 Qaderi K. p562 False Conference 211 Progress on photophoretic trap displays We review the fundamentals photophoretic trap displays and discuss the possibility of creating occlusion capable image points. Anisotropic scattering is observed independently in single and double point traps. © 2018 The Author(s).
1426 a56532087700 Qaderi K. p591 False Conference 234 Volumetric display by movement of particles trapped in a laser via photophoresis Photophoresis can stably hold opaque microscopic particles in a laser focus surrounded by room air with strength sufficient to enable centimeter-scale patterns to be drawn by sweeping the laser beam. The resulting images rely on visual persistence as laser light scatters from the particle, which is rapidly swept through the 3-D pattern. Control can be maintained while moving the particle with air speeds up to 2 m/s. A desire to greatly increase the sweep speed motivates a re-examination of the fundamentals of photophoresis-based laser-particle traps. Most explanations offered are qualitative, with differing opinions as to whether, for example, asymmetric heating or asymmetric thermal accommodation is primarily at work. Which particles become trapped in the beam is typically based on self-selection, as a variety of particles with possible differing shapes and sizes are offered to the laser focus for capture. Characteristics that make some particles preferred over others are especially relevant. There is broad consensus that structure in the laser focus greatly aids in stable trapping. Nevertheless, it is still possible for even a relatively smooth TEM00 beam to capture and hold particles. Moreover, even in a structured focus (i.e. with aberrations and local intensity minima and maxima), questions remain as to exactly how a particle becomes stably trapped in certain beam locations. A zoomed-in look at trapped particles reveals oscillations or orbits with excursions over tens of microns and accelerations up to 10 gs. We trapped particles in zero-gravity as well as 2-g environments with no noticeable difference in stability. © 2018 SPIE.
1427 a57202602903 Christensen C. p508 True Conference 188 Systems analysis of EV adoption and criteria pollutant accumulation during inversion events Exploring the system-level interactions between vehicle exhaust criteria pollutants, human health, and natural weather patterns such as inversion events is increasingly expedient given the accelerated growth and concentration of human populations in recent years. Pollutants often accumulate to unhealthy concentrations during winter inversion events like those that commonly occur in the state of Utah and other mountainous regions. Electric vehicles (EV) are a potential solution to reduce harmful tail-pipe emissions that accumulate during inversions. This work represents a systems-level analysis of the degree to which replacing internal combustion engine vehicles (ICE) with EVs would reduce the near-road accumulation of criteria pollutants. The analysis draws on vehicle miles travelled data from major highways in Utah, vehicle fuel efficiency data, EPA-specified vehicle pollution emission standards, and local weather pattern trends. It employs two models, built in MATLAB and the agent-based modeling environment NetLogo, to determine pollutant concentrations, accumulation, and dispersion rates. These results are processed to determine changes in the Air Quality Index (AQI) caused by adjusting the percentage of EVs present within the vehicle population. The analysis concludes that replacing a significant percentage (80-100%) of the existing, fossil-fuel powered vehicle population with EVs would improve local AQI by 13 points. During extreme inversion events in Utah, these reductions would delay AQI levels from reaching 'red,' or unhealthy, status for enough time to allow local weather patterns to shift and dissipate the inversion event and accompanying pollution. Such a drastic reduction in AQI translates into better adolescent and elderly health and could minimize the risk of early onset asthma and other respiratory illnesses in regions negatively affected by high traffic pollution and winter inversion events. © 2018 IEEE.
1428 a57202612703 Vasquez D. p508 False Conference 188 Systems analysis of EV adoption and criteria pollutant accumulation during inversion events Exploring the system-level interactions between vehicle exhaust criteria pollutants, human health, and natural weather patterns such as inversion events is increasingly expedient given the accelerated growth and concentration of human populations in recent years. Pollutants often accumulate to unhealthy concentrations during winter inversion events like those that commonly occur in the state of Utah and other mountainous regions. Electric vehicles (EV) are a potential solution to reduce harmful tail-pipe emissions that accumulate during inversions. This work represents a systems-level analysis of the degree to which replacing internal combustion engine vehicles (ICE) with EVs would reduce the near-road accumulation of criteria pollutants. The analysis draws on vehicle miles travelled data from major highways in Utah, vehicle fuel efficiency data, EPA-specified vehicle pollution emission standards, and local weather pattern trends. It employs two models, built in MATLAB and the agent-based modeling environment NetLogo, to determine pollutant concentrations, accumulation, and dispersion rates. These results are processed to determine changes in the Air Quality Index (AQI) caused by adjusting the percentage of EVs present within the vehicle population. The analysis concludes that replacing a significant percentage (80-100%) of the existing, fossil-fuel powered vehicle population with EVs would improve local AQI by 13 points. During extreme inversion events in Utah, these reductions would delay AQI levels from reaching 'red,' or unhealthy, status for enough time to allow local weather patterns to shift and dissipate the inversion event and accompanying pollution. Such a drastic reduction in AQI translates into better adolescent and elderly health and could minimize the risk of early onset asthma and other respiratory illnesses in regions negatively affected by high traffic pollution and winter inversion events. © 2018 IEEE.
1429 a36843900000 Dennis E.L. p509 True Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1430 a8397084400 Wilde E.A. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1431 a6602089995 Newsome M.R. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1432 a6603684079 Scheibel R.S. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1433 a15521088300 Troyanskaya M. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1434 a56585583100 Velez C. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1435 a55449746800 Wade B.S.C. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1436 a57190247414 Drennon A.M. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1437 a7005085503 York G.E. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1438 a35228854600 Bigler E.D. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1439 a6505936159 Abildskov T.J. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1440 a23487261200 Taylor B.A. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1441 a7005412154 Jaramillo C.A. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1442 a55946643000 Eapen B. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1443 a6603354235 Belanger H. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1444 a57192063650 Gupta V. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1445 a8602381900 Morey R. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1446 a55249658600 Haswell C. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1447 a57207782220 Levin H.S. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1448 a23987692400 Hinds S.R. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1449 a24323203800 Walker W.C. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1450 a7403220237 Thompson P.M. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1450 a7403220237 Thompson P.M. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1451 a7103286989 Tate D.F. p509 False Conference 189 ENIGMA military brain injury: A coordinated meta-analysis of diffusion MRI from multiple cohorts Traumatic brain injury (TBI) is a significant cause of morbidity in military Veterans and Service Members. While most individuals recover fully from mild injuries within weeks, some continue to experience symptoms including headaches, disrupted sleep, and other cognitive, behavioral or physical symptoms. Diffusion magnetic resonance imaging (dMRI) shows promise in identifying areas of structural disruption and predicting outcomes. Although some studies suggest widespread structural disruption after brain injury, dMRI studies of military brain injury have yielded mixed results so far, perhaps due to the subtlety of mild injury, individual differences in injury location, severity and mechanism, and co-morbidity with other disorders such as post-traumatic stress disorder (PTSD), depression, and substance abuse. We present preliminary dMRI results from the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) military brain injury working group. We found higher fractional anisotropy (FA) in participants with a history of TBI. Understanding the injury and recovery process, along with factors that influence these, will lead to improved diagnosis and treatment. © 2018 IEEE.
1452 a55708105800 Pohl M.B. p510 False Journal 279 Midtarsal locking, the windlass mechanism, and running strike pattern: A kinematic and kinetic assessment Changes in running strike pattern affect ankle and knee mechanics, but little is known about the influence of strike pattern on the joints distal to the ankle. The purpose of this study was to explore the effects of forefoot strike (FFS) and rearfoot strike (RFS) running patterns on foot kinematics and kinetics, from the perspectives of the midtarsal locking theory and the windlass mechanism. Per the midtarsal locking theory, we hypothesized that the ankle would be more inverted in early stance when using a FFS, resulting in decreased midtarsal joint excursions and increased dynamic stiffness. Associated with a more engaged windlass mechanism, we hypothesized that a FFS would elicit increased metatarsophalangeal joint excursions and negative work in late stance. Eighteen healthy female runners ran overground with both FFS and RFS patterns. Instrumented motion capture and a validated multi-segment foot model were used to analyze midtarsal and metatarsophalangeal joint kinematics and kinetics. During early stance in FFS the ankle was more inverted, with concurrently decreased midtarsal eversion (p < 0.001) and abduction excursions (p = 0.003) but increased dorsiflexion excursion (p = 0.005). Dynamic midtarsal stiffness did not differ (p = 0.761). During late stance in FFS, metatarsophalangeal extension was increased (p = 0.009), with concurrently increased negative work (p < 0.001). In addition, there was simultaneously increased midtarsal positive work (p < 0.001), suggesting enhanced power transfer in FFS. Clear evidence for the presence of midtarsal locking was not observed in either strike pattern during running. However, the windlass mechanism appeared to be engaged to a greater extent during FFS. © 2018 Elsevier Ltd
1453 a56164575400 Takahashi K.Z. p510 False Journal 279 Midtarsal locking, the windlass mechanism, and running strike pattern: A kinematic and kinetic assessment Changes in running strike pattern affect ankle and knee mechanics, but little is known about the influence of strike pattern on the joints distal to the ankle. The purpose of this study was to explore the effects of forefoot strike (FFS) and rearfoot strike (RFS) running patterns on foot kinematics and kinetics, from the perspectives of the midtarsal locking theory and the windlass mechanism. Per the midtarsal locking theory, we hypothesized that the ankle would be more inverted in early stance when using a FFS, resulting in decreased midtarsal joint excursions and increased dynamic stiffness. Associated with a more engaged windlass mechanism, we hypothesized that a FFS would elicit increased metatarsophalangeal joint excursions and negative work in late stance. Eighteen healthy female runners ran overground with both FFS and RFS patterns. Instrumented motion capture and a validated multi-segment foot model were used to analyze midtarsal and metatarsophalangeal joint kinematics and kinetics. During early stance in FFS the ankle was more inverted, with concurrently decreased midtarsal eversion (p < 0.001) and abduction excursions (p = 0.003) but increased dorsiflexion excursion (p = 0.005). Dynamic midtarsal stiffness did not differ (p = 0.761). During late stance in FFS, metatarsophalangeal extension was increased (p = 0.009), with concurrently increased negative work (p < 0.001). In addition, there was simultaneously increased midtarsal positive work (p < 0.001), suggesting enhanced power transfer in FFS. Clear evidence for the presence of midtarsal locking was not observed in either strike pattern during running. However, the windlass mechanism appeared to be engaged to a greater extent during FFS. © 2018 Elsevier Ltd
1454 a35236338800 Barrios J.A. p510 False Journal 279 Midtarsal locking, the windlass mechanism, and running strike pattern: A kinematic and kinetic assessment Changes in running strike pattern affect ankle and knee mechanics, but little is known about the influence of strike pattern on the joints distal to the ankle. The purpose of this study was to explore the effects of forefoot strike (FFS) and rearfoot strike (RFS) running patterns on foot kinematics and kinetics, from the perspectives of the midtarsal locking theory and the windlass mechanism. Per the midtarsal locking theory, we hypothesized that the ankle would be more inverted in early stance when using a FFS, resulting in decreased midtarsal joint excursions and increased dynamic stiffness. Associated with a more engaged windlass mechanism, we hypothesized that a FFS would elicit increased metatarsophalangeal joint excursions and negative work in late stance. Eighteen healthy female runners ran overground with both FFS and RFS patterns. Instrumented motion capture and a validated multi-segment foot model were used to analyze midtarsal and metatarsophalangeal joint kinematics and kinetics. During early stance in FFS the ankle was more inverted, with concurrently decreased midtarsal eversion (p < 0.001) and abduction excursions (p = 0.003) but increased dorsiflexion excursion (p = 0.005). Dynamic midtarsal stiffness did not differ (p = 0.761). During late stance in FFS, metatarsophalangeal extension was increased (p = 0.009), with concurrently increased negative work (p < 0.001). In addition, there was simultaneously increased midtarsal positive work (p < 0.001), suggesting enhanced power transfer in FFS. Clear evidence for the presence of midtarsal locking was not observed in either strike pattern during running. However, the windlass mechanism appeared to be engaged to a greater extent during FFS. © 2018 Elsevier Ltd
1455 a55212512700 Stan N. p511 False Journal 280 Noise reduction techniques in fiber optic sensors Test and evaluation needs are becoming more and more demanding on the sensors being used. Fiber optic sensors are known for their ability to survive in harsh environments such as high pressure and temperature like those within oil/gas wells, or high vibration like those with electromagnetic railguns. As these sensors become commercially available, one challenge is overcoming multiple noise sources simultaneously in the sensor and its network imposed from the harsh environment. Optical amplifiers are typically used in fiber optic sensors to improve the signal-to-noise ratio (SNR). This method is suitable for boosting the signal above the floor caused by electrical noise. However, certain noise sources in fiber optic sensors directly modulate the optical signal. This can be due to other measurands being induced on the system. For example, while a slab coupled optical sensor (SCOS) is sensitive to electric field, it is also inherently sensitive to strain; therefore, any strain noise imposed on the sensor would overwhelm the electric field measurement and be considered noise. In this chapter, optical phase induced interference noise (PIIN) in a sensor network is reduced by using optical phase modulation in both a SCOS and a fiber Bragg grating (FBG). Strain induced noise on the optical fiber sensor is reduced using a differential sensor setup called a push-pull SCOS. Phase modulation and differentiation are then combined to allow for simultaneous noise reduction from different noise sources and allow for optical sensing of electric fields in harsh environments. These principles are applicable to other types of fiber optic sensors and sensors in general. © 2018 Nova Science Publishers, Inc.
1455 a55212512700 Stan N. p678 False Conference 291 High-Speed Interrogation of Multiplexed Fiber Bragg Gratings with Spectral Distortion Fiber Bragg grating (FBG) sensors can be multiplexed in large numbers to monitor the performance of large structures. This paper addresses the collection of FBG reflection spectra from wavelength division multiplexed sensors at fast acquisition rates. The spectral and temporal resolution is first derived as a function of the tunable filter and measurement system properties. The method is applied to impact loading investigations of a stiffened composite skin panel. The reflected spectrum of each FBG in an array, embedded in the panel, is collected at 100 kHz during the impact events with a spectral resolution down to 40 pm. Visualization of the FBG responses to these impact events, including the presence of spectral distortion in some FBG spectra, is presented. Future analyses based on the full-spectral data sets can enable the assessment of the localized progression of internal damage in such structures. © 2001-2012 IEEE.
1455 a55212512700 Stan N. p705 True Journal 346 Non-perturbing voltage measurement in a coaxial cable with slab-coupled optical sensors Voltage in a coaxial cable is measured by an electric-field optical fiber sensor exploiting the proportionality of voltage and electric field in a fixed structure. The sensor is inserted in a hole drilled through the dielectric of the RG-218 coaxial cable and sealed with epoxy to displace all air and prevent the adverse effects of charge buildup during high-voltage measurements. It is shown that the presence of the sensor in the coaxial cable does not significantly increase electrical reflections in the cable. A slab-coupled optical fiber sensor (SCOS) is used for its compact size and dielectric make. The dynamic range of 50 dB is shown experimentally with detection of signals as low as 1 V and up to 157 kV. A low corner of 0.3 Hz is demonstrated and the SCOS is shown to be able to measure 90 ns rise time. © 2017 Optical Society of America.
1455 a55212512700 Stan N. p740 False Journal 346 Optical electric field sensor sensitivity direction rerouting and enhancement using a passive integrated dipole antenna This work introduces a passive dipole antenna integrated into the packaging of a slab-coupled optical sensor to enhance the directional sensitivity of electro-optic electric field measurements parallel to the fiber axis. Using the passive integrated dipole antenna described in this work, a sensor that can typically only sense fields transverse to the fiber direction is able to sense a 1.25 kV/m field along the fiber direction with a gain of 17.5. This is verified through simulation and experiment. © 2017 Optical Society of America.
1456 a56680505500 King R. p511 False Journal 280 Noise reduction techniques in fiber optic sensors Test and evaluation needs are becoming more and more demanding on the sensors being used. Fiber optic sensors are known for their ability to survive in harsh environments such as high pressure and temperature like those within oil/gas wells, or high vibration like those with electromagnetic railguns. As these sensors become commercially available, one challenge is overcoming multiple noise sources simultaneously in the sensor and its network imposed from the harsh environment. Optical amplifiers are typically used in fiber optic sensors to improve the signal-to-noise ratio (SNR). This method is suitable for boosting the signal above the floor caused by electrical noise. However, certain noise sources in fiber optic sensors directly modulate the optical signal. This can be due to other measurands being induced on the system. For example, while a slab coupled optical sensor (SCOS) is sensitive to electric field, it is also inherently sensitive to strain; therefore, any strain noise imposed on the sensor would overwhelm the electric field measurement and be considered noise. In this chapter, optical phase induced interference noise (PIIN) in a sensor network is reduced by using optical phase modulation in both a SCOS and a fiber Bragg grating (FBG). Strain induced noise on the optical fiber sensor is reduced using a differential sensor setup called a push-pull SCOS. Phase modulation and differentiation are then combined to allow for simultaneous noise reduction from different noise sources and allow for optical sensing of electric fields in harsh environments. These principles are applicable to other types of fiber optic sensors and sensors in general. © 2018 Nova Science Publishers, Inc.
1456 a56680505500 King R. p705 False Journal 346 Non-perturbing voltage measurement in a coaxial cable with slab-coupled optical sensors Voltage in a coaxial cable is measured by an electric-field optical fiber sensor exploiting the proportionality of voltage and electric field in a fixed structure. The sensor is inserted in a hole drilled through the dielectric of the RG-218 coaxial cable and sealed with epoxy to displace all air and prevent the adverse effects of charge buildup during high-voltage measurements. It is shown that the presence of the sensor in the coaxial cable does not significantly increase electrical reflections in the cable. A slab-coupled optical fiber sensor (SCOS) is used for its compact size and dielectric make. The dynamic range of 50 dB is shown experimentally with detection of signals as low as 1 V and up to 157 kV. A low corner of 0.3 Hz is demonstrated and the SCOS is shown to be able to measure 90 ns rise time. © 2017 Optical Society of America.
1456 a56680505500 King R. p740 False Journal 346 Optical electric field sensor sensitivity direction rerouting and enhancement using a passive integrated dipole antenna This work introduces a passive dipole antenna integrated into the packaging of a slab-coupled optical sensor to enhance the directional sensitivity of electro-optic electric field measurements parallel to the fiber axis. Using the passive integrated dipole antenna described in this work, a sensor that can typically only sense fields transverse to the fiber direction is able to sense a 1.25 kV/m field along the fiber direction with a gain of 17.5. This is verified through simulation and experiment. © 2017 Optical Society of America.
1457 a35323710800 Chen G. p512 True Journal 281 Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 μm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes. © 2018 American Chemical Society.
1458 a57202045558 Dodson B. p512 False Journal 281 Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 μm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes. © 2018 American Chemical Society.
1459 a56165315000 Hedges D.M. p512 False Journal 281 Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 μm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes. © 2018 American Chemical Society.
1460 a7003387464 Steffensen S.C. p512 False Journal 281 Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 μm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes. © 2018 American Chemical Society.
1461 a26039464700 Puleo C. p512 False Journal 281 Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 μm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes. © 2018 American Chemical Society.
1462 a56747755300 Galligan C. p512 False Journal 281 Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 μm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes. © 2018 American Chemical Society.
1463 a7005612595 Ashe J. p512 False Journal 281 Fabrication of High Aspect Ratio Millimeter-Tall Free-Standing Carbon Nanotube-Based Microelectrode Arrays Microelectrode arrays of carbon nanotube (CNT)/carbon composite posts with high aspect ratio and millimeter-length were fabricated using carbon-nanotube-templated microfabrication with a sacrificial "hedge". The high aspect ratio, mechanical robustness, and electrical conductivity of these electrodes make them a potential candidate for next-generation neural interfacing. Electrochemical measurements were also demonstrated using an individual CNT post microelectrode with a diameter of 25 μm and a length of 1 mm to perform cyclic voltammetry on both methyl viologen and dopamine in a phosphate-buffered saline solution. In addition to detection of the characteristic peaks, the CNT post microelectrodes show a fast electrochemical response, which may be enabling for in vivo and/or in vitro measurements. The CNT post electrode fabrication process was also integrated with other microfabrication techniques, resulting in individually addressable electrodes. © 2018 American Chemical Society.
1464 a56386056100 Brivadis E. p515 False Journal 284 Isogeometric Bézier dual mortaring: Refineable higher-order spline dual bases and weakly continuous geometry In this paper we develop the isogeometric Bézier dual mortar method. It is based on Bézier extraction and projection and is applicable to any spline space which can be represented in Bézier form (i.e., NURBS, T-splines, LR-splines, etc.). The approach weakly enforces the continuity of the solution at patch interfaces and the error can be adaptively controlled by leveraging the refineability of the underlying slave dual spline basis without introducing any additional degrees of freedom. As a consequence, optimal higher-order convergence rates can be achieved without the need for an expensive shared master/slave segmentation step. We also develop weakly continuous geometry as a particular application of isogeometric Bézier dual mortaring. Weakly continuous geometry is a geometry description where the weak continuity constraints are built into properly modified Bézier extraction operators. As a result, multi-patch models can be processed in a solver directly without having to employ a mortaring solution strategy. We demonstrate the utility of the approach on several challenging benchmark problems. © 2018 Elsevier B.V.
1465 a56755464700 Wanik D. p516 True Journal 285 Estimated Time of Restoration (ETR) Guidance for Electric Distribution Networks Electric distribution utilities have an obligation to inform the public and government regulators about when they expect to complete service restoration after a major storm. In this study, we explore methods for calculating the estimated time of restoration (ETR) from weather impacts, defined as the time it will take for 99.5% of customers to be restored. Actual data from Storm Irene (2011), the October Nor'easter (2011) and Hurricane Sandy (2012) within the Eversource Energy-Connecticut service territory were used to calibrate and test the methods; data used included predicted outages, the peak number of customers affected, a ratio of how many outages a restoration crew can repair per day, and the count of crews working per day. Data known before a storm strikes (such as predicted outages and available crews) can be used to calculate ETR and support pre-storm allocation of crews and resources, while data available immediately after the storm passes (such as customers affected) can be used as motivation for securing or releasing crews to complete the restoration in a timely manner. Used together, the methods presented in this paper will help utilities provide a reasonable, data-driven ETR without relying solely on qualitative past experiences or instinct. © 2018 Walter de Gruyter GmbH, Berlin/Boston.
1465 a56755464700 Wanik D. p752 True Journal 366 Using vegetation management and LiDAR-derived tree height data to improve outage predictions for electric utilities The interaction of severe weather, overhead electric infrastructure and surrounding vegetation contributes to power outages. Given that 90% of storm outages in Connecticut are tree-related, accurate modeling of power outages before a storm arrives could result in improved pre-staging of crews and equipment resulting in improved electric reliability. The authors have generated a light detection and ranging (LiDAR) data product that provides a 1-m resolution measurement of vegetation that is tall enough to strike overhead distribution powerlines, called “ProxPix”. These data, along with other vegetation management (e.g. tree trimming) and infrastructure data were evaluated for their improvement an outage prediction model over eastern Connecticut during Hurricane Sandy. A random forest model utilizing a repeated balanced sampling (RBS) approach with 10,000 iterations was used to evaluate which model forcing data accurately predicted the occurrence of a power outage in a 0.5 km grid cell. The authors found that models inputted with infrastructure, vegetation management, ProxPix, performed up to 5–13% better than simpler models depending on model evaluation criteria and input data; and that the model forced with utility infrastructure and ProxPix had the best overall performance. The ProxPix data created for this study have application to other research topics such as prioritizing areas for vegetation management near utilities and providing data on potential tree threats to roads, railways, or other infrastructure networks. © 2017 Elsevier B.V.
1465 a56755464700 Wanik D. p773 False Journal 380 Nonparametric Tree-Based Predictive Modeling of Storm Outages on an Electric Distribution Network This article compares two nonparametric tree-based models, quantile regression forests (QRF) and Bayesian additive regression trees (BART), for predicting storm outages on an electric distribution network in Connecticut, USA. We evaluated point estimates and prediction intervals of outage predictions for both models using high-resolution weather, infrastructure, and land use data for 89 storm events (including hurricanes, blizzards, and thunderstorms). We found that spatially BART predicted more accurate point estimates than QRF. However, QRF produced better prediction intervals for high spatial resolutions (2-km grid cells and towns), while BART predictions aggregated to coarser resolutions (divisions and service territory) more effectively. We also found that the predictive accuracy was dependent on the season (e.g., tree-leaf condition, storm characteristics), and that the predictions were most accurate for winter storms. Given the merits of each individual model, we suggest that BART and QRF be implemented together to show the complete picture of a storm's potential impact on the electric distribution network, which would allow for a utility to make better decisions about allocating prestorm resources. © 2016 Society for Risk Analysis
1466 a7005523706 Anagnostou E. p516 False Journal 285 Estimated Time of Restoration (ETR) Guidance for Electric Distribution Networks Electric distribution utilities have an obligation to inform the public and government regulators about when they expect to complete service restoration after a major storm. In this study, we explore methods for calculating the estimated time of restoration (ETR) from weather impacts, defined as the time it will take for 99.5% of customers to be restored. Actual data from Storm Irene (2011), the October Nor'easter (2011) and Hurricane Sandy (2012) within the Eversource Energy-Connecticut service territory were used to calibrate and test the methods; data used included predicted outages, the peak number of customers affected, a ratio of how many outages a restoration crew can repair per day, and the count of crews working per day. Data known before a storm strikes (such as predicted outages and available crews) can be used to calculate ETR and support pre-storm allocation of crews and resources, while data available immediately after the storm passes (such as customers affected) can be used as motivation for securing or releasing crews to complete the restoration in a timely manner. Used together, the methods presented in this paper will help utilities provide a reasonable, data-driven ETR without relying solely on qualitative past experiences or instinct. © 2018 Walter de Gruyter GmbH, Berlin/Boston.
1466 a7005523706 Anagnostou E. p752 False Journal 366 Using vegetation management and LiDAR-derived tree height data to improve outage predictions for electric utilities The interaction of severe weather, overhead electric infrastructure and surrounding vegetation contributes to power outages. Given that 90% of storm outages in Connecticut are tree-related, accurate modeling of power outages before a storm arrives could result in improved pre-staging of crews and equipment resulting in improved electric reliability. The authors have generated a light detection and ranging (LiDAR) data product that provides a 1-m resolution measurement of vegetation that is tall enough to strike overhead distribution powerlines, called “ProxPix”. These data, along with other vegetation management (e.g. tree trimming) and infrastructure data were evaluated for their improvement an outage prediction model over eastern Connecticut during Hurricane Sandy. A random forest model utilizing a repeated balanced sampling (RBS) approach with 10,000 iterations was used to evaluate which model forcing data accurately predicted the occurrence of a power outage in a 0.5 km grid cell. The authors found that models inputted with infrastructure, vegetation management, ProxPix, performed up to 5–13% better than simpler models depending on model evaluation criteria and input data; and that the model forced with utility infrastructure and ProxPix had the best overall performance. The ProxPix data created for this study have application to other research topics such as prioritizing areas for vegetation management near utilities and providing data on potential tree threats to roads, railways, or other infrastructure networks. © 2017 Elsevier B.V.
1466 a7005523706 Anagnostou E. p773 False Journal 380 Nonparametric Tree-Based Predictive Modeling of Storm Outages on an Electric Distribution Network This article compares two nonparametric tree-based models, quantile regression forests (QRF) and Bayesian additive regression trees (BART), for predicting storm outages on an electric distribution network in Connecticut, USA. We evaluated point estimates and prediction intervals of outage predictions for both models using high-resolution weather, infrastructure, and land use data for 89 storm events (including hurricanes, blizzards, and thunderstorms). We found that spatially BART predicted more accurate point estimates than QRF. However, QRF produced better prediction intervals for high spatial resolutions (2-km grid cells and towns), while BART predictions aggregated to coarser resolutions (divisions and service territory) more effectively. We also found that the predictive accuracy was dependent on the season (e.g., tree-leaf condition, storm characteristics), and that the predictions were most accurate for winter storms. Given the merits of each individual model, we suggest that BART and QRF be implemented together to show the complete picture of a storm's potential impact on the electric distribution network, which would allow for a utility to make better decisions about allocating prestorm resources. © 2016 Society for Risk Analysis
1467 a57031532600 Hartman B. p516 False Journal 285 Estimated Time of Restoration (ETR) Guidance for Electric Distribution Networks Electric distribution utilities have an obligation to inform the public and government regulators about when they expect to complete service restoration after a major storm. In this study, we explore methods for calculating the estimated time of restoration (ETR) from weather impacts, defined as the time it will take for 99.5% of customers to be restored. Actual data from Storm Irene (2011), the October Nor'easter (2011) and Hurricane Sandy (2012) within the Eversource Energy-Connecticut service territory were used to calibrate and test the methods; data used included predicted outages, the peak number of customers affected, a ratio of how many outages a restoration crew can repair per day, and the count of crews working per day. Data known before a storm strikes (such as predicted outages and available crews) can be used to calculate ETR and support pre-storm allocation of crews and resources, while data available immediately after the storm passes (such as customers affected) can be used as motivation for securing or releasing crews to complete the restoration in a timely manner. Used together, the methods presented in this paper will help utilities provide a reasonable, data-driven ETR without relying solely on qualitative past experiences or instinct. © 2018 Walter de Gruyter GmbH, Berlin/Boston.
1467 a57031532600 Hartman B. p752 False Journal 366 Using vegetation management and LiDAR-derived tree height data to improve outage predictions for electric utilities The interaction of severe weather, overhead electric infrastructure and surrounding vegetation contributes to power outages. Given that 90% of storm outages in Connecticut are tree-related, accurate modeling of power outages before a storm arrives could result in improved pre-staging of crews and equipment resulting in improved electric reliability. The authors have generated a light detection and ranging (LiDAR) data product that provides a 1-m resolution measurement of vegetation that is tall enough to strike overhead distribution powerlines, called “ProxPix”. These data, along with other vegetation management (e.g. tree trimming) and infrastructure data were evaluated for their improvement an outage prediction model over eastern Connecticut during Hurricane Sandy. A random forest model utilizing a repeated balanced sampling (RBS) approach with 10,000 iterations was used to evaluate which model forcing data accurately predicted the occurrence of a power outage in a 0.5 km grid cell. The authors found that models inputted with infrastructure, vegetation management, ProxPix, performed up to 5–13% better than simpler models depending on model evaluation criteria and input data; and that the model forced with utility infrastructure and ProxPix had the best overall performance. The ProxPix data created for this study have application to other research topics such as prioritizing areas for vegetation management near utilities and providing data on potential tree threats to roads, railways, or other infrastructure networks. © 2017 Elsevier B.V.
1467 a57031532600 Hartman B. p773 False Journal 380 Nonparametric Tree-Based Predictive Modeling of Storm Outages on an Electric Distribution Network This article compares two nonparametric tree-based models, quantile regression forests (QRF) and Bayesian additive regression trees (BART), for predicting storm outages on an electric distribution network in Connecticut, USA. We evaluated point estimates and prediction intervals of outage predictions for both models using high-resolution weather, infrastructure, and land use data for 89 storm events (including hurricanes, blizzards, and thunderstorms). We found that spatially BART predicted more accurate point estimates than QRF. However, QRF produced better prediction intervals for high spatial resolutions (2-km grid cells and towns), while BART predictions aggregated to coarser resolutions (divisions and service territory) more effectively. We also found that the predictive accuracy was dependent on the season (e.g., tree-leaf condition, storm characteristics), and that the predictions were most accurate for winter storms. Given the merits of each individual model, we suggest that BART and QRF be implemented together to show the complete picture of a storm's potential impact on the electric distribution network, which would allow for a utility to make better decisions about allocating prestorm resources. © 2016 Society for Risk Analysis
1468 a57200497294 Layton T. p516 False Journal 285 Estimated Time of Restoration (ETR) Guidance for Electric Distribution Networks Electric distribution utilities have an obligation to inform the public and government regulators about when they expect to complete service restoration after a major storm. In this study, we explore methods for calculating the estimated time of restoration (ETR) from weather impacts, defined as the time it will take for 99.5% of customers to be restored. Actual data from Storm Irene (2011), the October Nor'easter (2011) and Hurricane Sandy (2012) within the Eversource Energy-Connecticut service territory were used to calibrate and test the methods; data used included predicted outages, the peak number of customers affected, a ratio of how many outages a restoration crew can repair per day, and the count of crews working per day. Data known before a storm strikes (such as predicted outages and available crews) can be used to calculate ETR and support pre-storm allocation of crews and resources, while data available immediately after the storm passes (such as customers affected) can be used as motivation for securing or releasing crews to complete the restoration in a timely manner. Used together, the methods presented in this paper will help utilities provide a reasonable, data-driven ETR without relying solely on qualitative past experiences or instinct. © 2018 Walter de Gruyter GmbH, Berlin/Boston.
1469 a57190794386 Bird E. p517 True Journal 286 Effect of environmental and material factors on the response of nanocomposite foam impact sensors Nanocomposite foam (NCF) is a multifunctional material that can be used to measure impact. Interactions between the flexible polymer matrix and conductive particles dispersed throughout it produce a voltage signal under dynamic strain, which correlates to the magnitude of impact. Though promising in applications requiring both impact sensing and energy absorption, NCF's voltage response has been observed to suffer from significant signal drift. This paper investigates several causes of variance in the response of NCF sensors to consistent impacts. These effects can be classified into three general types: recoverable transient effects (such as those relating to viscoelasticity or capacitive charging), environmental drift (due to humidity and temperature), and permanent signal decay from material degradation. The motivation for the study arises from various potential repeat-impact applications where periodic recalibration of the sensor would be difficult (such as a gait-tracking insole in use for a marathon event). A cyclic drop testing machine was used to apply consistent impacts to NCF, and drift resulting from each factor (in ranges typical of an insole environment) was experimentally isolated. Models representing each factor's contribution to signal drift are presented. Of the factors investigated, humidity and temperature caused the most significant drift, with permanent material degradation accounting for only minor decay in voltage response. Transient effects were also observed, with a characteristic 'warm-up' (or 'charging') time required for the NCF to achieve steady-state; this phenomenon, and the related 'recovery' time for the material to return to its original state, were determined. The resultant data can be leveraged to implement a correction algorithm or other drift-compensating method to retain an NCF sensor's accuracy in both long and short data collection scenarios. © 2018 IOP Publishing Ltd.
1469 a57190794386 Bird E. p546 True Journal 300 Materials selection of flexible open-cell foams in energy absorption applications Foam must be engineered to absorb a particular range of energy in various impact-related applications. Since energy absorption is dependent upon the unique stress-strain response of each foam specimen, it is difficult to quantify analytically; thus, energy absorption cannot be easily compared across materials. Current methods accomplish this using an experimental approach, individually testing foam materials, densities, and geometries to quantify how each influences energy absorption. Such methods require large amounts of time and money to characterize a narrow range of foams. This paper facilitates foam selection by deriving generalized energy absorption material indices. Assuming Euler buckling of columns in the open-cell foam structure, this paper applies equations derived by Maiti et al. to a typical impact scenario wherein the indices are extracted. Using existing Ashby charts, these indices allow polymers to be ranked by the mass and cost each would require as a foamed structure to satisfy specific energy absorption constraints. The presented method allows the energy absorption of a wide range of flexible foams to be compared and relieves the need for extensive factor-specific testing. This method is applied to football helmet foam selection; however, it can be used for many applications where energy absorption is of interest. © 2017 Elsevier Ltd
1469 a57190794386 Bird E. p694 False Journal 320 Estimation of 3D Ground Reaction Force Using Nanocomposite Piezo-Responsive Foam Sensors During Walking This paper describes a method for the estimation of the 3D ground reaction force (GRF) during human walking using novel nanocomposite piezo-responsive foam (NCPF) sensors. Nine subjects (5 male, 4 female) walked on a force-instrumented treadmill at 1.34 m/s for 120 s each while wearing a shoe that was instrumented with four NCPF sensors. GRF data, measured via the treadmill, and sensor data, measured via the NCPF inserts, were used in a tenfold cross validation process to calibrate a separate model for each individual. The calibration model estimated average anterior–posterior, mediolateral and vertical GRF with mean average errors (MAE) of 6.52 N (2.14%), 4.79 N (6.34%), and 15.4 N (2.15%), respectively. Two additional models were created using the sensor data from all subjects and subject demographics. A tenfold cross validation process for this combined data set resulted in models that estimated average anterior–posterior, mediolateral and vertical GRF with less than 8.16 N (2.41%), 6.63 N (7.37%), and 19.4 N (2.31%) errors, respectively. Intra-subject estimates based on the model had a higher accuracy than inter-subject estimates, likely due to the relatively small subject cohort used in creating the model. The novel NCPF sensors demonstrate the ability to accurately estimate 3D GRF during human movement outside of the traditional biomechanics laboratory setting. © 2017, Biomedical Engineering Society.
1470 a57201980753 Merrell J. p517 False Journal 286 Effect of environmental and material factors on the response of nanocomposite foam impact sensors Nanocomposite foam (NCF) is a multifunctional material that can be used to measure impact. Interactions between the flexible polymer matrix and conductive particles dispersed throughout it produce a voltage signal under dynamic strain, which correlates to the magnitude of impact. Though promising in applications requiring both impact sensing and energy absorption, NCF's voltage response has been observed to suffer from significant signal drift. This paper investigates several causes of variance in the response of NCF sensors to consistent impacts. These effects can be classified into three general types: recoverable transient effects (such as those relating to viscoelasticity or capacitive charging), environmental drift (due to humidity and temperature), and permanent signal decay from material degradation. The motivation for the study arises from various potential repeat-impact applications where periodic recalibration of the sensor would be difficult (such as a gait-tracking insole in use for a marathon event). A cyclic drop testing machine was used to apply consistent impacts to NCF, and drift resulting from each factor (in ranges typical of an insole environment) was experimentally isolated. Models representing each factor's contribution to signal drift are presented. Of the factors investigated, humidity and temperature caused the most significant drift, with permanent material degradation accounting for only minor decay in voltage response. Transient effects were also observed, with a characteristic 'warm-up' (or 'charging') time required for the NCF to achieve steady-state; this phenomenon, and the related 'recovery' time for the material to return to its original state, were determined. The resultant data can be leveraged to implement a correction algorithm or other drift-compensating method to retain an NCF sensor's accuracy in both long and short data collection scenarios. © 2018 IOP Publishing Ltd.
1471 a57190797086 Rosquist P. p517 False Journal 286 Effect of environmental and material factors on the response of nanocomposite foam impact sensors Nanocomposite foam (NCF) is a multifunctional material that can be used to measure impact. Interactions between the flexible polymer matrix and conductive particles dispersed throughout it produce a voltage signal under dynamic strain, which correlates to the magnitude of impact. Though promising in applications requiring both impact sensing and energy absorption, NCF's voltage response has been observed to suffer from significant signal drift. This paper investigates several causes of variance in the response of NCF sensors to consistent impacts. These effects can be classified into three general types: recoverable transient effects (such as those relating to viscoelasticity or capacitive charging), environmental drift (due to humidity and temperature), and permanent signal decay from material degradation. The motivation for the study arises from various potential repeat-impact applications where periodic recalibration of the sensor would be difficult (such as a gait-tracking insole in use for a marathon event). A cyclic drop testing machine was used to apply consistent impacts to NCF, and drift resulting from each factor (in ranges typical of an insole environment) was experimentally isolated. Models representing each factor's contribution to signal drift are presented. Of the factors investigated, humidity and temperature caused the most significant drift, with permanent material degradation accounting for only minor decay in voltage response. Transient effects were also observed, with a characteristic 'warm-up' (or 'charging') time required for the NCF to achieve steady-state; this phenomenon, and the related 'recovery' time for the material to return to its original state, were determined. The resultant data can be leveraged to implement a correction algorithm or other drift-compensating method to retain an NCF sensor's accuracy in both long and short data collection scenarios. © 2018 IOP Publishing Ltd.
1471 a57190797086 Rosquist P. p694 True Journal 320 Estimation of 3D Ground Reaction Force Using Nanocomposite Piezo-Responsive Foam Sensors During Walking This paper describes a method for the estimation of the 3D ground reaction force (GRF) during human walking using novel nanocomposite piezo-responsive foam (NCPF) sensors. Nine subjects (5 male, 4 female) walked on a force-instrumented treadmill at 1.34 m/s for 120 s each while wearing a shoe that was instrumented with four NCPF sensors. GRF data, measured via the treadmill, and sensor data, measured via the NCPF inserts, were used in a tenfold cross validation process to calibrate a separate model for each individual. The calibration model estimated average anterior–posterior, mediolateral and vertical GRF with mean average errors (MAE) of 6.52 N (2.14%), 4.79 N (6.34%), and 15.4 N (2.15%), respectively. Two additional models were created using the sensor data from all subjects and subject demographics. A tenfold cross validation process for this combined data set resulted in models that estimated average anterior–posterior, mediolateral and vertical GRF with less than 8.16 N (2.41%), 6.63 N (7.37%), and 19.4 N (2.31%) errors, respectively. Intra-subject estimates based on the model had a higher accuracy than inter-subject estimates, likely due to the relatively small subject cohort used in creating the model. The novel NCPF sensors demonstrate the ability to accurately estimate 3D GRF during human movement outside of the traditional biomechanics laboratory setting. © 2017, Biomedical Engineering Society.
1472 a57201983321 Martineau A. p517 False Journal 286 Effect of environmental and material factors on the response of nanocomposite foam impact sensors Nanocomposite foam (NCF) is a multifunctional material that can be used to measure impact. Interactions between the flexible polymer matrix and conductive particles dispersed throughout it produce a voltage signal under dynamic strain, which correlates to the magnitude of impact. Though promising in applications requiring both impact sensing and energy absorption, NCF's voltage response has been observed to suffer from significant signal drift. This paper investigates several causes of variance in the response of NCF sensors to consistent impacts. These effects can be classified into three general types: recoverable transient effects (such as those relating to viscoelasticity or capacitive charging), environmental drift (due to humidity and temperature), and permanent signal decay from material degradation. The motivation for the study arises from various potential repeat-impact applications where periodic recalibration of the sensor would be difficult (such as a gait-tracking insole in use for a marathon event). A cyclic drop testing machine was used to apply consistent impacts to NCF, and drift resulting from each factor (in ranges typical of an insole environment) was experimentally isolated. Models representing each factor's contribution to signal drift are presented. Of the factors investigated, humidity and temperature caused the most significant drift, with permanent material degradation accounting for only minor decay in voltage response. Transient effects were also observed, with a characteristic 'warm-up' (or 'charging') time required for the NCF to achieve steady-state; this phenomenon, and the related 'recovery' time for the material to return to its original state, were determined. The resultant data can be leveraged to implement a correction algorithm or other drift-compensating method to retain an NCF sensor's accuracy in both long and short data collection scenarios. © 2018 IOP Publishing Ltd.
1473 a56181255300 Balijepalli S.K. p518 False Journal 287 Low Temperature Oxidative Dehydrogenation of Ethane by Ce-Modified NiNb Catalysts Low temperature oxidative dehydrogenation catalysts are becoming a viable material for drastically altering the production of small chain alkenes. Among materials used, bimetallic and trimetallic nickel catalysts have shown great promise. In this study, we report a 38% increase in the rate of ethylene production with the addition of Ce to NiNb catalysts. Oxidative dehydrogenation of ethane was performed in the temperature range of 250-350 °C. At 300 °C, the rate of ethylene production was maximized with a rate of 6.91 × 10-4 mmol gcat-1 s-1. At higher temperatures, the rate of deep oxidation to CO2 outcompeted the rate of ethylene formation. The improved rate due to the addition of Ce is attributed to ceria's ability to rapidly transport oxygen to the NiO active sites. © 2018 American Chemical Society.
1474 a24177939700 Barker B. p519 True Journal 288 Evans function computation for the stability of travelling waves In recent years, the Evans function has become an important tool for the determination of stability of travelling waves. This function, a Wronskian of decaying solutions of the eigenvalue equation, is useful both analytically and computationally for the spectral analysis of the linearized operator about the wave. In particular, Evans-function computation allows one to locate any unstable eigenvalues of the linear operator (if they exist); this allows one to establish spectral stability of a given wave and identify bifurcation points (loss of stability) as model parameters vary. In this paper, we review computational aspects of the Evans function and apply it to multidimensional detonation waves. This article is part of the theme issue 'Stability of nonlinear waves and patterns and related topics'. © 2018 The Author(s) Published by the Royal Society. All rights reserved.
1474 a24177939700 Barker B. p785 True Journal 389 Stability of Viscous St. Venant Roll Waves: From Onset to Infinite Froude Number Limit We study the spectral stability of roll wave solutions of the viscous St. Venant equations modeling inclined shallow water flow, both at onset in the small Froude number or “weakly unstable” limit F→ 2 + and for general values of the Froude number F, including the limit F→ + ∞. In the former, F→ 2 +, limit, the shallow water equations are formally approximated by a Korteweg-de Vries/Kuramoto–Sivashinsky (KdV–KS) equation that is a singular perturbation of the standard Korteweg-de Vries (KdV) equation modeling horizontal shallow water flow. Our main analytical result is to rigorously validate this formal limit, showing that stability as F→ 2 + is equivalent to stability of the corresponding KdV–KS waves in the KdV limit. Together with recent results obtained for KdV–KS by Johnson–Noble–Rodrigues–Zumbrun and Barker, this gives not only the first rigorous verification of stability for any single viscous St. Venant roll wave, but a complete classification of stability in the weakly unstable limit. In the remainder of the paper, we investigate numerically and analytically the evolution of the stability diagram as Froude number increases to infinity. Notably, we find transition at around F= 2.3 from weakly unstable to different, large-F behavior, with stability determined by simple power-law relations. The latter stability criteria are potentially useful in hydraulic engineering applications, for which typically 2.5 ≤ F≤ 6.0. © 2016, Springer Science+Business Media New York.
1475 a6507412888 Humpherys J. p519 False Journal 288 Evans function computation for the stability of travelling waves In recent years, the Evans function has become an important tool for the determination of stability of travelling waves. This function, a Wronskian of decaying solutions of the eigenvalue equation, is useful both analytically and computationally for the spectral analysis of the linearized operator about the wave. In particular, Evans-function computation allows one to locate any unstable eigenvalues of the linear operator (if they exist); this allows one to establish spectral stability of a given wave and identify bifurcation points (loss of stability) as model parameters vary. In this paper, we review computational aspects of the Evans function and apply it to multidimensional detonation waves. This article is part of the theme issue 'Stability of nonlinear waves and patterns and related topics'. © 2018 The Author(s) Published by the Royal Society. All rights reserved.
1475 a6507412888 Humpherys J. p670 True Journal 323 Multidimensional Stability of Large-Amplitude Navier–Stokes Shocks Extending results of Humpherys–Lyng–Zumbrun in the one-dimensional case, we use a combination of asymptotic ODE estimates and numerical Evans-function computations to examine the multidimensional stability of planar Navier–Stokes shocks across the full range of shock amplitudes, including the infinite-amplitude limit, for monatomic or diatomic ideal gas equations of state and viscosity and heat conduction coefficients μ, μ+ η, and ν= κ/ cv constant and in the physical ratios predicted by statistical mechanics, and Mach number M&gt; 1.035. Our results indicate unconditional stability within the parameter range considered; this agrees with the results of Erpenbeck and Majda for the corresponding inviscid case of Euler shocks. Notably, this study includes the first successful numerical computation of an Evans function associated with the multidimensional stability of a viscous shock wave. The methods introduced can be used in principle to decide stability for shocks in any polytropic gas, or indeed for shocks of other models, including in, particular, viscoelasticity, combustion, and magnetohydrodynamics (MHD). © 2017, Springer-Verlag GmbH Germany.
1476 a57204229694 Lyng G. p519 False Journal 288 Evans function computation for the stability of travelling waves In recent years, the Evans function has become an important tool for the determination of stability of travelling waves. This function, a Wronskian of decaying solutions of the eigenvalue equation, is useful both analytically and computationally for the spectral analysis of the linearized operator about the wave. In particular, Evans-function computation allows one to locate any unstable eigenvalues of the linear operator (if they exist); this allows one to establish spectral stability of a given wave and identify bifurcation points (loss of stability) as model parameters vary. In this paper, we review computational aspects of the Evans function and apply it to multidimensional detonation waves. This article is part of the theme issue 'Stability of nonlinear waves and patterns and related topics'. © 2018 The Author(s) Published by the Royal Society. All rights reserved.
1476 a57204229694 Lyng G. p670 False Journal 323 Multidimensional Stability of Large-Amplitude Navier–Stokes Shocks Extending results of Humpherys–Lyng–Zumbrun in the one-dimensional case, we use a combination of asymptotic ODE estimates and numerical Evans-function computations to examine the multidimensional stability of planar Navier–Stokes shocks across the full range of shock amplitudes, including the infinite-amplitude limit, for monatomic or diatomic ideal gas equations of state and viscosity and heat conduction coefficients μ, μ+ η, and ν= κ/ cv constant and in the physical ratios predicted by statistical mechanics, and Mach number M&gt; 1.035. Our results indicate unconditional stability within the parameter range considered; this agrees with the results of Erpenbeck and Majda for the corresponding inviscid case of Euler shocks. Notably, this study includes the first successful numerical computation of an Evans function associated with the multidimensional stability of a viscous shock wave. The methods introduced can be used in principle to decide stability for shocks in any polytropic gas, or indeed for shocks of other models, including in, particular, viscoelasticity, combustion, and magnetohydrodynamics (MHD). © 2017, Springer-Verlag GmbH Germany.
1477 a55652903800 Lytle J. p519 False Journal 288 Evans function computation for the stability of travelling waves In recent years, the Evans function has become an important tool for the determination of stability of travelling waves. This function, a Wronskian of decaying solutions of the eigenvalue equation, is useful both analytically and computationally for the spectral analysis of the linearized operator about the wave. In particular, Evans-function computation allows one to locate any unstable eigenvalues of the linear operator (if they exist); this allows one to establish spectral stability of a given wave and identify bifurcation points (loss of stability) as model parameters vary. In this paper, we review computational aspects of the Evans function and apply it to multidimensional detonation waves. This article is part of the theme issue 'Stability of nonlinear waves and patterns and related topics'. © 2018 The Author(s) Published by the Royal Society. All rights reserved.
1478 a57201724099 Penaloza J. p520 False Journal 289 Scalable fabric tactile sensor arrays for soft bodies Soft robots have the potential to transform the way robots interact with their environment. This is due to their low inertia and inherent ability to more safely interact with the world without damaging themselves or the people around them. However, existing sensing for soft robots has at least partially limited their ability to control interactions with their environment. Tactile sensors could enable soft robots to sense interaction, but most tactile sensors are made from rigid substrates and are not well suited to applications for soft robots which can deform. In addition, the benefit of being able to cheaply manufacture soft robots may be lost if the tactile sensors that cover them are expensive and their resolution does not scale well for manufacturability. This paper discusses the development of a method to make affordable, high-resolution, tactile sensor arrays (manufactured in rows and columns) that can be used for sensorizing soft robots and other soft bodies. However, the construction results in a sensor array that exhibits significant amounts of cross-talk when two taxels in the same row are compressed. Using the same fabric-based tactile sensor array construction design, two different methods for cross-talk compensation are presented. The first uses a mathematical model to calculate a change in resistance of each taxel directly. The second method introduces additional simple circuit components that enable us to isolate each taxel electrically and relate voltage to force directly. Fabric sensor arrays are demonstrated for two different soft-bodied applications: an inflatable single link robot and a human wrist. © 2018 IOP Publishing Ltd.
1479 a24465525600 Santos V.J. p520 False Journal 289 Scalable fabric tactile sensor arrays for soft bodies Soft robots have the potential to transform the way robots interact with their environment. This is due to their low inertia and inherent ability to more safely interact with the world without damaging themselves or the people around them. However, existing sensing for soft robots has at least partially limited their ability to control interactions with their environment. Tactile sensors could enable soft robots to sense interaction, but most tactile sensors are made from rigid substrates and are not well suited to applications for soft robots which can deform. In addition, the benefit of being able to cheaply manufacture soft robots may be lost if the tactile sensors that cover them are expensive and their resolution does not scale well for manufacturability. This paper discusses the development of a method to make affordable, high-resolution, tactile sensor arrays (manufactured in rows and columns) that can be used for sensorizing soft robots and other soft bodies. However, the construction results in a sensor array that exhibits significant amounts of cross-talk when two taxels in the same row are compressed. Using the same fabric-based tactile sensor array construction design, two different methods for cross-talk compensation are presented. The first uses a mathematical model to calculate a change in resistance of each taxel directly. The second method introduces additional simple circuit components that enable us to isolate each taxel electrically and relate voltage to force directly. Fabric sensor arrays are demonstrated for two different soft-bodied applications: an inflatable single link robot and a human wrist. © 2018 IOP Publishing Ltd.
1480 a57203246058 Kim D. p522 False Journal 262 Antireflective light-blocking layers using a liquid top matte coating Methods exist for the creation of antireflective thin film layers; however, many of these methods depend on the use of high temperatures, harsh chemical etches, or are made with difficult pattern materials, rendering them unusable for many applications. In addition, most methods of light blocking are specifically designed to increase light coupling and absorption in the substrate, making them incompatible with some applications that also require blocking transmission of light. A method of forming a simple, patternable light-blocking layer that drastically reduces both transmission and reflection of light without dependence on processes that could damage underlying structures using a light scattering matte coating over a partially antireflective thin film light-blocking layer is presented. © 2018 Society of Photo-Optical Instrumentation Engineers (SPIE).
1481 a35994294500 Bryden K.M. p525 False Journal 274 Toward a Universal Social Impact Metric for Engineered Products That Alleviate Poverty One of the purposes of creating products for developing countries is to improve the consumer's quality of life. Currently, there is no standard method for measuring the social impact of these types of products. As a result, engineers have used their own metrics, if at all. Some of the common metrics used include products sold and revenue, which measure the financial success of a product without recognizing the social successes or failures it might have. In this paper, we introduce a potential universal metric, the product impact metric (PIM), which quantifies the impact a product has on impoverished individuals - especially those living in developing countries. It measures social impact broadly in five dimensions: health, education, standard of living, employment quality, and security. By measuring impact multidimensionally, it captures impacts both anticipated and unanticipated, thereby providing a broader assessment of the product's total impact than with other more specific metrics. The PIM is calculated based on 18 simple field measurements of the consumer. It is inspired by the UN's Multidimensional Poverty Index (UNMPI) created by the United Nations Development Programme (UNDP). The UNMPI measures how level of poverty within a nation changes year after year, and the PIM measures how an individual's poverty level changes after being affected by an engineered product. The PIM can be used to measure social impact (using specific data from products introduced into the market) or predict social impact (using personas that represent real individuals). Copyright © 2018 by ASME.
1481 a35994294500 Bryden K.M. p874 False Conference 392 Towards a universal social impact metric for engineered products that alleviate poverty More than ever before, engineers are creating products for developing countries. One of the purposes of these products is to improve the consumer's quality of life. Currently, there is no established method of measuring the social impact of these types of products. As a result, engineers have used their own metrics to assess their product's impact, if at all. Some of the common metrics used include products sold and revenue, which measure the financial success of a product without recognizing the social successes or failures it might have. In this paper we introduce a potential metric, the Product Impact Metric (PIM), which quantifies the impact a product has on impoverished individuals - especially those living in developing countries. It measures social impact broadly in five dimensions: Health, education, standard of living, employment quality, and security. The PIM is inspired by the Multidimensional Poverty Index (MPI) created by the United Nations Development Programme. The MPI measures how the depth of poverty within a nation changes year after year, and the PIM measures how an individual's quality of life changes after being affected by an engineered product. The Product Impact Metric can be used to predict social impacts (using personas that represent real individuals) or measure social impacts (using specific data from products introduced into the market). © 2017 ASME.
1482 a24758929200 Maccarty N.A. p525 False Journal 274 Toward a Universal Social Impact Metric for Engineered Products That Alleviate Poverty One of the purposes of creating products for developing countries is to improve the consumer's quality of life. Currently, there is no standard method for measuring the social impact of these types of products. As a result, engineers have used their own metrics, if at all. Some of the common metrics used include products sold and revenue, which measure the financial success of a product without recognizing the social successes or failures it might have. In this paper, we introduce a potential universal metric, the product impact metric (PIM), which quantifies the impact a product has on impoverished individuals - especially those living in developing countries. It measures social impact broadly in five dimensions: health, education, standard of living, employment quality, and security. By measuring impact multidimensionally, it captures impacts both anticipated and unanticipated, thereby providing a broader assessment of the product's total impact than with other more specific metrics. The PIM is calculated based on 18 simple field measurements of the consumer. It is inspired by the UN's Multidimensional Poverty Index (UNMPI) created by the United Nations Development Programme (UNDP). The UNMPI measures how level of poverty within a nation changes year after year, and the PIM measures how an individual's poverty level changes after being affected by an engineered product. The PIM can be used to measure social impact (using specific data from products introduced into the market) or predict social impact (using personas that represent real individuals). Copyright © 2018 by ASME.
1482 a24758929200 Maccarty N.A. p874 False Conference 392 Towards a universal social impact metric for engineered products that alleviate poverty More than ever before, engineers are creating products for developing countries. One of the purposes of these products is to improve the consumer's quality of life. Currently, there is no established method of measuring the social impact of these types of products. As a result, engineers have used their own metrics to assess their product's impact, if at all. Some of the common metrics used include products sold and revenue, which measure the financial success of a product without recognizing the social successes or failures it might have. In this paper we introduce a potential metric, the Product Impact Metric (PIM), which quantifies the impact a product has on impoverished individuals - especially those living in developing countries. It measures social impact broadly in five dimensions: Health, education, standard of living, employment quality, and security. The PIM is inspired by the Multidimensional Poverty Index (MPI) created by the United Nations Development Programme. The MPI measures how the depth of poverty within a nation changes year after year, and the PIM measures how an individual's quality of life changes after being affected by an engineered product. The Product Impact Metric can be used to predict social impacts (using personas that represent real individuals) or measure social impacts (using specific data from products introduced into the market). © 2017 ASME.
1483 a57201645135 Stringer B.J. p526 True Journal 291 Dual-wavelength reflectance spectroscopy of the superior vena cava: A method for placing central venous catheters at the cavoatrial junction There are a limited number of methods to guide and confirm the placement of a peripherally inserted central catheter (PICC) at the cavoatrial junction. The aim of this study was to design, test and validate a dual-wavelength, diode laser-based, single optical fiber instrument that would accurately confirm PICC tip location at the cavoatrial junction of an animal heart, in vivo. This was accomplished by inserting the optical fiber into a PICC and ratiometrically comparing simultaneous visible and near-infrared reflection intensities of venous and atrial tissues found near the cavoatrial junction. The system was successful in placing the PICC line tip within 5 mm of the cavoatrial junction. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1484 a57201646242 Shumway S.B. p526 False Journal 291 Dual-wavelength reflectance spectroscopy of the superior vena cava: A method for placing central venous catheters at the cavoatrial junction There are a limited number of methods to guide and confirm the placement of a peripherally inserted central catheter (PICC) at the cavoatrial junction. The aim of this study was to design, test and validate a dual-wavelength, diode laser-based, single optical fiber instrument that would accurately confirm PICC tip location at the cavoatrial junction of an animal heart, in vivo. This was accomplished by inserting the optical fiber into a PICC and ratiometrically comparing simultaneous visible and near-infrared reflection intensities of venous and atrial tissues found near the cavoatrial junction. The system was successful in placing the PICC line tip within 5 mm of the cavoatrial junction. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1485 a57200335858 Holbrook M.D. p526 False Journal 291 Dual-wavelength reflectance spectroscopy of the superior vena cava: A method for placing central venous catheters at the cavoatrial junction There are a limited number of methods to guide and confirm the placement of a peripherally inserted central catheter (PICC) at the cavoatrial junction. The aim of this study was to design, test and validate a dual-wavelength, diode laser-based, single optical fiber instrument that would accurately confirm PICC tip location at the cavoatrial junction of an animal heart, in vivo. This was accomplished by inserting the optical fiber into a PICC and ratiometrically comparing simultaneous visible and near-infrared reflection intensities of venous and atrial tissues found near the cavoatrial junction. The system was successful in placing the PICC line tip within 5 mm of the cavoatrial junction. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1486 a57217508772 Copeland C.G. p526 False Journal 291 Dual-wavelength reflectance spectroscopy of the superior vena cava: A method for placing central venous catheters at the cavoatrial junction There are a limited number of methods to guide and confirm the placement of a peripherally inserted central catheter (PICC) at the cavoatrial junction. The aim of this study was to design, test and validate a dual-wavelength, diode laser-based, single optical fiber instrument that would accurately confirm PICC tip location at the cavoatrial junction of an animal heart, in vivo. This was accomplished by inserting the optical fiber into a PICC and ratiometrically comparing simultaneous visible and near-infrared reflection intensities of venous and atrial tissues found near the cavoatrial junction. The system was successful in placing the PICC line tip within 5 mm of the cavoatrial junction. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1487 a57201650328 Gosch A.A. p526 False Journal 291 Dual-wavelength reflectance spectroscopy of the superior vena cava: A method for placing central venous catheters at the cavoatrial junction There are a limited number of methods to guide and confirm the placement of a peripherally inserted central catheter (PICC) at the cavoatrial junction. The aim of this study was to design, test and validate a dual-wavelength, diode laser-based, single optical fiber instrument that would accurately confirm PICC tip location at the cavoatrial junction of an animal heart, in vivo. This was accomplished by inserting the optical fiber into a PICC and ratiometrically comparing simultaneous visible and near-infrared reflection intensities of venous and atrial tissues found near the cavoatrial junction. The system was successful in placing the PICC line tip within 5 mm of the cavoatrial junction. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1488 a7102837693 Kück K. p526 False Journal 291 Dual-wavelength reflectance spectroscopy of the superior vena cava: A method for placing central venous catheters at the cavoatrial junction There are a limited number of methods to guide and confirm the placement of a peripherally inserted central catheter (PICC) at the cavoatrial junction. The aim of this study was to design, test and validate a dual-wavelength, diode laser-based, single optical fiber instrument that would accurately confirm PICC tip location at the cavoatrial junction of an animal heart, in vivo. This was accomplished by inserting the optical fiber into a PICC and ratiometrically comparing simultaneous visible and near-infrared reflection intensities of venous and atrial tissues found near the cavoatrial junction. The system was successful in placing the PICC line tip within 5 mm of the cavoatrial junction. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1489 a55736845400 Wang X. p527 True Journal 292 Investigating the safety impact of roadway network features of suburban arterials in Shanghai With rapid changes in land use development along suburban arterials in Shanghai, there is a corresponding increase in traffic demand on these arterials. To accommodate the local traffic needs of high accessibility and efficiency, an increased number of signalized intersections and accesses have been installed. However, the absence of a defined hierarchical road network, together with irregular signal spacing and access density, tends to deteriorate arterial safety. Previous studies on arterial safety were generally based on a single type of road entity, either intersection or roadway segment, and they analyzed the safety contributing factors (e.g. signal density and access density) on only that type of road entity, while these suburban arterial characteristics could significantly influence the safety performance of both intersections and roadway segments. Macro-level safety modeling was usually applied to investigate the relationships between zonal crash frequencies and demographics, road network features, and traffic characteristics, but the previous researchers did not consider the specific arterial characteristics of signal density and access density. In this study, a new modeling strategy was proposed to analyze the safety impacts of zonal roadway network features (i.e., road network patterns and road network density) along with the suburban arterial characteristics of signal density and access density. Bayesian Conditional Autoregressive Poisson Log-normal models were developed for suburban arterials in 173 traffic analysis zones in the suburban area of Shanghai. Results identified that the grid pattern road network with collector roads parallel to arterials was associated with fewer crashes than networks without parallel collectors. On the other hand, lower road network density, higher signal density and higher access density tended to increase the crash occurrence on suburban arterials. © 2018 Elsevier Ltd
1490 a57139150400 Yuan J. p527 False Journal 292 Investigating the safety impact of roadway network features of suburban arterials in Shanghai With rapid changes in land use development along suburban arterials in Shanghai, there is a corresponding increase in traffic demand on these arterials. To accommodate the local traffic needs of high accessibility and efficiency, an increased number of signalized intersections and accesses have been installed. However, the absence of a defined hierarchical road network, together with irregular signal spacing and access density, tends to deteriorate arterial safety. Previous studies on arterial safety were generally based on a single type of road entity, either intersection or roadway segment, and they analyzed the safety contributing factors (e.g. signal density and access density) on only that type of road entity, while these suburban arterial characteristics could significantly influence the safety performance of both intersections and roadway segments. Macro-level safety modeling was usually applied to investigate the relationships between zonal crash frequencies and demographics, road network features, and traffic characteristics, but the previous researchers did not consider the specific arterial characteristics of signal density and access density. In this study, a new modeling strategy was proposed to analyze the safety impacts of zonal roadway network features (i.e., road network patterns and road network density) along with the suburban arterial characteristics of signal density and access density. Bayesian Conditional Autoregressive Poisson Log-normal models were developed for suburban arterials in 173 traffic analysis zones in the suburban area of Shanghai. Results identified that the grid pattern road network with collector roads parallel to arterials was associated with fewer crashes than networks without parallel collectors. On the other hand, lower road network density, higher signal density and higher access density tended to increase the crash occurrence on suburban arterials. © 2018 Elsevier Ltd
1491 a7402422734 Fang S. p527 False Journal 292 Investigating the safety impact of roadway network features of suburban arterials in Shanghai With rapid changes in land use development along suburban arterials in Shanghai, there is a corresponding increase in traffic demand on these arterials. To accommodate the local traffic needs of high accessibility and efficiency, an increased number of signalized intersections and accesses have been installed. However, the absence of a defined hierarchical road network, together with irregular signal spacing and access density, tends to deteriorate arterial safety. Previous studies on arterial safety were generally based on a single type of road entity, either intersection or roadway segment, and they analyzed the safety contributing factors (e.g. signal density and access density) on only that type of road entity, while these suburban arterial characteristics could significantly influence the safety performance of both intersections and roadway segments. Macro-level safety modeling was usually applied to investigate the relationships between zonal crash frequencies and demographics, road network features, and traffic characteristics, but the previous researchers did not consider the specific arterial characteristics of signal density and access density. In this study, a new modeling strategy was proposed to analyze the safety impacts of zonal roadway network features (i.e., road network patterns and road network density) along with the suburban arterial characteristics of signal density and access density. Bayesian Conditional Autoregressive Poisson Log-normal models were developed for suburban arterials in 173 traffic analysis zones in the suburban area of Shanghai. Results identified that the grid pattern road network with collector roads parallel to arterials was associated with fewer crashes than networks without parallel collectors. On the other hand, lower road network density, higher signal density and higher access density tended to increase the crash occurrence on suburban arterials. © 2018 Elsevier Ltd
1492 a57218886189 Stanković A.M. p528 False Journal 293 Information geometry for model identification and parameter estimation in renewable energy - DFIG plant case This study describes a new class of system identification procedures, tailored to electric power systems with renewable resources. The procedure described here builds on computational advances in differential geometry, and offers a new, global, and intrinsic characterisation of challenges in data-derived identification of electric power systems. The approach benefits from increased availability of high-quality measurements. The procedure is illustrated on the multi-machine benchmark example of IEEE 14-bus system with renewable resources, but it is equally applicable to identification of other components and systems (e.g. dynamic loads). The authors consider doubly-fed induction generators (DFIG) operating in a wind farm with system level proportional-integral controllers. © The Institution of Engineering and Technology 2017.
1492 a57218886189 Stanković A.M. p541 True Conference 195 Hybrid power system state estimation with irregular sampling The paper proposes a power system state estimation algorithm in the presence of irregular sensor sampling and random communication delays. Our state estimator incorporates Phasor Measurement Units (PMU) and SCADA measurements. We use an Extended Kalman filter based algorithm for time alignment of measurements and state variables. Time stamps are assumed for PMU, SCADA and state estimation. Application of the proposed algorithm is illustrated for hourly/daily load/generation variations on two test examples: 14-bus and 118-bus. © 2017 IEEE.
1493 a57203179434 Yuksel M.C. p529 False Conference 190 Predicting the maximum endurance time for left-side bridge exercise using machine learning methods and hybrid data This study was carried out with the intention to create new models to predict the maximum endurance time for the left-side bridge exercise using machine learning methods and hybrid data. Particularly, four different methods including Multilayer Feed-Forward Artificial Neural Network (MFANN), Generalized Regression Neural Network (GRNN), Radial Basis Function Neural Network (RBFNN) and Single Decision Tree (SDT) have been used for model development. The dataset used to create the prediction models includes physiological, exercise and questionnaire data related to individuals who performed the left-side bridge exercise and completed the Perceived Activity Rating (PAR) and Perceived Functional Ability (PFA) questionnaires. To evaluate the performance of the models, two well-known metrics, namely Root Mean Square Error (RMSE) and Multiple Correlation Coefficient (R) have been used, whereas the generalization errors have been assessed using 10-fold cross validation. The best prediction performance among the models has been obtained by using MFANN along with the predictor variables gender, age, body mass index (BMI), the times to reach a rate of perceived exertion values of 7 and 8 (RPE-7 and RPE-8, respectively) and PAR, producing the lowest RMSE and the highest R with 10.61 seconds (s) and 0.92, respectively. © 2017 IEEE.
1494 a57213087387 Tas F.M. p529 False Conference 190 Predicting the maximum endurance time for left-side bridge exercise using machine learning methods and hybrid data This study was carried out with the intention to create new models to predict the maximum endurance time for the left-side bridge exercise using machine learning methods and hybrid data. Particularly, four different methods including Multilayer Feed-Forward Artificial Neural Network (MFANN), Generalized Regression Neural Network (GRNN), Radial Basis Function Neural Network (RBFNN) and Single Decision Tree (SDT) have been used for model development. The dataset used to create the prediction models includes physiological, exercise and questionnaire data related to individuals who performed the left-side bridge exercise and completed the Perceived Activity Rating (PAR) and Perceived Functional Ability (PFA) questionnaires. To evaluate the performance of the models, two well-known metrics, namely Root Mean Square Error (RMSE) and Multiple Correlation Coefficient (R) have been used, whereas the generalization errors have been assessed using 10-fold cross validation. The best prediction performance among the models has been obtained by using MFANN along with the predictor variables gender, age, body mass index (BMI), the times to reach a rate of perceived exertion values of 7 and 8 (RPE-7 and RPE-8, respectively) and PAR, producing the lowest RMSE and the highest R with 10.61 seconds (s) and 0.92, respectively. © 2017 IEEE.
1495 a57202320825 Linn J. p530 False Conference 191 CrsRecs: A personalized course recommendation system for college students Every college student has different needs when it comes to learning. It can be difficult to decide which course is best to take on the road to graduation, and which professor will best suit the student's learning style. CrsRecs, our proposed course/professor recommendation system, makes that process much easier. Using topic analysis, tag analysis, sentiment analysis, predicted course/professor ratings, and survey data revealing student priorities with respect to classes (i.e., easy A, quality of the class, etc.), CrsRecs ranks potential courses in order of perceived preference for the student based on a hybrid technique combining the analysis results of a course. Empirical studies conducted to evaluate the performance of CrsRecs have revealed that CrsRecs not only suggests relevant courses to users by considering all the features of a course, but also outperforms existing state-of-the-art course recommendation approaches. © 2017 IEEE.
1496 a57207470751 Johnson J. p531 True Conference 192 Using tripartite graphs to make long tail recommendations While current state-of-the-art recommendation systems perform fairly well, they generally do better at recommending the popular subset of all products available rather than matching consumers with the vast amount of niche products in what has been termed the "Long Tail". In their seminal work, "Challenging the Long Tail Recommendation", Yin et al. make an eloquent argument that the long tail is where organizations can create the most value for their consumers. They also argue that existing recommender systems operate fundamentally different for long tail products than for mainstream goods. While matrix factorization, nearest-neighbors, and clustering work well for the "head" market, the long tail is better represented by a graph; specifically a bipartite graph that connects a set of users to a set of goods. In this paper, we show the algorithms presented by Yin et al., as well as a set of similar algorithms proposed by Shang et al., which traverse the bipartite graphs through a random walker in order to identify similar users and products. We build on elements from each work, as well as elements from a Markov process, to facilitate the random walker's traversal of the graph into the long tail regions. This method specifically constructs paths into regions of the long tail that are favorable to users. © 2017 IEEE.
1497 a7005098852 Schuh C.A. p532 False Journal 294 Texture mediated grain boundary network design in three dimensions Experimental grain boundary engineering studies have demonstrated the potential for materials properties enhancement via the modification of grain boundary network structure. These techniques apply to materials that readily form annealing twins and are amenable to cyclic thermomechanical processing and have resulted in dramatic property enhancement. In this work we present a theoretical framework that enables the design of grain boundary networks in polycrystalline materials through an alternative approach: exploitation of a relationship between crystallographic texture and grain boundary network structure. Because crystallographic texture is a universal characteristic of polycrystalline materials, this work has the potential to significantly expand the class of materials whose grain boundary networks can be controlled. We demonstrate the utility of the approach by application to a concrete design problem involving competing design objectives for yield strength, elastic compliance, and resistance to electromigration. We construct the first materials properties closure to comprise grain boundary network sensitive properties and identify an optimal microstructure that is predicted to outperform an undesigned isotropic material. © 2017 Elsevier Ltd
1498 a56896919700 Gallacher J.R. p533 True Journal 295 Lab-scale observations of flame attachment on slopes with implications for firefighter safety zones The Coanda effect is the phenomenon in which a jet entering quiescent fluid attaches to a nearby solid object due to inhibited entrainment of ambient fluid near the solid. Little is known about the influence of the Coanda effect on wildland fire behavior. Specifically, there is a lack of knowledge regarding how the flame attachment on slopes influences firefighter safety zone considerations in rugged terrain. This paper presents results for small-scale n-heptane pool fire experiments near a slope, showing how flame shape and heat flux are influenced by slope angle, slope boundary condition and distance from flame base. Flames near slopes leaned toward the slope, and at some slope angles the flames attached to the slope. The average angle at which the effects of slope were noticeable was between 10° and 45°, depending on the criteria used. No difference was observed between a bare slope and an insulated slope. Dimensional analysis showed that important characteristics of flame attachment on slopes in the small-scale experiments were in the range estimated for the large fires. The implication is that the traditional view of safe separation distance as being the distance from the flame base is inadequate for fires near slopes. © 2018 Elsevier Ltd
1498 a56896919700 Gallacher J.R. p801 False Conference 337 Semi-empirical model for fire spread in chamise and big sagebrush shrubs with spatially-defined fuel elements and flames Current operational fire spread models are mostly based on experimental results from dead, low moisture fuel beds and thus do not perform well when modeling fire behavior in live shrubs. A previously-developed semi-empirical shrub combustion model was improved and expanded to treat live chamise and big sagebrush. Fire spread in live chamise and big sagebrush shrubs was measured in an open-roofed wind tunnel, which was used as the basis to develop the current model. Shrub geometry was modeled by coupling a Lindenmayer-systems (L-systems) approach with terrestrial LiDAR scan data. Wind speed was held constant at 1.4 m/s. Species specific correlations for physical properties and combustion characteristics of individual fuel element were incorporate in this model. Modeling results compared well with measured time-dependent fire behavior. Variations in local fuel density affected flame spread more than the overall fuel bed density. This model is an innovative approach to simulate shrub combustion via flame propagation at individual fuel element scale with a fairly low computational cost. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
1499 a57190371042 Ripa B. p533 False Journal 295 Lab-scale observations of flame attachment on slopes with implications for firefighter safety zones The Coanda effect is the phenomenon in which a jet entering quiescent fluid attaches to a nearby solid object due to inhibited entrainment of ambient fluid near the solid. Little is known about the influence of the Coanda effect on wildland fire behavior. Specifically, there is a lack of knowledge regarding how the flame attachment on slopes influences firefighter safety zone considerations in rugged terrain. This paper presents results for small-scale n-heptane pool fire experiments near a slope, showing how flame shape and heat flux are influenced by slope angle, slope boundary condition and distance from flame base. Flames near slopes leaned toward the slope, and at some slope angles the flames attached to the slope. The average angle at which the effects of slope were noticeable was between 10° and 45°, depending on the criteria used. No difference was observed between a bare slope and an insulated slope. Dimensional analysis showed that important characteristics of flame attachment on slopes in the small-scale experiments were in the range estimated for the large fires. The implication is that the traditional view of safe separation distance as being the distance from the flame base is inadequate for fires near slopes. © 2018 Elsevier Ltd
1500 a7202035366 Butler B.W. p533 False Journal 295 Lab-scale observations of flame attachment on slopes with implications for firefighter safety zones The Coanda effect is the phenomenon in which a jet entering quiescent fluid attaches to a nearby solid object due to inhibited entrainment of ambient fluid near the solid. Little is known about the influence of the Coanda effect on wildland fire behavior. Specifically, there is a lack of knowledge regarding how the flame attachment on slopes influences firefighter safety zone considerations in rugged terrain. This paper presents results for small-scale n-heptane pool fire experiments near a slope, showing how flame shape and heat flux are influenced by slope angle, slope boundary condition and distance from flame base. Flames near slopes leaned toward the slope, and at some slope angles the flames attached to the slope. The average angle at which the effects of slope were noticeable was between 10° and 45°, depending on the criteria used. No difference was observed between a bare slope and an insulated slope. Dimensional analysis showed that important characteristics of flame attachment on slopes in the small-scale experiments were in the range estimated for the large fires. The implication is that the traditional view of safe separation distance as being the distance from the flame base is inadequate for fires near slopes. © 2018 Elsevier Ltd
1500 a7202035366 Butler B.W. p851 False Conference 375 Modeling the coanda effect with FDS and STARCCM+ to predict the effect of fires on slopes for implications of wildland firefighter safety The Coanda effect is the behavior of a fluid flowing next to a solid surface which creates a change in pressure, thereby causing the fluid to attach to the surface. Little is known concerning the Coanda effect as it pertains to flame attachment in relation to wildfires. There is a need for improvement in the correlations between fire behavior on or near a slope and fire safety zones. An understanding of this effect could lead to more reliable guidelines for the establishment of firefighter safety zones, which are regions in wildfire areas that have been determined as safe for the survival of the firefighter. This paper discusses the ability of two commercial computational fluid dynamics (CFD) codes (Fire Dynamics Simulator (FDS) and STAR-CCM+) to model the results of actual flame experiments near barren slopes. Simulation results were compared to measured values of flame attachment length and radiative and convective heat fluxes. Pressure and temperature gradient measurements along the slope are reported. Proper modeling of small-scale experiments with such software packages can lead to more confidence in large scale simulations and eventual development of firefighter safety zones in wildfires.
1501 a7102857304 Fletcher T.H. p533 False Journal 295 Lab-scale observations of flame attachment on slopes with implications for firefighter safety zones The Coanda effect is the phenomenon in which a jet entering quiescent fluid attaches to a nearby solid object due to inhibited entrainment of ambient fluid near the solid. Little is known about the influence of the Coanda effect on wildland fire behavior. Specifically, there is a lack of knowledge regarding how the flame attachment on slopes influences firefighter safety zone considerations in rugged terrain. This paper presents results for small-scale n-heptane pool fire experiments near a slope, showing how flame shape and heat flux are influenced by slope angle, slope boundary condition and distance from flame base. Flames near slopes leaned toward the slope, and at some slope angles the flames attached to the slope. The average angle at which the effects of slope were noticeable was between 10° and 45°, depending on the criteria used. No difference was observed between a bare slope and an insulated slope. Dimensional analysis showed that important characteristics of flame attachment on slopes in the small-scale experiments were in the range estimated for the large fires. The implication is that the traditional view of safe separation distance as being the distance from the flame base is inadequate for fires near slopes. © 2018 Elsevier Ltd
1501 a7102857304 Fletcher T.H. p751 False Journal 365 Semi-empirical Model for Fire Spread in Shrubs with Spatially-Defined Fuel Elements and Flames A semi-empirical model was developed which forms shrub geometries from distinct fuel elements (e.g. leaves) and describes flame spread from element to element. Ignition, flame growth and flame decay patterns were based on combustion data of single leaves. Extension of the model to various heating conditions was achieved by scaling the flame growth parameters using physics-based heat transfer models. The resulting model offers a novel approach to examine fire spread and to explicitly describe both distinct fuel elements and fire behavior. This approach balances computational speed and modeling detail while providing a unique perspective into fire spread phenomena. Comparisons of the tuned model to fire spread behavior measured in an open-roofed wind tunnel benchmarked the model’s ability to simulate fire spread in manzanita shrubs. © 2017, Springer Science+Business Media New York.
1501 a7102857304 Fletcher T.H. p789 False Conference 326 Formation of deposits from heavy fuel oil ash in an Accelerated Deposition Facility at temperatures up to 1206°C Some industrial gas turbines are currently being fired directly using heavy fuel oil, which contains a small percentage of inorganic material that can lead to fouling and corrosion of turbine components. Deposits of heavy fuel oil ash were created in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University under gas turbine-related conditions. Ash was produced by burning heavy fuel oil in a downward-fired combustor and collecting the ash from the exhaust stream. The mass mean ash particle diameter from these tests was 33 microns. This ash was then introduced into the TADF and entrained in a hot gas flow that varied from 1088 to 1206°C. The gas and particle velocity was accelerated to over 200 m/s in these tests. This particle-laden hot gas stream then impinged on a nickel base superalloy metal coupon approximately 3 cm in diameter, and an ash deposit formed on the coupon. Sulfur dioxide was introduced to the system to achieve 1.1 mol% SO2 in the exhaust stream in order to simulate SO2 levels in turbines currently burning heavy fuel oil. The ash deposits were collected, and the capture efficiency, surface roughness, and deposit composition were measured. The deposits were then washed with deionized water, dried, and underwent the same analysis. It was found that, as the gas temperature increased, there was no effect on capture efficiency and the post-wash roughness of the samples decreased. Washing aided in the removal of sulfur, magnesium, potassium, and calcium. Copyright © 2017 ASME.
1501 a7102857304 Fletcher T.H. p801 False Conference 337 Semi-empirical model for fire spread in chamise and big sagebrush shrubs with spatially-defined fuel elements and flames Current operational fire spread models are mostly based on experimental results from dead, low moisture fuel beds and thus do not perform well when modeling fire behavior in live shrubs. A previously-developed semi-empirical shrub combustion model was improved and expanded to treat live chamise and big sagebrush. Fire spread in live chamise and big sagebrush shrubs was measured in an open-roofed wind tunnel, which was used as the basis to develop the current model. Shrub geometry was modeled by coupling a Lindenmayer-systems (L-systems) approach with terrestrial LiDAR scan data. Wind speed was held constant at 1.4 m/s. Species specific correlations for physical properties and combustion characteristics of individual fuel element were incorporate in this model. Modeling results compared well with measured time-dependent fire behavior. Variations in local fuel density affected flame spread more than the overall fuel bed density. This model is an innovative approach to simulate shrub combustion via flame propagation at individual fuel element scale with a fairly low computational cost. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
1501 a7102857304 Fletcher T.H. p802 False Conference 338 Investigation of merging flames in horizontal and vertical geometries One of the main needs for accurate shrub combustion modeling is the complicated flame growth pattern due to merging of flames from multiple leaves and small branches. The interactions of neighboring flames have only been studied using regularly spaced fuel sources located on a horizontal plane. Flames in a burning shrub or tree merge to form large flames from fuel arrangements, which are not described by horizontal plane geometries. A careful study of flame interactions from fuels in three-dimensional arrangements is a necessary step in strengthening operational field models in complex fuel structures. The purpose of this research is to imitate the flame merging of the solid fuels in different geometries in order to describe fire behavior in complex fuel structures, such as trees or shrubs. Ceramic felt soaked in n-heptane were used as a fuel source to conduct flame-merging experiments. Flame characteristics such as flame length and flame width were measured for both single and merged flames. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
1501 a7102857304 Fletcher T.H. p803 False Conference 339 A comprehensive model for predicting elemental composition of coal pyrolysis products Large-scale coal combustion simulations depend highly on the accuracy and utility of the physical submodels used to describe the various physical behaviors of the system. Coal combustion simulations depend on the particle physics to predict product compositions, temperatures, energy outputs, and other useful information. The focus of this paper is to improve the accuracy of devolatilization submodels, to be used in conjunction with other particle physics models. Many large simulations today rely on inaccurate assumptions about particle compositions, including that the volatiles that are released during pyrolysis are of the same elemental composition as the char particle. Another common assumption is that the char particle can be approximated by pure carbon. These assumptions will lead to inaccuracies in the overall simulation. There are many factors that influence pyrolysis product composition, including parent coal composition, pyrolysis conditions (including particle temperature history and heating rate), and others. All of these factors are incorporated into the correlations to predict the elemental composition of the major pyrolysis products, including coal tar, char, and light gases. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
1501 a7102857304 Fletcher T.H. p804 False Conference 340 Modeling soot in coal systems The formation of soot in power-boiler systems can have a significant impact on boiler performance due to direct effects on local flame temperatures and wall heat flux. In this work, a soot model was developed for coal systems that accommodates differences between solid fuel systems and gaseous systems, for which most traditional soot models are developed. The developed soot model contains terms for: particle nucleation based on tar evolution in a coal system, a nucle-ation mechanism based on the formation of PAH from gaseous species, gaseous interactions with particles (including: surface growth through HACA, particle oxidation/gasification), coagulation, and aggregation of existing particles. A monodispersed-particle size distribution form of this model can be used for cost-effective simulations, or for simulations with higher fidelity, the method of moments is used to transport higher moments of the particle size distribution. Validation work is presented, comparing numerically-derived soot values from the proposed model against measured soot concentrations in a flat-flame burner. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
1501 a7102857304 Fletcher T.H. p809 False Conference 344 Analysis of pyrolysis products from live shrub fuels Approximately 6 million acres per year are burned by prescribed fire shrublands in the southeastern United States. Burning the understory every 2-4 years prevents fires from spreading to the canopy. However, combustion of live shrubs is not well understood, and has been shown to differ from combustion of dead biomass fuels. The purpose of this study is to investigate pyrolysis products from live shrub fuels. The pyrolysis products constitute the fuel for the gaseous flames in a fire. Amounts of pyrolyzed species depend on heating rate, temperature, fuel type, and fuel properties. In order to provide pyrolysis conditions and oxygen-free environment, a flat-flame burner (FFB) was designed and operated in a fuel-rich mode. Hot and cold traps were used to separate low and high molecular weight (tars) pyrolysis products and then analyzed in two different GC-MS systems. The data obtained help focus modeling efforts for combustion of live shrubs. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
1501 a7102857304 Fletcher T.H. p810 False Conference 345 Pyrolysis of live vegetation at slow heating rates Wildland fire is an important component of many American ecosystems. Wildland fires can have necessary ecological influences in many North American ecosystems or can dangerously affect life, property and natural resources. These hazards decrease with the proper application of controlled burning. Controlled burning destroys smaller plants and also decreases combustible materials and the potential for ignition and fire propagation in the fuel bed. Fuel bed pyrolysis and ignition determine fire ignition and propagation rates in both wildland fires and prescribed burning, but the details of solid fuel reaction under wildland fire conditions remain poorly understood. The purpose of this study is to provide fundamental information about pyrolysis of live shrub fuels at slow heating rates. A programmable heater apparatus was used to study the pyrolysis products of three different kind of live shrubs from forests of the Southeastern United States. Low and high molecular weight pyrolysis products were collected in a cold trap and then analyzed using GC-MS.
1501 a7102857304 Fletcher T.H. p812 False Conference 347 Investigation of merging flames in Horizontal and vertical Geometries One of the main needs for accurate shrub combustion modeling is the complicated flame growth pattern due to merging of flames from multiple leaves and small branches. A careful study of flame interactions from fuels in three-dimensional arrangements is a necessary step in strengthening operational field models in complex fuel structures. The purpose of this research is to imitate the flame merging of the solid fuels in different geometries in order to describe fire behavior in complex fuel structures, such as trees or shrubs. Ceramic felts soaked in n-heptane were used as a fuel source to conduct flame-merging experiments. Flame characteristics such as flame length and flame width were measured for both single and merged flames. Our data shows that by altering the separation distance between felts in both vertical and horizontal directions, flame area, height and width vary to a large extent. The region of flame merging is mapped in both the horizontal and vertical directions. These data are being used to develop flame-merging correlations as a function of flame spacing, similar to correlations that have been developed for multiple flames in the horizontal plane.
1501 a7102857304 Fletcher T.H. p850 False Conference 374 Modeling effects of annealing on coal char reactivity to O2 and CO2 based on preparation conditions Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive CFD simulations are valuable tools in evaluating and deploying oxy-fuel and other carbon capture technologies either as retrofit technologies or for new construction. However, accurate predictive combustor simulations require physically realistic submodels with low computational requirements. A recent sensitivity analysis of a detailed char conversion model (Char Conversion Kinetics (CCK)) found thermal annealing to be an extremely sensitive submodel. In the present work, further analysis of the previous annealing model revealed significant disagreement with numerous data sets from experiments performed after that annealing model was developed. The annealing model was accordingly extended to reflect experimentally observed reactivity loss due to thermal annealing of a variety of coals in diverse char preparation conditions. The model extension was informed by a Bayesian calibration analysis. Additionally, because oxy-fuel conditions include extraordinarily high levels of CO2, development of a first-ever CO2 reactivity loss model due to annealing is presented.
1501 a7102857304 Fletcher T.H. p851 False Conference 375 Modeling the coanda effect with FDS and STARCCM+ to predict the effect of fires on slopes for implications of wildland firefighter safety The Coanda effect is the behavior of a fluid flowing next to a solid surface which creates a change in pressure, thereby causing the fluid to attach to the surface. Little is known concerning the Coanda effect as it pertains to flame attachment in relation to wildfires. There is a need for improvement in the correlations between fire behavior on or near a slope and fire safety zones. An understanding of this effect could lead to more reliable guidelines for the establishment of firefighter safety zones, which are regions in wildfire areas that have been determined as safe for the survival of the firefighter. This paper discusses the ability of two commercial computational fluid dynamics (CFD) codes (Fire Dynamics Simulator (FDS) and STAR-CCM+) to model the results of actual flame experiments near barren slopes. Simulation results were compared to measured values of flame attachment length and radiative and convective heat fluxes. Pressure and temperature gradient measurements along the slope are reported. Proper modeling of small-scale experiments with such software packages can lead to more confidence in large scale simulations and eventual development of firefighter safety zones in wildfires.
1501 a7102857304 Fletcher T.H. p871 False Conference 391 A comprehensive model of single particle pulverized coal combustion extended to oxy-coal conditions Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive CFD simulations are valuable tools in evaluating and deploying oxy-fuel and other carbon capture technologies either as retrofit technologies or for new construction. However, accurate predictive simulations require physically realistic submodels with low computational requirements. In particular, comprehensive char oxidation and gasification models have been developed that describe multiple reaction and diffusion processes. This work extends a comprehensive char conversion code (CCK), which treats surface oxidation and gasification reactions as well as the processes such as film diffusion, pore diffusion, ash encapsulation, and annealing. In this work several submodels in the CCK code were updated with more realistic physics or otherwise extended to function in oxycoal conditions. Improved submodels include the annealing model, the swelling model, the mode of burning parameter, and the kinetic model, as well as the addition of the Chemical Percolation Devolatilization (CPD) model. Results of the char combustion model are compared to oxy-coal data, and further compared to parallel data sets near conventional conditions. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
1502 a23003275100 Chen J.Y.C. p534 False Conference 193 Swarm Transparency A key element of system transparency is allowing humans to calibrate their trust in a system, given the implicit inherent uncertainty, emergent behaviors, etc. As robotic swarms progress towards real-world missions, such transparency becomes increasingly necessary in order to reduce the disuse, misuse and errors humans make when influencing and directing the swarm. However,achieving this objective requires addressing the complex challenges associated with providing transparency. Two swarm transparency challenge categories, with exemplar challenges, are provided. © 2018 Authors.
1503 a6604032598 Kayen R. p535 True Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1503 a6604032598 Kayen R. p671 False Journal 296 Water supply damage caused by the 2016 Kumamoto Earthquake Widespread damage to lifeline systems occurred as a result from the Kumamoto Earthquakes that initiated on April 14, 2016. Interruption to the water, gas, and electric power supply affected thousands of people. Landslides and surface rupture caused significant damage to transportation systems, especially roads and bridges. This paper provides an overview of observations and information gathered by US researchers (sponsored by Geotechnical Extreme Events Reconnaissance Association), Japanese researchers, and others regarding water supply damage. Emphasis is placed on the largest water authority in the region of the earthquake, Kumamoto City, including damage metrics for various pipe materials and diameters. The greatest damage occurred at valves and other fundamental mechanisms of large diameter pipelines. Pipelines constructed of ERDIP and HDPE performed most favorably while steel and cast iron pipelines were shown to be the more vulnerable. A liquefaction-induced lateral spreading site at which pipeline damage occurred is identified for further study. © 2017 International Association of Lowland Technology. All rights reserved.
1504 a9733496700 Kokusho T. p535 False Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1505 a6602866368 Hazarika H. p535 False Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1506 a26640997500 Dashti S. p535 False Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1506 a26640997500 Dashti S. p671 False Journal 296 Water supply damage caused by the 2016 Kumamoto Earthquake Widespread damage to lifeline systems occurred as a result from the Kumamoto Earthquakes that initiated on April 14, 2016. Interruption to the water, gas, and electric power supply affected thousands of people. Landslides and surface rupture caused significant damage to transportation systems, especially roads and bridges. This paper provides an overview of observations and information gathered by US researchers (sponsored by Geotechnical Extreme Events Reconnaissance Association), Japanese researchers, and others regarding water supply damage. Emphasis is placed on the largest water authority in the region of the earthquake, Kumamoto City, including damage metrics for various pipe materials and diameters. The greatest damage occurred at valves and other fundamental mechanisms of large diameter pipelines. Pipelines constructed of ERDIP and HDPE performed most favorably while steel and cast iron pipelines were shown to be the more vulnerable. A liquefaction-induced lateral spreading site at which pipeline damage occurred is identified for further study. © 2017 International Association of Lowland Technology. All rights reserved.
1507 a57203180948 Calderon J.R. p535 False Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1508 a57203180667 Franke T.K. p535 False Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1509 a25522430900 Oettle N.K. p535 False Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1509 a25522430900 Oettle N.K. p671 False Journal 296 Water supply damage caused by the 2016 Kumamoto Earthquake Widespread damage to lifeline systems occurred as a result from the Kumamoto Earthquakes that initiated on April 14, 2016. Interruption to the water, gas, and electric power supply affected thousands of people. Landslides and surface rupture caused significant damage to transportation systems, especially roads and bridges. This paper provides an overview of observations and information gathered by US researchers (sponsored by Geotechnical Extreme Events Reconnaissance Association), Japanese researchers, and others regarding water supply damage. Emphasis is placed on the largest water authority in the region of the earthquake, Kumamoto City, including damage metrics for various pipe materials and diameters. The greatest damage occurred at valves and other fundamental mechanisms of large diameter pipelines. Pipelines constructed of ERDIP and HDPE performed most favorably while steel and cast iron pipelines were shown to be the more vulnerable. A liquefaction-induced lateral spreading site at which pipeline damage occurred is identified for further study. © 2017 International Association of Lowland Technology. All rights reserved.
1510 a56244956300 Wham B. p535 False Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1510 a56244956300 Wham B. p671 True Journal 296 Water supply damage caused by the 2016 Kumamoto Earthquake Widespread damage to lifeline systems occurred as a result from the Kumamoto Earthquakes that initiated on April 14, 2016. Interruption to the water, gas, and electric power supply affected thousands of people. Landslides and surface rupture caused significant damage to transportation systems, especially roads and bridges. This paper provides an overview of observations and information gathered by US researchers (sponsored by Geotechnical Extreme Events Reconnaissance Association), Japanese researchers, and others regarding water supply damage. Emphasis is placed on the largest water authority in the region of the earthquake, Kumamoto City, including damage metrics for various pipe materials and diameters. The greatest damage occurred at valves and other fundamental mechanisms of large diameter pipelines. Pipelines constructed of ERDIP and HDPE performed most favorably while steel and cast iron pipelines were shown to be the more vulnerable. A liquefaction-induced lateral spreading site at which pipeline damage occurred is identified for further study. © 2017 International Association of Lowland Technology. All rights reserved.
1511 a57203192812 Louis-Kayen G.P. p535 False Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1512 a57203180452 Sitar R. p535 False Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1513 a57203185550 Louis-Kayen N.M. p535 False Journal 296 Geotechnical extreme-event reconnaissance (GEER) investigation to the 2016 Mw 6.0, Mw 6.2 and Mw 7.0 Kumamoto Japan Earthquakes The Kumamoto, Kyushu, Japan earthquakes began with an earthquake (M6.2) on the Hinagu Fault on April 14, 2016 followed by a second (M7.0) event on the Futagawa Fault, that on April 16. These shallow 10-11 deep km events are the strongest earthquakes recorded in Kyushu prefecture during the modern instrumental era. The United States' National Science Foundation (US NSF) supported Geotechnical Extreme Events Reconnaissance (GEER) Association conducted a reconnaissance of the region. These earthquakes resulted in substantial damage to infrastructure, buildings, cultural heritage of Kumamoto castle, roads and highways, slopes, and river embankments. Surface fault rupture produced offset to roads, buildings, river levees, and an agricultural dam. Surprisingly, given the extremely intense earthquake motions, liquefaction-induced damage was mostly limited to a few districts of Kumamoto City and in port areas, indicating that either the volcanic soils were largely unsusceptible to liquefaction or the presence of fines reduced the surficial manifestation of liquefaction and its effects. The important case histories identified by the study are [1] fault rupture through Oh-Kirihata Dam; [2] subsidence in Aso Caldera; [3] fault rupture through Shimojin-Cho River Canal; [4] surprising paucity of liquefaction and its effects; and [5] possible identification of a nearly non-displacement lateral spread. Copyright © 2018 International Association of Lowland Technology.
1514 a57200686665 Smith A.K. p537 False Journal 297 The Locational Impact of Site-Specific PEGylation: Streamlined Screening with Cell-Free Protein Expression and Coarse-Grain Simulation Although polyethylene glycol (PEG) is commonly used to improve protein stability and therapeutic efficacy, the optimal location for attaching PEG onto proteins is not well understood. Here, we present a cell-free protein synthesis-based screening platform that facilitates site-specific PEGylation and efficient evaluation of PEG attachment efficiency, thermal stability, and activity for different variants of PEGylated T4 lysozyme, including a di-PEGylated variant. We also report developing a computationally efficient coarse-grain simulation model as a potential tool to narrow experimental screening candidates. We use this simulation method as a novel tool to evaluate the locational impact of PEGylation. Using this screen, we also evaluated the predictive impact of PEGylation site solvent accessibility, conjugation site structure, PEG size, and double PEGylation. Our findings indicate that PEGylation efficiency, protein stability, and protein activity varied considerably with PEGylation site, variations that were not well predicted by common PEGylation guidelines. Overall our results suggest current guidelines are insufficiently predictive, highlighting the need for experimental and simulation screening systems such as the one presented here. © 2018 American Chemical Society.
1515 a57200685059 Wilkerson J.W. p537 False Journal 297 The Locational Impact of Site-Specific PEGylation: Streamlined Screening with Cell-Free Protein Expression and Coarse-Grain Simulation Although polyethylene glycol (PEG) is commonly used to improve protein stability and therapeutic efficacy, the optimal location for attaching PEG onto proteins is not well understood. Here, we present a cell-free protein synthesis-based screening platform that facilitates site-specific PEGylation and efficient evaluation of PEG attachment efficiency, thermal stability, and activity for different variants of PEGylated T4 lysozyme, including a di-PEGylated variant. We also report developing a computationally efficient coarse-grain simulation model as a potential tool to narrow experimental screening candidates. We use this simulation method as a novel tool to evaluate the locational impact of PEGylation. Using this screen, we also evaluated the predictive impact of PEGylation site solvent accessibility, conjugation site structure, PEG size, and double PEGylation. Our findings indicate that PEGylation efficiency, protein stability, and protein activity varied considerably with PEGylation site, variations that were not well predicted by common PEGylation guidelines. Overall our results suggest current guidelines are insufficiently predictive, highlighting the need for experimental and simulation screening systems such as the one presented here. © 2018 American Chemical Society.
1516 a56425409300 Bush D.B. p537 False Journal 297 The Locational Impact of Site-Specific PEGylation: Streamlined Screening with Cell-Free Protein Expression and Coarse-Grain Simulation Although polyethylene glycol (PEG) is commonly used to improve protein stability and therapeutic efficacy, the optimal location for attaching PEG onto proteins is not well understood. Here, we present a cell-free protein synthesis-based screening platform that facilitates site-specific PEGylation and efficient evaluation of PEG attachment efficiency, thermal stability, and activity for different variants of PEGylated T4 lysozyme, including a di-PEGylated variant. We also report developing a computationally efficient coarse-grain simulation model as a potential tool to narrow experimental screening candidates. We use this simulation method as a novel tool to evaluate the locational impact of PEGylation. Using this screen, we also evaluated the predictive impact of PEGylation site solvent accessibility, conjugation site structure, PEG size, and double PEGylation. Our findings indicate that PEGylation efficiency, protein stability, and protein activity varied considerably with PEGylation site, variations that were not well predicted by common PEGylation guidelines. Overall our results suggest current guidelines are insufficiently predictive, highlighting the need for experimental and simulation screening systems such as the one presented here. © 2018 American Chemical Society.
1517 a6603410853 Knotts T.A. p537 False Journal 297 The Locational Impact of Site-Specific PEGylation: Streamlined Screening with Cell-Free Protein Expression and Coarse-Grain Simulation Although polyethylene glycol (PEG) is commonly used to improve protein stability and therapeutic efficacy, the optimal location for attaching PEG onto proteins is not well understood. Here, we present a cell-free protein synthesis-based screening platform that facilitates site-specific PEGylation and efficient evaluation of PEG attachment efficiency, thermal stability, and activity for different variants of PEGylated T4 lysozyme, including a di-PEGylated variant. We also report developing a computationally efficient coarse-grain simulation model as a potential tool to narrow experimental screening candidates. We use this simulation method as a novel tool to evaluate the locational impact of PEGylation. Using this screen, we also evaluated the predictive impact of PEGylation site solvent accessibility, conjugation site structure, PEG size, and double PEGylation. Our findings indicate that PEGylation efficiency, protein stability, and protein activity varied considerably with PEGylation site, variations that were not well predicted by common PEGylation guidelines. Overall our results suggest current guidelines are insufficiently predictive, highlighting the need for experimental and simulation screening systems such as the one presented here. © 2018 American Chemical Society.
1517 a6603410853 Knotts T.A. p663 False Journal 318 New Vapor-Pressure Prediction with Improved Thermodynamic Consistency using the Riedel Equation Vapor pressure, heat of vaporization, liquid heat capacity, and ideal-gas heat capacity for pure compounds between the triple point and critical point are important properties for process design and optimization. These thermophysical properties are related to each other through temperature derivatives of thermodynamic relationships stemming from a temperature-dependent vapor-pressure correlation. The Riedel equation has been considered to be an excellent and simple choice among vapor-pressure correlating equations [ Velasco et al. J. Chem. Thermodyn. 2008, 40 (5), 789-797 ] but requires modification of the final coefficient to provide thermodynamic consistency with thermal data [ Hogge et al. Fluid Phase Equilib. 2016, 429, 149-165 ]. New predictive correlations with final coefficients in integer steps from 1 to 6 have been created for compounds with limited or no vapor-pressure data, based on the methodology used originally by Riedel [ Chem. Ing. Tech. 1954, 26 (2), 83-89 ]. Liquid heat capacity was predicted using these vapor-pressure correlations, and the best final coefficient values were chosen based on the ability to simultaneously represent vapor pressure and liquid heat capacity. This procedure improves the fit to liquid heat-capacity data by 5-10% (average absolute deviation), while maintaining the fit of vapor-pressure data similar to those of other prediction methods. Additionally, low-temperature vapor-pressure predictions were improved by relying on liquid heat-capacity data. © 2017 American Chemical Society.
1518 a56040243400 Jamal A.-S. p538 True Conference 194 Architecture exploration for HLS-oriented FPGA debug overlays High-Level Synthesis (HLS) promises improved designer productivity, but requires a debug ecosystem that allows designers to debug in the context of the original source code. Recent work has presented in-system debug frameworks where instrumentation added to the design collects trace data as the circuit runs, and a software tool that allows the user to replay the execution using the captured data. When searching for the root cause of a bug, the designer may need to modify the instrumentation to collect data from a new part of the design, requiring a lengthy recompile. In this paper, we propose a flexible debug overlay family that provides software-like debug turn-around times for HLS generated circuits. At compile time, the overlay is added to the design and compiled. At debug time, the overlay can be configured many times to implement specific debug scenarios without a recompilation. This paper first outlines a number of “capabilities” that such an overlay should have, and then describes architectural support for each of these capabilities. The cheapest overlay variant allows selective variable tracing with only a 1.7% increase in area overhead from the baseline debug instrumentation, while the deluxe variant offers 2x-7x improvement in trace buffer memory utilization with conditional buffer freeze support. © 2018 Association for Computing Machinery.
1519 a17136347400 Unnikrishnan V. p539 False Journal 298 Computational Modeling of Wound Suture: A Review Suturing is an acquired skill which is based on a surgeon's experience. To date, no two sutures are the same with respect to the type of knot, tension, or suture material. With advancement in medical technologies, robotic suturing is becoming more and more important to operate on complex and difficult to reach internal surgical sites. While it is very difficult to translate a surgeon's suturing expertise to an automated environment, computational models could be employed to estimate baseline suture force requirements for a given wound shape, size, and suture material, which could be subsequently processed by a robot. In the literature, there have been few attempts to characterize wound closure and suture mechanics using simple two- and three-dimensional computational models. Single and multiple skin layers (epidermis, dermis, and hypodermis) and tissues with different wound geometries and sizes have been simulated under simple wound flap displacements to estimate suture force requirements. Also, recently, sutures were modeled to simulate a realistic wound closure via suture pulling, and skin prestress effect due to the natural tension of skin was incorporated in a few models to understand its effects on wound closure mechanics. An extensive review of this literature on computational modeling of wound suture would provide valuable insights into the areas in which further research work is required. Discussion of various computational challenges in modeling sutures in a numerical environment will help in better understanding the roadblocks and the required advancements in suture modeling. © 2008-2011 IEEE.
1520 a57193027820 Jung J.M. p540 True Journal 299 A dual sensor selective for Hg2+ and cysteine detection A new sensor for Hg2+ and cysteine detection has been synthesized and tested. The sensor based on cinamaldehyde and pyrimidine absorbs visible light when exposed to Hg2+ and becomes colored. The sensor only changes color due to Hg2+ and does not change when exposed to some other metal ions. Calculations show the change in color is due to lowering of the HOMO-LUMO transition. Titrations show the sensor-Hg2+ complex is composed of two sensor molecules per Hg2+. The limit of detection for Hg2+ is 0.39 μM. The sensor-Hg2+ complex selectively responds to cysteine (Cys), but does not show a color change due to other amino acids. The limit of detection of Cys by the sensor-Hg2+ complex is 0.10 μM. © 2017 Elsevier B.V.
1521 a7409879911 Kim C. p540 False Journal 299 A dual sensor selective for Hg2+ and cysteine detection A new sensor for Hg2+ and cysteine detection has been synthesized and tested. The sensor based on cinamaldehyde and pyrimidine absorbs visible light when exposed to Hg2+ and becomes colored. The sensor only changes color due to Hg2+ and does not change when exposed to some other metal ions. Calculations show the change in color is due to lowering of the HOMO-LUMO transition. Titrations show the sensor-Hg2+ complex is composed of two sensor molecules per Hg2+. The limit of detection for Hg2+ is 0.39 μM. The sensor-Hg2+ complex selectively responds to cysteine (Cys), but does not show a color change due to other amino acids. The limit of detection of Cys by the sensor-Hg2+ complex is 0.10 μM. © 2017 Elsevier B.V.
1522 a56029648000 Harrison R.G. p540 False Journal 299 A dual sensor selective for Hg2+ and cysteine detection A new sensor for Hg2+ and cysteine detection has been synthesized and tested. The sensor based on cinamaldehyde and pyrimidine absorbs visible light when exposed to Hg2+ and becomes colored. The sensor only changes color due to Hg2+ and does not change when exposed to some other metal ions. Calculations show the change in color is due to lowering of the HOMO-LUMO transition. Titrations show the sensor-Hg2+ complex is composed of two sensor molecules per Hg2+. The limit of detection for Hg2+ is 0.39 μM. The sensor-Hg2+ complex selectively responds to cysteine (Cys), but does not show a color change due to other amino acids. The limit of detection of Cys by the sensor-Hg2+ complex is 0.10 μM. © 2017 Elsevier B.V.
1523 a55130094700 Chetty V. p543 True Conference 197 Necessary and sufficient conditions for identifiability of interconnected subsystems Identifiability conditions refers to the information required, beyond input-output data, to identify the structure of the system. Since there are different ways to describe a system mathematically, there are different notions of structure associated with a single system. In this work we detail the identifiability conditions of interconnected subsystems, referred to as structured linear fractional transformations. The identifiability conditions of the structured linear fractional transformation are then compared to those of the dynamical structure function, another partial system representation, whose cost for identification was detailed in previous work [1]. Both representations appear to detail the same notions of structure of a system; however, this works demonstrates that the cost of identification of the structured linear fractional transformation is always higher than that of the dynamical structure function. © 2017 IEEE.
1523 a55130094700 Chetty V. p682 True Conference 294 Applying a passive network reconstruction technique to Twitter data in order to identify trend setters In this work we apply a systems-theoretic approach to identifying trend setters on Twitter. A network reconstruction algorithm was applied to Twitter data to determine causal relationships among topics discussed by popular Twitter users. Causal relationships in this context means that the topics tweeted by a single user influences the topics tweeted by another user, regardless of sentiment. A user that causally influences other users, without themselves being strongly influenced is identified as a trendsetter. This work seeks to identify potential trendsetters among popular Twitter users and demonstrating that causal influence does not always directly correlate with a user's popularity in terms of followers-demonstrating that popularity alone may not be sufficient for identifying trendsetters on Twitter. © 2017 IEEE.
1524 a57193356353 Eves K. p545 True Journal 230 A comparative analysis of computer-aided design team performance with collaboration software For the past several years, the BYU CAD Lab has been developing collaborative computer-aided design (CAD) software. As this software is being developed, industry seeks to better understand the differences in performance between teams using multi-user CAD and single-user CAD to make informed decisions about implementing this new software into their engineering processes. In order to better understand the differences in performance between teams, an experimental study was conducted in which four multi-user teams and four single-user teams competed to create the best model of a hand drill. Key findings of this study were that multi-user CAD increases awareness of teammates’ activities as well as communication between team members. Performance, with respect to the metrics of quality and time for completion, could be improved with increased familiarity with the multi-user CAD software. Future research directions are suggested and discussed. © 2018 CAD Solutions, LLC.
1524 a57193356353 Eves K. p700 False Journal 339 A multi-user computer-aided design competition: Experimental findings and analysis of team-member dynamics A competition for teams of three students using a prototype multi-user computer-aided design (MUCAD) tool was held to investigate various hypotheses regarding the performance of teams in such a setting. By comparing models from the competition to the same model in a single-user CAD environment, it is seen that use of a MUCAD system can significantly increase the value-added per unit of calendar time for a modeling effort. An investigation was also made into the causes of the performance differences among the various MUCAD teams which participated in the competition. Analysis of the results shows that teams that encouraged effective forms of communication and teams whose members scored similarly on the Purdue Spatial Visualization Test: Visualization of Rotations (PSVT:R) performed better than other teams. Areas of future research in analyzing teams in MUCAD environments are suggested. Copyright © 2017 by ASME.
1525 a57200371154 Olsen J. p545 False Journal 230 A comparative analysis of computer-aided design team performance with collaboration software For the past several years, the BYU CAD Lab has been developing collaborative computer-aided design (CAD) software. As this software is being developed, industry seeks to better understand the differences in performance between teams using multi-user CAD and single-user CAD to make informed decisions about implementing this new software into their engineering processes. In order to better understand the differences in performance between teams, an experimental study was conducted in which four multi-user teams and four single-user teams competed to create the best model of a hand drill. Key findings of this study were that multi-user CAD increases awareness of teammates’ activities as well as communication between team members. Performance, with respect to the metrics of quality and time for completion, could be improved with increased familiarity with the multi-user CAD software. Future research directions are suggested and discussed. © 2018 CAD Solutions, LLC.
1526 a56331127200 Shumway D. p548 True Journal 230 Hybrid state transactional database for product lifecycle management features in a multi-engineer synchronous heterogeneous CAD environment As interoperability between Computer Aided Design (CAD) systems becomes a possibility, a need arises for a way for the Neutral Parametric Canonical Form (NPCF), as designed at the BYU Site of the NSF Center for e-Design, to be integrated with Product Lifecycle Management (PLM). The only method currently available to users to sync with a PLM system at this time would be to choose one CAD system and create files based off of the NPCF data then save those part files in the PLM system. This database expansion to the NPCF allows the NPCF to hold the entire part history as well as enable future work revision history and configuration management. Enforcing referential integrity within the database allows for part data to never get corrupted and the NPCF allows any CAD system with the appropriate plug-ins to read the uncorrupted data. © 2017 CAD Solutions, LLC.
1526 a56331127200 Shumway D. p759 False Journal 352 Pseudo-singleton pattern and agnostic business layer for multi-engineer, synchronous, heterogeneous CAD Product development processes are currently highly serial workflows that prevent needed cycle time reduction. Multi-user synchronous CAD is already improving the parallelization of these workflows and the next step is to facilitate multi-user synchronous heterogeneous CAD. This paper proposes a pseudo-singleton design pattern and a class signature which are necessary in the business logic layer of an application architecture that affects multi-user synchronous collaboration across heterogeneous CAD clients. © 2016 CAD Solutions, LLC.
1527 a35269204800 Hepworth A. p550 False Conference 200 Rapid visualization of compressor blade finite element models using surrogate modeling The design process for compressor blades is a highly iterative and often slow process. This research applied and measured the impact of using surrogates to quickly model the stresses on a compressor blade. By modeling distinct points on a finite element (FE) model with unique surrogates, the stress field of the entire FE model was quickly predicted. This required that the distinct points remain in the same relative location on each blade used in training the surrogate. This research studied the ability of mesh morphing, and using the surface nodes as those distinct points, to satisfy this requirement. The results show that mesh morphing performed well on the tested compressor blades. The research also found that the surrogate accuracy depended not only on the number of training samples, but also the number and types of parameters being emulated. The surrogate models achieved less than 5% error on all the tested blades. Finally, the method provided a 96% decrease in time required for a structural iteration of a compressor blade. Such speeds eliminate bottlenecks that may occur in the structural design process. The combination of mesh morphing and surrogate modeling in compressor blade analysis enables exploration of various geometric parameters and their effect on structural responses. Application of this process would produce a more thoroughly refined and understood compressor blade design. Copyright © 2018 by ASME.
1527 a35269204800 Hepworth A. p715 False Journal 352 Methods for determining the optimal number of simultaneous contributors for multi-user CAD parts The development of multi-user CAD (MUCAD) tools has opened up exciting new opportunities and applications. The capability for multiple users to simultaneously model and design a CAD part has far-reaching potential. However, many basic questions remains unanswered, such as how many users should work together on a given part. This research proposes and develops a set of methods to determine the optimal number of users for a given part within a MUCAD environment, based on the characteristics of the part itself. Two candidate models are evaluated with a set of 60 experiments with design teams composed of different numbers of users. The models show modest correlations with the test data while more-refined models are explored to improve predictive power. On the other hand, highly significant correlations between the ability to predict completion time and multi-user team size were identified in the experimental data. Observations regarding the speed and quality of MUCAD teams are also made with future areas of research suggested. © 2017 CAD Solutions, LLC.
1528 a57203433787 Alvarez E.J. p551 True Conference 201 Development of a vortex particle code for the modeling of wake interaction in distributed propulsion Recent developments in electric aircraft technology have enabled the use of distributed propulsion for the next generation of vertical lift vehicles. However, the ability to rapidly assess the performance of these design concepts, with sufficient fidelity, is a current weakness of this nascent industry. This paper explores the capacity of the viscous Vortex Particle Method (VPM) to model wake interactions found in distributed propulsion. The elements of the vortex particle method are summarized, and a new approach for the calculation of vortex stretching through the complex-step derivative approximation is presented. Preliminary validation is performed on vortex ring cases resembling the fundamental dynamics encountered in propeller wakes. Unsteady wake dynamics of individual propellers are successfully modeled, replicating the instabilities that lead to vortex breakdown as observed experimentally. Comparing the method with results from momentum theory, it is shown that VPM is consistent with theoretical values of near and far field induced velocities, and a notable feature is its ability to model near/far field transition. Furthermore, VPM is able to fully characterize induced velocities across the entire wake, from the stable region where momentum theory operates, through instability transition and eventual vortex breakdown. The simulation of a multirotor configuration of two tip-to-tip propellers is shown, displaying the capacity of VPM to model wake mixing. The results presented here are intermediate steps in the development of a mid-fidelity modeling tool for the early design stages of distributed-propulsion electric aircraft. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1529 a57201393186 McDonnell T. p553 True Conference 203 Multidisciplinary design optimization of flexible solar-regenerative high-altitude long-endurance aircraft Solar-Regenerative High-Altitude Long-Endurance (SR-HALE) aircraft are designed to sustain year-round ight at high altitudes indefinitely. No SR-HALE aircraft has yet accomplished this task due to the complex network of environmental, solar, structural, and aerodynamic trade-offs, among which aircraft exibility plays a key role. A comprehensive SR-HALE aircraft multidisciplinary design optimization framework is developed in which the exible aircraft analysis tool ASWING is incorporated in order to constrain nonlinear aeroelasticity. Energy, battery, ply thickness, material failure, local buckling, aerodynamic stall, longitudinal stability, and general stability (including utter) constraints are applied in order to reasonably constrain the optimized SR-HALE aircraft design. An SR-HALE aircraft design with a span length of 60:15m and a total aircraft weight of 432:2 kg is found which fulfills all SR-HALE mission requirements and minimizes aircraft mass. A further 21% reduction in total aircraft mass is found through the use of high modulus carbon fiber reinforced polymer. Significant decreases in aircraft mass, down to a total aircraft mass of 250.6 kg, are found to be possible if altitude requirements for SR-HALE aircraft are lowered from 18;288m to 16;764 m. A feasible SR-HALE aircraft with a mass of 357:9 kg was also found to be possible if battery specific energies of 360Wh kg–1 are developed. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1530 a57201397713 Mehr J. p553 False Conference 203 Multidisciplinary design optimization of flexible solar-regenerative high-altitude long-endurance aircraft Solar-Regenerative High-Altitude Long-Endurance (SR-HALE) aircraft are designed to sustain year-round ight at high altitudes indefinitely. No SR-HALE aircraft has yet accomplished this task due to the complex network of environmental, solar, structural, and aerodynamic trade-offs, among which aircraft exibility plays a key role. A comprehensive SR-HALE aircraft multidisciplinary design optimization framework is developed in which the exible aircraft analysis tool ASWING is incorporated in order to constrain nonlinear aeroelasticity. Energy, battery, ply thickness, material failure, local buckling, aerodynamic stall, longitudinal stability, and general stability (including utter) constraints are applied in order to reasonably constrain the optimized SR-HALE aircraft design. An SR-HALE aircraft design with a span length of 60:15m and a total aircraft weight of 432:2 kg is found which fulfills all SR-HALE mission requirements and minimizes aircraft mass. A further 21% reduction in total aircraft mass is found through the use of high modulus carbon fiber reinforced polymer. Significant decreases in aircraft mass, down to a total aircraft mass of 250.6 kg, are found to be possible if altitude requirements for SR-HALE aircraft are lowered from 18;288m to 16;764 m. A feasible SR-HALE aircraft with a mass of 357:9 kg was also found to be possible if battery specific energies of 360Wh kg–1 are developed. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1530 a57201397713 Mehr J. p596 False Conference 239 Universal airfoil parametrization using B-splines In this paper, we apply well-known techniques for parametric curves to the definition and deformation of airfoil sections. While it has already been shown that many versions of Kulfan’s Class Shape Transformation (CST) are exactly equivalent to Bézier curves, we show here that all NACA 4-digit thickness distributions and the PARSEC parametrization of Sobiezcky are also higher-order Bézier curves. As with CST, Béziers and B-Splines provide direct control over aerodynamically meaningful features such as nose radius and boat-tail angle, but also provide more a intuitive parametrization of the rest of the airfoil surface. We show the efficacy of B-Spline-based parametrizations for approximating airfoil coordinates and for clean-sheet airfoil design. Finally, we show that this parametrization is ideally suited for progressive design. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1531 a57215366913 Perdue T. p557 False Conference 206 The secure socket API: TLS as an operating system service SSL/TLS libraries are notoriously hard for developers to use, leaving system administrators at the mercy of buggy and vulnerable applications. We explore the use of the standard POSIX socket API as a vehicle for a simplified TLS API, while also giving administrators the ability to control applications and tailor TLS configuration to their needs. We first assess OpenSSL and its uses in open source software, recommending how this functionality should be accommodated within the POSIX API. We then propose the Secure Socket API (SSA), a minimalist TLS API built using existing network functions and find that it can be employed by existing network applications by modifications requiring as little as one line of code. We next describe a prototype SSA implementation that leverages network system calls to provide privilege separation and support for other programming languages. We end with a discussion of the benefits and limitations of the SSA and our accompanying implementation, noting avenues for future work. © 2018 Proceedings of the 27th USENIX Security Symposium. All rights reserved.
1532 a57215344746 Collett T. p557 False Conference 206 The secure socket API: TLS as an operating system service SSL/TLS libraries are notoriously hard for developers to use, leaving system administrators at the mercy of buggy and vulnerable applications. We explore the use of the standard POSIX socket API as a vehicle for a simplified TLS API, while also giving administrators the ability to control applications and tailor TLS configuration to their needs. We first assess OpenSSL and its uses in open source software, recommending how this functionality should be accommodated within the POSIX API. We then propose the Secure Socket API (SSA), a minimalist TLS API built using existing network functions and find that it can be employed by existing network applications by modifications requiring as little as one line of code. We next describe a prototype SSA implementation that leverages network system calls to provide privilege separation and support for other programming languages. We end with a discussion of the benefits and limitations of the SSA and our accompanying implementation, noting avenues for future work. © 2018 Proceedings of the 27th USENIX Security Symposium. All rights reserved.
1533 a57213476529 Gong H. p558 False Conference 207 3D printed microfluidic selectable ratio mixer pump in 2 mm3 We report the use of 3D printing to fabricate a selectable ratio mixer pump in a volume of only 2 mm2. Our custom 3D printer and material is used to make very compact individual elements such as fluid channels, valves, and pumps that are laid out in 3D to achieve small overall device volume. The device includes two pumps, each connected to its own fluid source, and a two-chamber mixing unit that both mixes the fluid pumped into it from each fluid source, and acts itself as a pump to expel the mixed fluid. © 2016 TRF
1534 a57205629789 Hayden S. p560 True Conference 209 Thermal diffusivity measurements with fluorescent scanning microscope [No abstract available]
1535 a57205285400 Nygaard E. p562 False Conference 211 Progress on photophoretic trap displays We review the fundamentals photophoretic trap displays and discuss the possibility of creating occlusion capable image points. Anisotropic scattering is observed independently in single and double point traps. © 2018 The Author(s).
1535 a57205285400 Nygaard E. p591 False Conference 234 Volumetric display by movement of particles trapped in a laser via photophoresis Photophoresis can stably hold opaque microscopic particles in a laser focus surrounded by room air with strength sufficient to enable centimeter-scale patterns to be drawn by sweeping the laser beam. The resulting images rely on visual persistence as laser light scatters from the particle, which is rapidly swept through the 3-D pattern. Control can be maintained while moving the particle with air speeds up to 2 m/s. A desire to greatly increase the sweep speed motivates a re-examination of the fundamentals of photophoresis-based laser-particle traps. Most explanations offered are qualitative, with differing opinions as to whether, for example, asymmetric heating or asymmetric thermal accommodation is primarily at work. Which particles become trapped in the beam is typically based on self-selection, as a variety of particles with possible differing shapes and sizes are offered to the laser focus for capture. Characteristics that make some particles preferred over others are especially relevant. There is broad consensus that structure in the laser focus greatly aids in stable trapping. Nevertheless, it is still possible for even a relatively smooth TEM00 beam to capture and hold particles. Moreover, even in a structured focus (i.e. with aberrations and local intensity minima and maxima), questions remain as to exactly how a particle becomes stably trapped in certain beam locations. A zoomed-in look at trapped particles reveals oscillations or orbits with excursions over tens of microns and accelerations up to 10 gs. We trapped particles in zero-gravity as well as 2-g environments with no noticeable difference in stability. © 2018 SPIE.
1536 a57145797800 Jackson J.S. p563 True Conference 212 Demonstration of interference pattern structured illumination imaging We discuss a single-pixel imaging method using illumination structured with interference fringes. It requires no imaging lens or optics near the object, and has a resolution-independent depth of field and field of view. © 2018 The Author(s).
1536 a57145797800 Jackson J.S. p782 True Journal 346 Light splitting with imperfect wave plates We discuss the use of wave plates with arbitrary retardances, in conjunction with a linear polarizer, to split linearly polarized light into two linearly polarized beams with an arbitrary splitting fraction. We show that for non-ideal wave plates, a much broader range of splitting ratios is typically possible when a pair of wave plates, rather than a single wave plate, is used. We discuss the maximum range of splitting fractions possible with one or two wave plates as a function of the wave plate retardances, and how to align the wave plates to achieve the maximum splitting range possible when simply rotating one of the wave plates while keeping the other one fixed. We also briefly discuss an alignment-free polarization rotator constructed from a pair of half-wave plates. © 2017 Optical Society of America.
1537 a36944158600 Durfee D.S. p563 False Conference 212 Demonstration of interference pattern structured illumination imaging We discuss a single-pixel imaging method using illumination structured with interference fringes. It requires no imaging lens or optics near the object, and has a resolution-independent depth of field and field of view. © 2018 The Author(s).
1537 a36944158600 Durfee D.S. p782 False Journal 346 Light splitting with imperfect wave plates We discuss the use of wave plates with arbitrary retardances, in conjunction with a linear polarizer, to split linearly polarized light into two linearly polarized beams with an arbitrary splitting fraction. We show that for non-ideal wave plates, a much broader range of splitting ratios is typically possible when a pair of wave plates, rather than a single wave plate, is used. We discuss the maximum range of splitting fractions possible with one or two wave plates as a function of the wave plate retardances, and how to align the wave plates to achieve the maximum splitting range possible when simply rotating one of the wave plates while keeping the other one fixed. We also briefly discuss an alignment-free polarization rotator constructed from a pair of half-wave plates. © 2017 Optical Society of America.
1538 a57204896057 Cardall H. p564 True Conference 213 Using instagram to increase student engagement with design history In today’s rapidly evolving design disciplines, design history students should demonstrate an understanding of the social and cultural impact of design of both historical and contemporary designers and their methods. To increase student engagement with design history and discourse, we prototyped a new format for our design history course in Brigham Young University’s Industrial Design department. Our goal was to enable students to process designs they encounter, both in person and social media, through a critical and cultural perspective, and then turn those lenses towards their own design work with greater social and cultural awareness. To do this, we utilized Instagram as the primary platform (@byudesignhistory) for course discussion and altered the way we framed student assignments. This new curriculum was prototyped in the spring of 2018. Outcomes were measured by monitoring student engagement, responses, and comprehension scores on verbal and written assignments and examinations. Students also responded to a series of reviews to gather their perspectives on the class. Results indicate an increase in their understanding of the cultural position design holds in a way that was absent in student results from the previous course structure. If our course interventions are effective, students should move from concrete to abstract knowledge as well as from lower order to higher order thinking skills. Students will thus be better prepared to assess, understand and discuss both current and historical design cultures and trends while influencing their own design work through an informed perspective. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
1539 a57204902069 Larsen A. p565 True Conference 214 Increasing the educational impact following a field study programme Design students return from field trips abroad brimming with new ideas and a greater understanding of their chosen discipline. However, if their observations and knowledge are not soon applied, the students hold only fond memories of a fun trip abroad. We believe that student’s retention and application of concepts will increase if educators give students greater autonomy on the trip and also expect and enable opportunities to apply their accrued knowledge on their own projects upon returning home. Nine third and fourth-year industrial design students Brigham Young University participated in a weeklong field study abroad to Dutch Design Week (DDW) in Eindhoven, Netherlands. A week after the completion of the study abroad the students filled out a survey about their motivations, feelings, criticisms, and aspects of the trip that influenced them as designers. Three and a half months later the students took a second survey asking about how they have applied insights gained from participation in DDW to their current projects. The results from the both surveys suggest the impact of the field study trip decreased over time. The observations and more open-ended questions in the survey helped determine if and how the students applied their conceptual knowledge to their current projects as well as other outcomes of the trip. In addition, the paper suggests possible strategies and research opportunities for future field study experiences. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
1540 a23093686000 Fry R. p566 True Conference 215 Information reduction and studio project frameworks Studio projects increase from simple & straightforward to complex & indeterminate as undergraduate industrial design students’ progress through their educational experiences. As project complexity increases, students are faced with information overload and can struggle to move forward in a meaningful way. Complex Problem Solving studies and Cognitive Load Theory suggest information reduction as a way to grasp the critical aspects of a problem and move beyond the impasse inherent with too much information. Segmentation and chunking are common strategies for information reduction but the abstraction inherent in the chunking process provides better conceptual understanding. The simplified but meaningful results from the chunking process can then be leveraged to create a model or framework that helps students organise and clarify what they have observed as well as point to new opportunities for design activity. Despite the fear of oversimplification, significantly abstracted models have great “explanatory or predictive power” and can lead to rich results. Reviewing the concepts of complexity, cognitive load, and contrasting segmentation with data chunking, this paper will then highlight a portion of a student project where information reduction provided understanding beyond initial student impressions and encouraged them to move forward. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
1540 a23093686000 Fry R. p568 True Journal 302 Modeling and using secondary taste terms Previous investigation into cuteness literature resulted in a preliminary, three-factor model for defining and organizing information regarding taste terms. A theoretical definition of a taste term should have a declaration of: 1) aesthetic purpose, 2) the essential emotional responses, and 3) understandable themes and expressions. A small group of second-year industrial design students explored the model, and was tasked with identifying, defining, and experimenting with three taste terms of their choosing: Performance, Strength, and Simple Quiet. To test their knowledge, they applied their aesthetic insights to a simple industrial design problem. Even though the original intent was to explore and define concepts of taste, and expand visual and verbal vocabulary for students, it was anecdotally observed that this exercise had a positive effect on creative output. This article will summarize the results of their efforts, and offer suggestions for future work regarding understanding the more granular context of taste terms. © Common Ground Research Networks, Richard Fry, All Rights Reserved.
1541 a57203179871 Browning J.S. p570 True Conference 218 High Accuracy Achieved in Determining Lengths and Locations of Horizontal Curves Using Light Detection and Ranging Point Cloud Data The Utah Department of Transportation (UDOT) began collecting asset management data using light detection and ranging (LiDAR) technology in 2012, which included horizontal curve data. However, its horizontal curve data were highly segmented and not ready for crash prediction model development for curve segments. In 2014, an algorithm named the horizontal alignment finder (HAF) algorithm was developed to identify horizontal curves on rural two-lane two-way highways. Its accuracy was about 85 percent with 2012 data. The HAF was recently recalibrated for all other types of UDOT's highways and found to be applicable to them without any modifications in its main algorithm. During the calibration, six types of errors were identified. Four of the six errors were fixed and the HAF was calibrated with new 2015 LiDAR data. The improved HAF's accuracy now ranges from 97 to 98 percent for curve length and 87 to 100 percent for curve location identification. © 2018 American Society of Civil Engineers.
1542 a57207688964 Nelson K. p575 False Conference 220 Physical-layer security for aeronautical telemetry In this paper, we investigate the application of physical-layer security coding for next generation aeronautical telemetry communication systems. The coding we refer to is similar to error-control coding, but the codes are deployed for two purposes: to achieve reliable communications, and to achieve secure communications. We consider a single eavesdropper on an air-to-ground aeronautical telemetry link, and show how the overhead measured by the rate of the code can be used to keep secrets from eavesdroppers over noisy channels, rather than recover from channel errors. We show simple examples that work over erasure channels to achieve a security constraint, and then consider approaches to more practical coding constructions for Gaussian channels that satisfies both reliability and security constraints on the network. © held by the author; distribution rights International Foundation for Telemetering.
1543 a57207687563 Dye S. p575 False Conference 220 Physical-layer security for aeronautical telemetry In this paper, we investigate the application of physical-layer security coding for next generation aeronautical telemetry communication systems. The coding we refer to is similar to error-control coding, but the codes are deployed for two purposes: to achieve reliable communications, and to achieve secure communications. We consider a single eavesdropper on an air-to-ground aeronautical telemetry link, and show how the overhead measured by the rate of the code can be used to keep secrets from eavesdroppers over noisy channels, rather than recover from channel errors. We show simple examples that work over erasure channels to achieve a security constraint, and then consider approaches to more practical coding constructions for Gaussian channels that satisfies both reliability and security constraints on the network. © held by the author; distribution rights International Foundation for Telemetering.
1544 a57200077021 Holtom J. p576 False Conference 221 Femtosats: Elegant flight telemetry payloads for model rockets An elegant telemetry payload, which transmits IMU, atmospheric, or light data during flight and deployment from a small model rocket, is presented. Data is received by a custom, mobile, hand-pointed ground station. The payload is patterned after a thumb-sized satellite, called a femtosat. Its design is optimized for ease of implementation. The femtosat system resulted from a grassroots, student peer-mentoring program developed at Brigham Young University. © held by the author; distribution rights International Foundation for Telemetering.
1545 a57200077390 Walton P. p576 False Conference 221 Femtosats: Elegant flight telemetry payloads for model rockets An elegant telemetry payload, which transmits IMU, atmospheric, or light data during flight and deployment from a small model rocket, is presented. Data is received by a custom, mobile, hand-pointed ground station. The payload is patterned after a thumb-sized satellite, called a femtosat. Its design is optimized for ease of implementation. The femtosat system resulted from a grassroots, student peer-mentoring program developed at Brigham Young University. © held by the author; distribution rights International Foundation for Telemetering.
1546 a57207692990 Smith J. p576 False Conference 221 Femtosats: Elegant flight telemetry payloads for model rockets An elegant telemetry payload, which transmits IMU, atmospheric, or light data during flight and deployment from a small model rocket, is presented. Data is received by a custom, mobile, hand-pointed ground station. The payload is patterned after a thumb-sized satellite, called a femtosat. Its design is optimized for ease of implementation. The femtosat system resulted from a grassroots, student peer-mentoring program developed at Brigham Young University. © held by the author; distribution rights International Foundation for Telemetering.
1547 a57207687950 Wallin N. p576 False Conference 221 Femtosats: Elegant flight telemetry payloads for model rockets An elegant telemetry payload, which transmits IMU, atmospheric, or light data during flight and deployment from a small model rocket, is presented. Data is received by a custom, mobile, hand-pointed ground station. The payload is patterned after a thumb-sized satellite, called a femtosat. Its design is optimized for ease of implementation. The femtosat system resulted from a grassroots, student peer-mentoring program developed at Brigham Young University. © held by the author; distribution rights International Foundation for Telemetering.
1548 a57207688651 Averett T. p577 False Conference 222 Byu mars rover at the 2018 university rover challenge This paper describes the design and performance of the BYU mars rover with an emphasis on the wireless communications system and the transmission and reception of data vital to the performance of the rover. © held by the author; distribution rights International Foundation for Telemetering.
1549 a57207695326 Killpack M. p577 False Conference 222 Byu mars rover at the 2018 university rover challenge This paper describes the design and performance of the BYU mars rover with an emphasis on the wireless communications system and the transmission and reception of data vital to the performance of the rover. © held by the author; distribution rights International Foundation for Telemetering.
1550 a57207687041 Rice M. p577 False Conference 222 Byu mars rover at the 2018 university rover challenge This paper describes the design and performance of the BYU mars rover with an emphasis on the wireless communications system and the transmission and reception of data vital to the performance of the rover. © held by the author; distribution rights International Foundation for Telemetering.
1551 a57207686191 Thompson R. p578 True Conference 223 Eliminating wiring in aircraft instrumentation through energy harvesting Installing the many sensors required for flight testing is currently a difficult and awkward process requiring significant wiring. Short term sensor installation could be greatly improved if individual sensors did not have to be connected to a distant power source. This paper proposes that small aerodynamic vibration energy harvesting devices could provide power directly to sensors and simplify installation. To investigate feasibility, the simplest known energy harvester configuration is chosen. A mathematical model to represent the device is then developed. A test scenario using the aerodynamic vibrations present on the F-15B aircraft is then incorporated into the model. The test results are analyzed to determine if the energy harvesting device can produce sufficient energy to justify further analysis. Finally, potential design improvements are discussed. © held by the author; distribution rights International Foundation for Telemetering.
1552 a57207685496 Hull T. p578 False Conference 223 Eliminating wiring in aircraft instrumentation through energy harvesting Installing the many sensors required for flight testing is currently a difficult and awkward process requiring significant wiring. Short term sensor installation could be greatly improved if individual sensors did not have to be connected to a distant power source. This paper proposes that small aerodynamic vibration energy harvesting devices could provide power directly to sensors and simplify installation. To investigate feasibility, the simplest known energy harvester configuration is chosen. A mathematical model to represent the device is then developed. A test scenario using the aerodynamic vibrations present on the F-15B aircraft is then incorporated into the model. The test results are analyzed to determine if the energy harvesting device can produce sufficient energy to justify further analysis. Finally, potential design improvements are discussed. © held by the author; distribution rights International Foundation for Telemetering.
1553 a57207687043 Rice M. p578 False Conference 223 Eliminating wiring in aircraft instrumentation through energy harvesting Installing the many sensors required for flight testing is currently a difficult and awkward process requiring significant wiring. Short term sensor installation could be greatly improved if individual sensors did not have to be connected to a distant power source. This paper proposes that small aerodynamic vibration energy harvesting devices could provide power directly to sensors and simplify installation. To investigate feasibility, the simplest known energy harvester configuration is chosen. A mathematical model to represent the device is then developed. A test scenario using the aerodynamic vibrations present on the F-15B aircraft is then incorporated into the model. The test results are analyzed to determine if the energy harvesting device can produce sufficient energy to justify further analysis. Finally, potential design improvements are discussed. © held by the author; distribution rights International Foundation for Telemetering.
1554 a57209637810 Lee E.T. p579 False Conference 224 Adaptive net radiative heat transfer and thermal management with origami-structured surfaces The ability to control radiative behavior through the angular positioning of structured surfaces (e.g. the cavity effect) offers the ability to provide thermal management in dynamic radiative environments. Structures comprised of origami tessellations offer a means to achieve angular cavities that approach black-like behavior during collapse by exploiting use of the cavity effect. Expanded origami surfaces exhibit intrinsic radiative properties while collapsed surfaces exhibit increasingly black-like behavior as the cavity aspect ratio increases. Actuation of such surfaces provides the means to achieve any apparent radiative behavior between these two extremes. This work explores the use of three origami structures (finite V-groove, hinged V-groove and Miura-ori) and their respective apparent radiative properties as a function of cavity geometry using Monte Carlo ray tracing. Results are presented as a function of tessellation geometry and degree of actuation (i.e. collapse). Ray tracing models are benchmarked with V-groove geometries for which analytical models exist in the literature. Convergence for ray independence was determined to be satisfactory when the standard error of the mean for every test case was less than 0.005. Deviation in the apparent absorptivity for finite V-groove relative to the infinite V-groove is quantified. The apparent absorptivity of the Miura-ori fold exhibits sensitivity to the fold geometry when the angle of the unit cell is varied, but is relatively insensitive to the length ratio of the panel. The variable nature of the net radiative heat transfer, achievable through actuation, affords a method for thermal management of components with variable heat dissipation and/or variable radiative environments. © 2018 International Heat Transfer Conference. All rights reserved.
1555 a57204762755 Sellers A.D. p582 False Conference 227 Automating the design of thick-origami mechanisms Applying an origami pattern to thick, non-paper-like materials is a challenging task. Though many techniques have been developed to accommodate thickness in origami, creating 3D models of such thick-origami mechanisms is complex. The time and knowledge required to manually model an origami mechanism can impede the exploration of the design space and creation of robust designs. This work presents data structures based on origami that can be used in the automation of thick-origami mechanism design. These structures are described and an example computer program that implements them is investigated. The program automatically generates all the necessary 3D CAD part models and an assembly model for a user-specified origami crease pattern. Models resulting from the program for several crease patterns are demonstrated with a discussion of the advantages and limitations of the system. With further development of the data structures and program, this framework has the potential to help mitigate some of the barriers to more widespread use of origami-based design. Copyright © 2018 ASME
1556 a57204728159 Packer R. p586 True Conference 231 Design and modeling of a prosthetic venous valve Chronic Venous Insufficiency (CVI) is a disease of the lower limbs that affects millions of people in the United States. CVI results from incompetent venous valves. The purpose of venous valves is to prevent retrograde blood flow to the lower limbs. Valve failure can lead to edema, pain, and ulcers. One solution that has great potential is to create an implantable venous valve that could restore function of the venous system. No prosthetic venous valves are clinically used currently because of problems with biocompatiblility and thrombogenicity caused by high shear rates. This paper presents a prosthetic venous valve that could overcome these difficulties by using carbon-infiltrated carbon nanotubes (CI-CNTs). This material has been proven to be thrombo-resistant, biocompatible due to its non-reactive properties, and durable. The valve was designed to be initially open and to close with physiological pressures. Finite element modeling showed that, with a hydrostatic pressure of 20 mmHg (the minimum hydrostatic pressure in the common femoral vein), it fully closed with a maximum stress of 117 MPa, which is below the ultimate strength of CI-CNTs. A computational fluid dynamics analysis demonstrated the valve would cause a maximum shear rate of 225.1 s− 1, which is less than the maximum shear rate in the body. Hence, this valve would be less likely than previous prosthetic valves to develop blood clots. Currently, this is the lowest shear rate reported for a prosthetic venous valve. These results demonstrate that a CI-CNT prosthetic venous valve has the potential to be an effective treatment for CVI. Copyright © 2018 ASME.
1557 a57204719691 Prawitt D.G. p587 True Conference 232 Patterned carbon nanotube growth on stainless steel This paper presents, for the first time, the process of growing a pattern of carbon nanotubes (CNT(s)) on 316L stainless steel. The data presented is preliminary and requires further investigation to detail the growth behaviors of CNTs on stainless steel in regards to producing a pattern. However, this article presents the viability of producing a pattern on a stainless steel surface that can be used in bio-surfacing and electronic applications, among others. The results show that producing a CNT pattern on stainless steel can be achieved in a similar manner to that of producing a CNT pattern on a silicon wafer, with some vital differences in the photolithography and growth processes. The results also show that long CNT growth can lead to partial overgrowth of the pattern. Copyright © 2018 ASME.
1558 a57204719621 Porter D. p587 False Conference 232 Patterned carbon nanotube growth on stainless steel This paper presents, for the first time, the process of growing a pattern of carbon nanotubes (CNT(s)) on 316L stainless steel. The data presented is preliminary and requires further investigation to detail the growth behaviors of CNTs on stainless steel in regards to producing a pattern. However, this article presents the viability of producing a pattern on a stainless steel surface that can be used in bio-surfacing and electronic applications, among others. The results show that producing a CNT pattern on stainless steel can be achieved in a similar manner to that of producing a CNT pattern on a silicon wafer, with some vital differences in the photolithography and growth processes. The results also show that long CNT growth can lead to partial overgrowth of the pattern. Copyright © 2018 ASME.
1559 a57197733505 Whiting T.A. p588 False Journal 304 Dynamic SEU Sensitivity of Designs on Two 28-nm SRAM-Based FPGA Architectures Two field-programmable gate array (FPGA) designs are tested for dynamic single event upset (SEU) sensitivity on two different 28-nm static random access memory-based FPGAs - an Intel Stratix V and a Xilinx Kintex 7 FPGA. These designs were tested in both a conventional unmitigated version and a version to tolerate SEUs with feedback triple modular redundancy (TMR). The unmitigated design sensitivity and the low-level device sensitivity were found to be similar between the devices through neutron radiation testing. Results also show that feedback TMR and configuration scrubbing benefit both designs on both FPGAs. While TMR is helpful, the benefit of TMR depends on the design structure and the device architecture. TMR and scrubbing reduced dynamic SEU sensitivity by a factor of 4- 54×. © 1963-2012 IEEE.
1560 a57197728435 Sawyer K.B. p588 False Journal 304 Dynamic SEU Sensitivity of Designs on Two 28-nm SRAM-Based FPGA Architectures Two field-programmable gate array (FPGA) designs are tested for dynamic single event upset (SEU) sensitivity on two different 28-nm static random access memory-based FPGAs - an Intel Stratix V and a Xilinx Kintex 7 FPGA. These designs were tested in both a conventional unmitigated version and a version to tolerate SEUs with feedback triple modular redundancy (TMR). The unmitigated design sensitivity and the low-level device sensitivity were found to be similar between the devices through neutron radiation testing. Results also show that feedback TMR and configuration scrubbing benefit both designs on both FPGAs. While TMR is helpful, the benefit of TMR depends on the design structure and the device architecture. TMR and scrubbing reduced dynamic SEU sensitivity by a factor of 4- 54×. © 1963-2012 IEEE.
1561 a57190858572 Walton M.P. p590 True Conference 233 Architectures for Earth-observing CubeSat scatterometers Earth-observing satellite scatterometers are important instruments capable of measuring a variety of geophysical properties. Historically, the scatterometer design space has revolved around two main architectures: the fan beam and the scanning pencil beam. Since the implementation of these architectures, developments in satellite- relevant technology, spacecraft standards, and engineering practice have expanded the potential design space for Earth-observing scatterometer systems. This expanded design space is investigated and example designs are presented that utilize the expanded design space to improve performance and reduce cost. © 2018 SPIE.
1562 a57204435650 Laughlin E. p591 False Conference 234 Volumetric display by movement of particles trapped in a laser via photophoresis Photophoresis can stably hold opaque microscopic particles in a laser focus surrounded by room air with strength sufficient to enable centimeter-scale patterns to be drawn by sweeping the laser beam. The resulting images rely on visual persistence as laser light scatters from the particle, which is rapidly swept through the 3-D pattern. Control can be maintained while moving the particle with air speeds up to 2 m/s. A desire to greatly increase the sweep speed motivates a re-examination of the fundamentals of photophoresis-based laser-particle traps. Most explanations offered are qualitative, with differing opinions as to whether, for example, asymmetric heating or asymmetric thermal accommodation is primarily at work. Which particles become trapped in the beam is typically based on self-selection, as a variety of particles with possible differing shapes and sizes are offered to the laser focus for capture. Characteristics that make some particles preferred over others are especially relevant. There is broad consensus that structure in the laser focus greatly aids in stable trapping. Nevertheless, it is still possible for even a relatively smooth TEM00 beam to capture and hold particles. Moreover, even in a structured focus (i.e. with aberrations and local intensity minima and maxima), questions remain as to exactly how a particle becomes stably trapped in certain beam locations. A zoomed-in look at trapped particles reveals oscillations or orbits with excursions over tens of microns and accelerations up to 10 gs. We trapped particles in zero-gravity as well as 2-g environments with no noticeable difference in stability. © 2018 SPIE.
1563 a57204415715 Howe L. p591 False Conference 234 Volumetric display by movement of particles trapped in a laser via photophoresis Photophoresis can stably hold opaque microscopic particles in a laser focus surrounded by room air with strength sufficient to enable centimeter-scale patterns to be drawn by sweeping the laser beam. The resulting images rely on visual persistence as laser light scatters from the particle, which is rapidly swept through the 3-D pattern. Control can be maintained while moving the particle with air speeds up to 2 m/s. A desire to greatly increase the sweep speed motivates a re-examination of the fundamentals of photophoresis-based laser-particle traps. Most explanations offered are qualitative, with differing opinions as to whether, for example, asymmetric heating or asymmetric thermal accommodation is primarily at work. Which particles become trapped in the beam is typically based on self-selection, as a variety of particles with possible differing shapes and sizes are offered to the laser focus for capture. Characteristics that make some particles preferred over others are especially relevant. There is broad consensus that structure in the laser focus greatly aids in stable trapping. Nevertheless, it is still possible for even a relatively smooth TEM00 beam to capture and hold particles. Moreover, even in a structured focus (i.e. with aberrations and local intensity minima and maxima), questions remain as to exactly how a particle becomes stably trapped in certain beam locations. A zoomed-in look at trapped particles reveals oscillations or orbits with excursions over tens of microns and accelerations up to 10 gs. We trapped particles in zero-gravity as well as 2-g environments with no noticeable difference in stability. © 2018 SPIE.
1564 a57193610705 Talbot M. p594 False Conference 237 Evaluation and optimization of dynamic cone penetration test (DPT) for assessment of liquefaction in gravelly soils The dynamic cone penetration test (DPT) developed in China has been correlated with liquefaction resistance in gravelly soils based on field performance data from the Mw7.9 Wenchuan, China earthquake. The DPT consists of a 74 mm diameter cone tip driven by a 120 kg hammer with a free fall height of 1 m. To expand the data base, DPT soundings were performed at the Pence Ranch and Larter Ranch sites where gravelly soil liquefied during the 1983 Mw6.9 Borah Peak earthquake. DPT testing was performed using an automatic hammer with the energy specified in the Chinese standard and with an SPT hammer. In general, comparisons suggest that standard energy corrections developed for the SPT can be used for the DPT. The DPT correctly predicted liquefaction and non-liquefaction at these two test sites. Liquefaction resistance from the DPT (30% probability) also correlated reasonably well with that from Becker penetration testing (BPT). Copyright © 2018 Association of State Dam Safety Officials, Inc. All Rights Reserved.
1564 a57193610705 Talbot M. p612 False Conference 250 Evaluation of Dynamic Cone Penetration Test for Liquefaction Assessment of Gravels from Case Histories in Idaho The dynamic cone penetration test (DPT) developed in China has been correlated with liquefaction resistance in gravelly soils based on field performance data from the Mw7.9 Wenchuan earthquake. The DPT consists of a 74 mm diameter cone tip driven by a 120 kg hammer with a free fall height of 100 cm. To expand the data base, DPT soundings were performed at the Pence Ranch and Larter Ranch sites where gravelly soil liquefied during the 1983 Mw6.9 Borah Peak earthquake. DPT testing was performed using an automatic hammer with the energy specified in the Chinese standard and with an SPT hammer. Comparisons suggest that standard energy corrections developed for the SPT can be used for the DPT. In general, the DPT correctly predicted liquefaction and non-liquefaction at these two test sites. Liquefaction resistance from the DPT also correlated reasonably well with that from Becker penetration testing (BPT). © 2018 American Society of Civil Engineers.
1565 a15833172400 Rajnarayan D. p596 True Conference 239 Universal airfoil parametrization using B-splines In this paper, we apply well-known techniques for parametric curves to the definition and deformation of airfoil sections. While it has already been shown that many versions of Kulfan’s Class Shape Transformation (CST) are exactly equivalent to Bézier curves, we show here that all NACA 4-digit thickness distributions and the PARSEC parametrization of Sobiezcky are also higher-order Bézier curves. As with CST, Béziers and B-Splines provide direct control over aerodynamically meaningful features such as nose radius and boat-tail angle, but also provide more a intuitive parametrization of the rest of the airfoil surface. We show the efficacy of B-Spline-based parametrizations for approximating airfoil coordinates and for clean-sheet airfoil design. Finally, we show that this parametrization is ideally suited for progressive design. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1566 a36618663400 Custer C.H. p597 False Conference 240 Analysis of distortion transfer and generation through a compressor using the harmonic balance approach Inlet flow distortion significantly affects an engine’s overall performance. It can be difficult to predict the transfer of distortion through a compressor because traditional experimental and computational methods are very expensive and time consuming. The Harmonic Balance approach is a promising alternative which uses Fourier techniques to represent fluid flow solutions. Relatively little work has been done to assess how much Fourier information is necessary to calculate a sufficiently accurate solution with the Harmonic Balance Solver. This study focuses on analyzing the effects of varying the amount of modal content that is used in Harmonic Balance simulations. Inlet distortion profiles with varying magnitudes are used in order to analyze trends and provide insight into the distortion flow physics for various inlet conditions. The geometry is a single stage axial compressor that consists of an inlet guide vane followed by the NASA Stage 37 rotor. It is shown that simulations with greater magnitudes of distortion require more modal content in order to achieve sufficiently accurate results. Harmonic Balance simulations are shown to have significantly lower computational costs than simulations with a conventional unsteady solver. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1567 a57194636792 Dearden J. p600 True Journal 307 Cylindrical cross-axis flexural pivots The cylindrical cross-axis flexural pivot (CCAFP) is proposed as an ultra-compact flexure capable of being integrated into hollow cylindrical shafts, enabling shaft motion without inhibiting cables or other components inside the shaft. Mechanism geometry, materials, and manufacturing are proposed and the results analyzed and tested. A parametric finite element model of the CCAFP was created to analyze the force-deflection and strain-deflection relationships and the predicted behavior was verified by experiment. Analytic models of stress-limiting cam-surfaces suggest even larger motions may be possible when not limited by current practical constraints. The CCAFP is demonstrated and tested at multiple size scales and in multiple materials, ranging from 28.6 mm diameter 4130 steel (achieving 9 degrees of angular deflection) to 3 mm diameter NiTi (achieving an angular deflection of 85 degrees). The results are generalized to apply to a range of applications, and the CCAFP particularly shows promise for implementation in minimally invasive surgical instruments to decrease instrument size while maintaining instrument performance. © 2017 Elsevier Inc.
1567 a57194636792 Dearden J. p699 True Journal 342 Inverted L-arm gripper compliant mechanism This work exploits the advantages of compliant mechanisms (devices that achieve their motion through the deflection of flexible members) to enable the creation of small instruments for minimally invasive surgery (MIS). Using flexures to achieve motion presents challenges, three of which are considered in this work. First, compliant mechanisms generally perform inadequately in compression. Second, for a 690 deg range of motion desired for each jaw, the bending stresses in the flexures are prohibitive considering materials used in current instruments. Third, for cables attached at fixed points on the mechanism, the mechanical advantage will vary considerably during actuation. Research results are presented that address these challenges using compliant mechanism principles as demonstrated in a two-degree-of-freedom (2DoF) L-Arm gripper. © 2017 by ASME.
1568 a55916540700 Grames C. p600 False Journal 307 Cylindrical cross-axis flexural pivots The cylindrical cross-axis flexural pivot (CCAFP) is proposed as an ultra-compact flexure capable of being integrated into hollow cylindrical shafts, enabling shaft motion without inhibiting cables or other components inside the shaft. Mechanism geometry, materials, and manufacturing are proposed and the results analyzed and tested. A parametric finite element model of the CCAFP was created to analyze the force-deflection and strain-deflection relationships and the predicted behavior was verified by experiment. Analytic models of stress-limiting cam-surfaces suggest even larger motions may be possible when not limited by current practical constraints. The CCAFP is demonstrated and tested at multiple size scales and in multiple materials, ranging from 28.6 mm diameter 4130 steel (achieving 9 degrees of angular deflection) to 3 mm diameter NiTi (achieving an angular deflection of 85 degrees). The results are generalized to apply to a range of applications, and the CCAFP particularly shows promise for implementation in minimally invasive surgical instruments to decrease instrument size while maintaining instrument performance. © 2017 Elsevier Inc.
1568 a55916540700 Grames C. p699 False Journal 342 Inverted L-arm gripper compliant mechanism This work exploits the advantages of compliant mechanisms (devices that achieve their motion through the deflection of flexible members) to enable the creation of small instruments for minimally invasive surgery (MIS). Using flexures to achieve motion presents challenges, three of which are considered in this work. First, compliant mechanisms generally perform inadequately in compression. Second, for a 690 deg range of motion desired for each jaw, the bending stresses in the flexures are prohibitive considering materials used in current instruments. Third, for cables attached at fixed points on the mechanism, the mechanical advantage will vary considerably during actuation. Research results are presented that address these challenges using compliant mechanism principles as demonstrated in a two-degree-of-freedom (2DoF) L-Arm gripper. © 2017 by ASME.
1569 a57196484337 Orr J. p600 False Journal 307 Cylindrical cross-axis flexural pivots The cylindrical cross-axis flexural pivot (CCAFP) is proposed as an ultra-compact flexure capable of being integrated into hollow cylindrical shafts, enabling shaft motion without inhibiting cables or other components inside the shaft. Mechanism geometry, materials, and manufacturing are proposed and the results analyzed and tested. A parametric finite element model of the CCAFP was created to analyze the force-deflection and strain-deflection relationships and the predicted behavior was verified by experiment. Analytic models of stress-limiting cam-surfaces suggest even larger motions may be possible when not limited by current practical constraints. The CCAFP is demonstrated and tested at multiple size scales and in multiple materials, ranging from 28.6 mm diameter 4130 steel (achieving 9 degrees of angular deflection) to 3 mm diameter NiTi (achieving an angular deflection of 85 degrees). The results are generalized to apply to a range of applications, and the CCAFP particularly shows promise for implementation in minimally invasive surgical instruments to decrease instrument size while maintaining instrument performance. © 2017 Elsevier Inc.
1570 a57207228951 Dillon P.B. p601 True Conference 241 Strut-and-tie models for masonry walls with openings There is a large collection of masonry models due to the highly complex and heterogeneous nature of masonry as a structural material. While the individual masonry components can be considered isotropic at the material level, masonry assemblages are anisotropic at the structural level. These properties of masonry make it difficult to develop models that accurately describe the material behavior for all analysis and design scenarios. One analysis tool that is efficient and reliable is the use of stress fields. Stress fields are based on the lower-bound theorem of the theory of plasticity. Stress fields have been combined with the truss analogy to produce what is known as the strut-and-tie modelling procedure. This article presents ongoing research that has the objective to develop strut-and-tie modelling procedures for masonry. The presented methodology uses the existing strut-and-tie guidelines for reinforced concrete as starting point and applies that methodology to the modelling of several masonry shear walls with openings. The shear strength predictions from the proposed strut-and-tie modelling methodology are shown to perform well compared to the experimental strengths. This is associated with the ability of the strut-and-tie modelling procedure to account for the geometric particularities of each wall. © 2018 The International Masonry Society (IMS).
1571 a57193727615 Eixenberger J.G. p602 True Conference 242 Finite element model of dry-stack masonry shear walls Dry-stack masonry systems are constructed without mortar between the blocks. This reduces the cost of specialty laborers and the variability in construction that exists from the application of mortar. Several dry-stack systems exist and can be subcategorized as interlocking systems or surface bonded systems. In interlocking systems, the blocks are connected by their geometry while in surface bonded systems the blocks are connected by a structural coating applied to the surface of the wall. This article describes a finite element model that can be used to predict the in-plane capacity and behavior of dry-stack masonry walls with a surface coating. Four walls were built and tested for their in-plane shear capacity. Two walls were unreinforced and ungrouted and two walls were reinforced and grouted at 1.22 m both vertically and horizontally. The results of these tests were used to validate the finite element model. The finite element model was developed using VecTor2. The numerical response is in good agreement to measured response. For the ungrouted unreinforced walls, the calculated maximum load was within 4% and 14% of the measured maximum loads. For the reinforced and grouted walls, the calculated maximum load was within 8% and 1% of the measured maximum loads. © 2018 The International Masonry Society (IMS).
1572 a7402549729 Jensen D.W. p604 True Conference 243 Pull-out strength of fiberglass/epoxy composite rebar manufactured using a three-dimensional braiding process This research demonstrated the ability to produce high quality fiberglass-epoxy rebar using a continuous three-dimensional braiding process. The tensile pull-out strength of the composite rebar embedded in concrete was measured and compared to steel rebar. Fiberglass/epoxy is less likely to corrode than steel rebar, ensuring more sustainable concrete structures in infrastructure applications. The 0.5" diameter composite rebar was produced by pulling hundreds of strands of unidirectional fiberglass/epoxy towpreg to form the core of a cylindrical rod. The rods were consolidated by overwrapping strands of aramid fiber under tension in a spiral fashion, and cured using the manufacturer's (TCR Composites) recommended 250°F cure cycle. Configurations manufactured and tested included tow variations of aramid overwrap (dry and prepreg) with and without sand coating embedded in concrete cubes (8"x8"x8"). The results are compared to baseline values obtained by testing traditional steel rebar and commercially-Available fiberglass composite rebar. The tensile pull-out (bond) strength was quantified using a test fixture in accordance with ACI 440.3R-12. Measurements were collected at both the free and loaded ends of the rebar, with freeend results yielding a more accurate indication of rebar bond stress. The bond strength of the in-house manufactured fiberglass/epoxy rebar was comparable to steel rebar and commercial fiberglass composite rebar. The sand coating increased the surface roughness, improving the bond strength of the composite rebar by margins of 43-58% percent. Fiberglass/epoxy composite rebar consolidated with prepreg aramid tow and subsequently coated with sand resulted in a bond strength slightly higher, but comparable to steel. This study demonstrates the ability to consistently produce high quality fiberglass/epoxy composite rebar using an innovative, low cost, high production rate, three-dimensional braiding process. © 2018 33rd Technical Conference of the American Society for Composites 2018. All rights reserved.
1572 a7402549729 Jensen D.W. p806 False Conference 341 Pull-out strength of composite rebar made using a three-dimensional braiding machine The objective of this research was to explore and demonstrate the production and performance of fiber-reinforced polymer (FRP) rebar manufactured on a continuous three-dimensional braiding machine for use as reinforcement in concrete structures. FRP rebar is generally as strong as steel rebar, but less susceptible to corrosion, providing a significant advantage over traditional steel reinforcement in concrete structures. In this study, a variety of different design configurations of carbon/epoxy composite cylindrical rebar rods were manufactured, embedded in concrete, and tested in axial tension to identify the relationships between manufacturing parameters and tensile pull-out strength of the rebar. The rebar was produced by combining multiple tows of carbon/epoxy prepreg to form the core of cylindrical rods which were consolidated using various spirally-wound consolidation fibers. The rods were cured at 121 degrees Celsius as specified by the material manufacturer, TCR Composites. The manufactured rods were approximately 10.4 mm in diameter. Primary variables investigated included the consolidation fiber material (aramid, fiberglass and basalt), prepreg vs. dry consolidation tows, the number of tows used to consolidate the rebar (i.e., the size of tows used to consolidate the rebar). Larger consolidation tows were created by braiding three smaller tows together. The consolidation tows also served the purpose of providing the rebar with ribs similar to those on steel rebar to improve bonding. Select rebar samples were subsequently coated with sand to increase rebar surface roughness for improved bonding with concrete. The rebar was cast in 200 mm × 200 mm × 200 mm concrete cubes to investigate bond strength. The strength of the bond between concrete and FRP rebar was investigated using the pull-out test detailed by ACI 440.3R-12. A test fixture was manufactured to enable testing using a standard tensile testing machine. Standard 12.7 mm diameter steel rebar and a commercially comparable fiberglass rebar were also tested to provide baseline values. Results showed that the bond strength was below 344 MPa (50 ksi) when dry winding was used regardless of whether a single or a multiple tow consolidation bundle was used. Prepreg consolidation combined with sand resulted in a bond strength of 478 MPa (69.3 ksi), comparable to steel at 464 MPa (67.2 ksi). The results demonstrated that consolidating the rods with a wet tow resulted in a rebar which bonded better with concrete than using a dry tow. During testing, it was discovered that dry consolidating materials would easily strip off the rod due to poor bonding. Sand was shown to significantly increase the bond strength of the composite rebar, by more than 30 percent. This study provides the basis for a proposed new low-cost manufacturing method for composite rebar as structural reinforcement in concrete. These preliminary results allowed for a test matrix to be set up where FRP rebar bond strength could be investigated in detail using higher quality samples and more controlled parameters. © 2017 The Composites and Advanced Materials Expo (CAMX). All rights reserved.
1573 a57202088821 Machanzi T. p604 False Conference 243 Pull-out strength of fiberglass/epoxy composite rebar manufactured using a three-dimensional braiding process This research demonstrated the ability to produce high quality fiberglass-epoxy rebar using a continuous three-dimensional braiding process. The tensile pull-out strength of the composite rebar embedded in concrete was measured and compared to steel rebar. Fiberglass/epoxy is less likely to corrode than steel rebar, ensuring more sustainable concrete structures in infrastructure applications. The 0.5" diameter composite rebar was produced by pulling hundreds of strands of unidirectional fiberglass/epoxy towpreg to form the core of a cylindrical rod. The rods were consolidated by overwrapping strands of aramid fiber under tension in a spiral fashion, and cured using the manufacturer's (TCR Composites) recommended 250°F cure cycle. Configurations manufactured and tested included tow variations of aramid overwrap (dry and prepreg) with and without sand coating embedded in concrete cubes (8"x8"x8"). The results are compared to baseline values obtained by testing traditional steel rebar and commercially-Available fiberglass composite rebar. The tensile pull-out (bond) strength was quantified using a test fixture in accordance with ACI 440.3R-12. Measurements were collected at both the free and loaded ends of the rebar, with freeend results yielding a more accurate indication of rebar bond stress. The bond strength of the in-house manufactured fiberglass/epoxy rebar was comparable to steel rebar and commercial fiberglass composite rebar. The sand coating increased the surface roughness, improving the bond strength of the composite rebar by margins of 43-58% percent. Fiberglass/epoxy composite rebar consolidated with prepreg aramid tow and subsequently coated with sand resulted in a bond strength slightly higher, but comparable to steel. This study demonstrates the ability to consistently produce high quality fiberglass/epoxy composite rebar using an innovative, low cost, high production rate, three-dimensional braiding process. © 2018 33rd Technical Conference of the American Society for Composites 2018. All rights reserved.
1573 a57202088821 Machanzi T. p806 True Conference 341 Pull-out strength of composite rebar made using a three-dimensional braiding machine The objective of this research was to explore and demonstrate the production and performance of fiber-reinforced polymer (FRP) rebar manufactured on a continuous three-dimensional braiding machine for use as reinforcement in concrete structures. FRP rebar is generally as strong as steel rebar, but less susceptible to corrosion, providing a significant advantage over traditional steel reinforcement in concrete structures. In this study, a variety of different design configurations of carbon/epoxy composite cylindrical rebar rods were manufactured, embedded in concrete, and tested in axial tension to identify the relationships between manufacturing parameters and tensile pull-out strength of the rebar. The rebar was produced by combining multiple tows of carbon/epoxy prepreg to form the core of cylindrical rods which were consolidated using various spirally-wound consolidation fibers. The rods were cured at 121 degrees Celsius as specified by the material manufacturer, TCR Composites. The manufactured rods were approximately 10.4 mm in diameter. Primary variables investigated included the consolidation fiber material (aramid, fiberglass and basalt), prepreg vs. dry consolidation tows, the number of tows used to consolidate the rebar (i.e., the size of tows used to consolidate the rebar). Larger consolidation tows were created by braiding three smaller tows together. The consolidation tows also served the purpose of providing the rebar with ribs similar to those on steel rebar to improve bonding. Select rebar samples were subsequently coated with sand to increase rebar surface roughness for improved bonding with concrete. The rebar was cast in 200 mm × 200 mm × 200 mm concrete cubes to investigate bond strength. The strength of the bond between concrete and FRP rebar was investigated using the pull-out test detailed by ACI 440.3R-12. A test fixture was manufactured to enable testing using a standard tensile testing machine. Standard 12.7 mm diameter steel rebar and a commercially comparable fiberglass rebar were also tested to provide baseline values. Results showed that the bond strength was below 344 MPa (50 ksi) when dry winding was used regardless of whether a single or a multiple tow consolidation bundle was used. Prepreg consolidation combined with sand resulted in a bond strength of 478 MPa (69.3 ksi), comparable to steel at 464 MPa (67.2 ksi). The results demonstrated that consolidating the rods with a wet tow resulted in a rebar which bonded better with concrete than using a dry tow. During testing, it was discovered that dry consolidating materials would easily strip off the rod due to poor bonding. Sand was shown to significantly increase the bond strength of the composite rebar, by more than 30 percent. This study provides the basis for a proposed new low-cost manufacturing method for composite rebar as structural reinforcement in concrete. These preliminary results allowed for a test matrix to be set up where FRP rebar bond strength could be investigated in detail using higher quality samples and more controlled parameters. © 2017 The Composites and Advanced Materials Expo (CAMX). All rights reserved.
1574 a56300864300 Stone B.R. p605 True Journal 309 Collaboration task-technology fit for student distributed engineering design teams Engineers in industry are increasingly called on to work with teammates located in multiple geographic locations (virtual teams). Engineering education has an interest in helping students learn how to best collaborate in these types of situations. Four years of multi-university, multi-disciplinary engineering capstone projects are investigated and related literature is thoroughly examined to demonstrate which collaboration tools, at different stages of the product development process, meet the needs of virtual team members for communication tasks. Student engineering design teams with team members located at various locations should, during the early, middle, and late stages of the product development process, emphasize the use of collaboration tools that will best meet the needs of each stage. In the early stages, teams should emphasize rich communication mediums, such as in-person kick-off meetings. In the middle stages, tools which allow team members to perform their individual work while staying in-sync with their remotely located teammates, such as web conferencing and shared data editing tools, become important. In the late stages, as the team shifts from digital work to physical work, tools such as texting and in-person meetings become more necessary. © 2018 TEMPUS Publications.
1574 a56300864300 Stone B.R. p617 True Journal 309 Profile-based team organization in multi-university capstone engineering design teams Engineers are increasingly required to work in teams that span time zones and cultures. Engineering education has begun to attempt to prepare students for this environment. An important topic is how to best form teams of students for distributed design projects. The goals of this research were to validate a method for organizing teams to maximize team performance and identify and validate metrics for individuals that would help in the organization of distributed teams of student engineers. A review of previous, related research is provided. A description of the proposed method of team organization is given, along with methods of data collection and a comparison of the proposed method to common methods. How students were divided into teams and each team's method of organizing sub-teams are described. Use of online surveys, tests, statistical methods, and other data gathering and analysis methods are explained. Statistical analysis of survey results and qualitative results of interviews and observations suggest that a profile-based method for organizing teams results in significantly higher team satisfaction. Some methods for measuring and/or predicting individual attributes related to teamwork, such as the significance of participation in team sports, were validated. No correlation was found between which university a student attended and a student's level of satisfaction with his or her team. Team success in distributed, multi-disciplinary student design teams can be improved by gathering information about team members and using a profile-based method to organize team members into sub-teams and leadership positions. © 2018 TEMPUS Publications.
1574 a56300864300 Stone B.R. p700 True Journal 339 A multi-user computer-aided design competition: Experimental findings and analysis of team-member dynamics A competition for teams of three students using a prototype multi-user computer-aided design (MUCAD) tool was held to investigate various hypotheses regarding the performance of teams in such a setting. By comparing models from the competition to the same model in a single-user CAD environment, it is seen that use of a MUCAD system can significantly increase the value-added per unit of calendar time for a modeling effort. An investigation was also made into the causes of the performance differences among the various MUCAD teams which participated in the competition. Analysis of the results shows that teams that encouraged effective forms of communication and teams whose members scored similarly on the Purdue Spatial Visualization Test: Visualization of Rotations (PSVT:R) performed better than other teams. Areas of future research in analyzing teams in MUCAD environments are suggested. Copyright © 2017 by ASME.
1574 a56300864300 Stone B.R. p715 True Journal 352 Methods for determining the optimal number of simultaneous contributors for multi-user CAD parts The development of multi-user CAD (MUCAD) tools has opened up exciting new opportunities and applications. The capability for multiple users to simultaneously model and design a CAD part has far-reaching potential. However, many basic questions remains unanswered, such as how many users should work together on a given part. This research proposes and develops a set of methods to determine the optimal number of users for a given part within a MUCAD environment, based on the characteristics of the part itself. Two candidate models are evaluated with a set of 60 experiments with design teams composed of different numbers of users. The models show modest correlations with the test data while more-refined models are explored to improve predictive power. On the other hand, highly significant correlations between the ability to predict completion time and multi-user team size were identified in the experimental data. Observations regarding the speed and quality of MUCAD teams are also made with future areas of research suggested. © 2017 CAD Solutions, LLC.
1575 a57190492863 Wald M.O. p605 False Journal 309 Collaboration task-technology fit for student distributed engineering design teams Engineers in industry are increasingly called on to work with teammates located in multiple geographic locations (virtual teams). Engineering education has an interest in helping students learn how to best collaborate in these types of situations. Four years of multi-university, multi-disciplinary engineering capstone projects are investigated and related literature is thoroughly examined to demonstrate which collaboration tools, at different stages of the product development process, meet the needs of virtual team members for communication tasks. Student engineering design teams with team members located at various locations should, during the early, middle, and late stages of the product development process, emphasize the use of collaboration tools that will best meet the needs of each stage. In the early stages, teams should emphasize rich communication mediums, such as in-person kick-off meetings. In the middle stages, tools which allow team members to perform their individual work while staying in-sync with their remotely located teammates, such as web conferencing and shared data editing tools, become important. In the late stages, as the team shifts from digital work to physical work, tools such as texting and in-person meetings become more necessary. © 2018 TEMPUS Publications.
1576 a18042274300 Richey M.C. p605 False Journal 309 Collaboration task-technology fit for student distributed engineering design teams Engineers in industry are increasingly called on to work with teammates located in multiple geographic locations (virtual teams). Engineering education has an interest in helping students learn how to best collaborate in these types of situations. Four years of multi-university, multi-disciplinary engineering capstone projects are investigated and related literature is thoroughly examined to demonstrate which collaboration tools, at different stages of the product development process, meet the needs of virtual team members for communication tasks. Student engineering design teams with team members located at various locations should, during the early, middle, and late stages of the product development process, emphasize the use of collaboration tools that will best meet the needs of each stage. In the early stages, teams should emphasize rich communication mediums, such as in-person kick-off meetings. In the middle stages, tools which allow team members to perform their individual work while staying in-sync with their remotely located teammates, such as web conferencing and shared data editing tools, become important. In the late stages, as the team shifts from digital work to physical work, tools such as texting and in-person meetings become more necessary. © 2018 TEMPUS Publications.
1576 a18042274300 Richey M.C. p617 False Journal 309 Profile-based team organization in multi-university capstone engineering design teams Engineers are increasingly required to work in teams that span time zones and cultures. Engineering education has begun to attempt to prepare students for this environment. An important topic is how to best form teams of students for distributed design projects. The goals of this research were to validate a method for organizing teams to maximize team performance and identify and validate metrics for individuals that would help in the organization of distributed teams of student engineers. A review of previous, related research is provided. A description of the proposed method of team organization is given, along with methods of data collection and a comparison of the proposed method to common methods. How students were divided into teams and each team's method of organizing sub-teams are described. Use of online surveys, tests, statistical methods, and other data gathering and analysis methods are explained. Statistical analysis of survey results and qualitative results of interviews and observations suggest that a profile-based method for organizing teams results in significantly higher team satisfaction. Some methods for measuring and/or predicting individual attributes related to teamwork, such as the significance of participation in team sports, were validated. No correlation was found between which university a student attended and a student's level of satisfaction with his or her team. Team success in distributed, multi-disciplinary student design teams can be improved by gathering information about team members and using a profile-based method to organize team members into sub-teams and leadership positions. © 2018 TEMPUS Publications.
1576 a18042274300 Richey M.C. p700 False Journal 339 A multi-user computer-aided design competition: Experimental findings and analysis of team-member dynamics A competition for teams of three students using a prototype multi-user computer-aided design (MUCAD) tool was held to investigate various hypotheses regarding the performance of teams in such a setting. By comparing models from the competition to the same model in a single-user CAD environment, it is seen that use of a MUCAD system can significantly increase the value-added per unit of calendar time for a modeling effort. An investigation was also made into the causes of the performance differences among the various MUCAD teams which participated in the competition. Analysis of the results shows that teams that encouraged effective forms of communication and teams whose members scored similarly on the Purdue Spatial Visualization Test: Visualization of Rotations (PSVT:R) performed better than other teams. Areas of future research in analyzing teams in MUCAD environments are suggested. Copyright © 2017 by ASME.
1577 a7403368068 Campbell C. p606 True Conference 244 Comparing in Situ Soil Water Characteristic Curves to Those Generated in the Lab The soil water characteristic curve (SWCC) is of fundamental importance for understanding the characteristics and behavior of unsaturated soil. Recent improvements in measuring suction provided the ability to make fast, accurate SWCCs in the lab but sample throughput drastically limits the number that can be produced. Collocating matric suction and water content sensors in situ would add many more SWCCs to the knowledge base. The objective of this study is to determine how well in situ generated SWCCs using a new, calibrated matric sensor compare to those created in the lab. Field and lab SWCCs compared quite well, but a few factors reduced their agreement. In coarser textured soils, living roots caused a divergence as the soil suction increased. Not surprisingly, intact core samples compared more favorably than disturbed. In finer textured soils, comparisons were favorable, but were also affected when laboratory samples were disturbed. Data suggest collocated in situ sensors could provide an important augmentation to laboratory data for developing a wide range of SWCCs. © 2018 American Society of Civil Engineers (ASCE). All rights reserved.
1578 a57202916476 Campbell A. p606 False Conference 244 Comparing in Situ Soil Water Characteristic Curves to Those Generated in the Lab The soil water characteristic curve (SWCC) is of fundamental importance for understanding the characteristics and behavior of unsaturated soil. Recent improvements in measuring suction provided the ability to make fast, accurate SWCCs in the lab but sample throughput drastically limits the number that can be produced. Collocating matric suction and water content sensors in situ would add many more SWCCs to the knowledge base. The objective of this study is to determine how well in situ generated SWCCs using a new, calibrated matric sensor compare to those created in the lab. Field and lab SWCCs compared quite well, but a few factors reduced their agreement. In coarser textured soils, living roots caused a divergence as the soil suction increased. Not surprisingly, intact core samples compared more favorably than disturbed. In finer textured soils, comparisons were favorable, but were also affected when laboratory samples were disturbed. Data suggest collocated in situ sensors could provide an important augmentation to laboratory data for developing a wide range of SWCCs. © 2018 American Society of Civil Engineers (ASCE). All rights reserved.
1579 a7201389702 Hansen N. p606 False Conference 244 Comparing in Situ Soil Water Characteristic Curves to Those Generated in the Lab The soil water characteristic curve (SWCC) is of fundamental importance for understanding the characteristics and behavior of unsaturated soil. Recent improvements in measuring suction provided the ability to make fast, accurate SWCCs in the lab but sample throughput drastically limits the number that can be produced. Collocating matric suction and water content sensors in situ would add many more SWCCs to the knowledge base. The objective of this study is to determine how well in situ generated SWCCs using a new, calibrated matric sensor compare to those created in the lab. Field and lab SWCCs compared quite well, but a few factors reduced their agreement. In coarser textured soils, living roots caused a divergence as the soil suction increased. Not surprisingly, intact core samples compared more favorably than disturbed. In finer textured soils, comparisons were favorable, but were also affected when laboratory samples were disturbed. Data suggest collocated in situ sensors could provide an important augmentation to laboratory data for developing a wide range of SWCCs. © 2018 American Society of Civil Engineers (ASCE). All rights reserved.
1579 a7201389702 Hansen N. p889 True Journal 414 Dryland agriculture in north america Areas of North America with high density dryland farming include the Canadian Prairies, U.S. and Mexican Great Plains, and the inland pacific northwest of the U.S, with wheat (Tritcum aestivum L.) being the dominant crop. Dryland farming is less dense but important in nearly every state in the western U.S and in northern and central Mexico. In addition to wheat, North American dryland farming is important for the production of maize (Zea maize L.), sorghum (Sorghum bicolor L.), pulses, and oilseeds. The traditional and still prevalent cropping system is a two-year rotation of wheat and summer fallow. In this traditional practice, shallow tillage is used during fallow periods to control weeds and help store moisture in the soil. Sustainability of this practice is limited by soil degradation and erosion and poor water use efficiency. Where adopted, no-till practices improve precipitation storage and use efficiency, which has led to crop intensification and diversification and improvements in soil properties. This chapter highlights some current issues for dryland cropping in North America including integrated pest management for herbicide resistant weeds, diversification of crop rotations, soil carbon dynamics and residue management, and the application of models to aid decision making. Sustaining the dryland cropping systems of North America depends on research and application of practices that reverse past soil degradation, increase cropping system diversity, and apply integrated pest management strategies. Both experimental and modelling approaches are needed to address these challenges. © Springer International Publishing AG 2016.
1580 a16245460000 Hopkins B. p606 False Conference 244 Comparing in Situ Soil Water Characteristic Curves to Those Generated in the Lab The soil water characteristic curve (SWCC) is of fundamental importance for understanding the characteristics and behavior of unsaturated soil. Recent improvements in measuring suction provided the ability to make fast, accurate SWCCs in the lab but sample throughput drastically limits the number that can be produced. Collocating matric suction and water content sensors in situ would add many more SWCCs to the knowledge base. The objective of this study is to determine how well in situ generated SWCCs using a new, calibrated matric sensor compare to those created in the lab. Field and lab SWCCs compared quite well, but a few factors reduced their agreement. In coarser textured soils, living roots caused a divergence as the soil suction increased. Not surprisingly, intact core samples compared more favorably than disturbed. In finer textured soils, comparisons were favorable, but were also affected when laboratory samples were disturbed. Data suggest collocated in situ sensors could provide an important augmentation to laboratory data for developing a wide range of SWCCs. © 2018 American Society of Civil Engineers (ASCE). All rights reserved.
1581 a57202920062 Evans S. p606 False Conference 244 Comparing in Situ Soil Water Characteristic Curves to Those Generated in the Lab The soil water characteristic curve (SWCC) is of fundamental importance for understanding the characteristics and behavior of unsaturated soil. Recent improvements in measuring suction provided the ability to make fast, accurate SWCCs in the lab but sample throughput drastically limits the number that can be produced. Collocating matric suction and water content sensors in situ would add many more SWCCs to the knowledge base. The objective of this study is to determine how well in situ generated SWCCs using a new, calibrated matric sensor compare to those created in the lab. Field and lab SWCCs compared quite well, but a few factors reduced their agreement. In coarser textured soils, living roots caused a divergence as the soil suction increased. Not surprisingly, intact core samples compared more favorably than disturbed. In finer textured soils, comparisons were favorable, but were also affected when laboratory samples were disturbed. Data suggest collocated in situ sensors could provide an important augmentation to laboratory data for developing a wide range of SWCCs. © 2018 American Society of Civil Engineers (ASCE). All rights reserved.
1582 a57202911672 Campbell E. p606 False Conference 244 Comparing in Situ Soil Water Characteristic Curves to Those Generated in the Lab The soil water characteristic curve (SWCC) is of fundamental importance for understanding the characteristics and behavior of unsaturated soil. Recent improvements in measuring suction provided the ability to make fast, accurate SWCCs in the lab but sample throughput drastically limits the number that can be produced. Collocating matric suction and water content sensors in situ would add many more SWCCs to the knowledge base. The objective of this study is to determine how well in situ generated SWCCs using a new, calibrated matric sensor compare to those created in the lab. Field and lab SWCCs compared quite well, but a few factors reduced their agreement. In coarser textured soils, living roots caused a divergence as the soil suction increased. Not surprisingly, intact core samples compared more favorably than disturbed. In finer textured soils, comparisons were favorable, but were also affected when laboratory samples were disturbed. Data suggest collocated in situ sensors could provide an important augmentation to laboratory data for developing a wide range of SWCCs. © 2018 American Society of Civil Engineers (ASCE). All rights reserved.
1583 a6602761720 Cobos D. p606 False Conference 244 Comparing in Situ Soil Water Characteristic Curves to Those Generated in the Lab The soil water characteristic curve (SWCC) is of fundamental importance for understanding the characteristics and behavior of unsaturated soil. Recent improvements in measuring suction provided the ability to make fast, accurate SWCCs in the lab but sample throughput drastically limits the number that can be produced. Collocating matric suction and water content sensors in situ would add many more SWCCs to the knowledge base. The objective of this study is to determine how well in situ generated SWCCs using a new, calibrated matric sensor compare to those created in the lab. Field and lab SWCCs compared quite well, but a few factors reduced their agreement. In coarser textured soils, living roots caused a divergence as the soil suction increased. Not surprisingly, intact core samples compared more favorably than disturbed. In finer textured soils, comparisons were favorable, but were also affected when laboratory samples were disturbed. Data suggest collocated in situ sensors could provide an important augmentation to laboratory data for developing a wide range of SWCCs. © 2018 American Society of Civil Engineers (ASCE). All rights reserved.
1584 a57202607598 Russell D.N. p609 True Conference 247 Lateral resistance of piles within corrugated metal sleeves Pile foundations supporting bridge abutments are often driven inside corrugated metal pipe sleeves (CMS) which extend through the approach fill to reduce downdrag or for construction expediency. The annular space between the pile and the sleeve is typically filled with uncompacted pea gravel. Designers often assume that the lateral resistance of the pile within the sleeve will be minimal; however, no test results are available to confirm this assumption. To investigate the lateral resistance of piles driven within CMS, a full-scale lateral load test was performed. The test pile configuration included a 32.4 cm (12.75 in.) pipe pile within a 60 cm (24 in.) CMS with uncompacted pea gravel filling the annular space. Results indicate that after small pile displacements, the lateral pile resistance was similar to that provided by an individual pipe pile and was even greater at larger displacements. As the pile displaced laterally, the gravel within the annular space became engaged and displaced the CMS into the compacted fill. Back-analyses indicate that the ultimate lateral pile resistance for this case can be approximated by treating the pipe-gravel-CMS as a composite pile having an EI equal to the pipe pile but with a diameter equal to the CMS. © ASCE.
1585 a57196353469 Ishimwe E. p610 True Conference 248 Analysis of post-liquefaction axial capacities of driven pile and drilled shaft foundations The results presented in this paper were obtained from a large testing program that was conducted to evaluate the post-liquefaction axial load capacities of three drilled shaft and three driven pile foundations constructed at the Turrell Arkansas testing site (TATS), located within the New Madrid Seismic Zone. An increase of side and toe resistances, significant ground and driven piles and drilled shafts top settlements were observed following blasting. This increase and settlements were attributed to the increase of effective stress as the excess porewater pressure dissipated. The liquefaction-induced dragloads that developed, at the neutral plane ranged from 200 to 650 kN. The load and settlement distribution curves for each installed foundation during the application of load to the top of each foundation and after blasting are also discussed. The induced dragloads represented more than 5 and 10% of the total resistance of the drilled shaft and driven pile foundations, respectively. © ASCE.
1586 a38061138100 Coffman R.A. p610 False Conference 248 Analysis of post-liquefaction axial capacities of driven pile and drilled shaft foundations The results presented in this paper were obtained from a large testing program that was conducted to evaluate the post-liquefaction axial load capacities of three drilled shaft and three driven pile foundations constructed at the Turrell Arkansas testing site (TATS), located within the New Madrid Seismic Zone. An increase of side and toe resistances, significant ground and driven piles and drilled shafts top settlements were observed following blasting. This increase and settlements were attributed to the increase of effective stress as the excess porewater pressure dissipated. The liquefaction-induced dragloads that developed, at the neutral plane ranged from 200 to 650 kN. The load and settlement distribution curves for each installed foundation during the application of load to the top of each foundation and after blasting are also discussed. The induced dragloads represented more than 5 and 10% of the total resistance of the drilled shaft and driven pile foundations, respectively. © ASCE.
1587 a57202585105 Lopez J.S. p611 True Conference 249 Gravelly Soil Liquefaction after the 2016 Ecuador Earthquake The Mw 7.8 Muisne-Pedernales, Ecuador, earthquake on April 16, 2016, produced significant damage through the northwest coast of Ecuador. Important state infrastructure was seriously affected, including one of the major seaports in the country, the Port of Manta, located in the city that bears its name. This paper focuses on the geotechnical exploration, site characterization, and analyses performed for the marginal wharf's embankment of the port, where clear evidence of liquefaction was observed. Laboratory results showed that the embankment was composed of gravelly sand and sandy gravels, which limited the applicability of common exploration techniques, such as SPT and CPTu tests. Subsequently, liquefaction triggering evaluations were performed based on Vs and the Chinese dynamic penetration test (DPT), which can account for the large gravel content in the soils. The results of this evaluation are presented and compared with field observations showing that these methods correctly identified the potential for liquefaction in the embankment. © 2018 American Society of Civil Engineers.
1588 a24081598300 Vera-Grunauer X. p611 False Conference 249 Gravelly Soil Liquefaction after the 2016 Ecuador Earthquake The Mw 7.8 Muisne-Pedernales, Ecuador, earthquake on April 16, 2016, produced significant damage through the northwest coast of Ecuador. Important state infrastructure was seriously affected, including one of the major seaports in the country, the Port of Manta, located in the city that bears its name. This paper focuses on the geotechnical exploration, site characterization, and analyses performed for the marginal wharf's embankment of the port, where clear evidence of liquefaction was observed. Laboratory results showed that the embankment was composed of gravelly sand and sandy gravels, which limited the applicability of common exploration techniques, such as SPT and CPTu tests. Subsequently, liquefaction triggering evaluations were performed based on Vs and the Chinese dynamic penetration test (DPT), which can account for the large gravel content in the soils. The results of this evaluation are presented and compared with field observations showing that these methods correctly identified the potential for liquefaction in the embankment. © 2018 American Society of Civil Engineers.
1589 a57202572948 Salvatierra G. p611 False Conference 249 Gravelly Soil Liquefaction after the 2016 Ecuador Earthquake The Mw 7.8 Muisne-Pedernales, Ecuador, earthquake on April 16, 2016, produced significant damage through the northwest coast of Ecuador. Important state infrastructure was seriously affected, including one of the major seaports in the country, the Port of Manta, located in the city that bears its name. This paper focuses on the geotechnical exploration, site characterization, and analyses performed for the marginal wharf's embankment of the port, where clear evidence of liquefaction was observed. Laboratory results showed that the embankment was composed of gravelly sand and sandy gravels, which limited the applicability of common exploration techniques, such as SPT and CPTu tests. Subsequently, liquefaction triggering evaluations were performed based on Vs and the Chinese dynamic penetration test (DPT), which can account for the large gravel content in the soils. The results of this evaluation are presented and compared with field observations showing that these methods correctly identified the potential for liquefaction in the embankment. © 2018 American Society of Civil Engineers.
1590 a55898266700 Leslie Youd T. p612 False Conference 250 Evaluation of Dynamic Cone Penetration Test for Liquefaction Assessment of Gravels from Case Histories in Idaho The dynamic cone penetration test (DPT) developed in China has been correlated with liquefaction resistance in gravelly soils based on field performance data from the Mw7.9 Wenchuan earthquake. The DPT consists of a 74 mm diameter cone tip driven by a 120 kg hammer with a free fall height of 100 cm. To expand the data base, DPT soundings were performed at the Pence Ranch and Larter Ranch sites where gravelly soil liquefied during the 1983 Mw6.9 Borah Peak earthquake. DPT testing was performed using an automatic hammer with the energy specified in the Chinese standard and with an SPT hammer. Comparisons suggest that standard energy corrections developed for the SPT can be used for the DPT. In general, the DPT correctly predicted liquefaction and non-liquefaction at these two test sites. Liquefaction resistance from the DPT also correlated reasonably well with that from Becker penetration testing (BPT). © 2018 American Society of Civil Engineers.
1591 a57202580740 Error B.M. p613 False Conference 251 Optimization of Grid Spacing Pattern for the Development of Reference Parameter Maps for Liquefaction-Induced Free-Field Settlement Performance-based earthquake engineering analysis methods are desirable in geotechnical engineering due to their ability to incorporate the various uncertainties associated with complex problems and their ability to frame responses in terms of a targeted hazard. However, such methods are difficult to implement on routine projects without the use of specialized software because the many iterative probabilistic calculations required. Prior research has introduced a simplified approach of using performance-based reference parameter maps in conjunction with correction equations that account for site-specific geotechnical and topographical conditions. This paper addresses the development of such performance-based reference parameter maps for the calculation of post-liquefaction volumetric strains and settlements in the free field. A study is performed and presented to assess the optimized grid spacing for a performance-based volumetric strain analysis and development of a strain performance-based reference parameter map. Recommended grid spacing values as correlated to USGS seismic hazard maps for PGA are provided to produce a maximum of 0.15% strain error in interpolating the reference strain for the simplified performance-based analysis approach. © 2018 American Society of Civil Engineers.
1592 a8724084200 Bush W.S. p614 True Conference 252 Integrating community-level data resources for precision medicine research Precision Medicine focuses on collecting and using individual-level data to improve healthcare outcomes. To date, research efforts have been motivated by molecular-scale measurements, such as incorporating genomic data into clinical use. In many cases however, environmental, social, and economic factors are much more predictive of health outcomes, yet are not systematically used in clinical practice due to the difficulties in measurement and quantification. Advances in both the availability of electronic health information, environmental exposure data, and the more systematic use of geo-coding now provide ways to systematically assess community-level indicators of health, and link these factors to electronic health records for evaluating their influence on disease outcomes. In this workshop, we discuss new electronic sources of community-level data, and provide insight into their utility and validity when compared with gold-standard data collection approaches. © 2017 The Authors.
1593 a7403085570 Crawford D.C. p614 False Conference 252 Integrating community-level data resources for precision medicine research Precision Medicine focuses on collecting and using individual-level data to improve healthcare outcomes. To date, research efforts have been motivated by molecular-scale measurements, such as incorporating genomic data into clinical use. In many cases however, environmental, social, and economic factors are much more predictive of health outcomes, yet are not systematically used in clinical practice due to the difficulties in measurement and quantification. Advances in both the availability of electronic health information, environmental exposure data, and the more systematic use of geo-coding now provide ways to systematically assess community-level indicators of health, and link these factors to electronic health records for evaluating their influence on disease outcomes. In this workshop, we discuss new electronic sources of community-level data, and provide insight into their utility and validity when compared with gold-standard data collection approaches. © 2017 The Authors.
1594 a14621428300 Briggs F. p614 False Conference 252 Integrating community-level data resources for precision medicine research Precision Medicine focuses on collecting and using individual-level data to improve healthcare outcomes. To date, research efforts have been motivated by molecular-scale measurements, such as incorporating genomic data into clinical use. In many cases however, environmental, social, and economic factors are much more predictive of health outcomes, yet are not systematically used in clinical practice due to the difficulties in measurement and quantification. Advances in both the availability of electronic health information, environmental exposure data, and the more systematic use of geo-coding now provide ways to systematically assess community-level indicators of health, and link these factors to electronic health records for evaluating their influence on disease outcomes. In this workshop, we discuss new electronic sources of community-level data, and provide insight into their utility and validity when compared with gold-standard data collection approaches. © 2017 The Authors.
1595 a8667231600 Freedman D. p614 False Conference 252 Integrating community-level data resources for precision medicine research Precision Medicine focuses on collecting and using individual-level data to improve healthcare outcomes. To date, research efforts have been motivated by molecular-scale measurements, such as incorporating genomic data into clinical use. In many cases however, environmental, social, and economic factors are much more predictive of health outcomes, yet are not systematically used in clinical practice due to the difficulties in measurement and quantification. Advances in both the availability of electronic health information, environmental exposure data, and the more systematic use of geo-coding now provide ways to systematically assess community-level indicators of health, and link these factors to electronic health records for evaluating their influence on disease outcomes. In this workshop, we discuss new electronic sources of community-level data, and provide insight into their utility and validity when compared with gold-standard data collection approaches. © 2017 The Authors.
1596 a24382111400 Sloan C. p614 False Conference 252 Integrating community-level data resources for precision medicine research Precision Medicine focuses on collecting and using individual-level data to improve healthcare outcomes. To date, research efforts have been motivated by molecular-scale measurements, such as incorporating genomic data into clinical use. In many cases however, environmental, social, and economic factors are much more predictive of health outcomes, yet are not systematically used in clinical practice due to the difficulties in measurement and quantification. Advances in both the availability of electronic health information, environmental exposure data, and the more systematic use of geo-coding now provide ways to systematically assess community-level indicators of health, and link these factors to electronic health records for evaluating their influence on disease outcomes. In this workshop, we discuss new electronic sources of community-level data, and provide insight into their utility and validity when compared with gold-standard data collection approaches. © 2017 The Authors.
1597 a46062451500 Szymanski R. p615 False Conference 253 Initial Comparisons of Friction Stir Spot Welding and Self Piercing Riveting of Ultra-Thin Steel Sheet Due to the limitations on resistance spot welding of ultra-thin steel sheet (thicknesses below 0.5 mm) in high-volume automotive manufacturing, a comparison of friction stir spot welding and self-piercing riveting was performed to determine which process may be more amenable to enabling assembly of ultra-thin steel sheet. Statistical comparisons between mechanical properties of lap-shear tensile and T-peel were made in sheet thickness below 0.5 mm and for dissimilar thickness combinations. An evaluation of energy to fracture, fracture mechanisms, and joint consistency is presented. © 2018 SAE International; Ford Motor Company; General Motors LLC.
1598 a57188755995 Josephson A.J. p621 True Conference 257 Simplified modeling for soot formation from solid fuels Modeling soot formed from solid complex fuels such as coal or biomass is difficult and rare in the combustion community. Previously a detailed model was developed for soot formation depicting the soot particle size distribution using the method of moments with interpolative closure. This model is both accurate and complex. Computational expense of this model may be beyond many large-scale simulations. As a result, a simplified version of this detailed model has been developed. This simplified model makes two easy assumptions to drastically reduce the complexity of modeling soot formation. First assumption is that soot particles and soot precursors within a computational domain are assumed to be mono-dispersed, meaning all particles are the same size. This reduces the number of resolved terms to model both soot precursors and soot particles to three resolved terms rather than the 10+ terms required by the previously developed model. Second assumption is that all particles are spherical. While the simplified model is computationally less expensive, these two assumptions come with a cost in accuracy. Presented is both the development of this simplified model along with comparative simulations where the complex and simple models are ran. From these simulations, researchers and developers can justify which model may be used in their respective systems. © 2018 Western States Section/Combustion Institute. All rights reserved.
1598 a57188755995 Josephson A.J. p804 True Conference 340 Modeling soot in coal systems The formation of soot in power-boiler systems can have a significant impact on boiler performance due to direct effects on local flame temperatures and wall heat flux. In this work, a soot model was developed for coal systems that accommodates differences between solid fuel systems and gaseous systems, for which most traditional soot models are developed. The developed soot model contains terms for: particle nucleation based on tar evolution in a coal system, a nucle-ation mechanism based on the formation of PAH from gaseous species, gaseous interactions with particles (including: surface growth through HACA, particle oxidation/gasification), coagulation, and aggregation of existing particles. A monodispersed-particle size distribution form of this model can be used for cost-effective simulations, or for simulations with higher fidelity, the method of moments is used to transport higher moments of the particle size distribution. Validation work is presented, comparing numerically-derived soot values from the proposed model against measured soot concentrations in a flat-flame burner. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
1598 a57188755995 Josephson A.J. p849 True Conference 373 Modeling soot formation from solid complex fuels While the phenomena of soot formation in gaseous flames is well studied and understood, extension of the fundamental mechanisms to systems containing complex solid fuels can introduce large uncertainties and inaccuracies. In this study, we have developed a detailed physicsbased model for predicting the evolution of soot particles formed in systems containing complexsolid fuels such as wood or coal. This detailed physics-based model includes two particle-size distributions: that for soot particles and for soot precursor molecules. Sub-models for precursor creation, growth, and thermal cracking are included along with soot particle nucleation, coagulation, surface growth, aggregation, oxidation, and gasification. Validation work is presented comparing experimental results for a coal flame and biomass gasifier against model predicted values for soot concentrations and size distributions. The full detailed model can be computationally expensive when incorporated into CFD simulations; therefore, model simplifications are explored and presented in this work along with some preliminary work of applying particle formation physics to wildfire simulations.
1599 a7005044056 Linn R.R. p621 False Conference 257 Simplified modeling for soot formation from solid fuels Modeling soot formed from solid complex fuels such as coal or biomass is difficult and rare in the combustion community. Previously a detailed model was developed for soot formation depicting the soot particle size distribution using the method of moments with interpolative closure. This model is both accurate and complex. Computational expense of this model may be beyond many large-scale simulations. As a result, a simplified version of this detailed model has been developed. This simplified model makes two easy assumptions to drastically reduce the complexity of modeling soot formation. First assumption is that soot particles and soot precursors within a computational domain are assumed to be mono-dispersed, meaning all particles are the same size. This reduces the number of resolved terms to model both soot precursors and soot particles to three resolved terms rather than the 10+ terms required by the previously developed model. Second assumption is that all particles are spherical. While the simplified model is computationally less expensive, these two assumptions come with a cost in accuracy. Presented is both the development of this simplified model along with comparative simulations where the complex and simple models are ran. From these simulations, researchers and developers can justify which model may be used in their respective systems. © 2018 Western States Section/Combustion Institute. All rights reserved.
1599 a7005044056 Linn R.R. p849 False Conference 373 Modeling soot formation from solid complex fuels While the phenomena of soot formation in gaseous flames is well studied and understood, extension of the fundamental mechanisms to systems containing complex solid fuels can introduce large uncertainties and inaccuracies. In this study, we have developed a detailed physicsbased model for predicting the evolution of soot particles formed in systems containing complexsolid fuels such as wood or coal. This detailed physics-based model includes two particle-size distributions: that for soot particles and for soot precursor molecules. Sub-models for precursor creation, growth, and thermal cracking are included along with soot particle nucleation, coagulation, surface growth, aggregation, oxidation, and gasification. Validation work is presented comparing experimental results for a coal flame and biomass gasifier against model predicted values for soot concentrations and size distributions. The full detailed model can be computationally expensive when incorporated into CFD simulations; therefore, model simplifications are explored and presented in this work along with some preliminary work of applying particle formation physics to wildfire simulations.
1600 a56560099200 Abraham Martin R. p622 True Conference 258 Targeted 3D modeling from UAV imagery Reconstruction of 3D objects from UAV EO imagery yields useful information, but can be time consuming and computationally expensive. View planning reduces processing time by selecting the optimal image set needed to reconstruct a scene. This paper demonstrates how view planning is used in a targeted manner to select a subset of images from a large existing image set to model specific vehicles or structures. Potential applications of the method include enabling 3D target classification algorithms and rapid geo-location. The method could also facilitate on-board reconstruction. The view planning algorithm is tested on five different targets, and is shown to reduce processing time for target models by up to a factor of 50 with little decrease in accuracy. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
1601 a57202738247 Heiner B.K. p622 False Conference 258 Targeted 3D modeling from UAV imagery Reconstruction of 3D objects from UAV EO imagery yields useful information, but can be time consuming and computationally expensive. View planning reduces processing time by selecting the optimal image set needed to reconstruct a scene. This paper demonstrates how view planning is used in a targeted manner to select a subset of images from a large existing image set to model specific vehicles or structures. Potential applications of the method include enabling 3D target classification algorithms and rapid geo-location. The method could also facilitate on-board reconstruction. The view planning algorithm is tested on five different targets, and is shown to reduce processing time for target models by up to a factor of 50 with little decrease in accuracy. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
1602 a55502104200 Micah Downing J. p624 False Conference 260 Dependence of high-performance military aircraft noise on frequency and engine power To further understand the unique characteristics of military aircraft noise, the sound field in the vicinity of a tied-down F-35B was measured for various engine powers, from 25% to 150% Engine Thrust Request (ETR). Synchronous measurements along a linear ground array approximately parallel to the shear layer were used to image the entire field through multisource statistically optimized near-field acoustical holography (M-SONAH). The field in the direction of maximum radiation consists of multiple lobes in the spatiospectral domain, which are manifest as multiple local maxima in space for a fixed frequency or multiple peaks in the spectra at a fixed location. Multiple lobes are observed at non-afterburning and afterburning engine conditions. As frequency increases for a given engine power, lobes appear towards the sideline and shift aft until they disappear beyond the measurement aperture and new lobe(s) take their place. As engine power is increased at a fixed frequency, the forwardmost lobe increases in its relative contribution to the field, which is a major contributing factor to the forward shift in overall directivity with increasing engine power. Field reconstructions and data in the forward direction outside of the region of maximum radiation show the presence of broadband shock-associated noise (BBSAN) for 75% ETR and above. Reconstructions along the nozzle lipline of the jet indicate the BBSAN originates from approximately the same region as the sources for the main radiation direction. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1602 a55502104200 Micah Downing J. p625 False Conference 261 Inclusion of broadband shock-associated noise in spectral decomposition of noise from highperformance military aircraft Attempts to reduce the noise from high-performance military aircraft requires an understanding of the different jet noise generation mechanisms. The primary noise sources originate from interactions between turbulent mixing noise associated with large and finescale turbulent structures and the ambient air. A nonideally expanded jet also contains broadband shock-associated noise. A three-way decomposition of the spectral density measured near a tied-down F-35B quantifies the contribution from each type of noise. The decomposition is performed on noise from a ground-based, linear array of microphones, approximately 8 m from the estimated shear layer, which spanned an angular aperture of 35° to 152° (relative to engine inlet). This large spatial aperture allows for a detailed investigation into the spatial variation in broadband shock-associated noise and fine and large-scale turbulent mixing noise. The spectral decompositions match the measured spectral levels with three main exceptions: 1) the F-35B noise contains multiple spectral peaks in the maximum radiation region, 2) nonlinear propagation increases the high-frequency spectral levels, and 3) the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The main peak of the F-35B broadband shock-associated noise, evident from 35°-70°, has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. The F-35B broadband shockassociated noise peak level and width exhibit different trends than laboratory-scale BBSAN and those recently reported for the F/A-18E [Tam et al., Journal of Sound and Vibration, Vol. 422, 2018, pp. 92-111]. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation from high-performance military aircraft. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1602 a55502104200 Micah Downing J. p861 False Conference 382 Acoustic shock formation in noise propagation during ground run-up operations of military aircraft A distinctive feature of many propagating, high-amplitude jet noise waveforms is the presence of acoustic shocks. Metrics indicative of shock presence, specifically the skewness of the time derivative of the waveform, the average steepening factor, and a new wavelet-based metric called the shock energy fraction (SEF), are used to quantify the strength and prevalence of acoustic shocks within waveforms recorded 10-305 m from a tethered military aircraft. The derivative skewness is more sensitive to the presence of the largest and steepest shocks, while the ASF and SEF tend to emphasize aggregate behavior of the entire waveform. These metrics are applied at engine conditions ranging from 50% to 150% engine thrust request, over a wide range of angles and distances, to assess the growth and decay of shock waves. The responses of these metrics point to significant shock formation occurring through nonlinear propagation out to 76 m from the microphone array reference position. Although these strongest shocks decay, the metrics point to continued nonlinear propagation in the far-field, out to 305 m. Many of these features are accurately characterized using a nonlinear propagation scheme based on the Burgers equation, but this scheme fails to account for multipath interference and significant atmospheric effects over the long propagation distances, resulting in an overestimation of nonlinearity metrics. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1603 a57203330644 Vaugh A.B. p625 False Conference 261 Inclusion of broadband shock-associated noise in spectral decomposition of noise from highperformance military aircraft Attempts to reduce the noise from high-performance military aircraft requires an understanding of the different jet noise generation mechanisms. The primary noise sources originate from interactions between turbulent mixing noise associated with large and finescale turbulent structures and the ambient air. A nonideally expanded jet also contains broadband shock-associated noise. A three-way decomposition of the spectral density measured near a tied-down F-35B quantifies the contribution from each type of noise. The decomposition is performed on noise from a ground-based, linear array of microphones, approximately 8 m from the estimated shear layer, which spanned an angular aperture of 35° to 152° (relative to engine inlet). This large spatial aperture allows for a detailed investigation into the spatial variation in broadband shock-associated noise and fine and large-scale turbulent mixing noise. The spectral decompositions match the measured spectral levels with three main exceptions: 1) the F-35B noise contains multiple spectral peaks in the maximum radiation region, 2) nonlinear propagation increases the high-frequency spectral levels, and 3) the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The main peak of the F-35B broadband shock-associated noise, evident from 35°-70°, has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. The F-35B broadband shockassociated noise peak level and width exhibit different trends than laboratory-scale BBSAN and those recently reported for the F/A-18E [Tam et al., Journal of Sound and Vibration, Vol. 422, 2018, pp. 92-111]. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation from high-performance military aircraft. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1604 a55848648600 Hales Swift S. p625 False Conference 261 Inclusion of broadband shock-associated noise in spectral decomposition of noise from highperformance military aircraft Attempts to reduce the noise from high-performance military aircraft requires an understanding of the different jet noise generation mechanisms. The primary noise sources originate from interactions between turbulent mixing noise associated with large and finescale turbulent structures and the ambient air. A nonideally expanded jet also contains broadband shock-associated noise. A three-way decomposition of the spectral density measured near a tied-down F-35B quantifies the contribution from each type of noise. The decomposition is performed on noise from a ground-based, linear array of microphones, approximately 8 m from the estimated shear layer, which spanned an angular aperture of 35° to 152° (relative to engine inlet). This large spatial aperture allows for a detailed investigation into the spatial variation in broadband shock-associated noise and fine and large-scale turbulent mixing noise. The spectral decompositions match the measured spectral levels with three main exceptions: 1) the F-35B noise contains multiple spectral peaks in the maximum radiation region, 2) nonlinear propagation increases the high-frequency spectral levels, and 3) the low-frequency levels in the maximum radiation region are less than those predicted by the large-scale similarity spectrum. The main peak of the F-35B broadband shock-associated noise, evident from 35°-70°, has the same characteristic shape and variation in peak frequency as overexpanded, laboratory-scale jets. The F-35B broadband shockassociated noise peak level and width exhibit different trends than laboratory-scale BBSAN and those recently reported for the F/A-18E [Tam et al., Journal of Sound and Vibration, Vol. 422, 2018, pp. 92-111]. The strengths and limitations of current models to represent the spatial variation in the spectral content of F-35B noise can guide research efforts to more fully understand the sound radiation from high-performance military aircraft. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1604 a55848648600 Hales Swift S. p861 False Conference 382 Acoustic shock formation in noise propagation during ground run-up operations of military aircraft A distinctive feature of many propagating, high-amplitude jet noise waveforms is the presence of acoustic shocks. Metrics indicative of shock presence, specifically the skewness of the time derivative of the waveform, the average steepening factor, and a new wavelet-based metric called the shock energy fraction (SEF), are used to quantify the strength and prevalence of acoustic shocks within waveforms recorded 10-305 m from a tethered military aircraft. The derivative skewness is more sensitive to the presence of the largest and steepest shocks, while the ASF and SEF tend to emphasize aggregate behavior of the entire waveform. These metrics are applied at engine conditions ranging from 50% to 150% engine thrust request, over a wide range of angles and distances, to assess the growth and decay of shock waves. The responses of these metrics point to significant shock formation occurring through nonlinear propagation out to 76 m from the microphone array reference position. Although these strongest shocks decay, the metrics point to continued nonlinear propagation in the far-field, out to 305 m. Many of these features are accurately characterized using a nonlinear propagation scheme based on the Burgers equation, but this scheme fails to account for multipath interference and significant atmospheric effects over the long propagation distances, resulting in an overestimation of nonlinearity metrics. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1605 a56256103500 Reichman B. p626 True Conference 262 Comparison of noise from high-performance military aircraft for ground run-up and flyover operations While the majority of jet noise analysis takes place with a static jet or aircraft, airbase and community military jet noise exposure happens for the most part when the aircraft is in flight. Comparisons between flyover and ground run-up measurements for high-performance military aircraft have not been previously published. This paper presents comparisons between static ground run-up and flyover measurements for the F-35 operating at 150% Engine Thrust Request. The overall sound pressure levels and spectra are shown for the two scenarios, as well as indicators of nonlinear propagation and shock content, specifically the derivative skewness and average steepening factor. The overall sound pressure level is reduced in the peak radiation direction aft of the aircraft but increased in the forward direction. The peak frequency of the noise is relatively unaffected by flight effects, though the amplitude of each frequency may vary. The increase in level in the forward direction results in shock formation that is absent during ground run-up measurements. © 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
1605 a56256103500 Reichman B. p861 True Conference 382 Acoustic shock formation in noise propagation during ground run-up operations of military aircraft A distinctive feature of many propagating, high-amplitude jet noise waveforms is the presence of acoustic shocks. Metrics indicative of shock presence, specifically the skewness of the time derivative of the waveform, the average steepening factor, and a new wavelet-based metric called the shock energy fraction (SEF), are used to quantify the strength and prevalence of acoustic shocks within waveforms recorded 10-305 m from a tethered military aircraft. The derivative skewness is more sensitive to the presence of the largest and steepest shocks, while the ASF and SEF tend to emphasize aggregate behavior of the entire waveform. These metrics are applied at engine conditions ranging from 50% to 150% engine thrust request, over a wide range of angles and distances, to assess the growth and decay of shock waves. The responses of these metrics point to significant shock formation occurring through nonlinear propagation out to 76 m from the microphone array reference position. Although these strongest shocks decay, the metrics point to continued nonlinear propagation in the far-field, out to 305 m. Many of these features are accurately characterized using a nonlinear propagation scheme based on the Burgers equation, but this scheme fails to account for multipath interference and significant atmospheric effects over the long propagation distances, resulting in an overestimation of nonlinearity metrics. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1606 a55252859600 Hwang J.T. p627 True Conference 263 Large-scale multidisciplinary optimization of an electric aircraft for on-demand mobility Distributed electric propulsion is a key enabling technology for on-demand electric aircraft concepts. NASA’s X-57 Maxwell X-plane is a demonstrator for this technology, and it features a row of high-lift propellers distributed along the leading edge of its wing to enable better aerodynamic efficiency at cruise and improved ride quality in addition to less noise and emissions. This study applies adjointbased multidisciplinary design optimization to this highly coupled design problem. The propulsion, aerodynamics, and structures are modeled using blade element momentum theory, the vortex lattice method, and finite element analysis, respectively, and the full mission profile is discretized and analyzed. The design variables in the optimization problem include the altitude profile, the velocity profile, battery weight, propeller diameter, blade profile parameters, wing thickness distribution, and angle of attack. Optimizations take on the order of 10 hours, and a 12% increase in range is observed. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1607 a23012466600 Migliaccio M. p628 True Journal 311 Guest Editorial Special Issue on Marine and Maritime Radar Remote Sensing [No abstract available]
1608 a35578707100 Heron M.L. p628 False Journal 311 Guest Editorial Special Issue on Marine and Maritime Radar Remote Sensing [No abstract available]
1609 a8533888200 Brower D. p629 False Conference 264 New flow assurance system with high speed subsea fiber optic monitoring of pressure and temperature Subsea production control systems are instrumented to constantly monitor flowline pressure and temperature at key locations to prevent plugging and introduce mitigating control strategies. New fiber optic sensors with ruggedized construction and non-electrical components are subjected to accelerated aging tests and deployed in several installations with long service life. An overview of current progress with fiber optic technology is provided for fatigue monitoring, temperature, pressure, and strain sensing. Recent developments include improved service life, novel bonding methods, pipeline sensor station improvements, sensor calibration, and long-term fatigue analysis. The latest advancements are validated on multiple installations on a subsea tieback in the deepwater Mississippi Canyon of the Gulf of Mexico at 6, 500 ft depth. A prior third-party sensor design experienced multiple non-recoverable sensor failures. A new sensor station design is employed on two Flowline Terminations to monitor pressure and temperature at a rate of 100 Hz. Subsea tiebacks are susceptible to flow assurance issues caused by plugging events such as hydrate formation. The system was originally designed to track pig location but transitioned to pressure and temperature sensing. An issue with the transition was the lack of calibration relating the fiber Bragg grating (FBG) strain levels to the actual process conditions. A novel method is presented for in situ adjustment of the sensor array calibration. During the calibration procedure, the sensors produced unanticipated results during pipeline flow shut-in and later startup operations. The sensors helped uncover a configuration of the flowline and sensor locations that is valuable for detecting hydrate forming conditions at a key junction location. The sensors are located before and after the junction of two flowlines in the mixing zone of the pipeline streams. The novel contributions of this study are the high speed data collection, in situ fiber optic calibration, review of advancements in fiber optic sensing technology, and a field case study with multiple sensing arrays. The developments are part of the Clear Gulf study, a collaboration between the offshore energy industry and NASA that was formed in 2010. The objective of the Clear Gulf study is to employ space technology and testing facilities for use in the upstream industry to advance subsea sensor technology. The highly sensitive monitoring systems developed as part of this study are used to give early warnings for flow assurance issues, structural failures, or catastrophic events. Copyright © 2018 ASME.
1609 a8533888200 Brower D. p647 False Conference 279 Development and testing of a friction-based post-installable fiber-optic monitoring system for subsea applications This paper continues to document the design, development, and test of a friction-based (non-adhesive) post-installable fiberoptic strain sensing system for oil and gas applications - especially those that require deployment on existing subsea structures. (Ref: OMAE2017-61494 Development and Testing of a Friction-Based Post-Installable Sensor for Subsea FiberOptic Monitoring Systems [1]). The prototype fiber-optic monitoring system collects a wide range of real-time data, which can be used to determine structural loading, fatigue, temperature, pressure, and flow assurance on operational platforms. The primary challenge of a post-installed instrumentation monitoring system is to ensure secure coupling between the sensors and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome installation challenges caused by marine growth and soil contamination on subsea structures, flowlines, or risers. This particular design solution is compatible with structures that are suspended in the water column and those that are resting on the seabed. In addition, the system can be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. Operational limitations of the initial design concept were identified in the previous series of tests (2016-2017), and several innovative enhancements have been implemented which resulted in significant improvements in sensor system coupling and strain measurement correlation with traditional strain measuring devices. This paper provides a summary of the notable prototype design changes, full-scale test article buildup, and detailed performance data recorded during tension and compression loading that simulated representative offshore conditions. The test results were positive and demonstrated the effectiveness of the design enhancements. Compromises made during mounting of the sensing elements resulted in better performance in tension than compression. These effects are well understood and are fully discussed, and do not influence the viability of the design changes. This study is part of a continuing collaboration between the Houston-based NASA-Johnson Space Center and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries. Copyright © 2018 ASME.
1610 a57207365951 Wilson J.C. p629 False Conference 264 New flow assurance system with high speed subsea fiber optic monitoring of pressure and temperature Subsea production control systems are instrumented to constantly monitor flowline pressure and temperature at key locations to prevent plugging and introduce mitigating control strategies. New fiber optic sensors with ruggedized construction and non-electrical components are subjected to accelerated aging tests and deployed in several installations with long service life. An overview of current progress with fiber optic technology is provided for fatigue monitoring, temperature, pressure, and strain sensing. Recent developments include improved service life, novel bonding methods, pipeline sensor station improvements, sensor calibration, and long-term fatigue analysis. The latest advancements are validated on multiple installations on a subsea tieback in the deepwater Mississippi Canyon of the Gulf of Mexico at 6, 500 ft depth. A prior third-party sensor design experienced multiple non-recoverable sensor failures. A new sensor station design is employed on two Flowline Terminations to monitor pressure and temperature at a rate of 100 Hz. Subsea tiebacks are susceptible to flow assurance issues caused by plugging events such as hydrate formation. The system was originally designed to track pig location but transitioned to pressure and temperature sensing. An issue with the transition was the lack of calibration relating the fiber Bragg grating (FBG) strain levels to the actual process conditions. A novel method is presented for in situ adjustment of the sensor array calibration. During the calibration procedure, the sensors produced unanticipated results during pipeline flow shut-in and later startup operations. The sensors helped uncover a configuration of the flowline and sensor locations that is valuable for detecting hydrate forming conditions at a key junction location. The sensors are located before and after the junction of two flowlines in the mixing zone of the pipeline streams. The novel contributions of this study are the high speed data collection, in situ fiber optic calibration, review of advancements in fiber optic sensing technology, and a field case study with multiple sensing arrays. The developments are part of the Clear Gulf study, a collaboration between the offshore energy industry and NASA that was formed in 2010. The objective of the Clear Gulf study is to employ space technology and testing facilities for use in the upstream industry to advance subsea sensor technology. The highly sensitive monitoring systems developed as part of this study are used to give early warnings for flow assurance issues, structural failures, or catastrophic events. Copyright © 2018 ASME.
1610 a57207365951 Wilson J.C. p647 False Conference 279 Development and testing of a friction-based post-installable fiber-optic monitoring system for subsea applications This paper continues to document the design, development, and test of a friction-based (non-adhesive) post-installable fiberoptic strain sensing system for oil and gas applications - especially those that require deployment on existing subsea structures. (Ref: OMAE2017-61494 Development and Testing of a Friction-Based Post-Installable Sensor for Subsea FiberOptic Monitoring Systems [1]). The prototype fiber-optic monitoring system collects a wide range of real-time data, which can be used to determine structural loading, fatigue, temperature, pressure, and flow assurance on operational platforms. The primary challenge of a post-installed instrumentation monitoring system is to ensure secure coupling between the sensors and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome installation challenges caused by marine growth and soil contamination on subsea structures, flowlines, or risers. This particular design solution is compatible with structures that are suspended in the water column and those that are resting on the seabed. In addition, the system can be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. Operational limitations of the initial design concept were identified in the previous series of tests (2016-2017), and several innovative enhancements have been implemented which resulted in significant improvements in sensor system coupling and strain measurement correlation with traditional strain measuring devices. This paper provides a summary of the notable prototype design changes, full-scale test article buildup, and detailed performance data recorded during tension and compression loading that simulated representative offshore conditions. The test results were positive and demonstrated the effectiveness of the design enhancements. Compromises made during mounting of the sensing elements resulted in better performance in tension than compression. These effects are well understood and are fully discussed, and do not influence the viability of the design changes. This study is part of a continuing collaboration between the Houston-based NASA-Johnson Space Center and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries. Copyright © 2018 ASME.
1611 a6603042352 High G. p629 False Conference 264 New flow assurance system with high speed subsea fiber optic monitoring of pressure and temperature Subsea production control systems are instrumented to constantly monitor flowline pressure and temperature at key locations to prevent plugging and introduce mitigating control strategies. New fiber optic sensors with ruggedized construction and non-electrical components are subjected to accelerated aging tests and deployed in several installations with long service life. An overview of current progress with fiber optic technology is provided for fatigue monitoring, temperature, pressure, and strain sensing. Recent developments include improved service life, novel bonding methods, pipeline sensor station improvements, sensor calibration, and long-term fatigue analysis. The latest advancements are validated on multiple installations on a subsea tieback in the deepwater Mississippi Canyon of the Gulf of Mexico at 6, 500 ft depth. A prior third-party sensor design experienced multiple non-recoverable sensor failures. A new sensor station design is employed on two Flowline Terminations to monitor pressure and temperature at a rate of 100 Hz. Subsea tiebacks are susceptible to flow assurance issues caused by plugging events such as hydrate formation. The system was originally designed to track pig location but transitioned to pressure and temperature sensing. An issue with the transition was the lack of calibration relating the fiber Bragg grating (FBG) strain levels to the actual process conditions. A novel method is presented for in situ adjustment of the sensor array calibration. During the calibration procedure, the sensors produced unanticipated results during pipeline flow shut-in and later startup operations. The sensors helped uncover a configuration of the flowline and sensor locations that is valuable for detecting hydrate forming conditions at a key junction location. The sensors are located before and after the junction of two flowlines in the mixing zone of the pipeline streams. The novel contributions of this study are the high speed data collection, in situ fiber optic calibration, review of advancements in fiber optic sensing technology, and a field case study with multiple sensing arrays. The developments are part of the Clear Gulf study, a collaboration between the offshore energy industry and NASA that was formed in 2010. The objective of the Clear Gulf study is to employ space technology and testing facilities for use in the upstream industry to advance subsea sensor technology. The highly sensitive monitoring systems developed as part of this study are used to give early warnings for flow assurance issues, structural failures, or catastrophic events. Copyright © 2018 ASME.
1612 a6506484066 Witherow K. p629 False Conference 264 New flow assurance system with high speed subsea fiber optic monitoring of pressure and temperature Subsea production control systems are instrumented to constantly monitor flowline pressure and temperature at key locations to prevent plugging and introduce mitigating control strategies. New fiber optic sensors with ruggedized construction and non-electrical components are subjected to accelerated aging tests and deployed in several installations with long service life. An overview of current progress with fiber optic technology is provided for fatigue monitoring, temperature, pressure, and strain sensing. Recent developments include improved service life, novel bonding methods, pipeline sensor station improvements, sensor calibration, and long-term fatigue analysis. The latest advancements are validated on multiple installations on a subsea tieback in the deepwater Mississippi Canyon of the Gulf of Mexico at 6, 500 ft depth. A prior third-party sensor design experienced multiple non-recoverable sensor failures. A new sensor station design is employed on two Flowline Terminations to monitor pressure and temperature at a rate of 100 Hz. Subsea tiebacks are susceptible to flow assurance issues caused by plugging events such as hydrate formation. The system was originally designed to track pig location but transitioned to pressure and temperature sensing. An issue with the transition was the lack of calibration relating the fiber Bragg grating (FBG) strain levels to the actual process conditions. A novel method is presented for in situ adjustment of the sensor array calibration. During the calibration procedure, the sensors produced unanticipated results during pipeline flow shut-in and later startup operations. The sensors helped uncover a configuration of the flowline and sensor locations that is valuable for detecting hydrate forming conditions at a key junction location. The sensors are located before and after the junction of two flowlines in the mixing zone of the pipeline streams. The novel contributions of this study are the high speed data collection, in situ fiber optic calibration, review of advancements in fiber optic sensing technology, and a field case study with multiple sensing arrays. The developments are part of the Clear Gulf study, a collaboration between the offshore energy industry and NASA that was formed in 2010. The objective of the Clear Gulf study is to employ space technology and testing facilities for use in the upstream industry to advance subsea sensor technology. The highly sensitive monitoring systems developed as part of this study are used to give early warnings for flow assurance issues, structural failures, or catastrophic events. Copyright © 2018 ASME.
1613 a56263632000 Shen W. p630 True Conference 265 Information design in crowdfunding under thresholding policies Crowdfundmg has emerged as a prominent way for entrepreneurs to secure funding without sophisticated intermediation. In crowd- funding, an entrepreneur often has to decide how to disclose the campaign status in order to collect as many contributions as poss ible. Such decisions are difficult to make primarily due to incomp lete information. We propose information design as a tool to help the entrepreneur to improve revenue by influencing backers' bel iefs. We introduce a heuristic algorithm to dynamically compute information-disclosure policies for the entrepreneur, followed by an empirical evaluation to demonstrate its competitiveness over the widely-adopted immediate-disclosure policy. Our results demons trate that the immediate-disclosure policy is not optimal when backers follow thresholding policies despite its ease of implementat ion. With appropriate heuristics, an entrepreneur can benefit from dynamic information disclosure. Our work sheds light on inform ation design in a dynamic setting where agents make decisions using thresholding policies. © 2018 International Foundation for Autonomous Agents and Multiagent Systems.
1614 a56263145300 Yan K. p630 False Conference 265 Information design in crowdfunding under thresholding policies Crowdfundmg has emerged as a prominent way for entrepreneurs to secure funding without sophisticated intermediation. In crowd- funding, an entrepreneur often has to decide how to disclose the campaign status in order to collect as many contributions as poss ible. Such decisions are difficult to make primarily due to incomp lete information. We propose information design as a tool to help the entrepreneur to improve revenue by influencing backers' bel iefs. We introduce a heuristic algorithm to dynamically compute information-disclosure policies for the entrepreneur, followed by an empirical evaluation to demonstrate its competitiveness over the widely-adopted immediate-disclosure policy. Our results demons trate that the immediate-disclosure policy is not optimal when backers follow thresholding policies despite its ease of implementat ion. With appropriate heuristics, an entrepreneur can benefit from dynamic information disclosure. Our work sheds light on inform ation design in a dynamic setting where agents make decisions using thresholding policies. © 2018 International Foundation for Autonomous Agents and Multiagent Systems.
1615 a7103222266 Lopes C.V. p630 False Conference 265 Information design in crowdfunding under thresholding policies Crowdfundmg has emerged as a prominent way for entrepreneurs to secure funding without sophisticated intermediation. In crowd- funding, an entrepreneur often has to decide how to disclose the campaign status in order to collect as many contributions as poss ible. Such decisions are difficult to make primarily due to incomp lete information. We propose information design as a tool to help the entrepreneur to improve revenue by influencing backers' bel iefs. We introduce a heuristic algorithm to dynamically compute information-disclosure policies for the entrepreneur, followed by an empirical evaluation to demonstrate its competitiveness over the widely-adopted immediate-disclosure policy. Our results demons trate that the immediate-disclosure policy is not optimal when backers follow thresholding policies despite its ease of implementat ion. With appropriate heuristics, an entrepreneur can benefit from dynamic information disclosure. Our work sheds light on inform ation design in a dynamic setting where agents make decisions using thresholding policies. © 2018 International Foundation for Autonomous Agents and Multiagent Systems.
1616 a15069700700 Riding K.A. p631 True Conference 266 Environmental and track factors that contribute to abrasion damage Sites with known occurrences of mud pumping or other track concerns were investigated to determine the prevalence of concrete bottom tie abrasion and environmental and track conditions that could contribute to its occurrence. Field investigations showed that it occurs in diverse geographic locations around the U.S. and is a source of continued maintenance concern for railroads. Water appeared to be a significant factor involved in concrete bottom tie abrasion. Ballast fouling, center-binding cracking, rail surface profile variations, and large track movement during loading was seen in locations with concrete bottom tie abrasion. Bumps or track stiffness changes were often found at locations of abrasion damage. Specifically, some locations with known stiff track conditions exhibited significant abrasion damage. Copyright © 2018 ASME.
1617 a7005531426 Peterman R.J. p631 False Conference 266 Environmental and track factors that contribute to abrasion damage Sites with known occurrences of mud pumping or other track concerns were investigated to determine the prevalence of concrete bottom tie abrasion and environmental and track conditions that could contribute to its occurrence. Field investigations showed that it occurs in diverse geographic locations around the U.S. and is a source of continued maintenance concern for railroads. Water appeared to be a significant factor involved in concrete bottom tie abrasion. Ballast fouling, center-binding cracking, rail surface profile variations, and large track movement during loading was seen in locations with concrete bottom tie abrasion. Bumps or track stiffness changes were often found at locations of abrasion damage. Specifically, some locations with known stiff track conditions exhibited significant abrasion damage. Copyright © 2018 ASME.
1618 a57203180502 Guthrie S. p631 False Conference 266 Environmental and track factors that contribute to abrasion damage Sites with known occurrences of mud pumping or other track concerns were investigated to determine the prevalence of concrete bottom tie abrasion and environmental and track conditions that could contribute to its occurrence. Field investigations showed that it occurs in diverse geographic locations around the U.S. and is a source of continued maintenance concern for railroads. Water appeared to be a significant factor involved in concrete bottom tie abrasion. Ballast fouling, center-binding cracking, rail surface profile variations, and large track movement during loading was seen in locations with concrete bottom tie abrasion. Bumps or track stiffness changes were often found at locations of abrasion damage. Specifically, some locations with known stiff track conditions exhibited significant abrasion damage. Copyright © 2018 ASME.
1619 a15843313300 Brueseke M. p631 False Conference 266 Environmental and track factors that contribute to abrasion damage Sites with known occurrences of mud pumping or other track concerns were investigated to determine the prevalence of concrete bottom tie abrasion and environmental and track conditions that could contribute to its occurrence. Field investigations showed that it occurs in diverse geographic locations around the U.S. and is a source of continued maintenance concern for railroads. Water appeared to be a significant factor involved in concrete bottom tie abrasion. Ballast fouling, center-binding cracking, rail surface profile variations, and large track movement during loading was seen in locations with concrete bottom tie abrasion. Bumps or track stiffness changes were often found at locations of abrasion damage. Specifically, some locations with known stiff track conditions exhibited significant abrasion damage. Copyright © 2018 ASME.
1620 a57203186135 Mosavi H. p631 False Conference 266 Environmental and track factors that contribute to abrasion damage Sites with known occurrences of mud pumping or other track concerns were investigated to determine the prevalence of concrete bottom tie abrasion and environmental and track conditions that could contribute to its occurrence. Field investigations showed that it occurs in diverse geographic locations around the U.S. and is a source of continued maintenance concern for railroads. Water appeared to be a significant factor involved in concrete bottom tie abrasion. Ballast fouling, center-binding cracking, rail surface profile variations, and large track movement during loading was seen in locations with concrete bottom tie abrasion. Bumps or track stiffness changes were often found at locations of abrasion damage. Specifically, some locations with known stiff track conditions exhibited significant abrasion damage. Copyright © 2018 ASME.
1621 a57203188461 Daily K. p631 False Conference 266 Environmental and track factors that contribute to abrasion damage Sites with known occurrences of mud pumping or other track concerns were investigated to determine the prevalence of concrete bottom tie abrasion and environmental and track conditions that could contribute to its occurrence. Field investigations showed that it occurs in diverse geographic locations around the U.S. and is a source of continued maintenance concern for railroads. Water appeared to be a significant factor involved in concrete bottom tie abrasion. Ballast fouling, center-binding cracking, rail surface profile variations, and large track movement during loading was seen in locations with concrete bottom tie abrasion. Bumps or track stiffness changes were often found at locations of abrasion damage. Specifically, some locations with known stiff track conditions exhibited significant abrasion damage. Copyright © 2018 ASME.
1622 a57203192544 Risovi-Hendrickson W. p631 False Conference 266 Environmental and track factors that contribute to abrasion damage Sites with known occurrences of mud pumping or other track concerns were investigated to determine the prevalence of concrete bottom tie abrasion and environmental and track conditions that could contribute to its occurrence. Field investigations showed that it occurs in diverse geographic locations around the U.S. and is a source of continued maintenance concern for railroads. Water appeared to be a significant factor involved in concrete bottom tie abrasion. Ballast fouling, center-binding cracking, rail surface profile variations, and large track movement during loading was seen in locations with concrete bottom tie abrasion. Bumps or track stiffness changes were often found at locations of abrasion damage. Specifically, some locations with known stiff track conditions exhibited significant abrasion damage. Copyright © 2018 ASME.
1623 a55182745600 Amoroso S. p632 True Conference 267 Blast-Induced Liquefaction Results at the Silty-Sand Site of Mirabello, Emilia Romagna Region, Italy Recent experiences (e.g. New Zealand and United States) show that blast tests can cause liquefaction, inducing undrained cyclic loading, generating excess pore water pressure, and consequently producing real deformations. This paper introduces the results obtained from a research project on blast induced liquefaction, performed at a trial site located in Mirabello (near Ferrara, Italy), a little village strongly affected by liquefaction during the 2012 Emilia-Romagna earthquake. The liquefiable soils in this area contained significantly more fines than in previous blast tests. In particular, the objectives of the experiment were: (i) to evaluate liquefaction induced settlement of Apennine silts and sands, and Po River sands; (ii) to determine downdrag forces on pile foundations; (iii) to measure change in shear wave velocity/shear modulus with excess pore pressure; and (iv) to measure change in soil properties with time after liquefaction. This paper illustrates the results acquired before, during, and after the blast test using in-situ tests, pore pressure transducers, profilometers, topographical surveys, and a test micropile instrumented with strain gauges. © 2018 American Society of Civil Engineers.
1624 a57195292516 Lusvardi C. p632 False Conference 267 Blast-Induced Liquefaction Results at the Silty-Sand Site of Mirabello, Emilia Romagna Region, Italy Recent experiences (e.g. New Zealand and United States) show that blast tests can cause liquefaction, inducing undrained cyclic loading, generating excess pore water pressure, and consequently producing real deformations. This paper introduces the results obtained from a research project on blast induced liquefaction, performed at a trial site located in Mirabello (near Ferrara, Italy), a little village strongly affected by liquefaction during the 2012 Emilia-Romagna earthquake. The liquefiable soils in this area contained significantly more fines than in previous blast tests. In particular, the objectives of the experiment were: (i) to evaluate liquefaction induced settlement of Apennine silts and sands, and Po River sands; (ii) to determine downdrag forces on pile foundations; (iii) to measure change in shear wave velocity/shear modulus with excess pore pressure; and (iv) to measure change in soil properties with time after liquefaction. This paper illustrates the results acquired before, during, and after the blast test using in-situ tests, pore pressure transducers, profilometers, topographical surveys, and a test micropile instrumented with strain gauges. © 2018 American Society of Civil Engineers.
1625 a19934211900 Monaco P. p632 False Conference 267 Blast-Induced Liquefaction Results at the Silty-Sand Site of Mirabello, Emilia Romagna Region, Italy Recent experiences (e.g. New Zealand and United States) show that blast tests can cause liquefaction, inducing undrained cyclic loading, generating excess pore water pressure, and consequently producing real deformations. This paper introduces the results obtained from a research project on blast induced liquefaction, performed at a trial site located in Mirabello (near Ferrara, Italy), a little village strongly affected by liquefaction during the 2012 Emilia-Romagna earthquake. The liquefiable soils in this area contained significantly more fines than in previous blast tests. In particular, the objectives of the experiment were: (i) to evaluate liquefaction induced settlement of Apennine silts and sands, and Po River sands; (ii) to determine downdrag forces on pile foundations; (iii) to measure change in shear wave velocity/shear modulus with excess pore pressure; and (iv) to measure change in soil properties with time after liquefaction. This paper illustrates the results acquired before, during, and after the blast test using in-situ tests, pore pressure transducers, profilometers, topographical surveys, and a test micropile instrumented with strain gauges. © 2018 American Society of Civil Engineers.
1626 a6603866674 Milana G. p632 False Conference 267 Blast-Induced Liquefaction Results at the Silty-Sand Site of Mirabello, Emilia Romagna Region, Italy Recent experiences (e.g. New Zealand and United States) show that blast tests can cause liquefaction, inducing undrained cyclic loading, generating excess pore water pressure, and consequently producing real deformations. This paper introduces the results obtained from a research project on blast induced liquefaction, performed at a trial site located in Mirabello (near Ferrara, Italy), a little village strongly affected by liquefaction during the 2012 Emilia-Romagna earthquake. The liquefiable soils in this area contained significantly more fines than in previous blast tests. In particular, the objectives of the experiment were: (i) to evaluate liquefaction induced settlement of Apennine silts and sands, and Po River sands; (ii) to determine downdrag forces on pile foundations; (iii) to measure change in shear wave velocity/shear modulus with excess pore pressure; and (iv) to measure change in soil properties with time after liquefaction. This paper illustrates the results acquired before, during, and after the blast test using in-situ tests, pore pressure transducers, profilometers, topographical surveys, and a test micropile instrumented with strain gauges. © 2018 American Society of Civil Engineers.
1627 a57202577089 Morales C. p633 True Conference 268 Simplified Evaluation of the Seismic Failure of an Old Wharf during the 2014 Mw 8.2 Pisagua, Chile, Earthquake The seismic failure of an old quay wall, built in 1932, located in the Port of Iquique during the Mw 8.2 April 1, 2014, Pisagua, Chile, earthquake is studied. A geotechnical exploration, including boreholes, CPT soundings, and surface-based geophysical techniques, was performed to characterize the materials forming the wharf. The data and field observations are then analyzed and used to develop a geotechnical model of two cross-sections modeled in Plaxis2D, to conclude which is the most likely failure mechanism under a dynamic analysis. The results are compared against the deformations measured in a number cross sections of the wharf, suggesting that the failure can be explained by a combined effect of the dynamic increase in lateral earth pressures and the base rotation of the confining walls due to the lack of proper compaction of the rockfill prism below the confining walls. © 2018 American Society of Civil Engineers.
1628 a6505761847 Ledezma C. p633 False Conference 268 Simplified Evaluation of the Seismic Failure of an Old Wharf during the 2014 Mw 8.2 Pisagua, Chile, Earthquake The seismic failure of an old quay wall, built in 1932, located in the Port of Iquique during the Mw 8.2 April 1, 2014, Pisagua, Chile, earthquake is studied. A geotechnical exploration, including boreholes, CPT soundings, and surface-based geophysical techniques, was performed to characterize the materials forming the wharf. The data and field observations are then analyzed and used to develop a geotechnical model of two cross-sections modeled in Plaxis2D, to conclude which is the most likely failure mechanism under a dynamic analysis. The results are compared against the deformations measured in a number cross sections of the wharf, suggesting that the failure can be explained by a combined effect of the dynamic increase in lateral earth pressures and the base rotation of the confining walls due to the lack of proper compaction of the rockfill prism below the confining walls. © 2018 American Society of Civil Engineers.
1629 a36125615300 Sáez E. p633 False Conference 268 Simplified Evaluation of the Seismic Failure of an Old Wharf during the 2014 Mw 8.2 Pisagua, Chile, Earthquake The seismic failure of an old quay wall, built in 1932, located in the Port of Iquique during the Mw 8.2 April 1, 2014, Pisagua, Chile, earthquake is studied. A geotechnical exploration, including boreholes, CPT soundings, and surface-based geophysical techniques, was performed to characterize the materials forming the wharf. The data and field observations are then analyzed and used to develop a geotechnical model of two cross-sections modeled in Plaxis2D, to conclude which is the most likely failure mechanism under a dynamic analysis. The results are compared against the deformations measured in a number cross sections of the wharf, suggesting that the failure can be explained by a combined effect of the dynamic increase in lateral earth pressures and the base rotation of the confining walls due to the lack of proper compaction of the rockfill prism below the confining walls. © 2018 American Society of Civil Engineers.
1630 a36625254200 Hahn A. p635 False Conference 270 A modeling framework for assessing cyber disruptions and attacks to the national airspace system [No abstract available]
1631 a57201333744 Tamini A. p635 False Conference 270 A modeling framework for assessing cyber disruptions and attacks to the national airspace system [No abstract available]
1632 a35479684000 Das S.K. p635 False Conference 270 A modeling framework for assessing cyber disruptions and attacks to the national airspace system [No abstract available]
1633 a56328064900 Putney L. p636 False Journal 309 Puzzling the pieces: Conceptual blocks of engineering student ideas in a service learning project At its core, engineering and similar disciplines rely strongly on technical innovation to design and develop creative solutions to complex problems. However, for novice engineering students, conceptualizing engineering design activities is not an easy task. To do so, they must overcome cognitive blocks to facilitate unique and adequate engineering design solutions. This effect may be compounded when engineering design projects centered around service learning are introduced. The intent of this study was to explore if and what types of conceptual blocks may be present among novice engineering students when design heuristic cues are provided in the classroom. Findings suggest that using classroom interventions around design heuristic, students had a difficult time "shaking off" their conceptual blocks to the design solution. Primarily, communicative and perceptual blocks were found to predominate among novice engineering student groups. © 2018 TEMPUS Publications.
1634 a57191616632 Zhang J. p637 True Conference 271 Local texture evolution and mechanical performance of ultra-high-speed friction stir weld of AA 6111-T4 sheets Friction stir welding has gained wide interest in industry and drawn large research attention due to its high level of automation and superior joint performance. In this study we further expand the welding parameters to be of magnitudes higher than those previously reported to lower the cost and enable high volume joint production. Sound butt-joints were produced with aluminum alloy 6111-T4 blanks with welding speeds up to 6000, mm/min. Tensile tests of the joint pieces show >97% joint efficiency in terms of ultimate tensile strength. The T4 natural aging and grain refinement is found to contribute to the superior joint properties. Electron backscatter diffraction (EBSD) analysis is used to qualitatively study the local shear texture inside the nugget zones of the welds. The shear texture result is a good indicator of the material flow directions in the nugget zones. The flow directions behind the rotation tool are found to be flattened towards the top surface of the workpiece when the welding speed is increased, suggesting intense material mixing and transportation along the longitudinal welding direction (WD). © The Minerals, Metals & Materials Society 2018.
1634 a57191616632 Zhang J. p638 True Journal 227 High-Speed Friction Stir Welding of AA7075-T6 Sheet: Microstructure, Mechanical Properties, Micro-texture, and Thermal History Friction stir welding (FSW) is a cost-effective and high-quality joining process for aluminum alloys (especially heat-treatable alloys) that is historically operated at lower joining speeds (up to hundreds of millimeters per minute). In this study, we present a microstructural analysis of friction stir welded AA7075-T6 blanks with high welding speeds up to 3 M/min. Textures, microstructures, mechanical properties, and weld quality are analyzed using TEM, EBSD, metallographic imaging, and Vickers hardness. The higher welding speed results in narrower, stronger heat-affected zones (HAZs) and also higher hardness in the nugget zones. The material flow direction in the nugget zone is found to be leaning towards the welding direction as the welding speed increases. Results are coupled with welding parameters and thermal history to aid in the understanding of the complex material flow and texture gradients within the welds in an effort to optimize welding parameters for high-speed processing. © 2017, The Minerals, Metals & Materials Society and ASM International.
1634 a57191616632 Zhang J. p873 True Journal 405 High-Speed FSW Aluminum Alloy 7075 Microstructure and Corrosion Properties High-speed friction stir welding provides an opportunity to enable high-volume aluminum joining, thus lowering the expense of the process. To better understand this important industrial process the properties of the welds must be fully characterized. In this study we examined the microstructures of AA7075 butt welds with welding speeds of 1, 2 and 3 m/min. The welds were also tested for their corrosion resistance in a diluted EXCO solution at room temperature. The welds with higher speeds had a smaller corrosion sensitive area along with smaller HAZs, but the nugget zone became more corrosion susceptible. Their microstructure features were used to explain the non-uniform corrosion behavior across the weld. Both constituent particles and precipitate distribution were altered by the friction stir process and resulted in an overall sensitized weld affected region compared to the base material. © 2017, The Minerals, Metals & Materials Society.
1635 a7202713087 Field D.P. p637 False Conference 271 Local texture evolution and mechanical performance of ultra-high-speed friction stir weld of AA 6111-T4 sheets Friction stir welding has gained wide interest in industry and drawn large research attention due to its high level of automation and superior joint performance. In this study we further expand the welding parameters to be of magnitudes higher than those previously reported to lower the cost and enable high volume joint production. Sound butt-joints were produced with aluminum alloy 6111-T4 blanks with welding speeds up to 6000, mm/min. Tensile tests of the joint pieces show >97% joint efficiency in terms of ultimate tensile strength. The T4 natural aging and grain refinement is found to contribute to the superior joint properties. Electron backscatter diffraction (EBSD) analysis is used to qualitatively study the local shear texture inside the nugget zones of the welds. The shear texture result is a good indicator of the material flow directions in the nugget zones. The flow directions behind the rotation tool are found to be flattened towards the top surface of the workpiece when the welding speed is increased, suggesting intense material mixing and transportation along the longitudinal welding direction (WD). © The Minerals, Metals & Materials Society 2018.
1635 a7202713087 Field D.P. p638 False Journal 227 High-Speed Friction Stir Welding of AA7075-T6 Sheet: Microstructure, Mechanical Properties, Micro-texture, and Thermal History Friction stir welding (FSW) is a cost-effective and high-quality joining process for aluminum alloys (especially heat-treatable alloys) that is historically operated at lower joining speeds (up to hundreds of millimeters per minute). In this study, we present a microstructural analysis of friction stir welded AA7075-T6 blanks with high welding speeds up to 3 M/min. Textures, microstructures, mechanical properties, and weld quality are analyzed using TEM, EBSD, metallographic imaging, and Vickers hardness. The higher welding speed results in narrower, stronger heat-affected zones (HAZs) and also higher hardness in the nugget zones. The material flow direction in the nugget zone is found to be leaning towards the welding direction as the welding speed increases. Results are coupled with welding parameters and thermal history to aid in the understanding of the complex material flow and texture gradients within the welds in an effort to optimize welding parameters for high-speed processing. © 2017, The Minerals, Metals & Materials Society and ASM International.
1635 a7202713087 Field D.P. p873 False Journal 405 High-Speed FSW Aluminum Alloy 7075 Microstructure and Corrosion Properties High-speed friction stir welding provides an opportunity to enable high-volume aluminum joining, thus lowering the expense of the process. To better understand this important industrial process the properties of the welds must be fully characterized. In this study we examined the microstructures of AA7075 butt welds with welding speeds of 1, 2 and 3 m/min. The welds were also tested for their corrosion resistance in a diluted EXCO solution at room temperature. The welds with higher speeds had a smaller corrosion sensitive area along with smaller HAZs, but the nugget zone became more corrosion susceptible. Their microstructure features were used to explain the non-uniform corrosion behavior across the weld. Both constituent particles and precipitate distribution were altered by the friction stir process and resulted in an overall sensitized weld affected region compared to the base material. © 2017, The Minerals, Metals & Materials Society.
1636 a57202152391 Ruzindana M. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1637 a7003609448 Jeffs B.D. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1638 a57197521815 Black R.A. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1639 a57201658993 Burnett M. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1640 a7004347500 Pisano D.J. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1641 a7007155092 Lorimer D.R. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1642 a55286783200 Pingel N. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1643 a57120014600 Rajwade K. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1644 a6602913811 Prestage R.M. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1645 a55452524500 White S. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1646 a57212833949 Simon B. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1647 a57206024435 Hawkins L. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1648 a6507270351 Shillue W. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1649 a6602305778 Roshi D.A. p639 False Conference 272 Commissioning observations with the focal L-band Array on the Green Bank Telescope (FLAG) A Focal L-band Array Feed for the Green Bank Telescope (FLAG) has been in development for the last five years. The system comprises a 19 element, dual polarized hexagonal antenna array, cryogenic front end amplifiers, direct RF to digital over fiber conversion, and broadband, real time digital signal processing. Phased array feeds enable continuous wide field, radio camera imaging on a large reflector. FLAG was mounted in summer 2017 on the GBT in West Virginia, USA as part of commissioning tests. We report on measured receiver figures of merit and experimental results, and comparisons to simulated performance. The measured results indicate that the FLAG instrument achieves unprecedented field of view, sensitivity, and survey efficiency. © Institution of Engineering and Technology.All Rights Reserved.
1650 a56218368600 Akamine M. p640 True Journal 312 Effect of nozzle–plate distance on acoustic phenomena from supersonic impinging jet For an adequate understanding of the broadband acoustic phenomena generated by a rocket exhaust jet impinging on a flame deflector, this study experimentally clarifies the factors that cause the difference in the broadband acoustic field of a supersonic ideally expanded jet impinging on an inclined flat plate for various nozzle–plate distances. According to previous studies, there are two possible factors: the Mach waves, which are radiated from the free-jet region and reflected by the plate, and the acoustic waves generated in the impingement region. To distinguish the effects of these factors, this study compares the following three results: the overall sound pressure level distribution, images extracted from the schlieren visualization movies using acoustic-triggered conditional sampling, and tracing lines of the acoustic intensity vectors of the Mach waves. The results reveal that the nozzle–plate distance affects the fraction of the Mach waves that are generated in the free-jet region and reflected by the plate, resulting in a higher overall sound pressure level in the upstream direction for larger nozzle–plate distances. It is concluded that the location of the plate relative to the source region of the Mach waves significantly affects the acoustic phenomena, owing to the variation in the nozzle–plate distances. Copyright © 2018 by Masahito Akamine, Koji Okamoto, Kent L. Gee, Tracianne B. Neilsen, Susumu Teramoto, Takeo Okunuki, and Seiji Tsutsumi.
1650 a56218368600 Akamine M. p862 False Conference 383 Level-educed wavepacket representation of Mach 1.8 laboratory-scale jet noise The search for an equivalent acoustic source model for high-speed jet noise has recently focused on wavepacket representations. A wavepacket is defined as a spatially extended source with an axial amplitude distribution that grows, saturates and decays, an axial phase relationship that produces directional noise, and correlation lengths longer than the integral length scales of the turbulent structures. This definition of a wavepacket has the same characteristics as the large-scale turbulent mixing noise; if the turbulent mixing noise can be isolated, the associate equivalent acoustic wavepacket—defined as a pressure fluctuation on a cylinder around the jet nozzle—can be found. An estimate of the frequencydependent, spatial variation in the large-scale turbulent mixing noise comes from a similarity spectra decomposition of the measured autospectral density, which in turn leads to data-educed wavenumber axial spectra associated with the frequency-dependent equivalent wavepackets. This wavepacket eduction technique has been applied to acoustical measurements of an unheated, Mach 1.8 jet in the near and far fields. At both locations, the resulting frequency-dependent, data-educed wavenumber spectra exhibit different types of self-similarity for low and high frequency regimes that become apparent when the axial wavenumber is scaled by the acoustic wavenumber, with a transition band between the two regimes. As expected, the data-educed wavenumber spectra can be used to predict field levels in the dominant radiation lobe. Addition of an uncorrelated source distribution, derived from the similarity spectra decomposition associated with the fine-scale turbulent mixing noise, creates a model that accounts for the sideline levels. This field-prediction ability of the wavepacket-plus-uncorrelated-distribution model is tested using the near and far field measurements. When predicting the field at the other location, the model’s average error is less than 2 dB for St = 0.04-0.25 but increases for larger St because the apparent directivity changes from near to far field, likely due to the frequency dependence of the extended source region. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1650 a56218368600 Akamine M. p864 False Conference 385 Characterization of supersonic laboratory-scale jet noise with vector acoustic intensity A new method for the calculation of vector acoustic intensity from pressure microphone measurements has been applied to the aeroacoustic source characterization of an unheated, Mach 1.8 laboratory-scale jet. Because of the ability to unwrap the phase of the transfer functions between microphone pairs in the measurement of a radiating, broadband source, physically meaningful near-field intensity vectors are calculated up to the maximum analysis frequency of 32 kHz. The new intensity method is used to obtain a detailed description of the sound energy flow near the jet. The resulting intensity vectors have been used with a ray-tracing technique to identify the dominant source region over a broad range of frequencies. Additional aeroacoustics analyses provide insight into the frequency-dependent characteristics of jet noise radiation, including the nature of the hydrodynamic field and the transition between the principal lobe and sideline radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1651 a55837442300 Okamoto K. p640 False Journal 312 Effect of nozzle–plate distance on acoustic phenomena from supersonic impinging jet For an adequate understanding of the broadband acoustic phenomena generated by a rocket exhaust jet impinging on a flame deflector, this study experimentally clarifies the factors that cause the difference in the broadband acoustic field of a supersonic ideally expanded jet impinging on an inclined flat plate for various nozzle–plate distances. According to previous studies, there are two possible factors: the Mach waves, which are radiated from the free-jet region and reflected by the plate, and the acoustic waves generated in the impingement region. To distinguish the effects of these factors, this study compares the following three results: the overall sound pressure level distribution, images extracted from the schlieren visualization movies using acoustic-triggered conditional sampling, and tracing lines of the acoustic intensity vectors of the Mach waves. The results reveal that the nozzle–plate distance affects the fraction of the Mach waves that are generated in the free-jet region and reflected by the plate, resulting in a higher overall sound pressure level in the upstream direction for larger nozzle–plate distances. It is concluded that the location of the plate relative to the source region of the Mach waves significantly affects the acoustic phenomena, owing to the variation in the nozzle–plate distances. Copyright © 2018 by Masahito Akamine, Koji Okamoto, Kent L. Gee, Tracianne B. Neilsen, Susumu Teramoto, Takeo Okunuki, and Seiji Tsutsumi.
1651 a55837442300 Okamoto K. p862 False Conference 383 Level-educed wavepacket representation of Mach 1.8 laboratory-scale jet noise The search for an equivalent acoustic source model for high-speed jet noise has recently focused on wavepacket representations. A wavepacket is defined as a spatially extended source with an axial amplitude distribution that grows, saturates and decays, an axial phase relationship that produces directional noise, and correlation lengths longer than the integral length scales of the turbulent structures. This definition of a wavepacket has the same characteristics as the large-scale turbulent mixing noise; if the turbulent mixing noise can be isolated, the associate equivalent acoustic wavepacket—defined as a pressure fluctuation on a cylinder around the jet nozzle—can be found. An estimate of the frequencydependent, spatial variation in the large-scale turbulent mixing noise comes from a similarity spectra decomposition of the measured autospectral density, which in turn leads to data-educed wavenumber axial spectra associated with the frequency-dependent equivalent wavepackets. This wavepacket eduction technique has been applied to acoustical measurements of an unheated, Mach 1.8 jet in the near and far fields. At both locations, the resulting frequency-dependent, data-educed wavenumber spectra exhibit different types of self-similarity for low and high frequency regimes that become apparent when the axial wavenumber is scaled by the acoustic wavenumber, with a transition band between the two regimes. As expected, the data-educed wavenumber spectra can be used to predict field levels in the dominant radiation lobe. Addition of an uncorrelated source distribution, derived from the similarity spectra decomposition associated with the fine-scale turbulent mixing noise, creates a model that accounts for the sideline levels. This field-prediction ability of the wavepacket-plus-uncorrelated-distribution model is tested using the near and far field measurements. When predicting the field at the other location, the model’s average error is less than 2 dB for St = 0.04-0.25 but increases for larger St because the apparent directivity changes from near to far field, likely due to the frequency dependence of the extended source region. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1651 a55837442300 Okamoto K. p864 False Conference 385 Characterization of supersonic laboratory-scale jet noise with vector acoustic intensity A new method for the calculation of vector acoustic intensity from pressure microphone measurements has been applied to the aeroacoustic source characterization of an unheated, Mach 1.8 laboratory-scale jet. Because of the ability to unwrap the phase of the transfer functions between microphone pairs in the measurement of a radiating, broadband source, physically meaningful near-field intensity vectors are calculated up to the maximum analysis frequency of 32 kHz. The new intensity method is used to obtain a detailed description of the sound energy flow near the jet. The resulting intensity vectors have been used with a ray-tracing technique to identify the dominant source region over a broad range of frequencies. Additional aeroacoustics analyses provide insight into the frequency-dependent characteristics of jet noise radiation, including the nature of the hydrodynamic field and the transition between the principal lobe and sideline radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1652 a7202751866 Teramoto S. p640 False Journal 312 Effect of nozzle–plate distance on acoustic phenomena from supersonic impinging jet For an adequate understanding of the broadband acoustic phenomena generated by a rocket exhaust jet impinging on a flame deflector, this study experimentally clarifies the factors that cause the difference in the broadband acoustic field of a supersonic ideally expanded jet impinging on an inclined flat plate for various nozzle–plate distances. According to previous studies, there are two possible factors: the Mach waves, which are radiated from the free-jet region and reflected by the plate, and the acoustic waves generated in the impingement region. To distinguish the effects of these factors, this study compares the following three results: the overall sound pressure level distribution, images extracted from the schlieren visualization movies using acoustic-triggered conditional sampling, and tracing lines of the acoustic intensity vectors of the Mach waves. The results reveal that the nozzle–plate distance affects the fraction of the Mach waves that are generated in the free-jet region and reflected by the plate, resulting in a higher overall sound pressure level in the upstream direction for larger nozzle–plate distances. It is concluded that the location of the plate relative to the source region of the Mach waves significantly affects the acoustic phenomena, owing to the variation in the nozzle–plate distances. Copyright © 2018 by Masahito Akamine, Koji Okamoto, Kent L. Gee, Tracianne B. Neilsen, Susumu Teramoto, Takeo Okunuki, and Seiji Tsutsumi.
1652 a7202751866 Teramoto S. p862 False Conference 383 Level-educed wavepacket representation of Mach 1.8 laboratory-scale jet noise The search for an equivalent acoustic source model for high-speed jet noise has recently focused on wavepacket representations. A wavepacket is defined as a spatially extended source with an axial amplitude distribution that grows, saturates and decays, an axial phase relationship that produces directional noise, and correlation lengths longer than the integral length scales of the turbulent structures. This definition of a wavepacket has the same characteristics as the large-scale turbulent mixing noise; if the turbulent mixing noise can be isolated, the associate equivalent acoustic wavepacket—defined as a pressure fluctuation on a cylinder around the jet nozzle—can be found. An estimate of the frequencydependent, spatial variation in the large-scale turbulent mixing noise comes from a similarity spectra decomposition of the measured autospectral density, which in turn leads to data-educed wavenumber axial spectra associated with the frequency-dependent equivalent wavepackets. This wavepacket eduction technique has been applied to acoustical measurements of an unheated, Mach 1.8 jet in the near and far fields. At both locations, the resulting frequency-dependent, data-educed wavenumber spectra exhibit different types of self-similarity for low and high frequency regimes that become apparent when the axial wavenumber is scaled by the acoustic wavenumber, with a transition band between the two regimes. As expected, the data-educed wavenumber spectra can be used to predict field levels in the dominant radiation lobe. Addition of an uncorrelated source distribution, derived from the similarity spectra decomposition associated with the fine-scale turbulent mixing noise, creates a model that accounts for the sideline levels. This field-prediction ability of the wavepacket-plus-uncorrelated-distribution model is tested using the near and far field measurements. When predicting the field at the other location, the model’s average error is less than 2 dB for St = 0.04-0.25 but increases for larger St because the apparent directivity changes from near to far field, likely due to the frequency dependence of the extended source region. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1652 a7202751866 Teramoto S. p864 False Conference 385 Characterization of supersonic laboratory-scale jet noise with vector acoustic intensity A new method for the calculation of vector acoustic intensity from pressure microphone measurements has been applied to the aeroacoustic source characterization of an unheated, Mach 1.8 laboratory-scale jet. Because of the ability to unwrap the phase of the transfer functions between microphone pairs in the measurement of a radiating, broadband source, physically meaningful near-field intensity vectors are calculated up to the maximum analysis frequency of 32 kHz. The new intensity method is used to obtain a detailed description of the sound energy flow near the jet. The resulting intensity vectors have been used with a ray-tracing technique to identify the dominant source region over a broad range of frequencies. Additional aeroacoustics analyses provide insight into the frequency-dependent characteristics of jet noise radiation, including the nature of the hydrodynamic field and the transition between the principal lobe and sideline radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1653 a6506010179 Okunuki T. p640 False Journal 312 Effect of nozzle–plate distance on acoustic phenomena from supersonic impinging jet For an adequate understanding of the broadband acoustic phenomena generated by a rocket exhaust jet impinging on a flame deflector, this study experimentally clarifies the factors that cause the difference in the broadband acoustic field of a supersonic ideally expanded jet impinging on an inclined flat plate for various nozzle–plate distances. According to previous studies, there are two possible factors: the Mach waves, which are radiated from the free-jet region and reflected by the plate, and the acoustic waves generated in the impingement region. To distinguish the effects of these factors, this study compares the following three results: the overall sound pressure level distribution, images extracted from the schlieren visualization movies using acoustic-triggered conditional sampling, and tracing lines of the acoustic intensity vectors of the Mach waves. The results reveal that the nozzle–plate distance affects the fraction of the Mach waves that are generated in the free-jet region and reflected by the plate, resulting in a higher overall sound pressure level in the upstream direction for larger nozzle–plate distances. It is concluded that the location of the plate relative to the source region of the Mach waves significantly affects the acoustic phenomena, owing to the variation in the nozzle–plate distances. Copyright © 2018 by Masahito Akamine, Koji Okamoto, Kent L. Gee, Tracianne B. Neilsen, Susumu Teramoto, Takeo Okunuki, and Seiji Tsutsumi.
1653 a6506010179 Okunuki T. p864 False Conference 385 Characterization of supersonic laboratory-scale jet noise with vector acoustic intensity A new method for the calculation of vector acoustic intensity from pressure microphone measurements has been applied to the aeroacoustic source characterization of an unheated, Mach 1.8 laboratory-scale jet. Because of the ability to unwrap the phase of the transfer functions between microphone pairs in the measurement of a radiating, broadband source, physically meaningful near-field intensity vectors are calculated up to the maximum analysis frequency of 32 kHz. The new intensity method is used to obtain a detailed description of the sound energy flow near the jet. The resulting intensity vectors have been used with a ray-tracing technique to identify the dominant source region over a broad range of frequencies. Additional aeroacoustics analyses provide insight into the frequency-dependent characteristics of jet noise radiation, including the nature of the hydrodynamic field and the transition between the principal lobe and sideline radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1654 a35873737200 Tsutsumi S. p640 False Journal 312 Effect of nozzle–plate distance on acoustic phenomena from supersonic impinging jet For an adequate understanding of the broadband acoustic phenomena generated by a rocket exhaust jet impinging on a flame deflector, this study experimentally clarifies the factors that cause the difference in the broadband acoustic field of a supersonic ideally expanded jet impinging on an inclined flat plate for various nozzle–plate distances. According to previous studies, there are two possible factors: the Mach waves, which are radiated from the free-jet region and reflected by the plate, and the acoustic waves generated in the impingement region. To distinguish the effects of these factors, this study compares the following three results: the overall sound pressure level distribution, images extracted from the schlieren visualization movies using acoustic-triggered conditional sampling, and tracing lines of the acoustic intensity vectors of the Mach waves. The results reveal that the nozzle–plate distance affects the fraction of the Mach waves that are generated in the free-jet region and reflected by the plate, resulting in a higher overall sound pressure level in the upstream direction for larger nozzle–plate distances. It is concluded that the location of the plate relative to the source region of the Mach waves significantly affects the acoustic phenomena, owing to the variation in the nozzle–plate distances. Copyright © 2018 by Masahito Akamine, Koji Okamoto, Kent L. Gee, Tracianne B. Neilsen, Susumu Teramoto, Takeo Okunuki, and Seiji Tsutsumi.
1654 a35873737200 Tsutsumi S. p862 False Conference 383 Level-educed wavepacket representation of Mach 1.8 laboratory-scale jet noise The search for an equivalent acoustic source model for high-speed jet noise has recently focused on wavepacket representations. A wavepacket is defined as a spatially extended source with an axial amplitude distribution that grows, saturates and decays, an axial phase relationship that produces directional noise, and correlation lengths longer than the integral length scales of the turbulent structures. This definition of a wavepacket has the same characteristics as the large-scale turbulent mixing noise; if the turbulent mixing noise can be isolated, the associate equivalent acoustic wavepacket—defined as a pressure fluctuation on a cylinder around the jet nozzle—can be found. An estimate of the frequencydependent, spatial variation in the large-scale turbulent mixing noise comes from a similarity spectra decomposition of the measured autospectral density, which in turn leads to data-educed wavenumber axial spectra associated with the frequency-dependent equivalent wavepackets. This wavepacket eduction technique has been applied to acoustical measurements of an unheated, Mach 1.8 jet in the near and far fields. At both locations, the resulting frequency-dependent, data-educed wavenumber spectra exhibit different types of self-similarity for low and high frequency regimes that become apparent when the axial wavenumber is scaled by the acoustic wavenumber, with a transition band between the two regimes. As expected, the data-educed wavenumber spectra can be used to predict field levels in the dominant radiation lobe. Addition of an uncorrelated source distribution, derived from the similarity spectra decomposition associated with the fine-scale turbulent mixing noise, creates a model that accounts for the sideline levels. This field-prediction ability of the wavepacket-plus-uncorrelated-distribution model is tested using the near and far field measurements. When predicting the field at the other location, the model’s average error is less than 2 dB for St = 0.04-0.25 but increases for larger St because the apparent directivity changes from near to far field, likely due to the frequency dependence of the extended source region. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1654 a35873737200 Tsutsumi S. p864 False Conference 385 Characterization of supersonic laboratory-scale jet noise with vector acoustic intensity A new method for the calculation of vector acoustic intensity from pressure microphone measurements has been applied to the aeroacoustic source characterization of an unheated, Mach 1.8 laboratory-scale jet. Because of the ability to unwrap the phase of the transfer functions between microphone pairs in the measurement of a radiating, broadband source, physically meaningful near-field intensity vectors are calculated up to the maximum analysis frequency of 32 kHz. The new intensity method is used to obtain a detailed description of the sound energy flow near the jet. The resulting intensity vectors have been used with a ray-tracing technique to identify the dominant source region over a broad range of frequencies. Additional aeroacoustics analyses provide insight into the frequency-dependent characteristics of jet noise radiation, including the nature of the hydrodynamic field and the transition between the principal lobe and sideline radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
1655 a37113017300 Savidis N. p641 False Conference 273 Progress in transparent flat-panel holographic displays enabled by guided-wave acousto-optics We have previously introduced a monolithic, integrated optical platform for transparent, flat-panel holographic displays suitable for near-to-eye displays in augmented reality systems. This platform employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram. In this paper, we depict analysis of three key system attributes that inform and influence the display system performance: 1) single-axis diffraction-driven astigmatism, 2) strobed illumination to enforce acousto-optic grating stationarity, and 3) acousto-optically driven spatial Nyquist rate. Copyright © 2018 SPIE. Downloading of the abstract is permitted for personal use only.
1655 a37113017300 Savidis N. p878 False Conference 394 Near-to-eye electroholography via guided-wave acousto-optics for augmented reality Near-to-eye holographic displays act to directly project wavefronts into a viewer's eye in order to recreate 3-D scenes for augmented or virtual reality applications. Recently, several solutions for near-to-eye electroholography have been proposed based on digital spatial light modulators in conjunction with supporting optics, such as holographic waveguides for light delivery; however, such schemes are limited by the inherent low space-bandwidth product available with current digital SLMs. In this paper, we depict a fully monolithic, integrated optical platform for transparent near-to-eye holographic display requiring no supporting optics. Our solution employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram. © 2017 SPIE.
1656 a55919211300 Bove V.M. p641 False Conference 273 Progress in transparent flat-panel holographic displays enabled by guided-wave acousto-optics We have previously introduced a monolithic, integrated optical platform for transparent, flat-panel holographic displays suitable for near-to-eye displays in augmented reality systems. This platform employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram. In this paper, we depict analysis of three key system attributes that inform and influence the display system performance: 1) single-axis diffraction-driven astigmatism, 2) strobed illumination to enforce acousto-optic grating stationarity, and 3) acousto-optically driven spatial Nyquist rate. Copyright © 2018 SPIE. Downloading of the abstract is permitted for personal use only.
1656 a55919211300 Bove V.M. p878 False Conference 394 Near-to-eye electroholography via guided-wave acousto-optics for augmented reality Near-to-eye holographic displays act to directly project wavefronts into a viewer's eye in order to recreate 3-D scenes for augmented or virtual reality applications. Recently, several solutions for near-to-eye electroholography have been proposed based on digital spatial light modulators in conjunction with supporting optics, such as holographic waveguides for light delivery; however, such schemes are limited by the inherent low space-bandwidth product available with current digital SLMs. In this paper, we depict a fully monolithic, integrated optical platform for transparent near-to-eye holographic display requiring no supporting optics. Our solution employs a guided-wave acousto-optic spatial light modulator implemented in lithium niobate in conjunction with an integrated Bragg-regime reflection volume hologram. © 2017 SPIE.
1657 a57202785989 Lane S. p642 True Conference 274 A graph-theoretic understanding of network-wide implications of local cyber protections for mission assurance Modern Department of Defense mission systems are very complex and therefore arduous to defend, especially in the cyber domain. A major cause for this concern arises from the fact that implementation of security protections occur at a local scale, while the important operational security issues stem from a global perspective of the system, e.g., mission assurance. Being able to understand network-wide implications of local cyber protections has the potential to significantly impact the strategies we use to protect modern mission systems. In this work, we present a graph-theoretic perspective on this problem, which is based on a framework for modeling and assessing the integrated cyber-physical dynamics of complex systems. Under the framework, these dynamics (and their relationships) are modeled as a graph and then analyzed using processing techniques from graphtheory. We demonstrate the utility of this framework by conducting insider-attack threat analysis and show how the application of security protections at a local scale impact network-wide security properties from an insider perspective. As a test case, we study the problem of search and rescue (SAR) using unmanned aerial vehicle teams. Unmanned vehicle teams engaged in SAR are prototypical cyber-physical systems, in which local intrusions may cause global disruptions. Here, we describe how the insider modeling framework for cyber-physical dynamics applies to this problem and present results of a network-wide assessment of security properties of the system. We use this assessment to design a security protection for the system in which we use cryptographically secure computation techniques to limit the amount of information sharing required between system components without degrading the correct operation of the system. We show how the application of these techniques on a local scale impacts the security properties of the system on a global scale. © 2018 SPIE.
1658 a56020026900 Clark M.R. p642 False Conference 274 A graph-theoretic understanding of network-wide implications of local cyber protections for mission assurance Modern Department of Defense mission systems are very complex and therefore arduous to defend, especially in the cyber domain. A major cause for this concern arises from the fact that implementation of security protections occur at a local scale, while the important operational security issues stem from a global perspective of the system, e.g., mission assurance. Being able to understand network-wide implications of local cyber protections has the potential to significantly impact the strategies we use to protect modern mission systems. In this work, we present a graph-theoretic perspective on this problem, which is based on a framework for modeling and assessing the integrated cyber-physical dynamics of complex systems. Under the framework, these dynamics (and their relationships) are modeled as a graph and then analyzed using processing techniques from graphtheory. We demonstrate the utility of this framework by conducting insider-attack threat analysis and show how the application of security protections at a local scale impact network-wide security properties from an insider perspective. As a test case, we study the problem of search and rescue (SAR) using unmanned aerial vehicle teams. Unmanned vehicle teams engaged in SAR are prototypical cyber-physical systems, in which local intrusions may cause global disruptions. Here, we describe how the insider modeling framework for cyber-physical dynamics applies to this problem and present results of a network-wide assessment of security properties of the system. We use this assessment to design a security protection for the system in which we use cryptographically secure computation techniques to limit the amount of information sharing required between system components without degrading the correct operation of the system. We show how the application of these techniques on a local scale impacts the security properties of the system on a global scale. © 2018 SPIE.
1659 a57202743127 Jafek B. p643 True Conference 275 Factor analysis in automated face detection: Gender, occlusion, eyewear, brightness, contrast, and focus measure Computer-based facial recognition algorithms exploit the unique characteristics of faces in images. However, in non-cooperative situations these unique characteristics are often disturbed. In this study, we examine the effect of six different factors on face detection in an unconstrained imaging environment: Image brightness, image contrast, focus measure, eyewear, gender, and occlusion. The aim of this study is twofold: First, to quantify detection rates of conventional Haar cascade algorithms across these six factors; and second, to propose methods for automatically labeling datasets whose size prohibits manual labeling. First, we manually classify a uniquely challenging dataset comprising 9,688 images of passengers in vehicles acquired from a roadside camera system. Next, we quantify how each of the aforementioned factors affect face detection on this dataset. Of the six factors studied, occlusion had the most significant impact, resulting in a 54% decrease in detection rate between unoccluded and severely occluded faces in our unique dataset. Finally, we provide a methodology for data analytics of large datasets where manual labeling of the whole dataset is not possible. © 2018 SPIE.
1660 a36162907100 Eicholtz M. p643 False Conference 275 Factor analysis in automated face detection: Gender, occlusion, eyewear, brightness, contrast, and focus measure Computer-based facial recognition algorithms exploit the unique characteristics of faces in images. However, in non-cooperative situations these unique characteristics are often disturbed. In this study, we examine the effect of six different factors on face detection in an unconstrained imaging environment: Image brightness, image contrast, focus measure, eyewear, gender, and occlusion. The aim of this study is twofold: First, to quantify detection rates of conventional Haar cascade algorithms across these six factors; and second, to propose methods for automatically labeling datasets whose size prohibits manual labeling. First, we manually classify a uniquely challenging dataset comprising 9,688 images of passengers in vehicles acquired from a roadside camera system. Next, we quantify how each of the aforementioned factors affect face detection on this dataset. Of the six factors studied, occlusion had the most significant impact, resulting in a 54% decrease in detection rate between unoccluded and severely occluded faces in our unique dataset. Finally, we provide a methodology for data analytics of large datasets where manual labeling of the whole dataset is not possible. © 2018 SPIE.
1661 a57202741808 Hendershott J. p643 False Conference 275 Factor analysis in automated face detection: Gender, occlusion, eyewear, brightness, contrast, and focus measure Computer-based facial recognition algorithms exploit the unique characteristics of faces in images. However, in non-cooperative situations these unique characteristics are often disturbed. In this study, we examine the effect of six different factors on face detection in an unconstrained imaging environment: Image brightness, image contrast, focus measure, eyewear, gender, and occlusion. The aim of this study is twofold: First, to quantify detection rates of conventional Haar cascade algorithms across these six factors; and second, to propose methods for automatically labeling datasets whose size prohibits manual labeling. First, we manually classify a uniquely challenging dataset comprising 9,688 images of passengers in vehicles acquired from a roadside camera system. Next, we quantify how each of the aforementioned factors affect face detection on this dataset. Of the six factors studied, occlusion had the most significant impact, resulting in a 54% decrease in detection rate between unoccluded and severely occluded faces in our unique dataset. Finally, we provide a methodology for data analytics of large datasets where manual labeling of the whole dataset is not possible. © 2018 SPIE.
1662 a57007514800 Johnson C. p643 False Conference 275 Factor analysis in automated face detection: Gender, occlusion, eyewear, brightness, contrast, and focus measure Computer-based facial recognition algorithms exploit the unique characteristics of faces in images. However, in non-cooperative situations these unique characteristics are often disturbed. In this study, we examine the effect of six different factors on face detection in an unconstrained imaging environment: Image brightness, image contrast, focus measure, eyewear, gender, and occlusion. The aim of this study is twofold: First, to quantify detection rates of conventional Haar cascade algorithms across these six factors; and second, to propose methods for automatically labeling datasets whose size prohibits manual labeling. First, we manually classify a uniquely challenging dataset comprising 9,688 images of passengers in vehicles acquired from a roadside camera system. Next, we quantify how each of the aforementioned factors affect face detection on this dataset. Of the six factors studied, occlusion had the most significant impact, resulting in a 54% decrease in detection rate between unoccluded and severely occluded faces in our unique dataset. Finally, we provide a methodology for data analytics of large datasets where manual labeling of the whole dataset is not possible. © 2018 SPIE.
1663 a8410729500 Bolme D. p643 False Conference 275 Factor analysis in automated face detection: Gender, occlusion, eyewear, brightness, contrast, and focus measure Computer-based facial recognition algorithms exploit the unique characteristics of faces in images. However, in non-cooperative situations these unique characteristics are often disturbed. In this study, we examine the effect of six different factors on face detection in an unconstrained imaging environment: Image brightness, image contrast, focus measure, eyewear, gender, and occlusion. The aim of this study is twofold: First, to quantify detection rates of conventional Haar cascade algorithms across these six factors; and second, to propose methods for automatically labeling datasets whose size prohibits manual labeling. First, we manually classify a uniquely challenging dataset comprising 9,688 images of passengers in vehicles acquired from a roadside camera system. Next, we quantify how each of the aforementioned factors affect face detection on this dataset. Of the six factors studied, occlusion had the most significant impact, resulting in a 54% decrease in detection rate between unoccluded and severely occluded faces in our unique dataset. Finally, we provide a methodology for data analytics of large datasets where manual labeling of the whole dataset is not possible. © 2018 SPIE.
1664 a16043812000 Santos-Villalobos H. p643 False Conference 275 Factor analysis in automated face detection: Gender, occlusion, eyewear, brightness, contrast, and focus measure Computer-based facial recognition algorithms exploit the unique characteristics of faces in images. However, in non-cooperative situations these unique characteristics are often disturbed. In this study, we examine the effect of six different factors on face detection in an unconstrained imaging environment: Image brightness, image contrast, focus measure, eyewear, gender, and occlusion. The aim of this study is twofold: First, to quantify detection rates of conventional Haar cascade algorithms across these six factors; and second, to propose methods for automatically labeling datasets whose size prohibits manual labeling. First, we manually classify a uniquely challenging dataset comprising 9,688 images of passengers in vehicles acquired from a roadside camera system. Next, we quantify how each of the aforementioned factors affect face detection on this dataset. Of the six factors studied, occlusion had the most significant impact, resulting in a 54% decrease in detection rate between unoccluded and severely occluded faces in our unique dataset. Finally, we provide a methodology for data analytics of large datasets where manual labeling of the whole dataset is not possible. © 2018 SPIE.
1665 a56244640900 Kovacevic A. p646 True Conference 278 Application of “CODeve” methodology in transatlantic student design project COllaborative DEsign in Virtual Environment (CODEVE) is a teaching methodology developed within the European Global Product Realisation (EGPR) course over a number of years. It was developed to establish suitable teaching practice to educate students on efficient design methods in a distributed product realisation projects in conjunction with an industrial partner. Students work in international teams formed from multiple partner universities. Communication is primarily through video-conferencing and other synchronous and asynchronous means of communication to perform design tasks including the vision, conceptual design, detail design and prototyping. Students ultimately meet during the final workshop at the end of the course to assemble and test prototypes and to disseminate their work to the company and wider public. The CODEVE methodology was tested in the Erasmus+ funded project called Networked Activities for Realisation of Innovative Products (NARIP) from 2015-2107. It has been implemented in academic institution in Europe. This paper discusses applicability of this methodology in the project which connects universities and industry across the Atlantic. Three universities are participating this year: Brigham Young University from Utah, USA with Industrial Design students, University of Technology and Economics of Budapest in Hungary with product design students and City, University of London from the UK with mechanical, aeronautical and electrical engineering students. The industrial partner is Black Diamond, a global company based in Utah, USA, while the manufacturing of prototypes and final workshop are hosted at City, University of London. Time difference, culture and the discipline of study make implementation of CODEVE methodology in this transatlantic project more difficult than if the project is kept within European Universities. This paper outlines challenges and learning outcomes of students on both sides of Atlantic. Recommendations to modifications in CODEVE methodology to suit transatlantic projects are discussed in the paper. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
1666 a57204902241 Tarnok Z. p646 False Conference 278 Application of “CODeve” methodology in transatlantic student design project COllaborative DEsign in Virtual Environment (CODEVE) is a teaching methodology developed within the European Global Product Realisation (EGPR) course over a number of years. It was developed to establish suitable teaching practice to educate students on efficient design methods in a distributed product realisation projects in conjunction with an industrial partner. Students work in international teams formed from multiple partner universities. Communication is primarily through video-conferencing and other synchronous and asynchronous means of communication to perform design tasks including the vision, conceptual design, detail design and prototyping. Students ultimately meet during the final workshop at the end of the course to assemble and test prototypes and to disseminate their work to the company and wider public. The CODEVE methodology was tested in the Erasmus+ funded project called Networked Activities for Realisation of Innovative Products (NARIP) from 2015-2107. It has been implemented in academic institution in Europe. This paper discusses applicability of this methodology in the project which connects universities and industry across the Atlantic. Three universities are participating this year: Brigham Young University from Utah, USA with Industrial Design students, University of Technology and Economics of Budapest in Hungary with product design students and City, University of London from the UK with mechanical, aeronautical and electrical engineering students. The industrial partner is Black Diamond, a global company based in Utah, USA, while the manufacturing of prototypes and final workshop are hosted at City, University of London. Time difference, culture and the discipline of study make implementation of CODEVE methodology in this transatlantic project more difficult than if the project is kept within European Universities. This paper outlines challenges and learning outcomes of students on both sides of Atlantic. Recommendations to modifications in CODEVE methodology to suit transatlantic projects are discussed in the paper. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
1667 a55543519800 Jagadeesh C. p646 False Conference 278 Application of “CODeve” methodology in transatlantic student design project COllaborative DEsign in Virtual Environment (CODEVE) is a teaching methodology developed within the European Global Product Realisation (EGPR) course over a number of years. It was developed to establish suitable teaching practice to educate students on efficient design methods in a distributed product realisation projects in conjunction with an industrial partner. Students work in international teams formed from multiple partner universities. Communication is primarily through video-conferencing and other synchronous and asynchronous means of communication to perform design tasks including the vision, conceptual design, detail design and prototyping. Students ultimately meet during the final workshop at the end of the course to assemble and test prototypes and to disseminate their work to the company and wider public. The CODEVE methodology was tested in the Erasmus+ funded project called Networked Activities for Realisation of Innovative Products (NARIP) from 2015-2107. It has been implemented in academic institution in Europe. This paper discusses applicability of this methodology in the project which connects universities and industry across the Atlantic. Three universities are participating this year: Brigham Young University from Utah, USA with Industrial Design students, University of Technology and Economics of Budapest in Hungary with product design students and City, University of London from the UK with mechanical, aeronautical and electrical engineering students. The industrial partner is Black Diamond, a global company based in Utah, USA, while the manufacturing of prototypes and final workshop are hosted at City, University of London. Time difference, culture and the discipline of study make implementation of CODEVE methodology in this transatlantic project more difficult than if the project is kept within European Universities. This paper outlines challenges and learning outcomes of students on both sides of Atlantic. Recommendations to modifications in CODEVE methodology to suit transatlantic projects are discussed in the paper. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
1668 a56237456900 Read M. p646 False Conference 278 Application of “CODeve” methodology in transatlantic student design project COllaborative DEsign in Virtual Environment (CODEVE) is a teaching methodology developed within the European Global Product Realisation (EGPR) course over a number of years. It was developed to establish suitable teaching practice to educate students on efficient design methods in a distributed product realisation projects in conjunction with an industrial partner. Students work in international teams formed from multiple partner universities. Communication is primarily through video-conferencing and other synchronous and asynchronous means of communication to perform design tasks including the vision, conceptual design, detail design and prototyping. Students ultimately meet during the final workshop at the end of the course to assemble and test prototypes and to disseminate their work to the company and wider public. The CODEVE methodology was tested in the Erasmus+ funded project called Networked Activities for Realisation of Innovative Products (NARIP) from 2015-2107. It has been implemented in academic institution in Europe. This paper discusses applicability of this methodology in the project which connects universities and industry across the Atlantic. Three universities are participating this year: Brigham Young University from Utah, USA with Industrial Design students, University of Technology and Economics of Budapest in Hungary with product design students and City, University of London from the UK with mechanical, aeronautical and electrical engineering students. The industrial partner is Black Diamond, a global company based in Utah, USA, while the manufacturing of prototypes and final workshop are hosted at City, University of London. Time difference, culture and the discipline of study make implementation of CODEVE methodology in this transatlantic project more difficult than if the project is kept within European Universities. This paper outlines challenges and learning outcomes of students on both sides of Atlantic. Recommendations to modifications in CODEVE methodology to suit transatlantic projects are discussed in the paper. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
1669 a57200649104 Horak P. p646 False Conference 278 Application of “CODeve” methodology in transatlantic student design project COllaborative DEsign in Virtual Environment (CODEVE) is a teaching methodology developed within the European Global Product Realisation (EGPR) course over a number of years. It was developed to establish suitable teaching practice to educate students on efficient design methods in a distributed product realisation projects in conjunction with an industrial partner. Students work in international teams formed from multiple partner universities. Communication is primarily through video-conferencing and other synchronous and asynchronous means of communication to perform design tasks including the vision, conceptual design, detail design and prototyping. Students ultimately meet during the final workshop at the end of the course to assemble and test prototypes and to disseminate their work to the company and wider public. The CODEVE methodology was tested in the Erasmus+ funded project called Networked Activities for Realisation of Innovative Products (NARIP) from 2015-2107. It has been implemented in academic institution in Europe. This paper discusses applicability of this methodology in the project which connects universities and industry across the Atlantic. Three universities are participating this year: Brigham Young University from Utah, USA with Industrial Design students, University of Technology and Economics of Budapest in Hungary with product design students and City, University of London from the UK with mechanical, aeronautical and electrical engineering students. The industrial partner is Black Diamond, a global company based in Utah, USA, while the manufacturing of prototypes and final workshop are hosted at City, University of London. Time difference, culture and the discipline of study make implementation of CODEVE methodology in this transatlantic project more difficult than if the project is kept within European Universities. This paper outlines challenges and learning outcomes of students on both sides of Atlantic. Recommendations to modifications in CODEVE methodology to suit transatlantic projects are discussed in the paper. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
1670 a57208645178 Leto A. p646 False Conference 278 Application of “CODeve” methodology in transatlantic student design project COllaborative DEsign in Virtual Environment (CODEVE) is a teaching methodology developed within the European Global Product Realisation (EGPR) course over a number of years. It was developed to establish suitable teaching practice to educate students on efficient design methods in a distributed product realisation projects in conjunction with an industrial partner. Students work in international teams formed from multiple partner universities. Communication is primarily through video-conferencing and other synchronous and asynchronous means of communication to perform design tasks including the vision, conceptual design, detail design and prototyping. Students ultimately meet during the final workshop at the end of the course to assemble and test prototypes and to disseminate their work to the company and wider public. The CODEVE methodology was tested in the Erasmus+ funded project called Networked Activities for Realisation of Innovative Products (NARIP) from 2015-2107. It has been implemented in academic institution in Europe. This paper discusses applicability of this methodology in the project which connects universities and industry across the Atlantic. Three universities are participating this year: Brigham Young University from Utah, USA with Industrial Design students, University of Technology and Economics of Budapest in Hungary with product design students and City, University of London from the UK with mechanical, aeronautical and electrical engineering students. The industrial partner is Black Diamond, a global company based in Utah, USA, while the manufacturing of prototypes and final workshop are hosted at City, University of London. Time difference, culture and the discipline of study make implementation of CODEVE methodology in this transatlantic project more difficult than if the project is kept within European Universities. This paper outlines challenges and learning outcomes of students on both sides of Atlantic. Recommendations to modifications in CODEVE methodology to suit transatlantic projects are discussed in the paper. © 2018 Institution of Engineering Designers The Design Society. All Rights Reserved.
1671 a56890778700 Seaman C.H. p647 True Conference 279 Development and testing of a friction-based post-installable fiber-optic monitoring system for subsea applications This paper continues to document the design, development, and test of a friction-based (non-adhesive) post-installable fiberoptic strain sensing system for oil and gas applications - especially those that require deployment on existing subsea structures. (Ref: OMAE2017-61494 Development and Testing of a Friction-Based Post-Installable Sensor for Subsea FiberOptic Monitoring Systems [1]). The prototype fiber-optic monitoring system collects a wide range of real-time data, which can be used to determine structural loading, fatigue, temperature, pressure, and flow assurance on operational platforms. The primary challenge of a post-installed instrumentation monitoring system is to ensure secure coupling between the sensors and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome installation challenges caused by marine growth and soil contamination on subsea structures, flowlines, or risers. This particular design solution is compatible with structures that are suspended in the water column and those that are resting on the seabed. In addition, the system can be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. Operational limitations of the initial design concept were identified in the previous series of tests (2016-2017), and several innovative enhancements have been implemented which resulted in significant improvements in sensor system coupling and strain measurement correlation with traditional strain measuring devices. This paper provides a summary of the notable prototype design changes, full-scale test article buildup, and detailed performance data recorded during tension and compression loading that simulated representative offshore conditions. The test results were positive and demonstrated the effectiveness of the design enhancements. Compromises made during mounting of the sensing elements resulted in better performance in tension than compression. These effects are well understood and are fully discussed, and do not influence the viability of the design changes. This study is part of a continuing collaboration between the Houston-based NASA-Johnson Space Center and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries. Copyright © 2018 ASME.
1672 a56094587000 Kipp R.M. p647 False Conference 279 Development and testing of a friction-based post-installable fiber-optic monitoring system for subsea applications This paper continues to document the design, development, and test of a friction-based (non-adhesive) post-installable fiberoptic strain sensing system for oil and gas applications - especially those that require deployment on existing subsea structures. (Ref: OMAE2017-61494 Development and Testing of a Friction-Based Post-Installable Sensor for Subsea FiberOptic Monitoring Systems [1]). The prototype fiber-optic monitoring system collects a wide range of real-time data, which can be used to determine structural loading, fatigue, temperature, pressure, and flow assurance on operational platforms. The primary challenge of a post-installed instrumentation monitoring system is to ensure secure coupling between the sensors and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome installation challenges caused by marine growth and soil contamination on subsea structures, flowlines, or risers. This particular design solution is compatible with structures that are suspended in the water column and those that are resting on the seabed. In addition, the system can be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. Operational limitations of the initial design concept were identified in the previous series of tests (2016-2017), and several innovative enhancements have been implemented which resulted in significant improvements in sensor system coupling and strain measurement correlation with traditional strain measuring devices. This paper provides a summary of the notable prototype design changes, full-scale test article buildup, and detailed performance data recorded during tension and compression loading that simulated representative offshore conditions. The test results were positive and demonstrated the effectiveness of the design enhancements. Compromises made during mounting of the sensing elements resulted in better performance in tension than compression. These effects are well understood and are fully discussed, and do not influence the viability of the design changes. This study is part of a continuing collaboration between the Houston-based NASA-Johnson Space Center and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries. Copyright © 2018 ASME.
1673 a56890178400 Tang H.H. p647 False Conference 279 Development and testing of a friction-based post-installable fiber-optic monitoring system for subsea applications This paper continues to document the design, development, and test of a friction-based (non-adhesive) post-installable fiberoptic strain sensing system for oil and gas applications - especially those that require deployment on existing subsea structures. (Ref: OMAE2017-61494 Development and Testing of a Friction-Based Post-Installable Sensor for Subsea FiberOptic Monitoring Systems [1]). The prototype fiber-optic monitoring system collects a wide range of real-time data, which can be used to determine structural loading, fatigue, temperature, pressure, and flow assurance on operational platforms. The primary challenge of a post-installed instrumentation monitoring system is to ensure secure coupling between the sensors and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome installation challenges caused by marine growth and soil contamination on subsea structures, flowlines, or risers. This particular design solution is compatible with structures that are suspended in the water column and those that are resting on the seabed. In addition, the system can be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. Operational limitations of the initial design concept were identified in the previous series of tests (2016-2017), and several innovative enhancements have been implemented which resulted in significant improvements in sensor system coupling and strain measurement correlation with traditional strain measuring devices. This paper provides a summary of the notable prototype design changes, full-scale test article buildup, and detailed performance data recorded during tension and compression loading that simulated representative offshore conditions. The test results were positive and demonstrated the effectiveness of the design enhancements. Compromises made during mounting of the sensing elements resulted in better performance in tension than compression. These effects are well understood and are fully discussed, and do not influence the viability of the design changes. This study is part of a continuing collaboration between the Houston-based NASA-Johnson Space Center and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries. Copyright © 2018 ASME.
1674 a55806548500 Bentley N.L. p647 False Conference 279 Development and testing of a friction-based post-installable fiber-optic monitoring system for subsea applications This paper continues to document the design, development, and test of a friction-based (non-adhesive) post-installable fiberoptic strain sensing system for oil and gas applications - especially those that require deployment on existing subsea structures. (Ref: OMAE2017-61494 Development and Testing of a Friction-Based Post-Installable Sensor for Subsea FiberOptic Monitoring Systems [1]). The prototype fiber-optic monitoring system collects a wide range of real-time data, which can be used to determine structural loading, fatigue, temperature, pressure, and flow assurance on operational platforms. The primary challenge of a post-installed instrumentation monitoring system is to ensure secure coupling between the sensors and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome installation challenges caused by marine growth and soil contamination on subsea structures, flowlines, or risers. This particular design solution is compatible with structures that are suspended in the water column and those that are resting on the seabed. In addition, the system can be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. Operational limitations of the initial design concept were identified in the previous series of tests (2016-2017), and several innovative enhancements have been implemented which resulted in significant improvements in sensor system coupling and strain measurement correlation with traditional strain measuring devices. This paper provides a summary of the notable prototype design changes, full-scale test article buildup, and detailed performance data recorded during tension and compression loading that simulated representative offshore conditions. The test results were positive and demonstrated the effectiveness of the design enhancements. Compromises made during mounting of the sensing elements resulted in better performance in tension than compression. These effects are well understood and are fully discussed, and do not influence the viability of the design changes. This study is part of a continuing collaboration between the Houston-based NASA-Johnson Space Center and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries. Copyright © 2018 ASME.
1675 a56890669600 Le S.Q. p647 False Conference 279 Development and testing of a friction-based post-installable fiber-optic monitoring system for subsea applications This paper continues to document the design, development, and test of a friction-based (non-adhesive) post-installable fiberoptic strain sensing system for oil and gas applications - especially those that require deployment on existing subsea structures. (Ref: OMAE2017-61494 Development and Testing of a Friction-Based Post-Installable Sensor for Subsea FiberOptic Monitoring Systems [1]). The prototype fiber-optic monitoring system collects a wide range of real-time data, which can be used to determine structural loading, fatigue, temperature, pressure, and flow assurance on operational platforms. The primary challenge of a post-installed instrumentation monitoring system is to ensure secure coupling between the sensors and the structure of interest for reliable measurements. Friction-based coupling devices have the potential to overcome installation challenges caused by marine growth and soil contamination on subsea structures, flowlines, or risers. This particular design solution is compatible with structures that are suspended in the water column and those that are resting on the seabed. In addition, the system can be installed by commercial divers in shallow depths or by remotely operated vehicles in deep-water applications. Operational limitations of the initial design concept were identified in the previous series of tests (2016-2017), and several innovative enhancements have been implemented which resulted in significant improvements in sensor system coupling and strain measurement correlation with traditional strain measuring devices. This paper provides a summary of the notable prototype design changes, full-scale test article buildup, and detailed performance data recorded during tension and compression loading that simulated representative offshore conditions. The test results were positive and demonstrated the effectiveness of the design enhancements. Compromises made during mounting of the sensing elements resulted in better performance in tension than compression. These effects are well understood and are fully discussed, and do not influence the viability of the design changes. This study is part of a continuing collaboration between the Houston-based NASA-Johnson Space Center and Astro Technology, Inc. within a study called Clear Gulf. The primary objective of the Clear Gulf study is to develop advanced instrumentation technologies that will improve operational safety and reduce the risk of hydrocarbon spillage. NASA provided unique insights, expansive test facilities, and technical expertise to advance these technologies that would benefit the environment, the public, and commercial industries. Copyright © 2018 ASME.
1676 a36082483100 Baird G.M. p648 True Conference 280 Fixing the O&M Budget with Asset Management to Create More Capital Debt Capacity for Pipe Projects Infrastructure asset management programs should be focused on managing assets in a way in which the investment for each asset can be optimized producing overall cost savings in both operations and capital budgets. While there is a great amount of evidence of increasing water main breaks and further aging water infrastructure failures an approach looking at each stage of the asset's life cycle is important in reducing costs, allocating resources effectively, and providing a financial condition where the debt ratio can have a margin necessary to issue debt to support water pipe repair and replacement projects. In order to best take into consideration all of the aspects of determining the likelihood of failure as part of the maintenance and capital repair and replacement programs, machine learning can be used as a desktop condition assessment exercise to increase accuracy in predicting the segments of pipe needing additional investment. © 2018 American Society of Civil Engineers.
1676 a36082483100 Baird G.M. p652 True Conference 282 Defining a Sustainable Underground Infrastructure Framework: ISO Asset Management and ISO Life Cycle Sustainability is broadly defined to mean systems that are able to meet the needs of current and future generations by being physically resilient, cost-effective, environmentally viable, and socially equitable. While the term is applied to various types of infrastructure, the real application of sustainability practices needs to be applied to underground water infrastructure. In order to determine the best sustainable outcomes a common standard of weighing alternatives and making decisions should be followed. The International Standards Organization (ISO) is an independent, non-governmental organization which facilitates world trade by providing common standards between nations. The ISO has standards which can benefit sustainable infrastructure decision making specifically in 3 main areas: life cycle assessment, life cycle costing, and asset management. This paper defines a sustainable framework for underground pipe infrastructure in the context of ISO standards and industry best practices. © 2018 American Society of Civil Engineers.
1676 a36082483100 Baird G.M. p653 True Conference 283 How Green Are You? Economic and Environmental Sustainability: Assessing the Global Warming Potential (GMP) of Your Underground Infrastructure As municipalities across the United States and Canada focus on delivering the essentials of clean water, efficient wastewater treatment, and judicious control of storm water, government officials, engineers, and the companies that install, operate, and maintain piping infrastructure need to understand that a life cycle systems approach. Sustainability concerns apply to many critical resources such as water. On a per capita basis, the U.S. leads the world in water usage, with a substantial portion of water consumed/leaked by infrastructure systems. Because of water availability, competing water demands, and changing hydrologic conditions, the U.S. Department of Interior predicts that multiple water conflicts will occur in the western U.S. by 2025. In addition, decades of excessive demands on ecological systems have reduced their capacities to absorb and process emissions and wastes. Sustainable water infrastructure is vital to providing the American public with clean and safe water and helping to ensure the environmental, economic, and social health of the nation's communities. The increasing interest in sustainability has led to the development of sustainability assessment tools such as life cycle assessments (LCA) analyzing the embodied energy and environmental impacts. Life cycle assessment (LCA) is a tool used to identify the environmental impacts of a product, process, or activity over the entire lifespan of the product. LCA studies also quantify and interpret the environmental flows to and from the environment (including emissions to air, water, and land, as well as the consumption of energy and other material resources) over the entire life cycle of a product (or process or service). By including the impacts throughout the product life cycle, LCA provides a comprehensive view of the environmental aspects of the product and an accurate picture of the true environmental tradeoffs in product selection. © 2018 American Society of Civil Engineers.
1676 a36082483100 Baird G.M. p655 True Conference 285 Benchmarking your break rates: A review of new findings and trends from north American water main break studies The water industry has seen many types of academic surveys and studies on water main replacement programs and the benefits of asset management and prioritization. However, many utilities have not historically tracked all of the elements of water main break data. One factor used to quantify the occurrences of failing underground pipe networks is water main break rates. Water main break rates are calculated for all pipe materials used in water delivery to create a measurement to judge pipe performance and durability. Water main break rates can vary year to year and by utility. However, in aggregate, break rates produce a compelling story which can aid our prudent decision making as it relates to repairing and replacing our underground pipes. In April 2012, Utah State University published an initial comprehensive survey of water utilities. This was a survey of water main breaks and operating characteristics at utilities located in U.S. and Canada. Six years later in 2018, a new water main break study was released reviewing the national metric for citizens served per one mile of pipe, aggregate data on pipe material break rates, the analysis of age and corrosion in failure modes, and related observations on pressure, delivery volumes, effects of soil corrosivity, and trenchless technology practices. This paper reviews the newest water main break study metrics and findings and outlines various trends and projections of water main breaks in the U.S. and Canada which can be used to benchmark an organization's water main breaks and use this critical data in asset management plans. © 2018 American Society of Civil Engineers.
1676 a36082483100 Baird G.M. p658 True Conference 286 Water main criticality scoring and GIS centric risk mitigation: Applying GIS spatial analysis tools and apps for greater insight for high risk underground infrastructure With the pressure to provide excellent services under constrained budgets, utilities are adopting asset management as the synergistic framework combining strategic and financial planning, levels of service, and risk-based analysis to determine investments. GIS (geographic information system) helps to empower a utility with the tools to drive a robust and strategic, decision making process. When a CMMS (computerized maintenance management system) has asset management functionality, the capabilities of service requests, inspections and work orders, capturing costs, and work history can be leveraged into asset condition and risk-based spatial analysis by determining what, when, why, and where the next round of investment should occur. A critical step in the process includes analyzing the data and location to potential take actions to reduce the risks. In alignment with ISO (International Standards Organization) 55000, risk is defined as the probability of failure (PoF) multiplied by the consequence of failure (CoF) which produces the business risk exposure (BRE). While calculating risk is important, the risk-based data can be used to build business cases and determine future projects. GIS can help users gain an understanding of what assets are high risk, where they are located and what factor can influence the risk. Risk-based analysis provides the reasoning for potential solutions and action. This paper defines and explores the use of GIS-centric analysis tools to enhance the asset management decision making process. © 2018 American Society of Civil Engineers.
1677 a57217723923 Guillou J. p649 True Journal 313 From lignocellulose to biocomposite: Multi-level modelling and experimental investigation of the thermal properties of kenaf fiber reinforced composites based on constituent materials Natural fibers (such as kenaf) have garnered interest recently for use in composites because of their relatively high specific properties, low cost, and low environmental impact. Their thermal property information is limited, lacking experimental data on key properties such as thermal conductivity, specific heat, and CTE of the component fiber. This paper presents, for the first time, the thermal property data on kenaf fiber reinforced composites, and an approach to obtain the composite thermal properties based on constituent properties. Individual, plant-based fibers were measured independently and were then used to inform successful predictions of the effective thermal conductivity of the fiber reinforced composites. A unit cell model has been developed to predict the thermal properties of a planar, randomly oriented kenaf fiber-reinforced composite (near 22% volume fraction loading), which includes the effect of void content on the predicted thermal conductivity. A lower-level model is also developed for individual fiber thermal properties based on its constituents (lignin, cellulose, and hemicellulose). To validate this multi-level model, experimental measurements of the thermal diffusivity, coefficient of thermal expansion, and specific heat for the composite, the matrix, and the fibers were performed in the range from 30 °C to 160 °C, based on TMA, DSC, LFA, and transient electro-thermal (TET) techniques. Model results compare favorably with the experimental data, and are consistent with FEM modelling results based on fiber properties and fiber constituent materials (lignin, cellulose, and hemicellulose). This approach provides the basis for understanding component contribution to the fiber properties, as well as a technique to obtain fiber composite thermal property based on component properties. The composite thermal property data also fills an information gap and can be directly used in component design. © 2017 Elsevier Ltd
1678 a50262207100 Lavadiya D.N. p649 False Journal 313 From lignocellulose to biocomposite: Multi-level modelling and experimental investigation of the thermal properties of kenaf fiber reinforced composites based on constituent materials Natural fibers (such as kenaf) have garnered interest recently for use in composites because of their relatively high specific properties, low cost, and low environmental impact. Their thermal property information is limited, lacking experimental data on key properties such as thermal conductivity, specific heat, and CTE of the component fiber. This paper presents, for the first time, the thermal property data on kenaf fiber reinforced composites, and an approach to obtain the composite thermal properties based on constituent properties. Individual, plant-based fibers were measured independently and were then used to inform successful predictions of the effective thermal conductivity of the fiber reinforced composites. A unit cell model has been developed to predict the thermal properties of a planar, randomly oriented kenaf fiber-reinforced composite (near 22% volume fraction loading), which includes the effect of void content on the predicted thermal conductivity. A lower-level model is also developed for individual fiber thermal properties based on its constituents (lignin, cellulose, and hemicellulose). To validate this multi-level model, experimental measurements of the thermal diffusivity, coefficient of thermal expansion, and specific heat for the composite, the matrix, and the fibers were performed in the range from 30 °C to 160 °C, based on TMA, DSC, LFA, and transient electro-thermal (TET) techniques. Model results compare favorably with the experimental data, and are consistent with FEM modelling results based on fiber properties and fiber constituent materials (lignin, cellulose, and hemicellulose). This approach provides the basis for understanding component contribution to the fiber properties, as well as a technique to obtain fiber composite thermal property based on component properties. The composite thermal property data also fills an information gap and can be directly used in component design. © 2017 Elsevier Ltd
1679 a6602335448 Fronk T. p649 False Journal 313 From lignocellulose to biocomposite: Multi-level modelling and experimental investigation of the thermal properties of kenaf fiber reinforced composites based on constituent materials Natural fibers (such as kenaf) have garnered interest recently for use in composites because of their relatively high specific properties, low cost, and low environmental impact. Their thermal property information is limited, lacking experimental data on key properties such as thermal conductivity, specific heat, and CTE of the component fiber. This paper presents, for the first time, the thermal property data on kenaf fiber reinforced composites, and an approach to obtain the composite thermal properties based on constituent properties. Individual, plant-based fibers were measured independently and were then used to inform successful predictions of the effective thermal conductivity of the fiber reinforced composites. A unit cell model has been developed to predict the thermal properties of a planar, randomly oriented kenaf fiber-reinforced composite (near 22% volume fraction loading), which includes the effect of void content on the predicted thermal conductivity. A lower-level model is also developed for individual fiber thermal properties based on its constituents (lignin, cellulose, and hemicellulose). To validate this multi-level model, experimental measurements of the thermal diffusivity, coefficient of thermal expansion, and specific heat for the composite, the matrix, and the fibers were performed in the range from 30 °C to 160 °C, based on TMA, DSC, LFA, and transient electro-thermal (TET) techniques. Model results compare favorably with the experimental data, and are consistent with FEM modelling results based on fiber properties and fiber constituent materials (lignin, cellulose, and hemicellulose). This approach provides the basis for understanding component contribution to the fiber properties, as well as a technique to obtain fiber composite thermal property based on component properties. The composite thermal property data also fills an information gap and can be directly used in component design. © 2017 Elsevier Ltd
1680 a7006253705 Ban H. p649 False Journal 313 From lignocellulose to biocomposite: Multi-level modelling and experimental investigation of the thermal properties of kenaf fiber reinforced composites based on constituent materials Natural fibers (such as kenaf) have garnered interest recently for use in composites because of their relatively high specific properties, low cost, and low environmental impact. Their thermal property information is limited, lacking experimental data on key properties such as thermal conductivity, specific heat, and CTE of the component fiber. This paper presents, for the first time, the thermal property data on kenaf fiber reinforced composites, and an approach to obtain the composite thermal properties based on constituent properties. Individual, plant-based fibers were measured independently and were then used to inform successful predictions of the effective thermal conductivity of the fiber reinforced composites. A unit cell model has been developed to predict the thermal properties of a planar, randomly oriented kenaf fiber-reinforced composite (near 22% volume fraction loading), which includes the effect of void content on the predicted thermal conductivity. A lower-level model is also developed for individual fiber thermal properties based on its constituents (lignin, cellulose, and hemicellulose). To validate this multi-level model, experimental measurements of the thermal diffusivity, coefficient of thermal expansion, and specific heat for the composite, the matrix, and the fibers were performed in the range from 30 °C to 160 °C, based on TMA, DSC, LFA, and transient electro-thermal (TET) techniques. Model results compare favorably with the experimental data, and are consistent with FEM modelling results based on fiber properties and fiber constituent materials (lignin, cellulose, and hemicellulose). This approach provides the basis for understanding component contribution to the fiber properties, as well as a technique to obtain fiber composite thermal property based on component properties. The composite thermal property data also fills an information gap and can be directly used in component design. © 2017 Elsevier Ltd
1680 a7006253705 Ban H. p760 False Journal 370 Thermal characterization of natural and synthetic spider silks by both the 3ω and transient electrothermal methods Thermal conductivity, thermal diffusivity, and volumetric heat capacity of three spider silks are measured in this paper as a benchmark for further studies. These silks include the major and minor ampullate silks of the Nephila clavipes spider, and a synthetic spider silk fiber made from recombinant dragline silk proteins purified from transgenic goats’ milk. Two complementary measurement techniques are employed in the thermal characterization of these microscale single fibers for self-verification. One is the transient electrothermal technique (TET) and the other is the 3ω method. Experimental measurements indicate that thermal properties of the dragline silk are very close to those of the minor ampullate silk, whereas the ones for the synthetic silk are much lower due in part to its low crystallinity. The directly measured thermal conductivity, thermal diffusivity, and volumetric heat capacity of the major and minor ampullate silks are 1.2–1.26 W m− 1 K− 1, 5.7–6 × 10− 7 m2 s− 1, and 2–2.17 MJm− 3 K− 1, respectively. The thermal conductivity and thermal diffusivity of the as-spun synthetic silk are 0.24 W m− 1 K− 1 and 1.6 × 10− 7 m2 s− 1 respectively. As part of this study, a detailed comparison of the TET and 3ω methods is provided showing the complementary nature of the techniques and illustrating the strengths and weaknesses of each. © 2017 Elsevier Ltd
1680 a7006253705 Ban H. p883 False Journal 410 Thermophysical properties of thin fibers via photothermal quantum dot fluorescence spectral shape-based thermometry To improve predictions of composite behavior under thermal loads, there is a need to measure the axial thermophysical properties of thin fibers. Current methods to accomplish this have prohibitively long lead times due to extensive sample preparation. This work details the use of quantum dots thermomarkers to measure the surface temperature of thin fibers in a non-contact manner and determine the fibers’ thermal diffusivity. Neural networks are trained on extracting the temperature of a sample from fluorescence spectra in calibrated, steady-state conditions, based on different spectral features such as peak intensity and peak wavelength. The trained neural networks are then used to reconstruct the evolution of the surface temperature in transient heating experiments. In order to determine the thermal properties of a thin fiber, modulated laser heating is applied and an FFT-based method is used to extract the phase and amplitude response of the temperature field at the modulation frequency. The spatiotemporal dependence of the fluorescence signal, obtained by scanning the distance between the excitation and detection laser spots and varying the frequency response due to an axial scan and a frequency scan, is then curve-fit to the resulting decay curves by a photothermal model in order to determine the thermal diffusivity of the fiber. The measured thermal diffusivity (3.3 ± 0.8 × 10−7 m2 s−1) of a synthetic spider silk fiber by the current method has similar properties to other synthetic silk fibers, and demonstrates the ability of the current method to more rapidly measure thermophysical properties of thin fibers. © 2017 Elsevier Ltd
1681 a56797372300 Russell C.S. p650 True Conference 281 Improving full-scale models of new carbon capture technologies with uncertainty quantification Carbon capture technologies for combustion power plants aim to remove CO2 from flue gas. One such technology is the novel CO2-Binding Organic Liquid (CO2BOL) process developed at the Pacific Northwest National Laboratory. The process utilizes their anhydrous CO2BOL solvent in place of amine mixtures to reduce the energy penalty. A full-scale model of this system based on NETL's Case 10 power plant is projected to produce 7-16% more net electric power over a traditional MEA system for the same plant. These full-scale model predictions are promising, however full-scale simulations are difficult to validate using only bench-scale data. There are errors in both the measurements and models that need to be considered in addition to uncertainties introduced by up-scaling. Uncertainty quantification (UQ) is a statistical framework used to better understand these uncertainties as well as data gaps in models. By constraining models to data, distributions of model parameters are estimated and then propagated through the model to obtain distributions of key outputs such as carbon capture percent, energy penalty, stripper temperature, etc. The results from this UQ analysis aid the design of experiments (DoE) which identifies data gaps to fill to improve model accuracy. Using UQ and DoE effectively can reduce the development time of new carbon capture by years and save time and money on the path to a pilot, and ultimately full-scale, plant. Copyright © (2018) by AIChE. All Rights Reserved.
1682 a57190380741 Bhat S.K. p650 False Conference 281 Improving full-scale models of new carbon capture technologies with uncertainty quantification Carbon capture technologies for combustion power plants aim to remove CO2 from flue gas. One such technology is the novel CO2-Binding Organic Liquid (CO2BOL) process developed at the Pacific Northwest National Laboratory. The process utilizes their anhydrous CO2BOL solvent in place of amine mixtures to reduce the energy penalty. A full-scale model of this system based on NETL's Case 10 power plant is projected to produce 7-16% more net electric power over a traditional MEA system for the same plant. These full-scale model predictions are promising, however full-scale simulations are difficult to validate using only bench-scale data. There are errors in both the measurements and models that need to be considered in addition to uncertainties introduced by up-scaling. Uncertainty quantification (UQ) is a statistical framework used to better understand these uncertainties as well as data gaps in models. By constraining models to data, distributions of model parameters are estimated and then propagated through the model to obtain distributions of key outputs such as carbon capture percent, energy penalty, stripper temperature, etc. The results from this UQ analysis aid the design of experiments (DoE) which identifies data gaps to fill to improve model accuracy. Using UQ and DoE effectively can reduce the development time of new carbon capture by years and save time and money on the path to a pilot, and ultimately full-scale, plant. Copyright © (2018) by AIChE. All Rights Reserved.
1683 a7102402058 Kress J.D. p650 False Conference 281 Improving full-scale models of new carbon capture technologies with uncertainty quantification Carbon capture technologies for combustion power plants aim to remove CO2 from flue gas. One such technology is the novel CO2-Binding Organic Liquid (CO2BOL) process developed at the Pacific Northwest National Laboratory. The process utilizes their anhydrous CO2BOL solvent in place of amine mixtures to reduce the energy penalty. A full-scale model of this system based on NETL's Case 10 power plant is projected to produce 7-16% more net electric power over a traditional MEA system for the same plant. These full-scale model predictions are promising, however full-scale simulations are difficult to validate using only bench-scale data. There are errors in both the measurements and models that need to be considered in addition to uncertainties introduced by up-scaling. Uncertainty quantification (UQ) is a statistical framework used to better understand these uncertainties as well as data gaps in models. By constraining models to data, distributions of model parameters are estimated and then propagated through the model to obtain distributions of key outputs such as carbon capture percent, energy penalty, stripper temperature, etc. The results from this UQ analysis aid the design of experiments (DoE) which identifies data gaps to fill to improve model accuracy. Using UQ and DoE effectively can reduce the development time of new carbon capture by years and save time and money on the path to a pilot, and ultimately full-scale, plant. Copyright © (2018) by AIChE. All Rights Reserved.
1684 a42261332500 Freeman C.J. p650 False Conference 281 Improving full-scale models of new carbon capture technologies with uncertainty quantification Carbon capture technologies for combustion power plants aim to remove CO2 from flue gas. One such technology is the novel CO2-Binding Organic Liquid (CO2BOL) process developed at the Pacific Northwest National Laboratory. The process utilizes their anhydrous CO2BOL solvent in place of amine mixtures to reduce the energy penalty. A full-scale model of this system based on NETL's Case 10 power plant is projected to produce 7-16% more net electric power over a traditional MEA system for the same plant. These full-scale model predictions are promising, however full-scale simulations are difficult to validate using only bench-scale data. There are errors in both the measurements and models that need to be considered in addition to uncertainties introduced by up-scaling. Uncertainty quantification (UQ) is a statistical framework used to better understand these uncertainties as well as data gaps in models. By constraining models to data, distributions of model parameters are estimated and then propagated through the model to obtain distributions of key outputs such as carbon capture percent, energy penalty, stripper temperature, etc. The results from this UQ analysis aid the design of experiments (DoE) which identifies data gaps to fill to improve model accuracy. Using UQ and DoE effectively can reduce the development time of new carbon capture by years and save time and money on the path to a pilot, and ultimately full-scale, plant. Copyright © (2018) by AIChE. All Rights Reserved.
1685 a56397285100 Jiang Y. p650 False Conference 281 Improving full-scale models of new carbon capture technologies with uncertainty quantification Carbon capture technologies for combustion power plants aim to remove CO2 from flue gas. One such technology is the novel CO2-Binding Organic Liquid (CO2BOL) process developed at the Pacific Northwest National Laboratory. The process utilizes their anhydrous CO2BOL solvent in place of amine mixtures to reduce the energy penalty. A full-scale model of this system based on NETL's Case 10 power plant is projected to produce 7-16% more net electric power over a traditional MEA system for the same plant. These full-scale model predictions are promising, however full-scale simulations are difficult to validate using only bench-scale data. There are errors in both the measurements and models that need to be considered in addition to uncertainties introduced by up-scaling. Uncertainty quantification (UQ) is a statistical framework used to better understand these uncertainties as well as data gaps in models. By constraining models to data, distributions of model parameters are estimated and then propagated through the model to obtain distributions of key outputs such as carbon capture percent, energy penalty, stripper temperature, etc. The results from this UQ analysis aid the design of experiments (DoE) which identifies data gaps to fill to improve model accuracy. Using UQ and DoE effectively can reduce the development time of new carbon capture by years and save time and money on the path to a pilot, and ultimately full-scale, plant. Copyright © (2018) by AIChE. All Rights Reserved.
1686 a56542307500 Morgan J.C. p650 False Conference 281 Improving full-scale models of new carbon capture technologies with uncertainty quantification Carbon capture technologies for combustion power plants aim to remove CO2 from flue gas. One such technology is the novel CO2-Binding Organic Liquid (CO2BOL) process developed at the Pacific Northwest National Laboratory. The process utilizes their anhydrous CO2BOL solvent in place of amine mixtures to reduce the energy penalty. A full-scale model of this system based on NETL's Case 10 power plant is projected to produce 7-16% more net electric power over a traditional MEA system for the same plant. These full-scale model predictions are promising, however full-scale simulations are difficult to validate using only bench-scale data. There are errors in both the measurements and models that need to be considered in addition to uncertainties introduced by up-scaling. Uncertainty quantification (UQ) is a statistical framework used to better understand these uncertainties as well as data gaps in models. By constraining models to data, distributions of model parameters are estimated and then propagated through the model to obtain distributions of key outputs such as carbon capture percent, energy penalty, stripper temperature, etc. The results from this UQ analysis aid the design of experiments (DoE) which identifies data gaps to fill to improve model accuracy. Using UQ and DoE effectively can reduce the development time of new carbon capture by years and save time and money on the path to a pilot, and ultimately full-scale, plant. Copyright © (2018) by AIChE. All Rights Reserved.
1687 a34168247900 Sahawneh L.R. p651 True Journal 314 Ground-based sense-and-avoid system for small unmanned aircraft In this Paper, we present a complete, proof-of-concept sense-and-avoid solution for small unmanned aircraft systems, including a small low-cost ground-based radar system, multitarget tracking and estimation, collision detection, and an avoidance planner. We describe the development of a small frequency-modulated continuous-wave phased-array radar system that provides a three-dimensional surveillance volume. The radar measurements are processed using the recursive random sample consensus algorithm, producing tracks for the intruders and the ownship. We propose a collision-detection algorithm based on the geometric relationship between encountering aircraft. If a collision threat is detected, a collision-free new path is generated for the ownship using a two-step path-planning algorithm. In the first step, an initial suboptimal path is generated using an A search. In the second step, the path is refined using a variant of the potential fields technique, adapted to the sense-and-avoid scenario. The performance of the complete system is demonstrated with flight-test experiments. © 2018 American Institute of Aeronautics and Astronautics Inc.. All rights reserved.
1687 a34168247900 Sahawneh L.R. p837 False Journal 397 Minimum required detection range for detect and avoid of unmanned aircraft systems For unmanned aircraft systems to gain full access to the National Airspace System, they must have the capability to detect and avoid other aircraft. To safely avoid another aircraft, an unmanned aircraft must detect the intruder aircraft with ample time and distance to allow the ownship to track the intruder, perform risk assessment, plan an avoidance path, and execute the maneuver. This paper describes two analytical methods for finding the minimum detection range to ensure that these detection and avoidance steps can be carried out. The first method, time-based geometric velocity vectors, includes the bank-angle dynamics of the ownship; whereas the second, geometric velocity vectors, assumes an instantaneous bank-angle maneuver. The solution using the first method must be found numerically, whereas the second has a closed-form analytical solution. These methods are compared to two existing methods. The results show the time-based geometric velocity vectors approach is precise, the geometric velocity vectors approach is a good approximation under many conditions, and the two existing approaches are good approximations at large ownship speeds relative to the intruder speed, fast ownship bank-angle transients, and small ownship bank angles. Copyright © 2017 by Brigham Young University.
1688 a57194787481 Wikle J.K. p651 False Journal 314 Ground-based sense-and-avoid system for small unmanned aircraft In this Paper, we present a complete, proof-of-concept sense-and-avoid solution for small unmanned aircraft systems, including a small low-cost ground-based radar system, multitarget tracking and estimation, collision detection, and an avoidance planner. We describe the development of a small frequency-modulated continuous-wave phased-array radar system that provides a three-dimensional surveillance volume. The radar measurements are processed using the recursive random sample consensus algorithm, producing tracks for the intruders and the ownship. We propose a collision-detection algorithm based on the geometric relationship between encountering aircraft. If a collision threat is detected, a collision-free new path is generated for the ownship using a two-step path-planning algorithm. In the first step, an initial suboptimal path is generated using an A search. In the second step, the path is refined using a variant of the potential fields technique, adapted to the sense-and-avoid scenario. The performance of the complete system is demonstrated with flight-test experiments. © 2018 American Institute of Aeronautics and Astronautics Inc.. All rights reserved.
1688 a57194787481 Wikle J.K. p837 True Journal 397 Minimum required detection range for detect and avoid of unmanned aircraft systems For unmanned aircraft systems to gain full access to the National Airspace System, they must have the capability to detect and avoid other aircraft. To safely avoid another aircraft, an unmanned aircraft must detect the intruder aircraft with ample time and distance to allow the ownship to track the intruder, perform risk assessment, plan an avoidance path, and execute the maneuver. This paper describes two analytical methods for finding the minimum detection range to ensure that these detection and avoidance steps can be carried out. The first method, time-based geometric velocity vectors, includes the bank-angle dynamics of the ownship; whereas the second, geometric velocity vectors, assumes an instantaneous bank-angle maneuver. The solution using the first method must be found numerically, whereas the second has a closed-form analytical solution. These methods are compared to two existing methods. The results show the time-based geometric velocity vectors approach is precise, the geometric velocity vectors approach is a good approximation under many conditions, and the two existing approaches are good approximations at large ownship speeds relative to the intruder speed, fast ownship bank-angle transients, and small ownship bank angles. Copyright © 2017 by Brigham Young University.
1689 a57203298908 Kaleo Roberts A. p651 False Journal 314 Ground-based sense-and-avoid system for small unmanned aircraft In this Paper, we present a complete, proof-of-concept sense-and-avoid solution for small unmanned aircraft systems, including a small low-cost ground-based radar system, multitarget tracking and estimation, collision detection, and an avoidance planner. We describe the development of a small frequency-modulated continuous-wave phased-array radar system that provides a three-dimensional surveillance volume. The radar measurements are processed using the recursive random sample consensus algorithm, producing tracks for the intruders and the ownship. We propose a collision-detection algorithm based on the geometric relationship between encountering aircraft. If a collision threat is detected, a collision-free new path is generated for the ownship using a two-step path-planning algorithm. In the first step, an initial suboptimal path is generated using an A search. In the second step, the path is refined using a variant of the potential fields technique, adapted to the sense-and-avoid scenario. The performance of the complete system is demonstrated with flight-test experiments. © 2018 American Institute of Aeronautics and Astronautics Inc.. All rights reserved.
1690 a56380927900 Spencer J.C. p651 False Journal 314 Ground-based sense-and-avoid system for small unmanned aircraft In this Paper, we present a complete, proof-of-concept sense-and-avoid solution for small unmanned aircraft systems, including a small low-cost ground-based radar system, multitarget tracking and estimation, collision detection, and an avoidance planner. We describe the development of a small frequency-modulated continuous-wave phased-array radar system that provides a three-dimensional surveillance volume. The radar measurements are processed using the recursive random sample consensus algorithm, producing tracks for the intruders and the ownship. We propose a collision-detection algorithm based on the geometric relationship between encountering aircraft. If a collision threat is detected, a collision-free new path is generated for the ownship using a two-step path-planning algorithm. In the first step, an initial suboptimal path is generated using an A search. In the second step, the path is refined using a variant of the potential fields technique, adapted to the sense-and-avoid scenario. The performance of the complete system is demonstrated with flight-test experiments. © 2018 American Institute of Aeronautics and Astronautics Inc.. All rights reserved.
1691 a57189026693 Radzinski T. p652 False Conference 282 Defining a Sustainable Underground Infrastructure Framework: ISO Asset Management and ISO Life Cycle Sustainability is broadly defined to mean systems that are able to meet the needs of current and future generations by being physically resilient, cost-effective, environmentally viable, and socially equitable. While the term is applied to various types of infrastructure, the real application of sustainability practices needs to be applied to underground water infrastructure. In order to determine the best sustainable outcomes a common standard of weighing alternatives and making decisions should be followed. The International Standards Organization (ISO) is an independent, non-governmental organization which facilitates world trade by providing common standards between nations. The ISO has standards which can benefit sustainable infrastructure decision making specifically in 3 main areas: life cycle assessment, life cycle costing, and asset management. This paper defines a sustainable framework for underground pipe infrastructure in the context of ISO standards and industry best practices. © 2018 American Society of Civil Engineers.
1691 a57189026693 Radzinski T. p653 False Conference 283 How Green Are You? Economic and Environmental Sustainability: Assessing the Global Warming Potential (GMP) of Your Underground Infrastructure As municipalities across the United States and Canada focus on delivering the essentials of clean water, efficient wastewater treatment, and judicious control of storm water, government officials, engineers, and the companies that install, operate, and maintain piping infrastructure need to understand that a life cycle systems approach. Sustainability concerns apply to many critical resources such as water. On a per capita basis, the U.S. leads the world in water usage, with a substantial portion of water consumed/leaked by infrastructure systems. Because of water availability, competing water demands, and changing hydrologic conditions, the U.S. Department of Interior predicts that multiple water conflicts will occur in the western U.S. by 2025. In addition, decades of excessive demands on ecological systems have reduced their capacities to absorb and process emissions and wastes. Sustainable water infrastructure is vital to providing the American public with clean and safe water and helping to ensure the environmental, economic, and social health of the nation's communities. The increasing interest in sustainability has led to the development of sustainability assessment tools such as life cycle assessments (LCA) analyzing the embodied energy and environmental impacts. Life cycle assessment (LCA) is a tool used to identify the environmental impacts of a product, process, or activity over the entire lifespan of the product. LCA studies also quantify and interpret the environmental flows to and from the environment (including emissions to air, water, and land, as well as the consumption of energy and other material resources) over the entire life cycle of a product (or process or service). By including the impacts throughout the product life cycle, LCA provides a comprehensive view of the environmental aspects of the product and an accurate picture of the true environmental tradeoffs in product selection. © 2018 American Society of Civil Engineers.
1692 a57202626673 Luna A. p654 False Conference 284 Lateral Resistance of Abutment Piles Near Mechanically Stabilized Earth Walls Pile foundations for bridges must often resist lateral loads produced by earthquakes and thermal variation. Because of the lack of large scale tests, there is almost no guidance for engineers in assessing the lateral resistance of piles located close to these MSE walls. The objective of this study was to assess lateral pile resistance as a function of distance from the wall face and predict force induced in the reinforcements. Full-scale lateral load tests were conducted on 24 piles located at 2, 3, 4, and 5 pile diameters behind 4.6 and 6-m high MSE walls. P-multipliers were developed to account for the decrease in lateral soil resistance. Little reduction occurred for piles located more than about 4 pile diameters from the wall. Measured tensile forces in the MSE reinforcements increased as the load on the pile increased and decreased rapidly with transverse distance from the direction of loading. Multiple linear regression equations were developed to predict maximum tensile force induced in reinforcing elements by lateral loading. © 2018 American Society of Civil Engineers (ASCE).All Rights Reserved.
1693 a57202627167 Budd R. p654 False Conference 284 Lateral Resistance of Abutment Piles Near Mechanically Stabilized Earth Walls Pile foundations for bridges must often resist lateral loads produced by earthquakes and thermal variation. Because of the lack of large scale tests, there is almost no guidance for engineers in assessing the lateral resistance of piles located close to these MSE walls. The objective of this study was to assess lateral pile resistance as a function of distance from the wall face and predict force induced in the reinforcements. Full-scale lateral load tests were conducted on 24 piles located at 2, 3, 4, and 5 pile diameters behind 4.6 and 6-m high MSE walls. P-multipliers were developed to account for the decrease in lateral soil resistance. Little reduction occurred for piles located more than about 4 pile diameters from the wall. Measured tensile forces in the MSE reinforcements increased as the load on the pile increased and decreased rapidly with transverse distance from the direction of loading. Multiple linear regression equations were developed to predict maximum tensile force induced in reinforcing elements by lateral loading. © 2018 American Society of Civil Engineers (ASCE).All Rights Reserved.
1694 a57202627912 Besendorfer J. p654 False Conference 284 Lateral Resistance of Abutment Piles Near Mechanically Stabilized Earth Walls Pile foundations for bridges must often resist lateral loads produced by earthquakes and thermal variation. Because of the lack of large scale tests, there is almost no guidance for engineers in assessing the lateral resistance of piles located close to these MSE walls. The objective of this study was to assess lateral pile resistance as a function of distance from the wall face and predict force induced in the reinforcements. Full-scale lateral load tests were conducted on 24 piles located at 2, 3, 4, and 5 pile diameters behind 4.6 and 6-m high MSE walls. P-multipliers were developed to account for the decrease in lateral soil resistance. Little reduction occurred for piles located more than about 4 pile diameters from the wall. Measured tensile forces in the MSE reinforcements increased as the load on the pile increased and decreased rapidly with transverse distance from the direction of loading. Multiple linear regression equations were developed to predict maximum tensile force induced in reinforcing elements by lateral loading. © 2018 American Society of Civil Engineers (ASCE).All Rights Reserved.
1695 a57202627263 Hatch C. p654 False Conference 284 Lateral Resistance of Abutment Piles Near Mechanically Stabilized Earth Walls Pile foundations for bridges must often resist lateral loads produced by earthquakes and thermal variation. Because of the lack of large scale tests, there is almost no guidance for engineers in assessing the lateral resistance of piles located close to these MSE walls. The objective of this study was to assess lateral pile resistance as a function of distance from the wall face and predict force induced in the reinforcements. Full-scale lateral load tests were conducted on 24 piles located at 2, 3, 4, and 5 pile diameters behind 4.6 and 6-m high MSE walls. P-multipliers were developed to account for the decrease in lateral soil resistance. Little reduction occurred for piles located more than about 4 pile diameters from the wall. Measured tensile forces in the MSE reinforcements increased as the load on the pile increased and decreased rapidly with transverse distance from the direction of loading. Multiple linear regression equations were developed to predict maximum tensile force induced in reinforcing elements by lateral loading. © 2018 American Society of Civil Engineers (ASCE).All Rights Reserved.
1696 a57202627050 Han J. p654 False Conference 284 Lateral Resistance of Abutment Piles Near Mechanically Stabilized Earth Walls Pile foundations for bridges must often resist lateral loads produced by earthquakes and thermal variation. Because of the lack of large scale tests, there is almost no guidance for engineers in assessing the lateral resistance of piles located close to these MSE walls. The objective of this study was to assess lateral pile resistance as a function of distance from the wall face and predict force induced in the reinforcements. Full-scale lateral load tests were conducted on 24 piles located at 2, 3, 4, and 5 pile diameters behind 4.6 and 6-m high MSE walls. P-multipliers were developed to account for the decrease in lateral soil resistance. Little reduction occurred for piles located more than about 4 pile diameters from the wall. Measured tensile forces in the MSE reinforcements increased as the load on the pile increased and decreased rapidly with transverse distance from the direction of loading. Multiple linear regression equations were developed to predict maximum tensile force induced in reinforcing elements by lateral loading. © 2018 American Society of Civil Engineers (ASCE).All Rights Reserved.
1697 a16021781200 Gladstone R. p654 False Conference 284 Lateral Resistance of Abutment Piles Near Mechanically Stabilized Earth Walls Pile foundations for bridges must often resist lateral loads produced by earthquakes and thermal variation. Because of the lack of large scale tests, there is almost no guidance for engineers in assessing the lateral resistance of piles located close to these MSE walls. The objective of this study was to assess lateral pile resistance as a function of distance from the wall face and predict force induced in the reinforcements. Full-scale lateral load tests were conducted on 24 piles located at 2, 3, 4, and 5 pile diameters behind 4.6 and 6-m high MSE walls. P-multipliers were developed to account for the decrease in lateral soil resistance. Little reduction occurred for piles located more than about 4 pile diameters from the wall. Measured tensile forces in the MSE reinforcements increased as the load on the pile increased and decreased rapidly with transverse distance from the direction of loading. Multiple linear regression equations were developed to predict maximum tensile force induced in reinforcing elements by lateral loading. © 2018 American Society of Civil Engineers (ASCE).All Rights Reserved.
1698 a7004403207 Folkman S. p655 False Conference 285 Benchmarking your break rates: A review of new findings and trends from north American water main break studies The water industry has seen many types of academic surveys and studies on water main replacement programs and the benefits of asset management and prioritization. However, many utilities have not historically tracked all of the elements of water main break data. One factor used to quantify the occurrences of failing underground pipe networks is water main break rates. Water main break rates are calculated for all pipe materials used in water delivery to create a measurement to judge pipe performance and durability. Water main break rates can vary year to year and by utility. However, in aggregate, break rates produce a compelling story which can aid our prudent decision making as it relates to repairing and replacing our underground pipes. In April 2012, Utah State University published an initial comprehensive survey of water utilities. This was a survey of water main breaks and operating characteristics at utilities located in U.S. and Canada. Six years later in 2018, a new water main break study was released reviewing the national metric for citizens served per one mile of pipe, aggregate data on pipe material break rates, the analysis of age and corrosion in failure modes, and related observations on pressure, delivery volumes, effects of soil corrosivity, and trenchless technology practices. This paper reviews the newest water main break study metrics and findings and outlines various trends and projections of water main breaks in the U.S. and Canada which can be used to benchmark an organization's water main breaks and use this critical data in asset management plans. © 2018 American Society of Civil Engineers.
1699 a56631537800 Sgobba T. p656 True Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1700 a56528475200 Watts-Englert J. p656 False Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1701 a56182798800 Woods D.D. p656 False Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1702 a7201529681 Patterson E.S. p656 False Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1703 a55801905300 Dittemore G. p656 False Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1704 a55801836400 Bertels C. p656 False Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1705 a57201111301 Poussin H. p656 False Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1706 a57201111988 Rochas L. p656 False Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1707 a14620010300 Vallée T. p656 False Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1708 a8674222900 Bertrand R. p656 False Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1709 a12799657800 Haber J.M. p656 False Journal 315 Human factors in mission control centers This chapter focuses on mission control centers that provide direct support of spaceflight operations in real time. Mission controllers and flight crew members perform many routine procedures, but just as flight crews need to be vigilant and prepared for unexpected anomalies that may occur during any mission phase, the ground controllers must be equally resilient in their response. This chapter focuses on the human factors and training that facilitate their effectiveness in support of flight safety. © 2018 Elsevier Ltd. All rights reserved.
1710 a57003792300 Chen Y.-F. p657 True Journal 316 Design of a clinical decision support system for fracture prediction using imbalanced dataset More than 1 billion people suffer from chronic respiratory diseases worldwide, accounting for more than 4 million deaths annually. Inhaled corticosteroid is a popular medication for treating chronic respiratory diseases. Its side effects include decreased bone mineral density and osteoporosis. The aims of this study are to investigate the association of inhaled corticosteroids and fracture and to design a clinical support system for fracture prediction. The data of patients aged 20 years and older, who had visited healthcare centers and been prescribed with inhaled corticosteroids within 2002-2010, were retrieved from the National Health Insurance Research Database (NHIRD). After excluding patients diagnosed with hip fracture or vertebrate fractures before using inhaled corticosteroid, a total of 11645 patients receiving inhaled corticosteroid therapy were included for this study. Among them, 1134 (9.7%) were diagnosed with hip fracture or vertebrate fracture. The statistical results showed that demographic information, chronic respiratory diseases and comorbidities, and corticosteroid-related variables (cumulative dose, mean exposed daily dose, follow-up duration, and exposed duration) were significantly different between fracture and nonfracture patients. The clinical decision support systems (CDSSs) were designed with integrated genetic algorithm (GA) and support vector machine (SVM) by training and validating the models with balanced training sets obtained by random and cluster-based undersampling methods and testing with the imbalanced NHIRD dataset. Two different objective functions were adopted for obtaining optimal models with best predictive performance. The predictive performance of the CDSSs exhibits a sensitivity of 69.84-77.00% and an AUC of 0.7495-0.7590. It was concluded that long-term use of inhaled corticosteroids may induce osteoporosis and exhibit higher incidence of hip or vertebrate fractures. The accumulated dose of ICS and OCS therapies should be continuously monitored, especially for patients with older age and women after menopause, to prevent from exceeding the maximum dosage. © 2018 Yung-Fu Chen et al.
1711 a24492691800 Wang K.-A. p657 False Journal 316 Design of a clinical decision support system for fracture prediction using imbalanced dataset More than 1 billion people suffer from chronic respiratory diseases worldwide, accounting for more than 4 million deaths annually. Inhaled corticosteroid is a popular medication for treating chronic respiratory diseases. Its side effects include decreased bone mineral density and osteoporosis. The aims of this study are to investigate the association of inhaled corticosteroids and fracture and to design a clinical support system for fracture prediction. The data of patients aged 20 years and older, who had visited healthcare centers and been prescribed with inhaled corticosteroids within 2002-2010, were retrieved from the National Health Insurance Research Database (NHIRD). After excluding patients diagnosed with hip fracture or vertebrate fractures before using inhaled corticosteroid, a total of 11645 patients receiving inhaled corticosteroid therapy were included for this study. Among them, 1134 (9.7%) were diagnosed with hip fracture or vertebrate fracture. The statistical results showed that demographic information, chronic respiratory diseases and comorbidities, and corticosteroid-related variables (cumulative dose, mean exposed daily dose, follow-up duration, and exposed duration) were significantly different between fracture and nonfracture patients. The clinical decision support systems (CDSSs) were designed with integrated genetic algorithm (GA) and support vector machine (SVM) by training and validating the models with balanced training sets obtained by random and cluster-based undersampling methods and testing with the imbalanced NHIRD dataset. Two different objective functions were adopted for obtaining optimal models with best predictive performance. The predictive performance of the CDSSs exhibits a sensitivity of 69.84-77.00% and an AUC of 0.7495-0.7590. It was concluded that long-term use of inhaled corticosteroids may induce osteoporosis and exhibit higher incidence of hip or vertebrate fractures. The accumulated dose of ICS and OCS therapies should be continuously monitored, especially for patients with older age and women after menopause, to prevent from exceeding the maximum dosage. © 2018 Yung-Fu Chen et al.
1712 a57201290781 Rahman L.O.A. p657 False Journal 316 Design of a clinical decision support system for fracture prediction using imbalanced dataset More than 1 billion people suffer from chronic respiratory diseases worldwide, accounting for more than 4 million deaths annually. Inhaled corticosteroid is a popular medication for treating chronic respiratory diseases. Its side effects include decreased bone mineral density and osteoporosis. The aims of this study are to investigate the association of inhaled corticosteroids and fracture and to design a clinical support system for fracture prediction. The data of patients aged 20 years and older, who had visited healthcare centers and been prescribed with inhaled corticosteroids within 2002-2010, were retrieved from the National Health Insurance Research Database (NHIRD). After excluding patients diagnosed with hip fracture or vertebrate fractures before using inhaled corticosteroid, a total of 11645 patients receiving inhaled corticosteroid therapy were included for this study. Among them, 1134 (9.7%) were diagnosed with hip fracture or vertebrate fracture. The statistical results showed that demographic information, chronic respiratory diseases and comorbidities, and corticosteroid-related variables (cumulative dose, mean exposed daily dose, follow-up duration, and exposed duration) were significantly different between fracture and nonfracture patients. The clinical decision support systems (CDSSs) were designed with integrated genetic algorithm (GA) and support vector machine (SVM) by training and validating the models with balanced training sets obtained by random and cluster-based undersampling methods and testing with the imbalanced NHIRD dataset. Two different objective functions were adopted for obtaining optimal models with best predictive performance. The predictive performance of the CDSSs exhibits a sensitivity of 69.84-77.00% and an AUC of 0.7495-0.7590. It was concluded that long-term use of inhaled corticosteroids may induce osteoporosis and exhibit higher incidence of hip or vertebrate fractures. The accumulated dose of ICS and OCS therapies should be continuously monitored, especially for patients with older age and women after menopause, to prevent from exceeding the maximum dosage. © 2018 Yung-Fu Chen et al.
1713 a55601054600 Chung W.-S. p657 False Journal 316 Design of a clinical decision support system for fracture prediction using imbalanced dataset More than 1 billion people suffer from chronic respiratory diseases worldwide, accounting for more than 4 million deaths annually. Inhaled corticosteroid is a popular medication for treating chronic respiratory diseases. Its side effects include decreased bone mineral density and osteoporosis. The aims of this study are to investigate the association of inhaled corticosteroids and fracture and to design a clinical support system for fracture prediction. The data of patients aged 20 years and older, who had visited healthcare centers and been prescribed with inhaled corticosteroids within 2002-2010, were retrieved from the National Health Insurance Research Database (NHIRD). After excluding patients diagnosed with hip fracture or vertebrate fractures before using inhaled corticosteroid, a total of 11645 patients receiving inhaled corticosteroid therapy were included for this study. Among them, 1134 (9.7%) were diagnosed with hip fracture or vertebrate fracture. The statistical results showed that demographic information, chronic respiratory diseases and comorbidities, and corticosteroid-related variables (cumulative dose, mean exposed daily dose, follow-up duration, and exposed duration) were significantly different between fracture and nonfracture patients. The clinical decision support systems (CDSSs) were designed with integrated genetic algorithm (GA) and support vector machine (SVM) by training and validating the models with balanced training sets obtained by random and cluster-based undersampling methods and testing with the imbalanced NHIRD dataset. Two different objective functions were adopted for obtaining optimal models with best predictive performance. The predictive performance of the CDSSs exhibits a sensitivity of 69.84-77.00% and an AUC of 0.7495-0.7590. It was concluded that long-term use of inhaled corticosteroids may induce osteoporosis and exhibit higher incidence of hip or vertebrate fractures. The accumulated dose of ICS and OCS therapies should be continuously monitored, especially for patients with older age and women after menopause, to prevent from exceeding the maximum dosage. © 2018 Yung-Fu Chen et al.
1714 a57207980336 Sanchez D.G. p658 False Conference 286 Water main criticality scoring and GIS centric risk mitigation: Applying GIS spatial analysis tools and apps for greater insight for high risk underground infrastructure With the pressure to provide excellent services under constrained budgets, utilities are adopting asset management as the synergistic framework combining strategic and financial planning, levels of service, and risk-based analysis to determine investments. GIS (geographic information system) helps to empower a utility with the tools to drive a robust and strategic, decision making process. When a CMMS (computerized maintenance management system) has asset management functionality, the capabilities of service requests, inspections and work orders, capturing costs, and work history can be leveraged into asset condition and risk-based spatial analysis by determining what, when, why, and where the next round of investment should occur. A critical step in the process includes analyzing the data and location to potential take actions to reduce the risks. In alignment with ISO (International Standards Organization) 55000, risk is defined as the probability of failure (PoF) multiplied by the consequence of failure (CoF) which produces the business risk exposure (BRE). While calculating risk is important, the risk-based data can be used to build business cases and determine future projects. GIS can help users gain an understanding of what assets are high risk, where they are located and what factor can influence the risk. Risk-based analysis provides the reasoning for potential solutions and action. This paper defines and explores the use of GIS-centric analysis tools to enhance the asset management decision making process. © 2018 American Society of Civil Engineers.
1715 a57207994872 Tamashasky B. p658 False Conference 286 Water main criticality scoring and GIS centric risk mitigation: Applying GIS spatial analysis tools and apps for greater insight for high risk underground infrastructure With the pressure to provide excellent services under constrained budgets, utilities are adopting asset management as the synergistic framework combining strategic and financial planning, levels of service, and risk-based analysis to determine investments. GIS (geographic information system) helps to empower a utility with the tools to drive a robust and strategic, decision making process. When a CMMS (computerized maintenance management system) has asset management functionality, the capabilities of service requests, inspections and work orders, capturing costs, and work history can be leveraged into asset condition and risk-based spatial analysis by determining what, when, why, and where the next round of investment should occur. A critical step in the process includes analyzing the data and location to potential take actions to reduce the risks. In alignment with ISO (International Standards Organization) 55000, risk is defined as the probability of failure (PoF) multiplied by the consequence of failure (CoF) which produces the business risk exposure (BRE). While calculating risk is important, the risk-based data can be used to build business cases and determine future projects. GIS can help users gain an understanding of what assets are high risk, where they are located and what factor can influence the risk. Risk-based analysis provides the reasoning for potential solutions and action. This paper defines and explores the use of GIS-centric analysis tools to enhance the asset management decision making process. © 2018 American Society of Civil Engineers.
1716 a6602512004 Radebaugh J. p659 True Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1717 a35320703200 Ventra D. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1718 a7402095346 Lorenz R.D. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1719 a7006106739 Farr T. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1720 a7201778289 Kirk R. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1721 a7201978585 Hayes A. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1722 a54684688700 Malaska M.J. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1723 a57023282300 Birch S. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1724 a55598549000 Liu Z.Y.-C. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1725 a57210198577 Lunine J. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1726 a7402288130 Barnes J. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1727 a25958165500 Le Gall A. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1728 a8362122100 Lopes R. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1729 a6701580763 Stofan E. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1730 a7203069877 Wall S. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1731 a7003915889 Paillou P. p659 False Journal 317 Alluvial and fluvial fans on Saturn's moon Titan reveal processes, materials and regional geology Fans, landforms that record the storage and transport of sediment from uplands to depositional basins, are found on Saturn's moon Titan, a body of significantly different process rates and material compositions from Earth. Images obtained by the Cassini spacecraft's synthetic aperture radar reveal morphologies, roughness, textural patterns and other properties consistent with fan analogues on Earth also viewed by synthetic aperture radar. The observed fan characteristics on Titan reveal some regions of high relative relief and others with gentle slopes over hundreds of kilometres, exposing topographic variations and influences on fan formation. There is evidence for a range of particle sizes across proximal to distal fan regions, from c. 2 cm or more to finegrained, which can provide details on sedimentary processes. Some features are best described as alluvial fans, which implies their proximity to high-relief source areas, while others are more likely to be fluvial fans, drawing from larger catchment areas and frequently characterized by more prolonged runoff events. The presence of fans corroborates the vast liquid storage capacity of the atmosphere and the resultant episodic behaviour. Fans join the growing list of landforms on Titan derived from atmospheric and fluvial processes similar to those on Earth, strengthening comparisons between these two planetary bodies. © 2018 The Author(s).
1732 a55776361200 Villalon-Reina J.E. p660 True Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1733 a37664688000 Ching C.R.K. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1734 a57205556489 Kothapalli D. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1735 a8691490200 Sun D. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1736 a55628341300 Nir T. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1737 a57201125120 Lin A. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1738 a47461179000 Forsyth J.K. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1739 a25930868900 Kushan L. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1740 a57194639611 Vajdi A. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1741 a8717447000 Jalbrzikowski M. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1742 a57194638369 Hansen L. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1743 a55832864500 Jonas R.K. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1744 a6701774874 Van Amelsvoort T. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1745 a55910450300 Bakker G. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1746 a57207550410 Kates W.R. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1747 a6603383055 Antshel K.M. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1748 a9741422500 Fremont W. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1749 a35236206700 Campbell L.E. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1750 a7005089148 McCabe K.L. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1751 a57202326782 Daly E. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1752 a55979578600 Gudbrandsen M. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1753 a7401764127 Murphy C. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1754 a7404062227 Murphy D. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1755 a7103269626 Craig M. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1756 a7103321645 Emanuel B. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1757 a7005251917 McDonald-Mcginn D. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1758 a9745660700 Ruparel K. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1759 a6507586174 Roalf D. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1760 a7103065698 Gur R.E. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1761 a57203234366 Schmitt J.E. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1762 a7202910012 Simon T.J. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1763 a9236660300 Goodrich-Hunsaker N.J. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1764 a57195976340 Durdle C.A. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1765 a54899597300 Doherty J. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1766 a57201121062 Cunningham A.C. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1767 a6701851503 Van Den Bree M. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1768 a7102905437 Linden D.E.J. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1769 a36044041500 Owen M. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1770 a57202194800 Moss H. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1771 a8517650500 Jahanshad N. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1772 a6701387944 Bearden C.E. p660 False Conference 287 Alternative diffusion anisotropy measures for the investigation of white matter alterations in 22q11.2 deletion syndrome Diffusion MRI (dMRI) is widely used to study the brain's white matter (WM) microstructure in a range of psychiatric and neurological diseases. As the diffusion tensor model has limitations in brain regions with crossing fibers, novel diffusion MRI reconstruction models may offer more accurate measures of tissue properties, and a better understanding of the brain abnormalities in specific diseases. Here we studied a large sample of 249 participants with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition associated with high rates of developmental neuropsychiatric disorders, and 224 age-matched healthy controls (HC) (age range: 8-35 years). Participants were scanned with dMRI at eight centers worldwide. Using a meta-analytic approach, we assessed the profile of group differences in four diffusion anisotropy measures to better understand the patterns of WM microstructural abnormalities and evaluate their consistency across alternative measures. When assessed in atlas-defined regions of interest, we found statistically significant differences for all anisotropy measures, all showing a widespread but not always coinciding pattern of effects. The tensor distribution function fractional anisotropy (TDF-FA) showed largest effect sizes all in the same direction (greater anisotropy in 22q11DS than HC). Fractional anisotropy based on the tensor model (FA) showed the second largest effect sizes after TDF-FA; some regions showed higher mean values in 22q11DS, but others lower. Generalized fractional anisotropy (GFA) showed the opposite pattern to TDF-FA with most regions showing lower anisotropy in 22q11DS versus HC. Anisotropic power maps (AP) showed the lowest effect sizes also with a mixed pattern of effects across regions. These results were also consistent across skeleton projection methods, with few differences when projecting anisotropy values from voxels sampled on the FA map or projecting values from voxels sampled from each anisotropy map. This study highlights that different mathematical definitions of anisotropy may lead to different profiles of group differences, even in large, well-powered population studies. Further studies of biophysical models derived from multi-shell dMRI and histological validations may help to understand the sources of these differences. 22q11DS is a promising model to study differences among novel anisotropy/dMRI measures, as group differences are relatively large and there exist animal models suitable for histological validation. © SPIE. Downloading of the abstract is permitted for personal use only.
1773 a57201212051 Sanders S. p661 True Conference 288 Informing the use of hyperparameter optimization through metalearning One of the challenges of data mining is finding hyperparameters for a learning algorithm that will produce the best model for a given dataset. Hyperparameter optimization automates this process, but it can still take significant time. It has been found that hyperparameter optimization does not always result in induced models with significant improvement over default values, yet no systematic analysis of the role of hyperparameter optimization in machine learning has been conducted. We use metalearning to inform the decision of whether to optimize hyperparameters based on expected performance improvement and computational cost. © 2017 IEEE.
1774 a23060352300 Giraud-Carrier C. p661 False Conference 288 Informing the use of hyperparameter optimization through metalearning One of the challenges of data mining is finding hyperparameters for a learning algorithm that will produce the best model for a given dataset. Hyperparameter optimization automates this process, but it can still take significant time. It has been found that hyperparameter optimization does not always result in induced models with significant improvement over default values, yet no systematic analysis of the role of hyperparameter optimization in machine learning has been conducted. We use metalearning to inform the decision of whether to optimize hyperparameters based on expected performance improvement and computational cost. © 2017 IEEE.
1775 a55258864700 Hogge J.W. p663 True Journal 318 New Vapor-Pressure Prediction with Improved Thermodynamic Consistency using the Riedel Equation Vapor pressure, heat of vaporization, liquid heat capacity, and ideal-gas heat capacity for pure compounds between the triple point and critical point are important properties for process design and optimization. These thermophysical properties are related to each other through temperature derivatives of thermodynamic relationships stemming from a temperature-dependent vapor-pressure correlation. The Riedel equation has been considered to be an excellent and simple choice among vapor-pressure correlating equations [ Velasco et al. J. Chem. Thermodyn. 2008, 40 (5), 789-797 ] but requires modification of the final coefficient to provide thermodynamic consistency with thermal data [ Hogge et al. Fluid Phase Equilib. 2016, 429, 149-165 ]. New predictive correlations with final coefficients in integer steps from 1 to 6 have been created for compounds with limited or no vapor-pressure data, based on the methodology used originally by Riedel [ Chem. Ing. Tech. 1954, 26 (2), 83-89 ]. Liquid heat capacity was predicted using these vapor-pressure correlations, and the best final coefficient values were chosen based on the ability to simultaneously represent vapor pressure and liquid heat capacity. This procedure improves the fit to liquid heat-capacity data by 5-10% (average absolute deviation), while maintaining the fit of vapor-pressure data similar to those of other prediction methods. Additionally, low-temperature vapor-pressure predictions were improved by relying on liquid heat-capacity data. © 2017 American Chemical Society.
1776 a7005371369 Giles N.F. p663 False Journal 318 New Vapor-Pressure Prediction with Improved Thermodynamic Consistency using the Riedel Equation Vapor pressure, heat of vaporization, liquid heat capacity, and ideal-gas heat capacity for pure compounds between the triple point and critical point are important properties for process design and optimization. These thermophysical properties are related to each other through temperature derivatives of thermodynamic relationships stemming from a temperature-dependent vapor-pressure correlation. The Riedel equation has been considered to be an excellent and simple choice among vapor-pressure correlating equations [ Velasco et al. J. Chem. Thermodyn. 2008, 40 (5), 789-797 ] but requires modification of the final coefficient to provide thermodynamic consistency with thermal data [ Hogge et al. Fluid Phase Equilib. 2016, 429, 149-165 ]. New predictive correlations with final coefficients in integer steps from 1 to 6 have been created for compounds with limited or no vapor-pressure data, based on the methodology used originally by Riedel [ Chem. Ing. Tech. 1954, 26 (2), 83-89 ]. Liquid heat capacity was predicted using these vapor-pressure correlations, and the best final coefficient values were chosen based on the ability to simultaneously represent vapor pressure and liquid heat capacity. This procedure improves the fit to liquid heat-capacity data by 5-10% (average absolute deviation), while maintaining the fit of vapor-pressure data similar to those of other prediction methods. Additionally, low-temperature vapor-pressure predictions were improved by relying on liquid heat-capacity data. © 2017 American Chemical Society.
1777 a7006085792 Rowley R.L. p663 False Journal 318 New Vapor-Pressure Prediction with Improved Thermodynamic Consistency using the Riedel Equation Vapor pressure, heat of vaporization, liquid heat capacity, and ideal-gas heat capacity for pure compounds between the triple point and critical point are important properties for process design and optimization. These thermophysical properties are related to each other through temperature derivatives of thermodynamic relationships stemming from a temperature-dependent vapor-pressure correlation. The Riedel equation has been considered to be an excellent and simple choice among vapor-pressure correlating equations [ Velasco et al. J. Chem. Thermodyn. 2008, 40 (5), 789-797 ] but requires modification of the final coefficient to provide thermodynamic consistency with thermal data [ Hogge et al. Fluid Phase Equilib. 2016, 429, 149-165 ]. New predictive correlations with final coefficients in integer steps from 1 to 6 have been created for compounds with limited or no vapor-pressure data, based on the methodology used originally by Riedel [ Chem. Ing. Tech. 1954, 26 (2), 83-89 ]. Liquid heat capacity was predicted using these vapor-pressure correlations, and the best final coefficient values were chosen based on the ability to simultaneously represent vapor pressure and liquid heat capacity. This procedure improves the fit to liquid heat-capacity data by 5-10% (average absolute deviation), while maintaining the fit of vapor-pressure data similar to those of other prediction methods. Additionally, low-temperature vapor-pressure predictions were improved by relying on liquid heat-capacity data. © 2017 American Chemical Society.
1778 a55665625900 Wilding W.V. p663 False Journal 318 New Vapor-Pressure Prediction with Improved Thermodynamic Consistency using the Riedel Equation Vapor pressure, heat of vaporization, liquid heat capacity, and ideal-gas heat capacity for pure compounds between the triple point and critical point are important properties for process design and optimization. These thermophysical properties are related to each other through temperature derivatives of thermodynamic relationships stemming from a temperature-dependent vapor-pressure correlation. The Riedel equation has been considered to be an excellent and simple choice among vapor-pressure correlating equations [ Velasco et al. J. Chem. Thermodyn. 2008, 40 (5), 789-797 ] but requires modification of the final coefficient to provide thermodynamic consistency with thermal data [ Hogge et al. Fluid Phase Equilib. 2016, 429, 149-165 ]. New predictive correlations with final coefficients in integer steps from 1 to 6 have been created for compounds with limited or no vapor-pressure data, based on the methodology used originally by Riedel [ Chem. Ing. Tech. 1954, 26 (2), 83-89 ]. Liquid heat capacity was predicted using these vapor-pressure correlations, and the best final coefficient values were chosen based on the ability to simultaneously represent vapor pressure and liquid heat capacity. This procedure improves the fit to liquid heat-capacity data by 5-10% (average absolute deviation), while maintaining the fit of vapor-pressure data similar to those of other prediction methods. Additionally, low-temperature vapor-pressure predictions were improved by relying on liquid heat-capacity data. © 2017 American Chemical Society.
1779 a24335536400 Martin S.R. p664 True Conference 290 Bias estimation for angle-only sensors in distributed multi-target tracking systems This paper describes a method of automatic sensor bias calculation for angle only sensor models in a target tracking scenario. It is assumed that separate Kalman filters are employed by each sensor and no measurements of known landmarks are available. Accurate bias estimation is achieved through the use of pseudo measurements of slant range from each sensor to the target and pseudo measurements of each sensor's bias. The covariance intersection (CI) algorithm is used to produce a pseudo measurement of slant range. This pseudo measurement of range allows pseudo measurements of sensor bias to be calculated based on each sensor's residuals and Kalman gains. Substantially improved tracking performance is demonstrated when estimating and accounting for constant biases on each sensor. © 2017 IEEE.
1780 a40561545600 Merrell A.J. p666 True Journal 320 Nano-Composite Foam Sensor System in Football Helmets American football has both the highest rate of concussion incidences as well as the highest number of concussions of all contact sports due to both the number of athletes and nature of the sport. Recent research has linked concussions with long term health complications such as chronic traumatic encephalopathy and early onset Alzheimer’s. Understanding the mechanical characteristics of concussive impacts is critical to help protect athletes from these debilitating diseases and is now possible using helmet-based sensor systems. To date, real time on-field measurement of head impacts has been almost exclusively measured by devices that rely on accelerometers or gyroscopes attached to the player’s helmet, or embedded in a mouth guard. These systems monitor motion of the head or helmet, but do not directly measure impact energy. This paper evaluates the accuracy of a novel, multifunctional foam-based sensor that replaces a portion of the helmet foam to measure impact. All modified helmets were tested using a National Operating Committee Standards for Athletic Equipment-style drop tower with a total of 24 drop tests (4 locations with 6 impact energies). The impacts were evaluated using a headform, instrumented with a tri-axial accelerometer, mounted to a Hybrid III neck assembly. The resultant accelerations were evaluated for both the peak acceleration and the severity indices. These data were then compared to the voltage response from multiple Nano Composite Foam sensors located throughout the helmet. The foam sensor system proved to be accurate in measuring both the HIC and Gadd severity index, as well as peak acceleration while also providing additional details that were previously difficult to obtain, such as impact energy. © 2017, Biomedical Engineering Society.
1780 a40561545600 Merrell A.J. p694 False Journal 320 Estimation of 3D Ground Reaction Force Using Nanocomposite Piezo-Responsive Foam Sensors During Walking This paper describes a method for the estimation of the 3D ground reaction force (GRF) during human walking using novel nanocomposite piezo-responsive foam (NCPF) sensors. Nine subjects (5 male, 4 female) walked on a force-instrumented treadmill at 1.34 m/s for 120 s each while wearing a shoe that was instrumented with four NCPF sensors. GRF data, measured via the treadmill, and sensor data, measured via the NCPF inserts, were used in a tenfold cross validation process to calibrate a separate model for each individual. The calibration model estimated average anterior–posterior, mediolateral and vertical GRF with mean average errors (MAE) of 6.52 N (2.14%), 4.79 N (6.34%), and 15.4 N (2.15%), respectively. Two additional models were created using the sensor data from all subjects and subject demographics. A tenfold cross validation process for this combined data set resulted in models that estimated average anterior–posterior, mediolateral and vertical GRF with less than 8.16 N (2.41%), 6.63 N (7.37%), and 19.4 N (2.31%) errors, respectively. Intra-subject estimates based on the model had a higher accuracy than inter-subject estimates, likely due to the relatively small subject cohort used in creating the model. The novel NCPF sensors demonstrate the ability to accurately estimate 3D GRF during human movement outside of the traditional biomechanics laboratory setting. © 2017, Biomedical Engineering Society.
1781 a7006001488 Christensen W.F. p666 False Journal 320 Nano-Composite Foam Sensor System in Football Helmets American football has both the highest rate of concussion incidences as well as the highest number of concussions of all contact sports due to both the number of athletes and nature of the sport. Recent research has linked concussions with long term health complications such as chronic traumatic encephalopathy and early onset Alzheimer’s. Understanding the mechanical characteristics of concussive impacts is critical to help protect athletes from these debilitating diseases and is now possible using helmet-based sensor systems. To date, real time on-field measurement of head impacts has been almost exclusively measured by devices that rely on accelerometers or gyroscopes attached to the player’s helmet, or embedded in a mouth guard. These systems monitor motion of the head or helmet, but do not directly measure impact energy. This paper evaluates the accuracy of a novel, multifunctional foam-based sensor that replaces a portion of the helmet foam to measure impact. All modified helmets were tested using a National Operating Committee Standards for Athletic Equipment-style drop tower with a total of 24 drop tests (4 locations with 6 impact energies). The impacts were evaluated using a headform, instrumented with a tri-axial accelerometer, mounted to a Hybrid III neck assembly. The resultant accelerations were evaluated for both the peak acceleration and the severity indices. These data were then compared to the voltage response from multiple Nano Composite Foam sensors located throughout the helmet. The foam sensor system proved to be accurate in measuring both the HIC and Gadd severity index, as well as peak acceleration while also providing additional details that were previously difficult to obtain, such as impact energy. © 2017, Biomedical Engineering Society.
1781 a7006001488 Christensen W.F. p694 False Journal 320 Estimation of 3D Ground Reaction Force Using Nanocomposite Piezo-Responsive Foam Sensors During Walking This paper describes a method for the estimation of the 3D ground reaction force (GRF) during human walking using novel nanocomposite piezo-responsive foam (NCPF) sensors. Nine subjects (5 male, 4 female) walked on a force-instrumented treadmill at 1.34 m/s for 120 s each while wearing a shoe that was instrumented with four NCPF sensors. GRF data, measured via the treadmill, and sensor data, measured via the NCPF inserts, were used in a tenfold cross validation process to calibrate a separate model for each individual. The calibration model estimated average anterior–posterior, mediolateral and vertical GRF with mean average errors (MAE) of 6.52 N (2.14%), 4.79 N (6.34%), and 15.4 N (2.15%), respectively. Two additional models were created using the sensor data from all subjects and subject demographics. A tenfold cross validation process for this combined data set resulted in models that estimated average anterior–posterior, mediolateral and vertical GRF with less than 8.16 N (2.41%), 6.63 N (7.37%), and 19.4 N (2.31%) errors, respectively. Intra-subject estimates based on the model had a higher accuracy than inter-subject estimates, likely due to the relatively small subject cohort used in creating the model. The novel NCPF sensors demonstrate the ability to accurately estimate 3D GRF during human movement outside of the traditional biomechanics laboratory setting. © 2017, Biomedical Engineering Society.
1782 a6701752452 Dromey C. p667 True Journal 321 Effects of Laryngeal Activity on Articulation This study examined the effects of three speech conditions (voiced, whispered, and mouthed) on global average measures of articulatory movement during sentence production. Participants were 20 adults (ten males and ten females) with no history of speech, language, or hearing disorders. They produced six target utterances in the three speaking conditions. Movements of the following articulators were recorded with an electromagnetic articulograph: Mid tongue, front of tongue, jaw, lower lip, and upper lip. The kinematic metrics were averages derived from movement strokes defined by minima in the speed record of each articulator. These measures revealed a number of significant changes between the voiced and mouthed conditions, with relatively few differences between voiced and whispered speech. Significant increases in sentence duration, articulatory stroke count, and stroke duration as well as significant decreases in peak stroke speed, stroke distance, and hull areas were found in the mouthed condition. These findings suggest that both laryngeal activation and auditory feedback play an important role in the production of normally articulated vocal tract movements, and that the absence of these may account for the significant changes in articulation between the voiced and mouthed conditions. © 2014 IEEE.
1783 a57200248178 Black K.M. p667 False Journal 321 Effects of Laryngeal Activity on Articulation This study examined the effects of three speech conditions (voiced, whispered, and mouthed) on global average measures of articulatory movement during sentence production. Participants were 20 adults (ten males and ten females) with no history of speech, language, or hearing disorders. They produced six target utterances in the three speaking conditions. Movements of the following articulators were recorded with an electromagnetic articulograph: Mid tongue, front of tongue, jaw, lower lip, and upper lip. The kinematic metrics were averages derived from movement strokes defined by minima in the speed record of each articulator. These measures revealed a number of significant changes between the voiced and mouthed conditions, with relatively few differences between voiced and whispered speech. Significant increases in sentence duration, articulatory stroke count, and stroke duration as well as significant decreases in peak stroke speed, stroke distance, and hull areas were found in the mouthed condition. These findings suggest that both laryngeal activation and auditory feedback play an important role in the production of normally articulated vocal tract movements, and that the absence of these may account for the significant changes in articulation between the voiced and mouthed conditions. © 2014 IEEE.
1784 a57196000820 Ahmad W. p669 False Journal 319 A Comparison of Indoor MIMO Measurements and Ray-Tracing at 24 and 2.55 GHz Colocated 4× 4 multiple-input multiple-output measurements at 2.55 and 24 GHz are presented for two university buildings consisting of classrooms and offices. Link gain in hallways and connected laboratories looks similar at the two frequencies when the effect of lower effective receive antenna aperture with increasing frequency is removed. Non-line-of-sight (NLOS) propagation through a wall or around hallway corners exhibits approximately 5-20 dB (11 dB on average) greater loss beyond the 20 dB aperture loss at 24 GHz compared to that at 2.55 GHz. Fixed directional antennas increase path loss (PL) by an average of 13 dB when misaligned. Capacity for normalized signal-to-noise ratio is very similar in the two bands and is close to that for the optimal independent identically distributed case, indicating sufficient multipath for spatial multiplexing at 24 GHz. A ray-tracing study suggests that material loss must increase from 2.55 to 24 GHz to correctly predict the higher PL at 24 GHz in severely obstructed scenarios, indicating a need for future material characterization in high microwave bands. The results suggest that 24 GHz is a viable option to replace medium-range (10-30 m) NLOS wireless services currently operating at 2.4 GHz. © 1963-2012 IEEE.
1785 a57195995765 Yang Y. p669 False Journal 319 A Comparison of Indoor MIMO Measurements and Ray-Tracing at 24 and 2.55 GHz Colocated 4× 4 multiple-input multiple-output measurements at 2.55 and 24 GHz are presented for two university buildings consisting of classrooms and offices. Link gain in hallways and connected laboratories looks similar at the two frequencies when the effect of lower effective receive antenna aperture with increasing frequency is removed. Non-line-of-sight (NLOS) propagation through a wall or around hallway corners exhibits approximately 5-20 dB (11 dB on average) greater loss beyond the 20 dB aperture loss at 24 GHz compared to that at 2.55 GHz. Fixed directional antennas increase path loss (PL) by an average of 13 dB when misaligned. Capacity for normalized signal-to-noise ratio is very similar in the two bands and is close to that for the optimal independent identically distributed case, indicating sufficient multipath for spatial multiplexing at 24 GHz. A ray-tracing study suggests that material loss must increase from 2.55 to 24 GHz to correctly predict the higher PL at 24 GHz in severely obstructed scenarios, indicating a need for future material characterization in high microwave bands. The results suggest that 24 GHz is a viable option to replace medium-range (10-30 m) NLOS wireless services currently operating at 2.4 GHz. © 1963-2012 IEEE.
1786 a7004450337 Zumbrun K. p670 False Journal 323 Multidimensional Stability of Large-Amplitude Navier–Stokes Shocks Extending results of Humpherys–Lyng–Zumbrun in the one-dimensional case, we use a combination of asymptotic ODE estimates and numerical Evans-function computations to examine the multidimensional stability of planar Navier–Stokes shocks across the full range of shock amplitudes, including the infinite-amplitude limit, for monatomic or diatomic ideal gas equations of state and viscosity and heat conduction coefficients μ, μ+ η, and ν= κ/ cv constant and in the physical ratios predicted by statistical mechanics, and Mach number M&gt; 1.035. Our results indicate unconditional stability within the parameter range considered; this agrees with the results of Erpenbeck and Majda for the corresponding inviscid case of Euler shocks. Notably, this study includes the first successful numerical computation of an Evans function associated with the multidimensional stability of a viscous shock wave. The methods introduced can be used in principle to decide stability for shocks in any polytropic gas, or indeed for shocks of other models, including in, particular, viscoelasticity, combustion, and magnetohydrodynamics (MHD). © 2017, Springer-Verlag GmbH Germany.
1786 a7004450337 Zumbrun K. p785 False Journal 389 Stability of Viscous St. Venant Roll Waves: From Onset to Infinite Froude Number Limit We study the spectral stability of roll wave solutions of the viscous St. Venant equations modeling inclined shallow water flow, both at onset in the small Froude number or “weakly unstable” limit F→ 2 + and for general values of the Froude number F, including the limit F→ + ∞. In the former, F→ 2 +, limit, the shallow water equations are formally approximated by a Korteweg-de Vries/Kuramoto–Sivashinsky (KdV–KS) equation that is a singular perturbation of the standard Korteweg-de Vries (KdV) equation modeling horizontal shallow water flow. Our main analytical result is to rigorously validate this formal limit, showing that stability as F→ 2 + is equivalent to stability of the corresponding KdV–KS waves in the KdV limit. Together with recent results obtained for KdV–KS by Johnson–Noble–Rodrigues–Zumbrun and Barker, this gives not only the first rigorous verification of stability for any single viscous St. Venant roll wave, but a complete classification of stability in the weakly unstable limit. In the remainder of the paper, we investigate numerically and analytically the evolution of the stability diagram as Froude number increases to infinity. Notably, we find transition at around F= 2.3 from weakly unstable to different, large-F behavior, with stability determined by simple power-law relations. The latter stability criteria are potentially useful in hydraulic engineering applications, for which typically 2.5 ≤ F≤ 6.0. © 2016, Springer Science+Business Media New York.
1787 a7402004420 Campbell K.S. p672 True Journal 324 Plain-Style Preferences of US Professionals Background: Although plain language is almost universally promoted by teachers of professional writing, editors, and communication professionals, some have argued that the effects of and preferences for plain style in written messages differ among groups of individuals. Research questions: 1. Do professionals prefer plain style? 2a. Do preferences differ for different categories of style? 2b. Do preferences differ for different groups of workers? Literature review: Style, the word- and sentence-level elements in a written text, is a critical element of plain language. There is evidence that plain style, however, affects readers differently based on their level of subject matter knowledge. Plain style is even criticized by a few. There is a long history of tensions surrounding linguistic prescriptivism, the notion that one manner of language use is superior to all others. Further, readers' preferences for writing style, plain or otherwise, may not be consistent across occupational positions, education levels, nationalities, personality types, or genders. Research methodology: We conducted a quantitative study of preferences for two major style categories (conciseness and word choice) using an online survey instrument. The student-recruiter technique provided us with usable responses from 614 working adults in the US. Using that data, we calculated proportions of respondents, with confidence intervals, who chose the plain-style options. We also used statistical tests to explore associations between preferences and respondent characteristics. Results and conclusions: Our findings support an overwhelming preference for plain style among US professionals who are native speakers of English. Reader preferences were stronger for elements associated with word choice than with conciseness. Those with lower education levels and blue-collar occupations had lower preferences for plain style. The study had two major limitations: 1. We investigated only two aspects of plain style rather than the full range of elements that make up plain language. 2. Our data-collection instrument presented readers with an artificial rather than an authentic reading experience. Future research may investigate the role of personality on stylistic preferences and the attributions readers make about writers based on their style. © 1988-2012 IEEE.
1788 a6602231941 Amare N. p672 False Journal 324 Plain-Style Preferences of US Professionals Background: Although plain language is almost universally promoted by teachers of professional writing, editors, and communication professionals, some have argued that the effects of and preferences for plain style in written messages differ among groups of individuals. Research questions: 1. Do professionals prefer plain style? 2a. Do preferences differ for different categories of style? 2b. Do preferences differ for different groups of workers? Literature review: Style, the word- and sentence-level elements in a written text, is a critical element of plain language. There is evidence that plain style, however, affects readers differently based on their level of subject matter knowledge. Plain style is even criticized by a few. There is a long history of tensions surrounding linguistic prescriptivism, the notion that one manner of language use is superior to all others. Further, readers' preferences for writing style, plain or otherwise, may not be consistent across occupational positions, education levels, nationalities, personality types, or genders. Research methodology: We conducted a quantitative study of preferences for two major style categories (conciseness and word choice) using an online survey instrument. The student-recruiter technique provided us with usable responses from 614 working adults in the US. Using that data, we calculated proportions of respondents, with confidence intervals, who chose the plain-style options. We also used statistical tests to explore associations between preferences and respondent characteristics. Results and conclusions: Our findings support an overwhelming preference for plain style among US professionals who are native speakers of English. Reader preferences were stronger for elements associated with word choice than with conciseness. Those with lower education levels and blue-collar occupations had lower preferences for plain style. The study had two major limitations: 1. We investigated only two aspects of plain style rather than the full range of elements that make up plain language. 2. Our data-collection instrument presented readers with an artificial rather than an authentic reading experience. Future research may investigate the role of personality on stylistic preferences and the attributions readers make about writers based on their style. © 1988-2012 IEEE.
1788 a6602231941 Amare N. p704 False Conference 298 Bad news first: How optimal directness depends on what is negated This article reports study results in which participants (n=145) responded to a variety of negative messages in a variety of message channels, visual, textual, and verbal. Participants participated in A-B testing of distinct message strategies and then identified communication values that seemed most important in distinct message contexts. Results showed very clear differences between two broad classes of negative information: negative information about perceived physical facts (e.g. the presence of hazardous materials or dangerous conditions) as opposed to negative information about social relationships (e.g., a romantic breakup, the death of a loved one, or termination of employment). Participants consistently identified directness as a communicative virtue, even in contexts where they preferred a message format with a consistently small buffer in order to also satisfy a perceived need for politeness. Conversely, explanatory information prior to bad news was never preferred over bad-news-first in cases involving physical-fact bad news. © 2017 IEEE.
1789 a57197730899 Kane E. p672 False Journal 324 Plain-Style Preferences of US Professionals Background: Although plain language is almost universally promoted by teachers of professional writing, editors, and communication professionals, some have argued that the effects of and preferences for plain style in written messages differ among groups of individuals. Research questions: 1. Do professionals prefer plain style? 2a. Do preferences differ for different categories of style? 2b. Do preferences differ for different groups of workers? Literature review: Style, the word- and sentence-level elements in a written text, is a critical element of plain language. There is evidence that plain style, however, affects readers differently based on their level of subject matter knowledge. Plain style is even criticized by a few. There is a long history of tensions surrounding linguistic prescriptivism, the notion that one manner of language use is superior to all others. Further, readers' preferences for writing style, plain or otherwise, may not be consistent across occupational positions, education levels, nationalities, personality types, or genders. Research methodology: We conducted a quantitative study of preferences for two major style categories (conciseness and word choice) using an online survey instrument. The student-recruiter technique provided us with usable responses from 614 working adults in the US. Using that data, we calculated proportions of respondents, with confidence intervals, who chose the plain-style options. We also used statistical tests to explore associations between preferences and respondent characteristics. Results and conclusions: Our findings support an overwhelming preference for plain style among US professionals who are native speakers of English. Reader preferences were stronger for elements associated with word choice than with conciseness. Those with lower education levels and blue-collar occupations had lower preferences for plain style. The study had two major limitations: 1. We investigated only two aspects of plain style rather than the full range of elements that make up plain language. 2. Our data-collection instrument presented readers with an artificial rather than an authentic reading experience. Future research may investigate the role of personality on stylistic preferences and the attributions readers make about writers based on their style. © 1988-2012 IEEE.
1790 a7101816438 Manning A.D. p672 False Journal 324 Plain-Style Preferences of US Professionals Background: Although plain language is almost universally promoted by teachers of professional writing, editors, and communication professionals, some have argued that the effects of and preferences for plain style in written messages differ among groups of individuals. Research questions: 1. Do professionals prefer plain style? 2a. Do preferences differ for different categories of style? 2b. Do preferences differ for different groups of workers? Literature review: Style, the word- and sentence-level elements in a written text, is a critical element of plain language. There is evidence that plain style, however, affects readers differently based on their level of subject matter knowledge. Plain style is even criticized by a few. There is a long history of tensions surrounding linguistic prescriptivism, the notion that one manner of language use is superior to all others. Further, readers' preferences for writing style, plain or otherwise, may not be consistent across occupational positions, education levels, nationalities, personality types, or genders. Research methodology: We conducted a quantitative study of preferences for two major style categories (conciseness and word choice) using an online survey instrument. The student-recruiter technique provided us with usable responses from 614 working adults in the US. Using that data, we calculated proportions of respondents, with confidence intervals, who chose the plain-style options. We also used statistical tests to explore associations between preferences and respondent characteristics. Results and conclusions: Our findings support an overwhelming preference for plain style among US professionals who are native speakers of English. Reader preferences were stronger for elements associated with word choice than with conciseness. Those with lower education levels and blue-collar occupations had lower preferences for plain style. The study had two major limitations: 1. We investigated only two aspects of plain style rather than the full range of elements that make up plain language. 2. Our data-collection instrument presented readers with an artificial rather than an authentic reading experience. Future research may investigate the role of personality on stylistic preferences and the attributions readers make about writers based on their style. © 1988-2012 IEEE.
1790 a7101816438 Manning A.D. p704 True Conference 298 Bad news first: How optimal directness depends on what is negated This article reports study results in which participants (n=145) responded to a variety of negative messages in a variety of message channels, visual, textual, and verbal. Participants participated in A-B testing of distinct message strategies and then identified communication values that seemed most important in distinct message contexts. Results showed very clear differences between two broad classes of negative information: negative information about perceived physical facts (e.g. the presence of hazardous materials or dangerous conditions) as opposed to negative information about social relationships (e.g., a romantic breakup, the death of a loved one, or termination of employment). Participants consistently identified directness as a communicative virtue, even in contexts where they preferred a message format with a consistently small buffer in order to also satisfy a perceived need for politeness. Conversely, explanatory information prior to bad news was never preferred over bad-news-first in cases involving physical-fact bad news. © 2017 IEEE.
1791 a56810920600 Naidoo J.S. p672 False Journal 324 Plain-Style Preferences of US Professionals Background: Although plain language is almost universally promoted by teachers of professional writing, editors, and communication professionals, some have argued that the effects of and preferences for plain style in written messages differ among groups of individuals. Research questions: 1. Do professionals prefer plain style? 2a. Do preferences differ for different categories of style? 2b. Do preferences differ for different groups of workers? Literature review: Style, the word- and sentence-level elements in a written text, is a critical element of plain language. There is evidence that plain style, however, affects readers differently based on their level of subject matter knowledge. Plain style is even criticized by a few. There is a long history of tensions surrounding linguistic prescriptivism, the notion that one manner of language use is superior to all others. Further, readers' preferences for writing style, plain or otherwise, may not be consistent across occupational positions, education levels, nationalities, personality types, or genders. Research methodology: We conducted a quantitative study of preferences for two major style categories (conciseness and word choice) using an online survey instrument. The student-recruiter technique provided us with usable responses from 614 working adults in the US. Using that data, we calculated proportions of respondents, with confidence intervals, who chose the plain-style options. We also used statistical tests to explore associations between preferences and respondent characteristics. Results and conclusions: Our findings support an overwhelming preference for plain style among US professionals who are native speakers of English. Reader preferences were stronger for elements associated with word choice than with conciseness. Those with lower education levels and blue-collar occupations had lower preferences for plain style. The study had two major limitations: 1. We investigated only two aspects of plain style rather than the full range of elements that make up plain language. 2. Our data-collection instrument presented readers with an artificial rather than an authentic reading experience. Future research may investigate the role of personality on stylistic preferences and the attributions readers make about writers based on their style. © 1988-2012 IEEE.
1792 a55764744500 Aslani P. p673 True Journal 325 Analysis of the external radiation from circular cylindrical shells Structurally radiated sound power is a critical design parameter. The acoustic radiation mode approach for computing sound power was developed in the early 1990s and has since been widely used. It has been shown to be a rather efficient approach for determining the radiated sound power. In previous research, radiation mode expressions have been developed for planar and spherical structures, as well as axisymmetric modes of internal and external radiation from cylinders. In this work, the radiation modes for external radiating cylinders which account for both axial and circumferential dependence are presented. The expressions are uniquely developed using cylindrical basis functions which are a more natural match to the geometry than past developments, which have been based on spherical harmonics. Higher order radiation modes than have been previously presented are shown. The “leapfrog effect”, whereby higher order modes leapfrog over lower modes in terms of their radiation efficiencies as the frequency goes above the cut-on frequency for those modes, is discussed in detail. The relationships between the mode efficiency and the coincidence effect associated with the cut-on frequencies of the vibration modes are described. © 2017 Elsevier Ltd
1793 a6603077820 Blotter J.D. p673 False Journal 325 Analysis of the external radiation from circular cylindrical shells Structurally radiated sound power is a critical design parameter. The acoustic radiation mode approach for computing sound power was developed in the early 1990s and has since been widely used. It has been shown to be a rather efficient approach for determining the radiated sound power. In previous research, radiation mode expressions have been developed for planar and spherical structures, as well as axisymmetric modes of internal and external radiation from cylinders. In this work, the radiation modes for external radiating cylinders which account for both axial and circumferential dependence are presented. The expressions are uniquely developed using cylindrical basis functions which are a more natural match to the geometry than past developments, which have been based on spherical harmonics. Higher order radiation modes than have been previously presented are shown. The “leapfrog effect”, whereby higher order modes leapfrog over lower modes in terms of their radiation efficiencies as the frequency goes above the cut-on frequency for those modes, is discussed in detail. The relationships between the mode efficiency and the coincidence effect associated with the cut-on frequencies of the vibration modes are described. © 2017 Elsevier Ltd
1794 a57217339723 Hoagland D. p675 True Journal 326 Continuous permeability measurement during unidirectional vacuum infusion processing Flow simulation for liquid composite molding is often performed to assist in process optimization and requires the permeability of the reinforcement to be characterized. For infusion under a flexible membrane, such as vacuum infusion, or for simulation of a part with non-uniform thickness, one must test the permeability at various levels of compaction. This process is time consuming and often relies on interpolation or extrapolation around a few experimental permeability measurements. To accelerate the process of permeability characterization, a small number of methodologies have been previously presented in the literature, in which the permeability may be tested at multiple fiber volume contents in a single test. Some of the methods even measure the permeability over a continuous range of thicknesses, thus requiring no later interpolation of permeability values. A novel method is presented here for the rapid measurement of permeability over a continuous range of fiber volume content, in a single unidirectional vacuum infusion flow experiment. The thickness gradient across the vacuum bag, as well as the fluid pressure at several locations in the mold were concurrently measured to calculate the fabric compressibility. An analytical flow model, which accounts for the compressibility, is then used by iterating the fitting constant in a permeability model until the predicted flow front progression matches empirical measurement. The method is demonstrated here for two reinforcement materials: (1) a fiberglass unbalanced weave and (2) a carbon biax non-crimped fabric. The standard deviation across the multiple experiments for each material and flow orientation ranged from 12.8% to 29.7%. Validation of these results was performed by comparing the resulting permeability with multiple non-continuous permeability measurement methods. © 2017, © The Author(s) 2017.
1795 a57140193000 Bustamante D. p676 True Journal 327 High-Precision, Mixed-Signal Mismatch Measurement of Metal-Oxide-Metal Capacitors This brief presents a high-precision, mixed-signal mismatch measurement technique for metal-oxide-metal capacitors. The proposed technique incorporates a switched-capacitor op amp within the measurement circuit to significantly improve the measurement precision while relaxing the resolution requirement on the backend analog-to-digital converter (ADC). The proposed technique is also robust against multiple types of errors. A detailed analysis is presented to quantify the sensitivity improvement of the proposed technique over the conventional one. In addition, this brief proposes a multiplexing technique to measure a large number of capacitors in a single chip and a new layout to improve matching. A prototype fabricated in 180 nm technology demonstrates the ability to sense capacitor mismatch standard deviation as low as 0.045% with excellent repeatability, all without the need of a high-resolution ADC. © 2004-2012 IEEE.
1796 a36011148100 Van Hoe B. p678 True Conference 291 High-Speed Interrogation of Multiplexed Fiber Bragg Gratings with Spectral Distortion Fiber Bragg grating (FBG) sensors can be multiplexed in large numbers to monitor the performance of large structures. This paper addresses the collection of FBG reflection spectra from wavelength division multiplexed sensors at fast acquisition rates. The spectral and temporal resolution is first derived as a function of the tunable filter and measurement system properties. The method is applied to impact loading investigations of a stiffened composite skin panel. The reflected spectrum of each FBG in an array, embedded in the panel, is collected at 100 kHz during the impact events with a spectral resolution down to 40 pm. Visualization of the FBG responses to these impact events, including the presence of spectral distortion in some FBG spectra, is presented. Future analyses based on the full-spectral data sets can enable the assessment of the localized progression of internal damage in such structures. © 2001-2012 IEEE.
1797 a56155127800 Oman K.G. p678 False Conference 291 High-Speed Interrogation of Multiplexed Fiber Bragg Gratings with Spectral Distortion Fiber Bragg grating (FBG) sensors can be multiplexed in large numbers to monitor the performance of large structures. This paper addresses the collection of FBG reflection spectra from wavelength division multiplexed sensors at fast acquisition rates. The spectral and temporal resolution is first derived as a function of the tunable filter and measurement system properties. The method is applied to impact loading investigations of a stiffened composite skin panel. The reflected spectrum of each FBG in an array, embedded in the panel, is collected at 100 kHz during the impact events with a spectral resolution down to 40 pm. Visualization of the FBG responses to these impact events, including the presence of spectral distortion in some FBG spectra, is presented. Future analyses based on the full-spectral data sets can enable the assessment of the localized progression of internal damage in such structures. © 2001-2012 IEEE.
1798 a6506311950 Van Steenberge G. p678 False Conference 291 High-Speed Interrogation of Multiplexed Fiber Bragg Gratings with Spectral Distortion Fiber Bragg grating (FBG) sensors can be multiplexed in large numbers to monitor the performance of large structures. This paper addresses the collection of FBG reflection spectra from wavelength division multiplexed sensors at fast acquisition rates. The spectral and temporal resolution is first derived as a function of the tunable filter and measurement system properties. The method is applied to impact loading investigations of a stiffened composite skin panel. The reflected spectrum of each FBG in an array, embedded in the panel, is collected at 100 kHz during the impact events with a spectral resolution down to 40 pm. Visualization of the FBG responses to these impact events, including the presence of spectral distortion in some FBG spectra, is presented. Future analyses based on the full-spectral data sets can enable the assessment of the localized progression of internal damage in such structures. © 2001-2012 IEEE.
1799 a57196086981 Draper S.R.E. p680 True Journal 329 Polyethylene Glycol Based Changes to β-Sheet Protein Conformational and Proteolytic Stability Depend on Conjugation Strategy and Location The development of chemical strategies for site-specific protein modification now enables researchers to attach polyethylene glycol (PEG) to a protein drug at one or more specific locations (i.e., protein PEGylation). However, aside from avoiding enzyme active sites or protein-binding interfaces, distinguishing the optimal PEGylation site from the available alternatives has conventionally been a matter of trial and error. As part of a continuing effort to develop guidelines for identifying optimal PEGylation sites within proteins, we show here that the impact of PEGylation at various sites within the β-sheet model protein WW depends strongly on the identity of the PEG-protein linker. The PEGylation of Gln or of azidohomoalanine has a similar impact on WW conformational stability as does Asn-PEGylation, whereas the PEGylation of propargyloxyphenylalanine is substantially stabilizing at locations where Asn-PEGylation was destabilizing. Importantly, we find that at least one of these three site-specific PEGylation strategies leads to substantial PEG-based stabilization at each of the positions investigated, highlighting the importance of considering conjugation strategy as an important variable in selecting optimal PEGylation sites. We further demonstrate that using a branched PEG oligomer intensifies the impact of PEGylation on WW conformational stability and also show that PEG-based increases to conformational stability are strongly associated with corresponding increases in proteolytic stability. © 2017 American Chemical Society.
1800 a55981276700 Lawrence P.B. p680 False Journal 329 Polyethylene Glycol Based Changes to β-Sheet Protein Conformational and Proteolytic Stability Depend on Conjugation Strategy and Location The development of chemical strategies for site-specific protein modification now enables researchers to attach polyethylene glycol (PEG) to a protein drug at one or more specific locations (i.e., protein PEGylation). However, aside from avoiding enzyme active sites or protein-binding interfaces, distinguishing the optimal PEGylation site from the available alternatives has conventionally been a matter of trial and error. As part of a continuing effort to develop guidelines for identifying optimal PEGylation sites within proteins, we show here that the impact of PEGylation at various sites within the β-sheet model protein WW depends strongly on the identity of the PEG-protein linker. The PEGylation of Gln or of azidohomoalanine has a similar impact on WW conformational stability as does Asn-PEGylation, whereas the PEGylation of propargyloxyphenylalanine is substantially stabilizing at locations where Asn-PEGylation was destabilizing. Importantly, we find that at least one of these three site-specific PEGylation strategies leads to substantial PEG-based stabilization at each of the positions investigated, highlighting the importance of considering conjugation strategy as an important variable in selecting optimal PEGylation sites. We further demonstrate that using a branched PEG oligomer intensifies the impact of PEGylation on WW conformational stability and also show that PEG-based increases to conformational stability are strongly associated with corresponding increases in proteolytic stability. © 2017 American Chemical Society.
1801 a57190261034 Billings W.M. p680 False Journal 329 Polyethylene Glycol Based Changes to β-Sheet Protein Conformational and Proteolytic Stability Depend on Conjugation Strategy and Location The development of chemical strategies for site-specific protein modification now enables researchers to attach polyethylene glycol (PEG) to a protein drug at one or more specific locations (i.e., protein PEGylation). However, aside from avoiding enzyme active sites or protein-binding interfaces, distinguishing the optimal PEGylation site from the available alternatives has conventionally been a matter of trial and error. As part of a continuing effort to develop guidelines for identifying optimal PEGylation sites within proteins, we show here that the impact of PEGylation at various sites within the β-sheet model protein WW depends strongly on the identity of the PEG-protein linker. The PEGylation of Gln or of azidohomoalanine has a similar impact on WW conformational stability as does Asn-PEGylation, whereas the PEGylation of propargyloxyphenylalanine is substantially stabilizing at locations where Asn-PEGylation was destabilizing. Importantly, we find that at least one of these three site-specific PEGylation strategies leads to substantial PEG-based stabilization at each of the positions investigated, highlighting the importance of considering conjugation strategy as an important variable in selecting optimal PEGylation sites. We further demonstrate that using a branched PEG oligomer intensifies the impact of PEGylation on WW conformational stability and also show that PEG-based increases to conformational stability are strongly associated with corresponding increases in proteolytic stability. © 2017 American Chemical Society.
1802 a57196097542 Xiao Q. p680 False Journal 329 Polyethylene Glycol Based Changes to β-Sheet Protein Conformational and Proteolytic Stability Depend on Conjugation Strategy and Location The development of chemical strategies for site-specific protein modification now enables researchers to attach polyethylene glycol (PEG) to a protein drug at one or more specific locations (i.e., protein PEGylation). However, aside from avoiding enzyme active sites or protein-binding interfaces, distinguishing the optimal PEGylation site from the available alternatives has conventionally been a matter of trial and error. As part of a continuing effort to develop guidelines for identifying optimal PEGylation sites within proteins, we show here that the impact of PEGylation at various sites within the β-sheet model protein WW depends strongly on the identity of the PEG-protein linker. The PEGylation of Gln or of azidohomoalanine has a similar impact on WW conformational stability as does Asn-PEGylation, whereas the PEGylation of propargyloxyphenylalanine is substantially stabilizing at locations where Asn-PEGylation was destabilizing. Importantly, we find that at least one of these three site-specific PEGylation strategies leads to substantial PEG-based stabilization at each of the positions investigated, highlighting the importance of considering conjugation strategy as an important variable in selecting optimal PEGylation sites. We further demonstrate that using a branched PEG oligomer intensifies the impact of PEGylation on WW conformational stability and also show that PEG-based increases to conformational stability are strongly associated with corresponding increases in proteolytic stability. © 2017 American Chemical Society.
1803 a57196096093 Brown N.P. p680 False Journal 329 Polyethylene Glycol Based Changes to β-Sheet Protein Conformational and Proteolytic Stability Depend on Conjugation Strategy and Location The development of chemical strategies for site-specific protein modification now enables researchers to attach polyethylene glycol (PEG) to a protein drug at one or more specific locations (i.e., protein PEGylation). However, aside from avoiding enzyme active sites or protein-binding interfaces, distinguishing the optimal PEGylation site from the available alternatives has conventionally been a matter of trial and error. As part of a continuing effort to develop guidelines for identifying optimal PEGylation sites within proteins, we show here that the impact of PEGylation at various sites within the β-sheet model protein WW depends strongly on the identity of the PEG-protein linker. The PEGylation of Gln or of azidohomoalanine has a similar impact on WW conformational stability as does Asn-PEGylation, whereas the PEGylation of propargyloxyphenylalanine is substantially stabilizing at locations where Asn-PEGylation was destabilizing. Importantly, we find that at least one of these three site-specific PEGylation strategies leads to substantial PEG-based stabilization at each of the positions investigated, highlighting the importance of considering conjugation strategy as an important variable in selecting optimal PEGylation sites. We further demonstrate that using a branched PEG oligomer intensifies the impact of PEGylation on WW conformational stability and also show that PEG-based increases to conformational stability are strongly associated with corresponding increases in proteolytic stability. © 2017 American Chemical Society.
1804 a57196088013 Bécar N.A. p680 False Journal 329 Polyethylene Glycol Based Changes to β-Sheet Protein Conformational and Proteolytic Stability Depend on Conjugation Strategy and Location The development of chemical strategies for site-specific protein modification now enables researchers to attach polyethylene glycol (PEG) to a protein drug at one or more specific locations (i.e., protein PEGylation). However, aside from avoiding enzyme active sites or protein-binding interfaces, distinguishing the optimal PEGylation site from the available alternatives has conventionally been a matter of trial and error. As part of a continuing effort to develop guidelines for identifying optimal PEGylation sites within proteins, we show here that the impact of PEGylation at various sites within the β-sheet model protein WW depends strongly on the identity of the PEG-protein linker. The PEGylation of Gln or of azidohomoalanine has a similar impact on WW conformational stability as does Asn-PEGylation, whereas the PEGylation of propargyloxyphenylalanine is substantially stabilizing at locations where Asn-PEGylation was destabilizing. Importantly, we find that at least one of these three site-specific PEGylation strategies leads to substantial PEG-based stabilization at each of the positions investigated, highlighting the importance of considering conjugation strategy as an important variable in selecting optimal PEGylation sites. We further demonstrate that using a branched PEG oligomer intensifies the impact of PEGylation on WW conformational stability and also show that PEG-based increases to conformational stability are strongly associated with corresponding increases in proteolytic stability. © 2017 American Chemical Society.
1805 a57196086109 Matheson D.J. p680 False Journal 329 Polyethylene Glycol Based Changes to β-Sheet Protein Conformational and Proteolytic Stability Depend on Conjugation Strategy and Location The development of chemical strategies for site-specific protein modification now enables researchers to attach polyethylene glycol (PEG) to a protein drug at one or more specific locations (i.e., protein PEGylation). However, aside from avoiding enzyme active sites or protein-binding interfaces, distinguishing the optimal PEGylation site from the available alternatives has conventionally been a matter of trial and error. As part of a continuing effort to develop guidelines for identifying optimal PEGylation sites within proteins, we show here that the impact of PEGylation at various sites within the β-sheet model protein WW depends strongly on the identity of the PEG-protein linker. The PEGylation of Gln or of azidohomoalanine has a similar impact on WW conformational stability as does Asn-PEGylation, whereas the PEGylation of propargyloxyphenylalanine is substantially stabilizing at locations where Asn-PEGylation was destabilizing. Importantly, we find that at least one of these three site-specific PEGylation strategies leads to substantial PEG-based stabilization at each of the positions investigated, highlighting the importance of considering conjugation strategy as an important variable in selecting optimal PEGylation sites. We further demonstrate that using a branched PEG oligomer intensifies the impact of PEGylation on WW conformational stability and also show that PEG-based increases to conformational stability are strongly associated with corresponding increases in proteolytic stability. © 2017 American Chemical Society.
1806 a57190252027 Stephens A.R. p680 False Journal 329 Polyethylene Glycol Based Changes to β-Sheet Protein Conformational and Proteolytic Stability Depend on Conjugation Strategy and Location The development of chemical strategies for site-specific protein modification now enables researchers to attach polyethylene glycol (PEG) to a protein drug at one or more specific locations (i.e., protein PEGylation). However, aside from avoiding enzyme active sites or protein-binding interfaces, distinguishing the optimal PEGylation site from the available alternatives has conventionally been a matter of trial and error. As part of a continuing effort to develop guidelines for identifying optimal PEGylation sites within proteins, we show here that the impact of PEGylation at various sites within the β-sheet model protein WW depends strongly on the identity of the PEG-protein linker. The PEGylation of Gln or of azidohomoalanine has a similar impact on WW conformational stability as does Asn-PEGylation, whereas the PEGylation of propargyloxyphenylalanine is substantially stabilizing at locations where Asn-PEGylation was destabilizing. Importantly, we find that at least one of these three site-specific PEGylation strategies leads to substantial PEG-based stabilization at each of the positions investigated, highlighting the importance of considering conjugation strategy as an important variable in selecting optimal PEGylation sites. We further demonstrate that using a branched PEG oligomer intensifies the impact of PEGylation on WW conformational stability and also show that PEG-based increases to conformational stability are strongly associated with corresponding increases in proteolytic stability. © 2017 American Chemical Society.
1807 a55456759700 Price J.L. p680 False Journal 329 Polyethylene Glycol Based Changes to β-Sheet Protein Conformational and Proteolytic Stability Depend on Conjugation Strategy and Location The development of chemical strategies for site-specific protein modification now enables researchers to attach polyethylene glycol (PEG) to a protein drug at one or more specific locations (i.e., protein PEGylation). However, aside from avoiding enzyme active sites or protein-binding interfaces, distinguishing the optimal PEGylation site from the available alternatives has conventionally been a matter of trial and error. As part of a continuing effort to develop guidelines for identifying optimal PEGylation sites within proteins, we show here that the impact of PEGylation at various sites within the β-sheet model protein WW depends strongly on the identity of the PEG-protein linker. The PEGylation of Gln or of azidohomoalanine has a similar impact on WW conformational stability as does Asn-PEGylation, whereas the PEGylation of propargyloxyphenylalanine is substantially stabilizing at locations where Asn-PEGylation was destabilizing. Importantly, we find that at least one of these three site-specific PEGylation strategies leads to substantial PEG-based stabilization at each of the positions investigated, highlighting the importance of considering conjugation strategy as an important variable in selecting optimal PEGylation sites. We further demonstrate that using a branched PEG oligomer intensifies the impact of PEGylation on WW conformational stability and also show that PEG-based increases to conformational stability are strongly associated with corresponding increases in proteolytic stability. © 2017 American Chemical Society.
1808 a57202280527 Brewer J. p682 False Conference 294 Applying a passive network reconstruction technique to Twitter data in order to identify trend setters In this work we apply a systems-theoretic approach to identifying trend setters on Twitter. A network reconstruction algorithm was applied to Twitter data to determine causal relationships among topics discussed by popular Twitter users. Causal relationships in this context means that the topics tweeted by a single user influences the topics tweeted by another user, regardless of sentiment. A user that causally influences other users, without themselves being strongly influenced is identified as a trendsetter. This work seeks to identify potential trendsetters among popular Twitter users and demonstrating that causal influence does not always directly correlate with a user's popularity in terms of followers-demonstrating that popularity alone may not be sufficient for identifying trendsetters on Twitter. © 2017 IEEE.
1809 a57202283319 Lee K. p682 False Conference 294 Applying a passive network reconstruction technique to Twitter data in order to identify trend setters In this work we apply a systems-theoretic approach to identifying trend setters on Twitter. A network reconstruction algorithm was applied to Twitter data to determine causal relationships among topics discussed by popular Twitter users. Causal relationships in this context means that the topics tweeted by a single user influences the topics tweeted by another user, regardless of sentiment. A user that causally influences other users, without themselves being strongly influenced is identified as a trendsetter. This work seeks to identify potential trendsetters among popular Twitter users and demonstrating that causal influence does not always directly correlate with a user's popularity in terms of followers-demonstrating that popularity alone may not be sufficient for identifying trendsetters on Twitter. © 2017 IEEE.
1810 a57198318094 Hollenbeck M. p683 True Conference 295 Selective Laser Melting aluminum waveguide attenuation at K-band Additive manufacturing allows for fabrication of highly complex structures that efficiently use a 3D volume of space. Current state of the art metal additive manufacturing methods such as Selective Laser Melting (SLM) allow for intricate parts with high mechanical strength but at the cost of increased surface roughness on internal faces of waveguide structures. This paper investigates the contribution to loss of the increased surface roughness on a set of SLM WR42 waveguides printed with a standard ALSi10Mg aluminum powder, and compares their attenuation performance to purchased single-piece WR42 waveguides and to an industry-standard method for CNC machining waveguide multi-piece assemblies. Single-piece construction of RF parts produces lower attenuation than multi-piece assembly, and lower surface roughness directly leads to lower attenuation, as expected. SLM RF waveguides had better part consistency and comparable or better attenuation performance compared to CNC waveguides, showing that this manu-facturing method has reached the point where it can be used in RF waveguide assemblies. © 2017 IEEE.
1811 a35195145200 Wamick K. p683 False Conference 295 Selective Laser Melting aluminum waveguide attenuation at K-band Additive manufacturing allows for fabrication of highly complex structures that efficiently use a 3D volume of space. Current state of the art metal additive manufacturing methods such as Selective Laser Melting (SLM) allow for intricate parts with high mechanical strength but at the cost of increased surface roughness on internal faces of waveguide structures. This paper investigates the contribution to loss of the increased surface roughness on a set of SLM WR42 waveguides printed with a standard ALSi10Mg aluminum powder, and compares their attenuation performance to purchased single-piece WR42 waveguides and to an industry-standard method for CNC machining waveguide multi-piece assemblies. Single-piece construction of RF parts produces lower attenuation than multi-piece assembly, and lower surface roughness directly leads to lower attenuation, as expected. SLM RF waveguides had better part consistency and comparable or better attenuation performance compared to CNC waveguides, showing that this manu-facturing method has reached the point where it can be used in RF waveguide assemblies. © 2017 IEEE.
1812 a57196275913 Cathey C. p683 False Conference 295 Selective Laser Melting aluminum waveguide attenuation at K-band Additive manufacturing allows for fabrication of highly complex structures that efficiently use a 3D volume of space. Current state of the art metal additive manufacturing methods such as Selective Laser Melting (SLM) allow for intricate parts with high mechanical strength but at the cost of increased surface roughness on internal faces of waveguide structures. This paper investigates the contribution to loss of the increased surface roughness on a set of SLM WR42 waveguides printed with a standard ALSi10Mg aluminum powder, and compares their attenuation performance to purchased single-piece WR42 waveguides and to an industry-standard method for CNC machining waveguide multi-piece assemblies. Single-piece construction of RF parts produces lower attenuation than multi-piece assembly, and lower surface roughness directly leads to lower attenuation, as expected. SLM RF waveguides had better part consistency and comparable or better attenuation performance compared to CNC waveguides, showing that this manu-facturing method has reached the point where it can be used in RF waveguide assemblies. © 2017 IEEE.
1813 a57196277369 Opra J. p683 False Conference 295 Selective Laser Melting aluminum waveguide attenuation at K-band Additive manufacturing allows for fabrication of highly complex structures that efficiently use a 3D volume of space. Current state of the art metal additive manufacturing methods such as Selective Laser Melting (SLM) allow for intricate parts with high mechanical strength but at the cost of increased surface roughness on internal faces of waveguide structures. This paper investigates the contribution to loss of the increased surface roughness on a set of SLM WR42 waveguides printed with a standard ALSi10Mg aluminum powder, and compares their attenuation performance to purchased single-piece WR42 waveguides and to an industry-standard method for CNC machining waveguide multi-piece assemblies. Single-piece construction of RF parts produces lower attenuation than multi-piece assembly, and lower surface roughness directly leads to lower attenuation, as expected. SLM RF waveguides had better part consistency and comparable or better attenuation performance compared to CNC waveguides, showing that this manu-facturing method has reached the point where it can be used in RF waveguide assemblies. © 2017 IEEE.
1814 a57211422454 Smith R. p683 False Conference 295 Selective Laser Melting aluminum waveguide attenuation at K-band Additive manufacturing allows for fabrication of highly complex structures that efficiently use a 3D volume of space. Current state of the art metal additive manufacturing methods such as Selective Laser Melting (SLM) allow for intricate parts with high mechanical strength but at the cost of increased surface roughness on internal faces of waveguide structures. This paper investigates the contribution to loss of the increased surface roughness on a set of SLM WR42 waveguides printed with a standard ALSi10Mg aluminum powder, and compares their attenuation performance to purchased single-piece WR42 waveguides and to an industry-standard method for CNC machining waveguide multi-piece assemblies. Single-piece construction of RF parts produces lower attenuation than multi-piece assembly, and lower surface roughness directly leads to lower attenuation, as expected. SLM RF waveguides had better part consistency and comparable or better attenuation performance compared to CNC waveguides, showing that this manu-facturing method has reached the point where it can be used in RF waveguide assemblies. © 2017 IEEE.
1815 a57192941583 Childs B.R. p684 True Journal 330 Use of Personality Profile Assessments in the U.S. Commercial Construction Industry Employee turnover is a continuing challenge in the construction industry with negative effects on construction companies. Other industries have begun using personality profile assessments as a tool for reducing employee turnover, and more specifically in their hiring, promoting, team building, and leadership development processes. However, it was unknown if this trend was effecting the construction industry. The purpose of this research was to determine if and how U.S. commercial construction companies utilize personality profiles in their employee retention processes. A survey was randomly sent to 235 of the top 400 commercial construction companies in the United States to determine if these companies were using assessments, and if it had any effect on the turnover within these companies. Interviews were conducted over the phone with human resources representatives from these companies, and responses were sorted into similar themes and ideas using qualitative pattern coding techniques. Of the 78 responding companies, one-third were using employee personality profiles within their business practices. This article reports the experiences and general attitudes for both the companies that do and do not utilize personality profiles. The results of this research provides strong evidence that using personality profile assessments can help construction companies reduce employee turnover. © 2017 Associated Schools of Construction.
1816 a6603945025 Christofferson J.P. p684 False Journal 330 Use of Personality Profile Assessments in the U.S. Commercial Construction Industry Employee turnover is a continuing challenge in the construction industry with negative effects on construction companies. Other industries have begun using personality profile assessments as a tool for reducing employee turnover, and more specifically in their hiring, promoting, team building, and leadership development processes. However, it was unknown if this trend was effecting the construction industry. The purpose of this research was to determine if and how U.S. commercial construction companies utilize personality profiles in their employee retention processes. A survey was randomly sent to 235 of the top 400 commercial construction companies in the United States to determine if these companies were using assessments, and if it had any effect on the turnover within these companies. Interviews were conducted over the phone with human resources representatives from these companies, and responses were sorted into similar themes and ideas using qualitative pattern coding techniques. Of the 78 responding companies, one-third were using employee personality profiles within their business practices. This article reports the experiences and general attitudes for both the companies that do and do not utilize personality profiles. The results of this research provides strong evidence that using personality profile assessments can help construction companies reduce employee turnover. © 2017 Associated Schools of Construction.
1817 a55249877500 Coombs D. p685 False Journal 331 Simulations in Construction and Engineering Management Education to Explore Professional Challenges Experiential learning opportunities in construction management courses allow students to explore principles and theories through direct, lived experiences that help them develop understandings of professional concepts foundational to their future work. This article examines the results of a multiple-case study that examines a simulation called marshmallow dodgeball conducted in an undergraduate project management course, designed to help students consider ethical and professional dilemmas that parallel those in the field. A thematic analysis of student reflections on the simulation shows students learned about dealing with ethical issues in the field, the role of teamwork, the importance of job skills and specialization, and communication on the job site. © 2017 American Society of Civil Engineers.
1818 a57200860487 Bulloch R. p685 False Journal 331 Simulations in Construction and Engineering Management Education to Explore Professional Challenges Experiential learning opportunities in construction management courses allow students to explore principles and theories through direct, lived experiences that help them develop understandings of professional concepts foundational to their future work. This article examines the results of a multiple-case study that examines a simulation called marshmallow dodgeball conducted in an undergraduate project management course, designed to help students consider ethical and professional dilemmas that parallel those in the field. A thematic analysis of student reflections on the simulation shows students learned about dealing with ethical issues in the field, the role of teamwork, the importance of job skills and specialization, and communication on the job site. © 2017 American Society of Civil Engineers.
1819 a57191256797 Chang D.K. p687 True Journal 333 Use of Hi-resolution data for evaluating accuracy of traffic volume counts collected by microwave sensors Over the past few years, the Utah Department of Transportation has developed the signal performance metrics (SPMs) system to evaluate the performance of signalized intersections dynamically. This system currently provides data summaries for several performance measures, one of them being turning movement counts collected by microwave sensors. As this system became public, there was a need to evaluate the accuracy of the data placed on the SPMs. A large-scale data collection was carried out to meet this need. Vehicles in the Hi-resolution data from microwave sensors were matched with the vehicles by ground-truth volume count data. Matching vehicles from the microwave sensor data and the ground-truth data manually collected required significant effort. A spreadsheet-based data analysis procedure was developed to carry out the task. A mixed model analysis of variance was used to analyze the effects of the factors considered on turning volume count accuracy. The analysis found that approach volume level and number of approach lanes would have significant effect on the accuracy of turning volume counts but the location of the sensors did not significantly affect the accuracy of turning volume counts. In addition, it was found that the location of lanes in relation to the sensor did not significantly affect the accuracy of lane-by-lane volume counts. This indicated that accuracy analysis could be performed by using total approach volumes without comparing specific turning counts, that is, left-turn, through and right-turn movements. In general, the accuracy of approach volume counts collected by microwave sensors were within the margin of error that traffic engineers could accept. The procedure taken to perform the analysis and a summary of accuracy of volume counts for the factor combinations considered are presented in this paper. © 2017 The Authors
1820 a13605498800 Verbert K. p688 False Journal 334 Review of research on student-facing learning analytics dashboards and educational recommender systems This article is a comprehensive literature review of student-facing learning analytics reporting systems that track learning analytics data and report it directly to students. This literature review builds on four previously conducted literature reviews in similar domains. Out of the 945 articles retrieved from databases and journals, 93 articles were included in the analysis. Articles were coded based on the following five categories: functionality, data sources, design analysis, student perceptions, and measured effects. Based on this review, we need research on learning analytics reporting systems that targets the design and development process of reporting systems, not only the final products. This design and development process includes needs analyses, visual design analyses, information selection justifications, and student perception surveys. In addition, experiments to determine the effect of these systems on student behavior, achievement, and skills are needed to add to the small existing body of evidence. Furthermore, experimental studies should include usability tests and methodologies to examine student use of these systems, as these factors may affect experimental findings. Finally, observational study methods, such as propensity score matching, should be used to increase student access to these systems but still rigorously measure experimental effects. © 2016 IEEE.
1821 a56716068400 Thacker K.S. p689 False Journal 335 Design for excess capability to handle uncertain product requirements in a developing world setting Products designed for the developing world often go unused or underused by the intended customers. One cause of this problem is uncertainty regarding the actual requirements of customers in the developing world. This can result when designers, with experience in technologically advanced countries, apply their own value structure to the products they design. Because of the designers’ lack of experience in the culture and environment of the developing world, the actual requirements are only partially known to them. This problem can be mitigated by (i) optimizing product flexibility and adaptability to react to uncertain requirements, and (ii) reducing the most critical uncertainties. The flexibility of a product to adapt to new or changing requirements has been shown to extend the service life of large complex engineered systems (e.g., aircraft carriers, aircraft, communication systems, and space craft). These systems must remain in service for extended periods of time, even though the environments and requirements may change dramatically. Applying these proven techniques to products designed for the developing world can alleviate the problem of uncertain requirements. This paper presents and demonstrates a technique aimed at improving the success of developing world engineering projects. Flexibility and adaptability minimize the impact of uncertainties, and are enabled by numerically optimized amounts of designed-in excess. A sensitivity analysis performed on the system model helps the designer prioritize the set of uncertain requirements and parameters for refinement. The technique is demonstrated in the design of a cookstove intended for use in the developing world. © 2017, Springer-Verlag London.
1822 a57203230997 Ferguson S.M. p689 False Journal 335 Design for excess capability to handle uncertain product requirements in a developing world setting Products designed for the developing world often go unused or underused by the intended customers. One cause of this problem is uncertainty regarding the actual requirements of customers in the developing world. This can result when designers, with experience in technologically advanced countries, apply their own value structure to the products they design. Because of the designers’ lack of experience in the culture and environment of the developing world, the actual requirements are only partially known to them. This problem can be mitigated by (i) optimizing product flexibility and adaptability to react to uncertain requirements, and (ii) reducing the most critical uncertainties. The flexibility of a product to adapt to new or changing requirements has been shown to extend the service life of large complex engineered systems (e.g., aircraft carriers, aircraft, communication systems, and space craft). These systems must remain in service for extended periods of time, even though the environments and requirements may change dramatically. Applying these proven techniques to products designed for the developing world can alleviate the problem of uncertain requirements. This paper presents and demonstrates a technique aimed at improving the success of developing world engineering projects. Flexibility and adaptability minimize the impact of uncertainties, and are enabled by numerically optimized amounts of designed-in excess. A sensitivity analysis performed on the system model helps the designer prioritize the set of uncertain requirements and parameters for refinement. The technique is demonstrated in the design of a cookstove intended for use in the developing world. © 2017, Springer-Verlag London.
1823 a57191031931 Brusati M. p690 True Journal 336 Mitigated FPGA design of multi-gigabit transceivers for application in high radiation environments of High Energy Physics experiments SRAM-based Field Programmable Gate Array (FPGA) logic devices are very attractive in applications where high data throughput is needed, such as the latest generation of High Energy Physics (HEP) experiments. FPGAs have been rarely used in such experiments because of their sensitivity to radiation. The present paper proposes a mitigation approach applied to commercial FPGA devices to meet the reliability requirements for the front-end electronics of the Liquid Argon (LAr) electromagnetic calorimeter of the ATLAS experiment, located at CERN. Particular attention will be devoted to define a proper mitigation scheme of the multi-gigabit transceivers embedded in the FPGA, which is a critical part of the LAr data acquisition chain. A demonstrator board is being developed to validate the proposed methodology. Mitigation techniques such as Triple Modular Redundancy (TMR) and scrubbing will be used to increase the robustness of the design and to maximize the fault tolerance from Single-Event Upsets (SEUs). © 2017 Elsevier Ltd
1824 a37098602100 Camplani A. p690 False Journal 336 Mitigated FPGA design of multi-gigabit transceivers for application in high radiation environments of High Energy Physics experiments SRAM-based Field Programmable Gate Array (FPGA) logic devices are very attractive in applications where high data throughput is needed, such as the latest generation of High Energy Physics (HEP) experiments. FPGAs have been rarely used in such experiments because of their sensitivity to radiation. The present paper proposes a mitigation approach applied to commercial FPGA devices to meet the reliability requirements for the front-end electronics of the Liquid Argon (LAr) electromagnetic calorimeter of the ATLAS experiment, located at CERN. Particular attention will be devoted to define a proper mitigation scheme of the multi-gigabit transceivers embedded in the FPGA, which is a critical part of the LAr data acquisition chain. A demonstrator board is being developed to validate the proposed methodology. Mitigation techniques such as Triple Modular Redundancy (TMR) and scrubbing will be used to increase the robustness of the design and to maximize the fault tolerance from Single-Event Upsets (SEUs). © 2017 Elsevier Ltd
1825 a56424241200 Chen H. p690 False Journal 336 Mitigated FPGA design of multi-gigabit transceivers for application in high radiation environments of High Energy Physics experiments SRAM-based Field Programmable Gate Array (FPGA) logic devices are very attractive in applications where high data throughput is needed, such as the latest generation of High Energy Physics (HEP) experiments. FPGAs have been rarely used in such experiments because of their sensitivity to radiation. The present paper proposes a mitigation approach applied to commercial FPGA devices to meet the reliability requirements for the front-end electronics of the Liquid Argon (LAr) electromagnetic calorimeter of the ATLAS experiment, located at CERN. Particular attention will be devoted to define a proper mitigation scheme of the multi-gigabit transceivers embedded in the FPGA, which is a critical part of the LAr data acquisition chain. A demonstrator board is being developed to validate the proposed methodology. Mitigation techniques such as Triple Modular Redundancy (TMR) and scrubbing will be used to increase the robustness of the design and to maximize the fault tolerance from Single-Event Upsets (SEUs). © 2017 Elsevier Ltd
1826 a6701695863 Citterio M. p690 False Journal 336 Mitigated FPGA design of multi-gigabit transceivers for application in high radiation environments of High Energy Physics experiments SRAM-based Field Programmable Gate Array (FPGA) logic devices are very attractive in applications where high data throughput is needed, such as the latest generation of High Energy Physics (HEP) experiments. FPGAs have been rarely used in such experiments because of their sensitivity to radiation. The present paper proposes a mitigation approach applied to commercial FPGA devices to meet the reliability requirements for the front-end electronics of the Liquid Argon (LAr) electromagnetic calorimeter of the ATLAS experiment, located at CERN. Particular attention will be devoted to define a proper mitigation scheme of the multi-gigabit transceivers embedded in the FPGA, which is a critical part of the LAr data acquisition chain. A demonstrator board is being developed to validate the proposed methodology. Mitigation techniques such as Triple Modular Redundancy (TMR) and scrubbing will be used to increase the robustness of the design and to maximize the fault tolerance from Single-Event Upsets (SEUs). © 2017 Elsevier Ltd
1827 a7006631262 Lazzaroni M. p690 False Journal 336 Mitigated FPGA design of multi-gigabit transceivers for application in high radiation environments of High Energy Physics experiments SRAM-based Field Programmable Gate Array (FPGA) logic devices are very attractive in applications where high data throughput is needed, such as the latest generation of High Energy Physics (HEP) experiments. FPGAs have been rarely used in such experiments because of their sensitivity to radiation. The present paper proposes a mitigation approach applied to commercial FPGA devices to meet the reliability requirements for the front-end electronics of the Liquid Argon (LAr) electromagnetic calorimeter of the ATLAS experiment, located at CERN. Particular attention will be devoted to define a proper mitigation scheme of the multi-gigabit transceivers embedded in the FPGA, which is a critical part of the LAr data acquisition chain. A demonstrator board is being developed to validate the proposed methodology. Mitigation techniques such as Triple Modular Redundancy (TMR) and scrubbing will be used to increase the robustness of the design and to maximize the fault tolerance from Single-Event Upsets (SEUs). © 2017 Elsevier Ltd
1828 a56404157200 Takai H. p690 False Journal 336 Mitigated FPGA design of multi-gigabit transceivers for application in high radiation environments of High Energy Physics experiments SRAM-based Field Programmable Gate Array (FPGA) logic devices are very attractive in applications where high data throughput is needed, such as the latest generation of High Energy Physics (HEP) experiments. FPGAs have been rarely used in such experiments because of their sensitivity to radiation. The present paper proposes a mitigation approach applied to commercial FPGA devices to meet the reliability requirements for the front-end electronics of the Liquid Argon (LAr) electromagnetic calorimeter of the ATLAS experiment, located at CERN. Particular attention will be devoted to define a proper mitigation scheme of the multi-gigabit transceivers embedded in the FPGA, which is a critical part of the LAr data acquisition chain. A demonstrator board is being developed to validate the proposed methodology. Mitigation techniques such as Triple Modular Redundancy (TMR) and scrubbing will be used to increase the robustness of the design and to maximize the fault tolerance from Single-Event Upsets (SEUs). © 2017 Elsevier Ltd
1829 a7005836251 Comer D.J. p691 True Conference 296 An ultra-high Q inductorless narrowband filter based on the voltage divider phase shift method The voltage divider phase shift filter (VDPSF) has been used in the past to construct inductorless narrowband filters with moderately high Q values, for example, Q = 50. This work reports a new configuration of this filter that can achieve extremely high Q values over a range of frequencies from very low to very high values. A typical value is Q = 2500, but can be even higher. These high values of Q can be obtained at very low frequencies, solving a long-standing problem for LC tank circuits. The new configuration consists of one voltage divider phase shift filter nested within a second such filter. A simulation is done to verify the accuracy of the theory and demonstrate the stability of Q with respect to circuit element value changes. One significant application of such a filter is in the creation of a tunable oscillator with a very high degree of spectral purity. © 2017 IEEE.
1829 a7005836251 Comer D.J. p742 False Journal 357 Design of low-power ultra-high voltage gain differential cascode stages The conventional cascode circuit has long been used as the basis for the differential input stage to an op amp. The voltage gain of this stage can be maximised by operating the MOS devices in the moderate inversion region rather than the strong inversion region. In so doing, the voltage gains of the differential stage can reach values of over 120 dB and the power dissipation is minimised due to the low currents required. Harmonic distortion is also minimised by moderate inversion operation. Although the composite cascode or self-cascode has been successfully used as an op-amp differential stage, the conventional cascode differential circuit offers additional advantages and is compared to the composite cascode differential circuit in this work. A design procedure is also reported in this work for low-power, high voltage gain differential stages. © 2017 Informa UK Limited, trading as Taylor & Francis Group.
1830 a57195596864 Sorensen S.T. p692 True Conference 297 SAE Aero Design East: BYU-Idaho Aero Team 326 - Final Report Document This report describes the aircraft designed and built by the Brigham Young University Idaho (BYU-Idaho) Aero Design Team. The aircraft was built for the SAE Aero East Competition 2017 hosted in Lakeland, Florida. The objective is to design an all-electric aircraft optimized to carry as much weight as possible, while also minimizing the empty weight of the aircraft capable of successfully completing a flight circuit. A flight circuit is defined as flying completely around two safety cones for a total distance of about 726ft. The challenge has provided the team with the opportunity to improve design and manufacturing skills, while also gaining experience in real life engineering challenges. As a result, the team greatly increased their knowledge of aeronautical design and manufacturing. BYU-Idaho has developed a balsa/plywood carbon fiber reinforced fixed wing aircraft weighing approximately.7lbs, capable of carrying more than 4lbs. When configured for flight, its wings span 60in, and an overall length of 20.8in. Its wing can be broken down into three 20in segments. The aircraft is easily transported in a 6in diameter tube that is 20.3in in length. In order to maximize interior space and manufacturability, the fuselage was not streamlined. Aerodynamic advantages gained from streamlining were considered negligible. The three wing segments are made out of balsa wood ribs attached to a carbon fiber balsa wood composite spar. © Copyright 2017 SAE International.
1830 a57195596864 Sorensen S.T. p720 True Conference 304 SAE Aero Design East: BYU-Idaho Aero Team 326 - Final Report Document This report describes the aircraft designed and built by the Brigham Young University Idaho (BYU-Idaho) Aero Design Team. The aircraft was built for the SAE Aero East Competition 2017 hosted in Lakeland, Florida. The objective is to design an all-electric aircraft optimized to carry as much weight as possible, while also minimizing the empty weight of the aircraft capable of successfully completing a flight circuit. A flight circuit is defined as flying completely around two safety cones for a total distance of about 726ft. The challenge has provided the team with the opportunity to improve design and manufacturing skills, while also gaining experience in real life engineering challenges. As a result, the team greatly increased their knowledge of aeronautical design and manufacturing. BYU-Idaho has developed a balsa/plywood carbon fiber reinforced fixed wing aircraft weighing approximately.7lbs, capable of carrying more than 4lbs. When configured for flight, its wings span 60in, and an overall length of 20.8in. Its wing can be broken down into three 20in segments. The aircraft is easily transported in a 6in diameter tube that is 20.3in in length. In order to maximize interior space and manufacturability, the fuselage was not streamlined. Aerodynamic advantages gained from streamlining were considered negligible. The three wing segments are made out of balsa wood ribs attached to a carbon fiber balsa wood composite spar. © 2017 SAE International.
1831 a57195596391 Hopman A. p692 False Conference 297 SAE Aero Design East: BYU-Idaho Aero Team 326 - Final Report Document This report describes the aircraft designed and built by the Brigham Young University Idaho (BYU-Idaho) Aero Design Team. The aircraft was built for the SAE Aero East Competition 2017 hosted in Lakeland, Florida. The objective is to design an all-electric aircraft optimized to carry as much weight as possible, while also minimizing the empty weight of the aircraft capable of successfully completing a flight circuit. A flight circuit is defined as flying completely around two safety cones for a total distance of about 726ft. The challenge has provided the team with the opportunity to improve design and manufacturing skills, while also gaining experience in real life engineering challenges. As a result, the team greatly increased their knowledge of aeronautical design and manufacturing. BYU-Idaho has developed a balsa/plywood carbon fiber reinforced fixed wing aircraft weighing approximately.7lbs, capable of carrying more than 4lbs. When configured for flight, its wings span 60in, and an overall length of 20.8in. Its wing can be broken down into three 20in segments. The aircraft is easily transported in a 6in diameter tube that is 20.3in in length. In order to maximize interior space and manufacturability, the fuselage was not streamlined. Aerodynamic advantages gained from streamlining were considered negligible. The three wing segments are made out of balsa wood ribs attached to a carbon fiber balsa wood composite spar. © Copyright 2017 SAE International.
1831 a57195596391 Hopman A. p720 False Conference 304 SAE Aero Design East: BYU-Idaho Aero Team 326 - Final Report Document This report describes the aircraft designed and built by the Brigham Young University Idaho (BYU-Idaho) Aero Design Team. The aircraft was built for the SAE Aero East Competition 2017 hosted in Lakeland, Florida. The objective is to design an all-electric aircraft optimized to carry as much weight as possible, while also minimizing the empty weight of the aircraft capable of successfully completing a flight circuit. A flight circuit is defined as flying completely around two safety cones for a total distance of about 726ft. The challenge has provided the team with the opportunity to improve design and manufacturing skills, while also gaining experience in real life engineering challenges. As a result, the team greatly increased their knowledge of aeronautical design and manufacturing. BYU-Idaho has developed a balsa/plywood carbon fiber reinforced fixed wing aircraft weighing approximately.7lbs, capable of carrying more than 4lbs. When configured for flight, its wings span 60in, and an overall length of 20.8in. Its wing can be broken down into three 20in segments. The aircraft is easily transported in a 6in diameter tube that is 20.3in in length. In order to maximize interior space and manufacturability, the fuselage was not streamlined. Aerodynamic advantages gained from streamlining were considered negligible. The three wing segments are made out of balsa wood ribs attached to a carbon fiber balsa wood composite spar. © 2017 SAE International.
1832 a57195598039 Petersen M. p692 False Conference 297 SAE Aero Design East: BYU-Idaho Aero Team 326 - Final Report Document This report describes the aircraft designed and built by the Brigham Young University Idaho (BYU-Idaho) Aero Design Team. The aircraft was built for the SAE Aero East Competition 2017 hosted in Lakeland, Florida. The objective is to design an all-electric aircraft optimized to carry as much weight as possible, while also minimizing the empty weight of the aircraft capable of successfully completing a flight circuit. A flight circuit is defined as flying completely around two safety cones for a total distance of about 726ft. The challenge has provided the team with the opportunity to improve design and manufacturing skills, while also gaining experience in real life engineering challenges. As a result, the team greatly increased their knowledge of aeronautical design and manufacturing. BYU-Idaho has developed a balsa/plywood carbon fiber reinforced fixed wing aircraft weighing approximately.7lbs, capable of carrying more than 4lbs. When configured for flight, its wings span 60in, and an overall length of 20.8in. Its wing can be broken down into three 20in segments. The aircraft is easily transported in a 6in diameter tube that is 20.3in in length. In order to maximize interior space and manufacturability, the fuselage was not streamlined. Aerodynamic advantages gained from streamlining were considered negligible. The three wing segments are made out of balsa wood ribs attached to a carbon fiber balsa wood composite spar. © Copyright 2017 SAE International.
1832 a57195598039 Petersen M. p720 False Conference 304 SAE Aero Design East: BYU-Idaho Aero Team 326 - Final Report Document This report describes the aircraft designed and built by the Brigham Young University Idaho (BYU-Idaho) Aero Design Team. The aircraft was built for the SAE Aero East Competition 2017 hosted in Lakeland, Florida. The objective is to design an all-electric aircraft optimized to carry as much weight as possible, while also minimizing the empty weight of the aircraft capable of successfully completing a flight circuit. A flight circuit is defined as flying completely around two safety cones for a total distance of about 726ft. The challenge has provided the team with the opportunity to improve design and manufacturing skills, while also gaining experience in real life engineering challenges. As a result, the team greatly increased their knowledge of aeronautical design and manufacturing. BYU-Idaho has developed a balsa/plywood carbon fiber reinforced fixed wing aircraft weighing approximately.7lbs, capable of carrying more than 4lbs. When configured for flight, its wings span 60in, and an overall length of 20.8in. Its wing can be broken down into three 20in segments. The aircraft is easily transported in a 6in diameter tube that is 20.3in in length. In order to maximize interior space and manufacturability, the fuselage was not streamlined. Aerodynamic advantages gained from streamlining were considered negligible. The three wing segments are made out of balsa wood ribs attached to a carbon fiber balsa wood composite spar. © 2017 SAE International.
1833 a57195595627 Basko R. p692 False Conference 297 SAE Aero Design East: BYU-Idaho Aero Team 326 - Final Report Document This report describes the aircraft designed and built by the Brigham Young University Idaho (BYU-Idaho) Aero Design Team. The aircraft was built for the SAE Aero East Competition 2017 hosted in Lakeland, Florida. The objective is to design an all-electric aircraft optimized to carry as much weight as possible, while also minimizing the empty weight of the aircraft capable of successfully completing a flight circuit. A flight circuit is defined as flying completely around two safety cones for a total distance of about 726ft. The challenge has provided the team with the opportunity to improve design and manufacturing skills, while also gaining experience in real life engineering challenges. As a result, the team greatly increased their knowledge of aeronautical design and manufacturing. BYU-Idaho has developed a balsa/plywood carbon fiber reinforced fixed wing aircraft weighing approximately.7lbs, capable of carrying more than 4lbs. When configured for flight, its wings span 60in, and an overall length of 20.8in. Its wing can be broken down into three 20in segments. The aircraft is easily transported in a 6in diameter tube that is 20.3in in length. In order to maximize interior space and manufacturability, the fuselage was not streamlined. Aerodynamic advantages gained from streamlining were considered negligible. The three wing segments are made out of balsa wood ribs attached to a carbon fiber balsa wood composite spar. © Copyright 2017 SAE International.
1833 a57195595627 Basko R. p720 False Conference 304 SAE Aero Design East: BYU-Idaho Aero Team 326 - Final Report Document This report describes the aircraft designed and built by the Brigham Young University Idaho (BYU-Idaho) Aero Design Team. The aircraft was built for the SAE Aero East Competition 2017 hosted in Lakeland, Florida. The objective is to design an all-electric aircraft optimized to carry as much weight as possible, while also minimizing the empty weight of the aircraft capable of successfully completing a flight circuit. A flight circuit is defined as flying completely around two safety cones for a total distance of about 726ft. The challenge has provided the team with the opportunity to improve design and manufacturing skills, while also gaining experience in real life engineering challenges. As a result, the team greatly increased their knowledge of aeronautical design and manufacturing. BYU-Idaho has developed a balsa/plywood carbon fiber reinforced fixed wing aircraft weighing approximately.7lbs, capable of carrying more than 4lbs. When configured for flight, its wings span 60in, and an overall length of 20.8in. Its wing can be broken down into three 20in segments. The aircraft is easily transported in a 6in diameter tube that is 20.3in in length. In order to maximize interior space and manufacturability, the fuselage was not streamlined. Aerodynamic advantages gained from streamlining were considered negligible. The three wing segments are made out of balsa wood ribs attached to a carbon fiber balsa wood composite spar. © 2017 SAE International.
1834 a57195600276 Ochsner S. p692 False Conference 297 SAE Aero Design East: BYU-Idaho Aero Team 326 - Final Report Document This report describes the aircraft designed and built by the Brigham Young University Idaho (BYU-Idaho) Aero Design Team. The aircraft was built for the SAE Aero East Competition 2017 hosted in Lakeland, Florida. The objective is to design an all-electric aircraft optimized to carry as much weight as possible, while also minimizing the empty weight of the aircraft capable of successfully completing a flight circuit. A flight circuit is defined as flying completely around two safety cones for a total distance of about 726ft. The challenge has provided the team with the opportunity to improve design and manufacturing skills, while also gaining experience in real life engineering challenges. As a result, the team greatly increased their knowledge of aeronautical design and manufacturing. BYU-Idaho has developed a balsa/plywood carbon fiber reinforced fixed wing aircraft weighing approximately.7lbs, capable of carrying more than 4lbs. When configured for flight, its wings span 60in, and an overall length of 20.8in. Its wing can be broken down into three 20in segments. The aircraft is easily transported in a 6in diameter tube that is 20.3in in length. In order to maximize interior space and manufacturability, the fuselage was not streamlined. Aerodynamic advantages gained from streamlining were considered negligible. The three wing segments are made out of balsa wood ribs attached to a carbon fiber balsa wood composite spar. © Copyright 2017 SAE International.
1834 a57195600276 Ochsner S. p720 False Conference 304 SAE Aero Design East: BYU-Idaho Aero Team 326 - Final Report Document This report describes the aircraft designed and built by the Brigham Young University Idaho (BYU-Idaho) Aero Design Team. The aircraft was built for the SAE Aero East Competition 2017 hosted in Lakeland, Florida. The objective is to design an all-electric aircraft optimized to carry as much weight as possible, while also minimizing the empty weight of the aircraft capable of successfully completing a flight circuit. A flight circuit is defined as flying completely around two safety cones for a total distance of about 726ft. The challenge has provided the team with the opportunity to improve design and manufacturing skills, while also gaining experience in real life engineering challenges. As a result, the team greatly increased their knowledge of aeronautical design and manufacturing. BYU-Idaho has developed a balsa/plywood carbon fiber reinforced fixed wing aircraft weighing approximately.7lbs, capable of carrying more than 4lbs. When configured for flight, its wings span 60in, and an overall length of 20.8in. Its wing can be broken down into three 20in segments. The aircraft is easily transported in a 6in diameter tube that is 20.3in in length. In order to maximize interior space and manufacturability, the fuselage was not streamlined. Aerodynamic advantages gained from streamlining were considered negligible. The three wing segments are made out of balsa wood ribs attached to a carbon fiber balsa wood composite spar. © 2017 SAE International.
1835 a57193015007 Collins G. p694 False Journal 320 Estimation of 3D Ground Reaction Force Using Nanocomposite Piezo-Responsive Foam Sensors During Walking This paper describes a method for the estimation of the 3D ground reaction force (GRF) during human walking using novel nanocomposite piezo-responsive foam (NCPF) sensors. Nine subjects (5 male, 4 female) walked on a force-instrumented treadmill at 1.34 m/s for 120 s each while wearing a shoe that was instrumented with four NCPF sensors. GRF data, measured via the treadmill, and sensor data, measured via the NCPF inserts, were used in a tenfold cross validation process to calibrate a separate model for each individual. The calibration model estimated average anterior–posterior, mediolateral and vertical GRF with mean average errors (MAE) of 6.52 N (2.14%), 4.79 N (6.34%), and 15.4 N (2.15%), respectively. Two additional models were created using the sensor data from all subjects and subject demographics. A tenfold cross validation process for this combined data set resulted in models that estimated average anterior–posterior, mediolateral and vertical GRF with less than 8.16 N (2.41%), 6.63 N (7.37%), and 19.4 N (2.31%) errors, respectively. Intra-subject estimates based on the model had a higher accuracy than inter-subject estimates, likely due to the relatively small subject cohort used in creating the model. The novel NCPF sensors demonstrate the ability to accurately estimate 3D GRF during human movement outside of the traditional biomechanics laboratory setting. © 2017, Biomedical Engineering Society.
1836 a57193015157 Tuttle N.J. p694 False Journal 320 Estimation of 3D Ground Reaction Force Using Nanocomposite Piezo-Responsive Foam Sensors During Walking This paper describes a method for the estimation of the 3D ground reaction force (GRF) during human walking using novel nanocomposite piezo-responsive foam (NCPF) sensors. Nine subjects (5 male, 4 female) walked on a force-instrumented treadmill at 1.34 m/s for 120 s each while wearing a shoe that was instrumented with four NCPF sensors. GRF data, measured via the treadmill, and sensor data, measured via the NCPF inserts, were used in a tenfold cross validation process to calibrate a separate model for each individual. The calibration model estimated average anterior–posterior, mediolateral and vertical GRF with mean average errors (MAE) of 6.52 N (2.14%), 4.79 N (6.34%), and 15.4 N (2.15%), respectively. Two additional models were created using the sensor data from all subjects and subject demographics. A tenfold cross validation process for this combined data set resulted in models that estimated average anterior–posterior, mediolateral and vertical GRF with less than 8.16 N (2.41%), 6.63 N (7.37%), and 19.4 N (2.31%) errors, respectively. Intra-subject estimates based on the model had a higher accuracy than inter-subject estimates, likely due to the relatively small subject cohort used in creating the model. The novel NCPF sensors demonstrate the ability to accurately estimate 3D GRF during human movement outside of the traditional biomechanics laboratory setting. © 2017, Biomedical Engineering Society.
1837 a57193016069 Tracy J.B. p694 False Journal 320 Estimation of 3D Ground Reaction Force Using Nanocomposite Piezo-Responsive Foam Sensors During Walking This paper describes a method for the estimation of the 3D ground reaction force (GRF) during human walking using novel nanocomposite piezo-responsive foam (NCPF) sensors. Nine subjects (5 male, 4 female) walked on a force-instrumented treadmill at 1.34 m/s for 120 s each while wearing a shoe that was instrumented with four NCPF sensors. GRF data, measured via the treadmill, and sensor data, measured via the NCPF inserts, were used in a tenfold cross validation process to calibrate a separate model for each individual. The calibration model estimated average anterior–posterior, mediolateral and vertical GRF with mean average errors (MAE) of 6.52 N (2.14%), 4.79 N (6.34%), and 15.4 N (2.15%), respectively. Two additional models were created using the sensor data from all subjects and subject demographics. A tenfold cross validation process for this combined data set resulted in models that estimated average anterior–posterior, mediolateral and vertical GRF with less than 8.16 N (2.41%), 6.63 N (7.37%), and 19.4 N (2.31%) errors, respectively. Intra-subject estimates based on the model had a higher accuracy than inter-subject estimates, likely due to the relatively small subject cohort used in creating the model. The novel NCPF sensors demonstrate the ability to accurately estimate 3D GRF during human movement outside of the traditional biomechanics laboratory setting. © 2017, Biomedical Engineering Society.
1838 a55859152500 Wheadon J. p695 True Journal 338 The need, development, and validation of the innovation test instrument This study discusses the need, development, and validation of the Innovation Test Instrument (ITI). This article outlines how the researchers identified the content domain of the assessment and created test items. Then, it describes initial validation testing of the instrument. The findings suggest that the ITI is a good first step in creating an innovation assessment because it is more inclusive of both divergent and convergent thinking. In comparison, past innovation assessments have only assessed either divergence or convergence. The ITI still needs further validation and improvement to make strong claims about its ability to determine the effectiveness of an innovation course. © 2017, Virginia Polytechnic Institute. All rights reserved.
1839 a24081319400 Platt B.C. p697 True Journal 340 Inferring ascending auction participation from observed bidders Participation in internet auctions goes well beyond those who place a bid. Participants arrive in random order, and if the auction's standing price has already exceeded a participant's valuation, she will not bid. Even so, her unreported valuation is a relevant part of demand for the item, and in an alternate random order, her bid would have been registered. I provide a method to estimate the average number of participants from the average number of bidders per auction. This enables estimation of the distribution of participant valuations from either the distribution of closing prices or the distribution of all observed bids. © 2017 Elsevier B.V.
1840 a57193435113 Kruman B.A. p698 False Journal 341 Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
1841 a57193430035 Nelson M.C. p698 False Journal 341 Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
1842 a57193433048 Hoybjerg T.G. p698 False Journal 341 Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
1843 a57192660307 Tuttle S.C. p698 False Journal 341 Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
1844 a57193429691 Myers S.J. p698 False Journal 341 Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
1845 a57193431261 Cook R.B. p698 False Journal 341 Differential effects of air conditioning type on residential endotoxin levels in a semi-arid climate Residential endotoxin exposure is associated with protective and pathogenic health outcomes. Evaporative coolers, an energy-efficient type of air conditioner used in dry climates, are a potential source of indoor endotoxins; however, this association is largely unstudied. We collected settled dust biannually from four locations in homes with evaporative coolers (n=18) and central air conditioners (n=22) in Utah County, Utah (USA), during winter (Jan-Apr) and summer (Aug-Sept), 2014. Dust samples (n=281) were analyzed by the Limulus amebocyte lysate test. Housing factors were measured by survey, and indoor temperature and relative humidity measures were collected during both seasons. Endotoxin concentrations (EU/mg) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons. Endotoxin surface loads (EU/m2) were significantly higher in homes with evaporative coolers from mattress and bedroom floor samples during both seasons and in upholstered furniture during winter. For the nine significant season-by-location comparisons, EU/mg and EU/m2 were approximately three to six times greater in homes using evaporative coolers. A plausible explanation for these findings is that evaporative coolers serve as a reservoir and distribution system for Gram-negative bacteria or their cell wall components in homes. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
1846 a57192964074 Killian M. p700 False Journal 339 A multi-user computer-aided design competition: Experimental findings and analysis of team-member dynamics A competition for teams of three students using a prototype multi-user computer-aided design (MUCAD) tool was held to investigate various hypotheses regarding the performance of teams in such a setting. By comparing models from the competition to the same model in a single-user CAD environment, it is seen that use of a MUCAD system can significantly increase the value-added per unit of calendar time for a modeling effort. An investigation was also made into the causes of the performance differences among the various MUCAD teams which participated in the competition. Analysis of the results shows that teams that encouraged effective forms of communication and teams whose members scored similarly on the Purdue Spatial Visualization Test: Visualization of Rotations (PSVT:R) performed better than other teams. Areas of future research in analyzing teams in MUCAD environments are suggested. Copyright © 2017 by ASME.
1846 a57192964074 Killian M. p715 False Journal 352 Methods for determining the optimal number of simultaneous contributors for multi-user CAD parts The development of multi-user CAD (MUCAD) tools has opened up exciting new opportunities and applications. The capability for multiple users to simultaneously model and design a CAD part has far-reaching potential. However, many basic questions remains unanswered, such as how many users should work together on a given part. This research proposes and develops a set of methods to determine the optimal number of users for a given part within a MUCAD environment, based on the characteristics of the part itself. Two candidate models are evaluated with a set of 60 experiments with design teams composed of different numbers of users. The models show modest correlations with the test data while more-refined models are explored to improve predictive power. On the other hand, highly significant correlations between the ability to predict completion time and multi-user team size were identified in the experimental data. Observations regarding the speed and quality of MUCAD teams are also made with future areas of research suggested. © 2017 CAD Solutions, LLC.
1847 a57193362917 Oldroyd J. p700 False Journal 339 A multi-user computer-aided design competition: Experimental findings and analysis of team-member dynamics A competition for teams of three students using a prototype multi-user computer-aided design (MUCAD) tool was held to investigate various hypotheses regarding the performance of teams in such a setting. By comparing models from the competition to the same model in a single-user CAD environment, it is seen that use of a MUCAD system can significantly increase the value-added per unit of calendar time for a modeling effort. An investigation was also made into the causes of the performance differences among the various MUCAD teams which participated in the competition. Analysis of the results shows that teams that encouraged effective forms of communication and teams whose members scored similarly on the Purdue Spatial Visualization Test: Visualization of Rotations (PSVT:R) performed better than other teams. Areas of future research in analyzing teams in MUCAD environments are suggested. Copyright © 2017 by ASME.
1848 a55674595800 Rombach I. p701 False Journal 343 Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip Background Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. Methods Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. Results Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = −0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. Conclusions The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis. © 2017 Osteoarthritis Research Society International
1849 a56390719200 Park D. p701 False Journal 343 Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip Background Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. Methods Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. Results Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = −0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. Conclusions The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis. © 2017 Osteoarthritis Research Society International
1850 a7102503611 Pollard T. p701 False Journal 343 Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip Background Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. Methods Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. Results Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = −0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. Conclusions The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis. © 2017 Osteoarthritis Research Society International
1851 a57190974399 Broomfield J. p701 False Journal 343 Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip Background Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis. Methods Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width. Results Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = −0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years. Conclusions The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis. © 2017 Osteoarthritis Research Society International
1852 a54410814200 Lee T.Y. p702 True Journal 344 The human touch: How non-expert users perceive, interpret, and fix topic models Topic modeling is a common tool for understanding large bodies of text, but is typically provided as a “take it or leave it” proposition. Incorporating human knowledge in unsupervised learning is a promising approach to create high-quality topic models. Existing interactive systems and modeling algorithms support a wide range of refinement operations to express feedback. However, these systems’ interactions are primarily driven by algorithmic convenience, ignoring users who may lack expertise in topic modeling. To better understand how non-expert users understand, assess, and refine topics, we conducted two user studies—an in-person interview study and an online crowdsourced study. These studies demonstrate a disconnect between what non-expert users want and the complex, low-level operations that current interactive systems support. In particular, our findings include: (1) analysis of how non-expert users perceive topic models; (2) characterization of primary refinement operations expected by non-expert users and ordered by relative preference; (3) further evidence of the benefits of supporting users in directly refining a topic model; (4) design implications for future human-in-the-loop topic modeling interfaces. © 2017
1853 a56716946800 Smith A. p702 False Journal 344 The human touch: How non-expert users perceive, interpret, and fix topic models Topic modeling is a common tool for understanding large bodies of text, but is typically provided as a “take it or leave it” proposition. Incorporating human knowledge in unsupervised learning is a promising approach to create high-quality topic models. Existing interactive systems and modeling algorithms support a wide range of refinement operations to express feedback. However, these systems’ interactions are primarily driven by algorithmic convenience, ignoring users who may lack expertise in topic modeling. To better understand how non-expert users understand, assess, and refine topics, we conducted two user studies—an in-person interview study and an online crowdsourced study. These studies demonstrate a disconnect between what non-expert users want and the complex, low-level operations that current interactive systems support. In particular, our findings include: (1) analysis of how non-expert users perceive topic models; (2) characterization of primary refinement operations expected by non-expert users and ordered by relative preference; (3) further evidence of the benefits of supporting users in directly refining a topic model; (4) design implications for future human-in-the-loop topic modeling interfaces. © 2017
1854 a6506645565 Elmqvist N. p702 False Journal 344 The human touch: How non-expert users perceive, interpret, and fix topic models Topic modeling is a common tool for understanding large bodies of text, but is typically provided as a “take it or leave it” proposition. Incorporating human knowledge in unsupervised learning is a promising approach to create high-quality topic models. Existing interactive systems and modeling algorithms support a wide range of refinement operations to express feedback. However, these systems’ interactions are primarily driven by algorithmic convenience, ignoring users who may lack expertise in topic modeling. To better understand how non-expert users understand, assess, and refine topics, we conducted two user studies—an in-person interview study and an online crowdsourced study. These studies demonstrate a disconnect between what non-expert users want and the complex, low-level operations that current interactive systems support. In particular, our findings include: (1) analysis of how non-expert users perceive topic models; (2) characterization of primary refinement operations expected by non-expert users and ordered by relative preference; (3) further evidence of the benefits of supporting users in directly refining a topic model; (4) design implications for future human-in-the-loop topic modeling interfaces. © 2017
1855 a14035040300 Boyd-Graber J. p702 False Journal 344 The human touch: How non-expert users perceive, interpret, and fix topic models Topic modeling is a common tool for understanding large bodies of text, but is typically provided as a “take it or leave it” proposition. Incorporating human knowledge in unsupervised learning is a promising approach to create high-quality topic models. Existing interactive systems and modeling algorithms support a wide range of refinement operations to express feedback. However, these systems’ interactions are primarily driven by algorithmic convenience, ignoring users who may lack expertise in topic modeling. To better understand how non-expert users understand, assess, and refine topics, we conducted two user studies—an in-person interview study and an online crowdsourced study. These studies demonstrate a disconnect between what non-expert users want and the complex, low-level operations that current interactive systems support. In particular, our findings include: (1) analysis of how non-expert users perceive topic models; (2) characterization of primary refinement operations expected by non-expert users and ordered by relative preference; (3) further evidence of the benefits of supporting users in directly refining a topic model; (4) design implications for future human-in-the-loop topic modeling interfaces. © 2017
1856 a10040303000 Findlater L. p702 False Journal 344 The human touch: How non-expert users perceive, interpret, and fix topic models Topic modeling is a common tool for understanding large bodies of text, but is typically provided as a “take it or leave it” proposition. Incorporating human knowledge in unsupervised learning is a promising approach to create high-quality topic models. Existing interactive systems and modeling algorithms support a wide range of refinement operations to express feedback. However, these systems’ interactions are primarily driven by algorithmic convenience, ignoring users who may lack expertise in topic modeling. To better understand how non-expert users understand, assess, and refine topics, we conducted two user studies—an in-person interview study and an online crowdsourced study. These studies demonstrate a disconnect between what non-expert users want and the complex, low-level operations that current interactive systems support. In particular, our findings include: (1) analysis of how non-expert users perceive topic models; (2) characterization of primary refinement operations expected by non-expert users and ordered by relative preference; (3) further evidence of the benefits of supporting users in directly refining a topic model; (4) design implications for future human-in-the-loop topic modeling interfaces. © 2017
1857 a55949256500 Hurd R.C. p703 True Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1857 a55949256500 Hurd R.C. p708 True Journal 348 Water entry of deformable spheres When a rigid body collides with a liquid surface with sufficient velocity, it creates a splash curtain above the surface and entrains air behind the sphere, creating a cavity below the surface. While cavity dynamics has been studied for over a century, this work focuses on the water entry characteristics of deformable elastomeric spheres, which has not been studied. Upon free surface impact, an elastomeric sphere deforms significantly, giving rise to large-scale material oscillations within the sphere resulting in unique nested cavities. We study these phenomena experimentally with high-speed imaging and image processing techniques. The water entry behaviour of deformable spheres differs from rigid spheres because of the pronounced deformation caused at impact as well as the subsequent material vibration. Our results show that this deformation and vibration can be predicted from material properties and impact conditions. Additionally, by accounting for the sphere deformation in an effective diameter term, we recover previously reported characteristics for time to cavity pinch off and hydrodynamic force coefficients for rigid spheres. Our results also show that velocity change over the first oscillation period scales with the dimensionless ratio of material shear modulus to impact hydrodynamic pressure. Therefore, we are able to describe the water entry characteristics of deformable spheres in terms of material properties and impact conditions. © 2017 Cambridge University PressÂ.
1858 a56875349800 Speirs N.B. p703 False Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1859 a36106810300 Belden J. p703 False Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1859 a36106810300 Belden J. p708 False Journal 348 Water entry of deformable spheres When a rigid body collides with a liquid surface with sufficient velocity, it creates a splash curtain above the surface and entrains air behind the sphere, creating a cavity below the surface. While cavity dynamics has been studied for over a century, this work focuses on the water entry characteristics of deformable elastomeric spheres, which has not been studied. Upon free surface impact, an elastomeric sphere deforms significantly, giving rise to large-scale material oscillations within the sphere resulting in unique nested cavities. We study these phenomena experimentally with high-speed imaging and image processing techniques. The water entry behaviour of deformable spheres differs from rigid spheres because of the pronounced deformation caused at impact as well as the subsequent material vibration. Our results show that this deformation and vibration can be predicted from material properties and impact conditions. Additionally, by accounting for the sphere deformation in an effective diameter term, we recover previously reported characteristics for time to cavity pinch off and hydrodynamic force coefficients for rigid spheres. Our results also show that velocity change over the first oscillation period scales with the dimensionless ratio of material shear modulus to impact hydrodynamic pressure. Therefore, we are able to describe the water entry characteristics of deformable spheres in terms of material properties and impact conditions. © 2017 Cambridge University PressÂ.
1859 a36106810300 Belden J. p776 False Journal 383 Three-dimensional microscopic light field particle image velocimetry A microscopic particle image velocimetry (μPIV) technique is developed based on light field microscopy and is applied to flow through a microchannel containing a backward-facing step. The only hardware difference from a conventional μPIV setup is the placement of a microlens array at the intermediate image plane of the microscope. The method combines this optical hardware alteration with post-capture computation to enable 3D reconstruction of particle fields. From these particle fields, we measure three-component velocity fields, but find that accurate velocity measurements are limited to the two in-plane components at discrete depths through the volume (i.e., 2C-3D). Results are compared with a computational fluid dynamics simulation. © 2017, Springer-Verlag Berlin Heidelberg.
1860 a56875089300 Pan Z. p703 False Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1861 a57198431633 Lovett B. p703 False Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1862 a57198450286 Robinson W. p703 False Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1863 a57198443855 Zamora M.A. p703 False Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1864 a57198451372 Sharker S.I. p703 False Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1865 a54911216200 Mansoor M.M. p703 False Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1866 a57195332895 Merritt A. p703 False Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1867 a14822519000 Truscott T.T. p703 False Journal 345 Shear joy of watching paint dry This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original video is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2016.GFM.V0095 © 2017 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
1867 a14822519000 Truscott T.T. p708 False Journal 348 Water entry of deformable spheres When a rigid body collides with a liquid surface with sufficient velocity, it creates a splash curtain above the surface and entrains air behind the sphere, creating a cavity below the surface. While cavity dynamics has been studied for over a century, this work focuses on the water entry characteristics of deformable elastomeric spheres, which has not been studied. Upon free surface impact, an elastomeric sphere deforms significantly, giving rise to large-scale material oscillations within the sphere resulting in unique nested cavities. We study these phenomena experimentally with high-speed imaging and image processing techniques. The water entry behaviour of deformable spheres differs from rigid spheres because of the pronounced deformation caused at impact as well as the subsequent material vibration. Our results show that this deformation and vibration can be predicted from material properties and impact conditions. Additionally, by accounting for the sphere deformation in an effective diameter term, we recover previously reported characteristics for time to cavity pinch off and hydrodynamic force coefficients for rigid spheres. Our results also show that velocity change over the first oscillation period scales with the dimensionless ratio of material shear modulus to impact hydrodynamic pressure. Therefore, we are able to describe the water entry characteristics of deformable spheres in terms of material properties and impact conditions. © 2017 Cambridge University PressÂ.
1867 a14822519000 Truscott T.T. p776 True Journal 383 Three-dimensional microscopic light field particle image velocimetry A microscopic particle image velocimetry (μPIV) technique is developed based on light field microscopy and is applied to flow through a microchannel containing a backward-facing step. The only hardware difference from a conventional μPIV setup is the placement of a microlens array at the intermediate image plane of the microscope. The method combines this optical hardware alteration with post-capture computation to enable 3D reconstruction of particle fields. From these particle fields, we measure three-component velocity fields, but find that accurate velocity measurements are limited to the two in-plane components at discrete depths through the volume (i.e., 2C-3D). Results are compared with a computational fluid dynamics simulation. © 2017, Springer-Verlag Berlin Heidelberg.
1868 a56315352000 Shumway L. p705 False Journal 346 Non-perturbing voltage measurement in a coaxial cable with slab-coupled optical sensors Voltage in a coaxial cable is measured by an electric-field optical fiber sensor exploiting the proportionality of voltage and electric field in a fixed structure. The sensor is inserted in a hole drilled through the dielectric of the RG-218 coaxial cable and sealed with epoxy to displace all air and prevent the adverse effects of charge buildup during high-voltage measurements. It is shown that the presence of the sensor in the coaxial cable does not significantly increase electrical reflections in the cable. A slab-coupled optical fiber sensor (SCOS) is used for its compact size and dielectric make. The dynamic range of 50 dB is shown experimentally with detection of signals as low as 1 V and up to 157 kV. A low corner of 0.3 Hz is demonstrated and the SCOS is shown to be able to measure 90 ns rise time. © 2017 Optical Society of America.
1868 a56315352000 Shumway L. p740 False Journal 346 Optical electric field sensor sensitivity direction rerouting and enhancement using a passive integrated dipole antenna This work introduces a passive dipole antenna integrated into the packaging of a slab-coupled optical sensor to enhance the directional sensitivity of electro-optic electric field measurements parallel to the fiber axis. Using the passive integrated dipole antenna described in this work, a sensor that can typically only sense fields transverse to the fiber direction is able to sense a 1.25 kV/m field along the fiber direction with a gain of 17.5. This is verified through simulation and experiment. © 2017 Optical Society of America.
1869 a56492379200 Wall T. p706 True Journal 347 Optofluidic lab-on-a-chip fluorescence sensor using integrated buried ARROW (bARROW) waveguides Optofluidic, lab-on-a-chip fluorescence sensors were fabricated using buried anti-resonant reflecting optical waveguides (bARROWs). The bARROWs are impervious to the negative water absorption effects that typically occur in waveguides made using hygroscopic, plasma-enhanced chemical vapor deposition (PECVD) oxides. These sensors were used to detect fluorescent microbeads and had an average signal-to-noise ratio (SNR) that was 81.3% higher than that of single-oxide ARROW fluorescence sensors. While the single-oxide ARROW sensors were annealed at 300 ◦ C to drive moisture out of the waveguides, the bARROW sensors required no annealing process to obtain a high SNR. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.
1869 a56492379200 Wall T. p749 True Journal 363 Mitigating Water Absorption in Waveguides Made from Unannealed PECVD SiO2 Water absorption was studied in two types of waveguides made from unannealed plasma enhanced chemical vapor deposition (PECVD) SiO2. Standard rib anti-resonant reflecting optical waveguides (ARROWs) were fabricated with thin films of different intrinsic stress and indices of refraction. Buried ARROWs (bARROWs) with low and high refractive index differences between the core and cladding regions were also fabricated from the same types of PECVD films. All waveguides were subjected to a heated, high humidity environment and their optical throughput was tested over time. Due to water absorption in the SiO2 films, the optical throughput of all of the ARROWs decreased with time spent in the wet environment. The ARROWs with the lowest stress SiO2 had the slowest rate of throughput change. High index difference bARROWs showed no decrease in optical throughput after 40 days in the wet environment and are presented as a solution for environmentally stable waveguides made from unannealed PECVD SiO2. © 2017 IEEE.
1869 a56492379200 Wall T. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
1869 a56492379200 Wall T. p786 False Conference 323 MMI waveguide based multispectral detection of nucleic acids for analysis of drug-resistant bacteria A multi-mode interference waveguide is used for creating distinct temporal fluorescence patterns at multiple excitation wavelengths. This allows for identification of bacterial nucleic acids labeled with molecular beacons in two colors. © 2016 IEEE.
1869 a56492379200 Wall T. p839 False Conference 366 Preserving optical confinement in unannealed PECVD SiO2 waveguides Rib and buried channel waveguides (BCWs) made of unannealed PECVD SiO2 were studied after exposure to high humidity. Low stressed rib waveguides had lower optical throughput change, while high index difference BCWs were practically unaffected. © 2017 OSA.
1870 a57192307368 Davidson A.D. p707 False Conference 299 Toward quantitative characterization of essential tremor for future tremor suppression Tremor is the most common movement deficit and manifests in a variety of disorders, including Essential Tremor, Parkinson's Disease, Dystonia, and Cerebellar Ataxia. Although medication and surgical interventions have significantly reduced patient suffering, they are only partially effective and can carry undesired side effects, leaving many patients without satisfactory treatment options. Wearable tremor-suppressing devices could provide an alternative to medication and surgery. Multiple research groups have developed orthotic prototypes to low-pass filter tremor, but these devices have not yet been optimized for in-vivo use. Optimizing non-invasive tremor suppression requires an understanding of where the tremor originates mechanically (which muscles) and how it propagates to the hand (where it matters most). Here we present on the beginnings of our multi-pronged work to determine the origin, propagation, and distribution of Essential Tremor, and we provide preliminary results. © 2017 IEEE.
1870 a57192307368 Davidson A.D. p761 True Journal 320 Fundamental Principles of Tremor Propagation in the Upper Limb Although tremor is the most common movement disorder, there exist few effective tremor-suppressing devices, in part because the characteristics of tremor throughout the upper limb are unknown. To clarify, optimally suppressing tremor requires a knowledge of the mechanical origin, propagation, and distribution of tremor throughout the upper limb. Here we present the first systematic investigation of how tremor propagates between the shoulder, elbow, forearm, and wrist. We simulated tremor propagation using a linear, time-invariant, lumped-parameter model relating joint torques and the resulting joint displacements. The model focused on the seven main degrees of freedom from the shoulder to the wrist and included coupled joint inertia, damping, and stiffness. We deliberately implemented a simple model to focus first on the most basic effects. Simulating tremorogenic joint torque as a sinusoidal input, we used the model to establish fundamental principles describing how input parameters (torque location and frequency) and joint impedance (inertia, damping, and stiffness) affect tremor propagation. We expect that the methods and principles presented here will serve as the groundwork for future refining studies to understand the origin, propagation, and distribution of tremor throughout the upper limb in order to enable the future development of optimal tremor-suppressing devices. © 2016, Biomedical Engineering Society.
1871 a57197800472 Pigg A.C. p707 False Conference 299 Toward quantitative characterization of essential tremor for future tremor suppression Tremor is the most common movement deficit and manifests in a variety of disorders, including Essential Tremor, Parkinson's Disease, Dystonia, and Cerebellar Ataxia. Although medication and surgical interventions have significantly reduced patient suffering, they are only partially effective and can carry undesired side effects, leaving many patients without satisfactory treatment options. Wearable tremor-suppressing devices could provide an alternative to medication and surgery. Multiple research groups have developed orthotic prototypes to low-pass filter tremor, but these devices have not yet been optimized for in-vivo use. Optimizing non-invasive tremor suppression requires an understanding of where the tremor originates mechanically (which muscles) and how it propagates to the hand (where it matters most). Here we present on the beginnings of our multi-pronged work to determine the origin, propagation, and distribution of Essential Tremor, and we provide preliminary results. © 2017 IEEE.
1872 a57197797367 Curtis C.P. p707 False Conference 299 Toward quantitative characterization of essential tremor for future tremor suppression Tremor is the most common movement deficit and manifests in a variety of disorders, including Essential Tremor, Parkinson's Disease, Dystonia, and Cerebellar Ataxia. Although medication and surgical interventions have significantly reduced patient suffering, they are only partially effective and can carry undesired side effects, leaving many patients without satisfactory treatment options. Wearable tremor-suppressing devices could provide an alternative to medication and surgery. Multiple research groups have developed orthotic prototypes to low-pass filter tremor, but these devices have not yet been optimized for in-vivo use. Optimizing non-invasive tremor suppression requires an understanding of where the tremor originates mechanically (which muscles) and how it propagates to the hand (where it matters most). Here we present on the beginnings of our multi-pronged work to determine the origin, propagation, and distribution of Essential Tremor, and we provide preliminary results. © 2017 IEEE.
1873 a56453304300 Jandron M.A. p708 False Journal 348 Water entry of deformable spheres When a rigid body collides with a liquid surface with sufficient velocity, it creates a splash curtain above the surface and entrains air behind the sphere, creating a cavity below the surface. While cavity dynamics has been studied for over a century, this work focuses on the water entry characteristics of deformable elastomeric spheres, which has not been studied. Upon free surface impact, an elastomeric sphere deforms significantly, giving rise to large-scale material oscillations within the sphere resulting in unique nested cavities. We study these phenomena experimentally with high-speed imaging and image processing techniques. The water entry behaviour of deformable spheres differs from rigid spheres because of the pronounced deformation caused at impact as well as the subsequent material vibration. Our results show that this deformation and vibration can be predicted from material properties and impact conditions. Additionally, by accounting for the sphere deformation in an effective diameter term, we recover previously reported characteristics for time to cavity pinch off and hydrodynamic force coefficients for rigid spheres. Our results also show that velocity change over the first oscillation period scales with the dimensionless ratio of material shear modulus to impact hydrodynamic pressure. Therefore, we are able to describe the water entry characteristics of deformable spheres in terms of material properties and impact conditions. © 2017 Cambridge University PressÂ.
1874 a57194875876 Tate Fanning D. p708 False Journal 348 Water entry of deformable spheres When a rigid body collides with a liquid surface with sufficient velocity, it creates a splash curtain above the surface and entrains air behind the sphere, creating a cavity below the surface. While cavity dynamics has been studied for over a century, this work focuses on the water entry characteristics of deformable elastomeric spheres, which has not been studied. Upon free surface impact, an elastomeric sphere deforms significantly, giving rise to large-scale material oscillations within the sphere resulting in unique nested cavities. We study these phenomena experimentally with high-speed imaging and image processing techniques. The water entry behaviour of deformable spheres differs from rigid spheres because of the pronounced deformation caused at impact as well as the subsequent material vibration. Our results show that this deformation and vibration can be predicted from material properties and impact conditions. Additionally, by accounting for the sphere deformation in an effective diameter term, we recover previously reported characteristics for time to cavity pinch off and hydrodynamic force coefficients for rigid spheres. Our results also show that velocity change over the first oscillation period scales with the dimensionless ratio of material shear modulus to impact hydrodynamic pressure. Therefore, we are able to describe the water entry characteristics of deformable spheres in terms of material properties and impact conditions. © 2017 Cambridge University PressÂ.
1875 a7005666650 Bower A.F. p708 False Journal 348 Water entry of deformable spheres When a rigid body collides with a liquid surface with sufficient velocity, it creates a splash curtain above the surface and entrains air behind the sphere, creating a cavity below the surface. While cavity dynamics has been studied for over a century, this work focuses on the water entry characteristics of deformable elastomeric spheres, which has not been studied. Upon free surface impact, an elastomeric sphere deforms significantly, giving rise to large-scale material oscillations within the sphere resulting in unique nested cavities. We study these phenomena experimentally with high-speed imaging and image processing techniques. The water entry behaviour of deformable spheres differs from rigid spheres because of the pronounced deformation caused at impact as well as the subsequent material vibration. Our results show that this deformation and vibration can be predicted from material properties and impact conditions. Additionally, by accounting for the sphere deformation in an effective diameter term, we recover previously reported characteristics for time to cavity pinch off and hydrodynamic force coefficients for rigid spheres. Our results also show that velocity change over the first oscillation period scales with the dimensionless ratio of material shear modulus to impact hydrodynamic pressure. Therefore, we are able to describe the water entry characteristics of deformable spheres in terms of material properties and impact conditions. © 2017 Cambridge University PressÂ.
1876 a35186389400 Senic D. p710 True Journal 319 Improved Antenna Efficiency Measurement Uncertainty in a Reverberation Chamber at Millimeter-Wave Frequencies We provide results of antenna radiation and total radiation efficiency at millimeter-wave frequencies gathered with a new open-ended waveguide-plate method that is compared to a well-known two-antenna method. The new method yields improved uncertainty in antenna efficiency measurements. Both methods are based on use of a reverberation chamber. Measurement results are compared to numerical simulations and good agreement (3% maximum difference) is achieved. Before performing the efficiency measurements, the chamber configuration was assessed with respect to the Rician $K$ -factor, number of uncorrelated paddle orientations, and coherence bandwidth. We calculated the uncertainty using the NIST microwave uncertainty framework capable of performing parallel sensitivity and Monte Carlo analyses. The framework enables us to capture and propagate the uncertainties in the S-parameter measurements to the final efficiency result. The expanded uncertainty that we achieved for these antenna efficiency measurements is 2.60%. © 1963-2012 IEEE.
1877 a7406552522 Williams D.F. p710 False Journal 319 Improved Antenna Efficiency Measurement Uncertainty in a Reverberation Chamber at Millimeter-Wave Frequencies We provide results of antenna radiation and total radiation efficiency at millimeter-wave frequencies gathered with a new open-ended waveguide-plate method that is compared to a well-known two-antenna method. The new method yields improved uncertainty in antenna efficiency measurements. Both methods are based on use of a reverberation chamber. Measurement results are compared to numerical simulations and good agreement (3% maximum difference) is achieved. Before performing the efficiency measurements, the chamber configuration was assessed with respect to the Rician $K$ -factor, number of uncorrelated paddle orientations, and coherence bandwidth. We calculated the uncertainty using the NIST microwave uncertainty framework capable of performing parallel sensitivity and Monte Carlo analyses. The framework enables us to capture and propagate the uncertainties in the S-parameter measurements to the final efficiency result. The expanded uncertainty that we achieved for these antenna efficiency measurements is 2.60%. © 1963-2012 IEEE.
1878 a7006715937 Remley K.A. p710 False Journal 319 Improved Antenna Efficiency Measurement Uncertainty in a Reverberation Chamber at Millimeter-Wave Frequencies We provide results of antenna radiation and total radiation efficiency at millimeter-wave frequencies gathered with a new open-ended waveguide-plate method that is compared to a well-known two-antenna method. The new method yields improved uncertainty in antenna efficiency measurements. Both methods are based on use of a reverberation chamber. Measurement results are compared to numerical simulations and good agreement (3% maximum difference) is achieved. Before performing the efficiency measurements, the chamber configuration was assessed with respect to the Rician $K$ -factor, number of uncorrelated paddle orientations, and coherence bandwidth. We calculated the uncertainty using the NIST microwave uncertainty framework capable of performing parallel sensitivity and Monte Carlo analyses. The framework enables us to capture and propagate the uncertainties in the S-parameter measurements to the final efficiency result. The expanded uncertainty that we achieved for these antenna efficiency measurements is 2.60%. © 1963-2012 IEEE.
1879 a57192595504 Wang C.-M. p710 False Journal 319 Improved Antenna Efficiency Measurement Uncertainty in a Reverberation Chamber at Millimeter-Wave Frequencies We provide results of antenna radiation and total radiation efficiency at millimeter-wave frequencies gathered with a new open-ended waveguide-plate method that is compared to a well-known two-antenna method. The new method yields improved uncertainty in antenna efficiency measurements. Both methods are based on use of a reverberation chamber. Measurement results are compared to numerical simulations and good agreement (3% maximum difference) is achieved. Before performing the efficiency measurements, the chamber configuration was assessed with respect to the Rician $K$ -factor, number of uncorrelated paddle orientations, and coherence bandwidth. We calculated the uncertainty using the NIST microwave uncertainty framework capable of performing parallel sensitivity and Monte Carlo analyses. The framework enables us to capture and propagate the uncertainties in the S-parameter measurements to the final efficiency result. The expanded uncertainty that we achieved for these antenna efficiency measurements is 2.60%. © 1963-2012 IEEE.
1880 a7101643443 Holloway C.L. p710 False Journal 319 Improved Antenna Efficiency Measurement Uncertainty in a Reverberation Chamber at Millimeter-Wave Frequencies We provide results of antenna radiation and total radiation efficiency at millimeter-wave frequencies gathered with a new open-ended waveguide-plate method that is compared to a well-known two-antenna method. The new method yields improved uncertainty in antenna efficiency measurements. Both methods are based on use of a reverberation chamber. Measurement results are compared to numerical simulations and good agreement (3% maximum difference) is achieved. Before performing the efficiency measurements, the chamber configuration was assessed with respect to the Rician $K$ -factor, number of uncorrelated paddle orientations, and coherence bandwidth. We calculated the uncertainty using the NIST microwave uncertainty framework capable of performing parallel sensitivity and Monte Carlo analyses. The framework enables us to capture and propagate the uncertainties in the S-parameter measurements to the final efficiency result. The expanded uncertainty that we achieved for these antenna efficiency measurements is 2.60%. © 1963-2012 IEEE.
1881 a55511230900 Yang Z. p710 False Journal 319 Improved Antenna Efficiency Measurement Uncertainty in a Reverberation Chamber at Millimeter-Wave Frequencies We provide results of antenna radiation and total radiation efficiency at millimeter-wave frequencies gathered with a new open-ended waveguide-plate method that is compared to a well-known two-antenna method. The new method yields improved uncertainty in antenna efficiency measurements. Both methods are based on use of a reverberation chamber. Measurement results are compared to numerical simulations and good agreement (3% maximum difference) is achieved. Before performing the efficiency measurements, the chamber configuration was assessed with respect to the Rician $K$ -factor, number of uncorrelated paddle orientations, and coherence bandwidth. We calculated the uncertainty using the NIST microwave uncertainty framework capable of performing parallel sensitivity and Monte Carlo analyses. The framework enables us to capture and propagate the uncertainties in the S-parameter measurements to the final efficiency result. The expanded uncertainty that we achieved for these antenna efficiency measurements is 2.60%. © 1963-2012 IEEE.
1881 a55511230900 Yang Z. p740 False Journal 346 Optical electric field sensor sensitivity direction rerouting and enhancement using a passive integrated dipole antenna This work introduces a passive dipole antenna integrated into the packaging of a slab-coupled optical sensor to enhance the directional sensitivity of electro-optic electric field measurements parallel to the fiber axis. Using the passive integrated dipole antenna described in this work, a sensor that can typically only sense fields transverse to the fiber direction is able to sense a 1.25 kV/m field along the fiber direction with a gain of 17.5. This is verified through simulation and experiment. © 2017 Optical Society of America.
1882 a24465414600 Palmer J. p711 False Journal 350 Space-Time Coding for Aeronautical Telemetry: Part i - Estimators This paper derives and analyzes the estimators required for detection and decoding of Alamouti-encoded-shaped offset QPSK version TG (SOQPSK-TG). The joint maximum likelihood (ML) estimators for the frequency offset, channel delays, and channel gains are derived and analyzed. As a complexity-reducing technique, a sequential version of the ML estimators is developed. The Cramér-Rao bound for the parameters is derived and used to analyze the performance of the estimators to determine pilot sequence length. The complexity of the frequency estimator is reduced by applying the Zoom FFT algorithm in the coarse search. The complexity of the channel delay estimator was reduced by developing a novel version of the simplex search algorithm that operated on a discrete two-dimensional grid. These estimation algorithms were implemented in a prototype demodulator that was field tested at Edwards AFB. © 2017 IEEE.
1882 a24465414600 Palmer J. p712 False Journal 350 Space-Time Coding for Aeronautical Telemetry: Part II - Decoder and System Performance This paper describes the use of Alamouti-encoded-shaped offset QPSK version TG (SOQPSK-TG) to solve the two-antenna problem in aeronautical telemetry. The Alamouti space-time block code is used to encode the phase states in the complex exponential representation of SOQPSK-TG. Because SOQPSK-TG possesses memory, the Alamouti decoder is a sequence estimator. Maximum likelihood and least squares sequence decoders are derived. To reduce the number of states, the eight-waveform cross-correlated trellis-coded quadrature modulation (XTCQM) approximate representation of SOQPSK-TG is used. A prototype decoder based on the least squares decoder and the estimators described in Part I and operating at a data rate of 10 Mb/s was tested in the laboratory in test flights at the Air Force Test Center, Edwards AFB. The test flights demonstrate that Alamouti-encoded SOQPSK-TG, as described in this paper, using the least squares decoder based on the estimators described in Part I solves the two antenna problem in aeronautical telemetry. © 2017 IEEE.
1883 a26644144000 Lavin C. p711 False Journal 350 Space-Time Coding for Aeronautical Telemetry: Part i - Estimators This paper derives and analyzes the estimators required for detection and decoding of Alamouti-encoded-shaped offset QPSK version TG (SOQPSK-TG). The joint maximum likelihood (ML) estimators for the frequency offset, channel delays, and channel gains are derived and analyzed. As a complexity-reducing technique, a sequential version of the ML estimators is developed. The Cramér-Rao bound for the parameters is derived and used to analyze the performance of the estimators to determine pilot sequence length. The complexity of the frequency estimator is reduced by applying the Zoom FFT algorithm in the coarse search. The complexity of the channel delay estimator was reduced by developing a novel version of the simplex search algorithm that operated on a discrete two-dimensional grid. These estimation algorithms were implemented in a prototype demodulator that was field tested at Edwards AFB. © 2017 IEEE.
1883 a26644144000 Lavin C. p712 False Journal 350 Space-Time Coding for Aeronautical Telemetry: Part II - Decoder and System Performance This paper describes the use of Alamouti-encoded-shaped offset QPSK version TG (SOQPSK-TG) to solve the two-antenna problem in aeronautical telemetry. The Alamouti space-time block code is used to encode the phase states in the complex exponential representation of SOQPSK-TG. Because SOQPSK-TG possesses memory, the Alamouti decoder is a sequence estimator. Maximum likelihood and least squares sequence decoders are derived. To reduce the number of states, the eight-waveform cross-correlated trellis-coded quadrature modulation (XTCQM) approximate representation of SOQPSK-TG is used. A prototype decoder based on the least squares decoder and the estimators described in Part I and operating at a data rate of 10 Mb/s was tested in the laboratory in test flights at the Air Force Test Center, Edwards AFB. The test flights demonstrate that Alamouti-encoded SOQPSK-TG, as described in this paper, using the least squares decoder based on the estimators described in Part I solves the two antenna problem in aeronautical telemetry. © 2017 IEEE.
1884 a55547115089 Nelson T. p711 False Journal 350 Space-Time Coding for Aeronautical Telemetry: Part i - Estimators This paper derives and analyzes the estimators required for detection and decoding of Alamouti-encoded-shaped offset QPSK version TG (SOQPSK-TG). The joint maximum likelihood (ML) estimators for the frequency offset, channel delays, and channel gains are derived and analyzed. As a complexity-reducing technique, a sequential version of the ML estimators is developed. The Cramér-Rao bound for the parameters is derived and used to analyze the performance of the estimators to determine pilot sequence length. The complexity of the frequency estimator is reduced by applying the Zoom FFT algorithm in the coarse search. The complexity of the channel delay estimator was reduced by developing a novel version of the simplex search algorithm that operated on a discrete two-dimensional grid. These estimation algorithms were implemented in a prototype demodulator that was field tested at Edwards AFB. © 2017 IEEE.
1884 a55547115089 Nelson T. p712 False Journal 350 Space-Time Coding for Aeronautical Telemetry: Part II - Decoder and System Performance This paper describes the use of Alamouti-encoded-shaped offset QPSK version TG (SOQPSK-TG) to solve the two-antenna problem in aeronautical telemetry. The Alamouti space-time block code is used to encode the phase states in the complex exponential representation of SOQPSK-TG. Because SOQPSK-TG possesses memory, the Alamouti decoder is a sequence estimator. Maximum likelihood and least squares sequence decoders are derived. To reduce the number of states, the eight-waveform cross-correlated trellis-coded quadrature modulation (XTCQM) approximate representation of SOQPSK-TG is used. A prototype decoder based on the least squares decoder and the estimators described in Part I and operating at a data rate of 10 Mb/s was tested in the laboratory in test flights at the Air Force Test Center, Edwards AFB. The test flights demonstrate that Alamouti-encoded SOQPSK-TG, as described in this paper, using the least squares decoder based on the estimators described in Part I solves the two antenna problem in aeronautical telemetry. © 2017 IEEE.
1885 a57193564939 Ahn E.-Y. p713 True Journal 351 Process responses and resultant joint properties of friction stir welding of dissimilar 5083 and 6061aluminum alloys The effects of combinations of dissimilar aluminum alloys during Friction stir welding (FSW) on the process response and resultant joint properties are experimentally investigated using two dissimilar automotive structural aluminum alloys. Depending on the materials on the advancing and retreating sides of the tool travel direction during FSW, four different material combinations are considered. FSW joints without macroscopic defects are successfully fabricated for the four different material combinations. The optical microscopy results show that the macroscopic material mixing behaviors of the two dissimilar material combinations during FSW are somewhat different from each other, even though the process responses during joining are not much different. The results of the quasi-static tensile tests and EBSD analysis demonstrate that the mechanical behaviors and orientation changes of the joint during tensile deformation are affected by the material locations with respect to the tool travel direction during FSW. © 2017, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany.
1885 a57193564939 Ahn E.-Y. p772 False Journal 379 Effect of tool geometry and process parameters on mechanical properties of friction stir spot welded dissimilar aluminum alloys The effects of tool geometry and process parameters on the mechanical properties of friction stir spot welded (FSSW) dissimilar aluminum alloys are experimentally investigated. Two tools with different shoulder profiles, concave and convex, were considered. Two typical automotive aluminum alloys were selected for FSSW, thus resulting in two different material combinations for each shoulder profile. The experimental results showed that the two shoulder profiles caused significant differences in the axial force, the mixing of materials, and the mechanical properties of the joint. The sensitivity of joint strength to the variation of the tool rotation speed and the plunge speed was also quite dependent on the shoulder profile. The experimental result shows that the change of joint strength can be quite significant. © 2017, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.
1886 a54399816500 Das H. p713 False Journal 351 Process responses and resultant joint properties of friction stir welding of dissimilar 5083 and 6061aluminum alloys The effects of combinations of dissimilar aluminum alloys during Friction stir welding (FSW) on the process response and resultant joint properties are experimentally investigated using two dissimilar automotive structural aluminum alloys. Depending on the materials on the advancing and retreating sides of the tool travel direction during FSW, four different material combinations are considered. FSW joints without macroscopic defects are successfully fabricated for the four different material combinations. The optical microscopy results show that the macroscopic material mixing behaviors of the two dissimilar material combinations during FSW are somewhat different from each other, even though the process responses during joining are not much different. The results of the quasi-static tensile tests and EBSD analysis demonstrate that the mechanical behaviors and orientation changes of the joint during tensile deformation are affected by the material locations with respect to the tool travel direction during FSW. © 2017, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany.
1886 a54399816500 Das H. p772 False Journal 379 Effect of tool geometry and process parameters on mechanical properties of friction stir spot welded dissimilar aluminum alloys The effects of tool geometry and process parameters on the mechanical properties of friction stir spot welded (FSSW) dissimilar aluminum alloys are experimentally investigated. Two tools with different shoulder profiles, concave and convex, were considered. Two typical automotive aluminum alloys were selected for FSSW, thus resulting in two different material combinations for each shoulder profile. The experimental results showed that the two shoulder profiles caused significant differences in the axial force, the mixing of materials, and the mechanical properties of the joint. The sensitivity of joint strength to the variation of the tool rotation speed and the plunge speed was also quite dependent on the shoulder profile. The experimental result shows that the change of joint strength can be quite significant. © 2017, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.
1887 a55726346900 Hong S.-T. p713 False Journal 351 Process responses and resultant joint properties of friction stir welding of dissimilar 5083 and 6061aluminum alloys The effects of combinations of dissimilar aluminum alloys during Friction stir welding (FSW) on the process response and resultant joint properties are experimentally investigated using two dissimilar automotive structural aluminum alloys. Depending on the materials on the advancing and retreating sides of the tool travel direction during FSW, four different material combinations are considered. FSW joints without macroscopic defects are successfully fabricated for the four different material combinations. The optical microscopy results show that the macroscopic material mixing behaviors of the two dissimilar material combinations during FSW are somewhat different from each other, even though the process responses during joining are not much different. The results of the quasi-static tensile tests and EBSD analysis demonstrate that the mechanical behaviors and orientation changes of the joint during tensile deformation are affected by the material locations with respect to the tool travel direction during FSW. © 2017, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany.
1887 a55726346900 Hong S.-T. p772 False Journal 379 Effect of tool geometry and process parameters on mechanical properties of friction stir spot welded dissimilar aluminum alloys The effects of tool geometry and process parameters on the mechanical properties of friction stir spot welded (FSSW) dissimilar aluminum alloys are experimentally investigated. Two tools with different shoulder profiles, concave and convex, were considered. Two typical automotive aluminum alloys were selected for FSSW, thus resulting in two different material combinations for each shoulder profile. The experimental results showed that the two shoulder profiles caused significant differences in the axial force, the mixing of materials, and the mechanical properties of the joint. The sensitivity of joint strength to the variation of the tool rotation speed and the plunge speed was also quite dependent on the shoulder profile. The experimental result shows that the change of joint strength can be quite significant. © 2017, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.
1888 a55585953300 Han K.-S. p713 False Journal 351 Process responses and resultant joint properties of friction stir welding of dissimilar 5083 and 6061aluminum alloys The effects of combinations of dissimilar aluminum alloys during Friction stir welding (FSW) on the process response and resultant joint properties are experimentally investigated using two dissimilar automotive structural aluminum alloys. Depending on the materials on the advancing and retreating sides of the tool travel direction during FSW, four different material combinations are considered. FSW joints without macroscopic defects are successfully fabricated for the four different material combinations. The optical microscopy results show that the macroscopic material mixing behaviors of the two dissimilar material combinations during FSW are somewhat different from each other, even though the process responses during joining are not much different. The results of the quasi-static tensile tests and EBSD analysis demonstrate that the mechanical behaviors and orientation changes of the joint during tensile deformation are affected by the material locations with respect to the tool travel direction during FSW. © 2017, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany.
1889 a8935514400 Lee K.-J. p713 False Journal 351 Process responses and resultant joint properties of friction stir welding of dissimilar 5083 and 6061aluminum alloys The effects of combinations of dissimilar aluminum alloys during Friction stir welding (FSW) on the process response and resultant joint properties are experimentally investigated using two dissimilar automotive structural aluminum alloys. Depending on the materials on the advancing and retreating sides of the tool travel direction during FSW, four different material combinations are considered. FSW joints without macroscopic defects are successfully fabricated for the four different material combinations. The optical microscopy results show that the macroscopic material mixing behaviors of the two dissimilar material combinations during FSW are somewhat different from each other, even though the process responses during joining are not much different. The results of the quasi-static tensile tests and EBSD analysis demonstrate that the mechanical behaviors and orientation changes of the joint during tensile deformation are affected by the material locations with respect to the tool travel direction during FSW. © 2017, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany.
1889 a8935514400 Lee K.-J. p772 False Journal 379 Effect of tool geometry and process parameters on mechanical properties of friction stir spot welded dissimilar aluminum alloys The effects of tool geometry and process parameters on the mechanical properties of friction stir spot welded (FSSW) dissimilar aluminum alloys are experimentally investigated. Two tools with different shoulder profiles, concave and convex, were considered. Two typical automotive aluminum alloys were selected for FSSW, thus resulting in two different material combinations for each shoulder profile. The experimental results showed that the two shoulder profiles caused significant differences in the axial force, the mixing of materials, and the mechanical properties of the joint. The sensitivity of joint strength to the variation of the tool rotation speed and the plunge speed was also quite dependent on the shoulder profile. The experimental result shows that the change of joint strength can be quite significant. © 2017, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.
1890 a56762988100 Park J.-W. p713 False Journal 351 Process responses and resultant joint properties of friction stir welding of dissimilar 5083 and 6061aluminum alloys The effects of combinations of dissimilar aluminum alloys during Friction stir welding (FSW) on the process response and resultant joint properties are experimentally investigated using two dissimilar automotive structural aluminum alloys. Depending on the materials on the advancing and retreating sides of the tool travel direction during FSW, four different material combinations are considered. FSW joints without macroscopic defects are successfully fabricated for the four different material combinations. The optical microscopy results show that the macroscopic material mixing behaviors of the two dissimilar material combinations during FSW are somewhat different from each other, even though the process responses during joining are not much different. The results of the quasi-static tensile tests and EBSD analysis demonstrate that the mechanical behaviors and orientation changes of the joint during tensile deformation are affected by the material locations with respect to the tool travel direction during FSW. © 2017, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany.
1891 a7401969039 Han H.N. p713 False Journal 351 Process responses and resultant joint properties of friction stir welding of dissimilar 5083 and 6061aluminum alloys The effects of combinations of dissimilar aluminum alloys during Friction stir welding (FSW) on the process response and resultant joint properties are experimentally investigated using two dissimilar automotive structural aluminum alloys. Depending on the materials on the advancing and retreating sides of the tool travel direction during FSW, four different material combinations are considered. FSW joints without macroscopic defects are successfully fabricated for the four different material combinations. The optical microscopy results show that the macroscopic material mixing behaviors of the two dissimilar material combinations during FSW are somewhat different from each other, even though the process responses during joining are not much different. The results of the quasi-static tensile tests and EBSD analysis demonstrate that the mechanical behaviors and orientation changes of the joint during tensile deformation are affected by the material locations with respect to the tool travel direction during FSW. © 2017, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany.
1892 a6603040755 Red E. p715 False Journal 352 Methods for determining the optimal number of simultaneous contributors for multi-user CAD parts The development of multi-user CAD (MUCAD) tools has opened up exciting new opportunities and applications. The capability for multiple users to simultaneously model and design a CAD part has far-reaching potential. However, many basic questions remains unanswered, such as how many users should work together on a given part. This research proposes and develops a set of methods to determine the optimal number of users for a given part within a MUCAD environment, based on the characteristics of the part itself. Two candidate models are evaluated with a set of 60 experiments with design teams composed of different numbers of users. The models show modest correlations with the test data while more-refined models are explored to improve predictive power. On the other hand, highly significant correlations between the ability to predict completion time and multi-user team size were identified in the experimental data. Observations regarding the speed and quality of MUCAD teams are also made with future areas of research suggested. © 2017 CAD Solutions, LLC.
1893 a57192959498 Pedersen A. p715 False Journal 352 Methods for determining the optimal number of simultaneous contributors for multi-user CAD parts The development of multi-user CAD (MUCAD) tools has opened up exciting new opportunities and applications. The capability for multiple users to simultaneously model and design a CAD part has far-reaching potential. However, many basic questions remains unanswered, such as how many users should work together on a given part. This research proposes and develops a set of methods to determine the optimal number of users for a given part within a MUCAD environment, based on the characteristics of the part itself. Two candidate models are evaluated with a set of 60 experiments with design teams composed of different numbers of users. The models show modest correlations with the test data while more-refined models are explored to improve predictive power. On the other hand, highly significant correlations between the ability to predict completion time and multi-user team size were identified in the experimental data. Observations regarding the speed and quality of MUCAD teams are also made with future areas of research suggested. © 2017 CAD Solutions, LLC.
1894 a57192961253 Jones T. p715 False Journal 352 Methods for determining the optimal number of simultaneous contributors for multi-user CAD parts The development of multi-user CAD (MUCAD) tools has opened up exciting new opportunities and applications. The capability for multiple users to simultaneously model and design a CAD part has far-reaching potential. However, many basic questions remains unanswered, such as how many users should work together on a given part. This research proposes and develops a set of methods to determine the optimal number of users for a given part within a MUCAD environment, based on the characteristics of the part itself. Two candidate models are evaluated with a set of 60 experiments with design teams composed of different numbers of users. The models show modest correlations with the test data while more-refined models are explored to improve predictive power. On the other hand, highly significant correlations between the ability to predict completion time and multi-user team size were identified in the experimental data. Observations regarding the speed and quality of MUCAD teams are also made with future areas of research suggested. © 2017 CAD Solutions, LLC.
1895 a57197710678 Tolman S. p716 True Conference 300 Counter UAS using a formation controlled dragnet Rapidly developing UAS technology necessitates reliable counter UAS systems. This paper proposes a formation controlled dragnet as a possible solution and compares potential intercept algorithms that can be used in this scenario. Proportional navigation and target-predictive path planning, both existing algorithms, are explored and an original approach, Adaptive Radius Optimal Defense (AROD), is introduced. Simulation results are given and the strengths and weaknesses of each approach are discussed. Based on the simulation results, some advantages that AROD offers over other existing algorithms are listed. Possible improvements and future research directions are also suggested. © 2017 IEEE.
1896 a57188688103 Wilson J.P. p717 True Conference 301 Variable stiffness adaptation to mitigate system failure in inflatable robots Although inflatable soft robots are not yet a common robot platform, air leaking from the internal structure is a common and undesirable mode of failure for these platforms. In this paper we demonstrate a method to detect leaks in the structural chamber of an inflatable, pneumatically actuated robot. We then show that our method can adaptively lower commanded joint stiffness which slows the mass flow rate of the leak. This extends the operational life of the robot by decreasing long term error during operation by as much as 50% of the steady state error at the end effector when compared to the same leak if our adaptation method is not used. In future applications where we expect soft, inflatable robots to be useful, our methods can enable failure mitigation in resource-limited situations such as space exploration or disaster response. © 2017 IEEE.
1897 a57195420301 Bodily D.M. p718 True Conference 302 Multi-objective design optimization of a soft, pneumatic robot We present a method for the design optimization of a soft, inflatable robot. The method described utilizes a multi-objective fitness function together with custom, platform-specific metrics related to the dexterity and load-bearing capacity of inflatable manipulators. Candidate designs are scored by computing these metrics at many randomly generated configurations and then by appropriately combining these scores within the multi-objective optimization framework. High performing designs are propagated through a genetic algorithm. The final result is a set of diverse, optimal designs lying along a Pareto front spanning the design space. By examining variations and trade-offs within this set, a designer can more appropriately choose design parameters for a target application. This is especially relevant for robots with many design parameters that can quickly be manufactured as is the case with emerging, soft robot technologies. © 2017 IEEE.
1897 a57195420301 Bodily D.M. p719 True Conference 303 Motion planning for mobile robots using inverse kinematics branching A novel algorithm for planning robotic manipulation tasks is presented in which the base position and joint motions of a robot are simultaneously optimized to follow a smooth desired end-effector trajectory. During the optimization routine, the manipulator's base position and joint motions are planned simultaneously by strategically moving a set of virtual robot arms (each representing a single configuration in a sequence) branching from a common base to a number of assigned target poses associated with a task. Additional goals (e.g. collision avoidance) and hard constraints, including joint limits are also incorporated. The optimization problem at the core of this method is a quadratic program, allowing constrained high-dimensional problems to be solved in very little time. This method has successfully planned motions allowing an 8-DOF manipulator to paint walls, and has proven to be highly efficient and scalable in practice. © 2017 IEEE.
1898 a7401970125 Allen T.F. p718 False Conference 302 Multi-objective design optimization of a soft, pneumatic robot We present a method for the design optimization of a soft, inflatable robot. The method described utilizes a multi-objective fitness function together with custom, platform-specific metrics related to the dexterity and load-bearing capacity of inflatable manipulators. Candidate designs are scored by computing these metrics at many randomly generated configurations and then by appropriately combining these scores within the multi-objective optimization framework. High performing designs are propagated through a genetic algorithm. The final result is a set of diverse, optimal designs lying along a Pareto front spanning the design space. By examining variations and trade-offs within this set, a designer can more appropriately choose design parameters for a target application. This is especially relevant for robots with many design parameters that can quickly be manufactured as is the case with emerging, soft robot technologies. © 2017 IEEE.
1898 a7401970125 Allen T.F. p719 False Conference 303 Motion planning for mobile robots using inverse kinematics branching A novel algorithm for planning robotic manipulation tasks is presented in which the base position and joint motions of a robot are simultaneously optimized to follow a smooth desired end-effector trajectory. During the optimization routine, the manipulator's base position and joint motions are planned simultaneously by strategically moving a set of virtual robot arms (each representing a single configuration in a sequence) branching from a common base to a number of assigned target poses associated with a task. Additional goals (e.g. collision avoidance) and hard constraints, including joint limits are also incorporated. The optimization problem at the core of this method is a quadratic program, allowing constrained high-dimensional problems to be solved in very little time. This method has successfully planned motions allowing an 8-DOF manipulator to paint walls, and has proven to be highly efficient and scalable in practice. © 2017 IEEE.
1899 a7103395611 Swift G. p721 False Conference 305 Move the Laser Spot, Not the DUT: Investigating the New Micro-mirror Capability and Challenges for Localizing SEE Sites on Large Modern ICs Small spot size laser testing for single-event effects has proven to be a particularly productive path to insights on the physics of charge collection and circuit response that are difficult or impossible to obtain through broad ion beam tests. As a result, there are a number of such laser facilities; for example, four of them were compared in 2012 [1], but a relatively new facility at the facility at the University of Saskatchewan offers a unique galvo-mirror, laser-spot scanning capability in addition to the usual micrometer-based DUT motion stage [2]. Operating in a fashion similar to LASIX eye surgery, fast pin-point redirection of the laser beam makes tractable (seconds, not hours or days) comprehensive scanning of a millimeter size field-of-view. Combined with auto-stepping the field-of-view, this new spot scanning capability opens up the possibility of comprehensively covering a large die and finding all SEE sites, including the rare, but important, ones such as SEFIs. © 2017 IEEE.
1899 a7103395611 Swift G. p722 True Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1900 a24831334500 Wong R. p721 False Conference 305 Move the Laser Spot, Not the DUT: Investigating the New Micro-mirror Capability and Challenges for Localizing SEE Sites on Large Modern ICs Small spot size laser testing for single-event effects has proven to be a particularly productive path to insights on the physics of charge collection and circuit response that are difficult or impossible to obtain through broad ion beam tests. As a result, there are a number of such laser facilities; for example, four of them were compared in 2012 [1], but a relatively new facility at the facility at the University of Saskatchewan offers a unique galvo-mirror, laser-spot scanning capability in addition to the usual micrometer-based DUT motion stage [2]. Operating in a fashion similar to LASIX eye surgery, fast pin-point redirection of the laser beam makes tractable (seconds, not hours or days) comprehensive scanning of a millimeter size field-of-view. Combined with auto-stepping the field-of-view, this new spot scanning capability opens up the possibility of comprehensively covering a large die and finding all SEE sites, including the rare, but important, ones such as SEFIs. © 2017 IEEE.
1901 a18038642000 Stone S.E. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1902 a57208709468 Garcia S.E. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1903 a57208710317 Wray K.W. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1904 a57208709846 Rowe W.J. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1905 a57170532300 Pfau K.H. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1906 a57208702517 Liu R. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1907 a57208707588 Holden J. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1908 a57208707585 Angeles A. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1909 a6508147112 Willits B.L. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1910 a57208706948 Robinson K.P. p722 False Conference 306 Dynamic SEE Testing of Selected Architectural Features of Xilinx 28 nm Virtex-7 FPGAs Recent proton and heavy ion SEE data are presented for selected Virtex-7 architectural features requiring dynamic in-beam testing: I/O blocks in various modes, IOSERDES, digital- and phase-locked loop clocks, and block memory's error correction circuitry. © 2017 IEEE.
1911 a57021948900 Jafek A. p723 True Journal 353 A Systems Engineering Approach to Harnessing Human Energy in Public Places: A Feasibility Study This study analyzes the feasibility of placing modified exercise equipment in public places to enable human energy harnessing. By assessing the impacts as a system-level synthesis of economic, environmental, productivity, and health benefits, it is shown that introducing human-powered equipment (HPE) in public places would be feasible and beneficial both to society in general and to the specific stakeholders investing in this technology. This study develops a framework to evaluate applications of this technology using benefits to costs analyses. The benefits and challenges for successful implementation of HPE technology are also presented and evaluated in various case studies involving public places at airports and schools. Copyright © 2017 by ASME.
1912 a55078951500 Bodily P.M. p724 False Conference 307 Modeling global and local codon bias with deep language models Codon bias, the usage patterns of synonymous codons for encoding a protein sequence as nucleotides, is a biological phenomenon that is not fully understood. Several methods exist to represent the codon bias of an organism: codon adaptation index (CAI) [1], individual codon usage (ICU), hidden stop codons (HSC) [2] and codon context (CC) [3]. These methods are often employed in the optimization of heterologous gene expression to increase the accuracy and rate of translation. They, however, have many shortcomings as they dont take into account the local and global context of a gene. We present a method for modeling global and local codon bias through deep language models that is more robust than current methods by providing more contextual information and long-range dependencies. © 2017 IEEE.
1912 a55078951500 Bodily P.M. p727 False Conference 308 Whole genome phylogenetic tree reconstruction using colored de bruijn graphs We present kleuren, a novel assembly-free method to reconstruct phylogenetic trees using the Colored de Bruijn Graph. kleuren works by constructing the Colored de Bruijn Graph and then traversing it, finding bubble structures in the graph that provide phylogenetic signal. The bubbles are then aligned and concatenated to form a supermatrix, from which a phylogenetic tree is inferred. We introduce the algorithms that kleuren uses to accomplish this task, and show its performance on reconstructing the phylogenetic tree of 12 Drosophila species. kleuren reconstructed the established phylogenetic tree accurately, and is a viable tool for phylogenetic tree reconstruction using whole genome sequences. Software package available at: https://github.com/Colelyman/kleuren. © 2017 IEEE.
1912 a55078951500 Bodily P.M. p728 False Conference 309 Genome polymorphism detection through relaxed de bruijn graph construction Comparing genomes to identify polymorphisms is a difficult task, especially beyond single nucleotide poly-morphisms. Polymorphism detection is important in disease association studies as well as in phylogenetic tree reconstruc-tion. We present a method for identifying polymorphisms in genomes by using a modified version de Bruijn graphs, data structures widely used in genome assembly from Next-Generation Sequencing. Using our method, we are able to identify polymorphisms that exist within a genome as well as well as see graph structures that form in the de Bruijn graph for particular types of polymorphisms (translocations, etc.) © 2017 IEEE.
1913 a57215280005 Jacobsen A.J. p724 False Conference 307 Modeling global and local codon bias with deep language models Codon bias, the usage patterns of synonymous codons for encoding a protein sequence as nucleotides, is a biological phenomenon that is not fully understood. Several methods exist to represent the codon bias of an organism: codon adaptation index (CAI) [1], individual codon usage (ICU), hidden stop codons (HSC) [2] and codon context (CC) [3]. These methods are often employed in the optimization of heterologous gene expression to increase the accuracy and rate of translation. They, however, have many shortcomings as they dont take into account the local and global context of a gene. We present a method for modeling global and local codon bias through deep language models that is more robust than current methods by providing more contextual information and long-range dependencies. © 2017 IEEE.
1914 a6602958570 Snell Q. p724 False Conference 307 Modeling global and local codon bias with deep language models Codon bias, the usage patterns of synonymous codons for encoding a protein sequence as nucleotides, is a biological phenomenon that is not fully understood. Several methods exist to represent the codon bias of an organism: codon adaptation index (CAI) [1], individual codon usage (ICU), hidden stop codons (HSC) [2] and codon context (CC) [3]. These methods are often employed in the optimization of heterologous gene expression to increase the accuracy and rate of translation. They, however, have many shortcomings as they dont take into account the local and global context of a gene. We present a method for modeling global and local codon bias through deep language models that is more robust than current methods by providing more contextual information and long-range dependencies. © 2017 IEEE.
1914 a6602958570 Snell Q. p727 False Conference 308 Whole genome phylogenetic tree reconstruction using colored de bruijn graphs We present kleuren, a novel assembly-free method to reconstruct phylogenetic trees using the Colored de Bruijn Graph. kleuren works by constructing the Colored de Bruijn Graph and then traversing it, finding bubble structures in the graph that provide phylogenetic signal. The bubbles are then aligned and concatenated to form a supermatrix, from which a phylogenetic tree is inferred. We introduce the algorithms that kleuren uses to accomplish this task, and show its performance on reconstructing the phylogenetic tree of 12 Drosophila species. kleuren reconstructed the established phylogenetic tree accurately, and is a viable tool for phylogenetic tree reconstruction using whole genome sequences. Software package available at: https://github.com/Colelyman/kleuren. © 2017 IEEE.
1914 a6602958570 Snell Q. p728 False Conference 309 Genome polymorphism detection through relaxed de bruijn graph construction Comparing genomes to identify polymorphisms is a difficult task, especially beyond single nucleotide poly-morphisms. Polymorphism detection is important in disease association studies as well as in phylogenetic tree reconstruc-tion. We present a method for identifying polymorphisms in genomes by using a modified version de Bruijn graphs, data structures widely used in genome assembly from Next-Generation Sequencing. Using our method, we are able to identify polymorphisms that exist within a genome as well as well as see graph structures that form in the de Bruijn graph for particular types of polymorphisms (translocations, etc.) © 2017 IEEE.
1915 a57214010282 Barrett L.K. p725 True Journal 354 Carbon monolith scaffolding for high volumetric capacity silicon Li-ion battery anodes A nanoporous carbon monolith structure has been developed for use as a scaffold for silicon anodes for lithium batteries. This scaffold was fabricated by coating vertically aligned carbon nanotubes in a highly conformal coating of nanocrystalline carbon, applied via atmospheric pressure chemical vapor deposition. The coating increases the mechanical stability of the nanotube structure, which provides electrically conductive pathways through the anode. Silicon anodes were fabricated with the monoliths by low pressure chemical vapor infiltration of silicon. This platform allows the carbon and silicon volume fractions to be independently varied in the anode. Anodes with a low silicon content (less than 5% by volume) showed high stability in cycling against lithium with a capacity retention of 89.7% between cycles 2 and 185. Anodes with a high silicon content (∼25% by volume) showed poor capacity retention when the carbon content was low (<40% by volume), and transmission electron microscopy analysis indicated that the anodes failed due to the destruction of the nanocrystalline carbon coating during cycling. However, by increasing the carbon content to ∼60% volume percent in the monolith, capacity retention was substantially stabilized even for anodes with very high silicon loadings. These stabilized electrodes exhibited volumetric capacities as high as ∼1000 mA h/ml and retained over 725 mA h/ml by cycle 100. © 2017 American Vacuum Society.
1916 a57189351639 Fan J. p725 False Journal 354 Carbon monolith scaffolding for high volumetric capacity silicon Li-ion battery anodes A nanoporous carbon monolith structure has been developed for use as a scaffold for silicon anodes for lithium batteries. This scaffold was fabricated by coating vertically aligned carbon nanotubes in a highly conformal coating of nanocrystalline carbon, applied via atmospheric pressure chemical vapor deposition. The coating increases the mechanical stability of the nanotube structure, which provides electrically conductive pathways through the anode. Silicon anodes were fabricated with the monoliths by low pressure chemical vapor infiltration of silicon. This platform allows the carbon and silicon volume fractions to be independently varied in the anode. Anodes with a low silicon content (less than 5% by volume) showed high stability in cycling against lithium with a capacity retention of 89.7% between cycles 2 and 185. Anodes with a high silicon content (∼25% by volume) showed poor capacity retention when the carbon content was low (<40% by volume), and transmission electron microscopy analysis indicated that the anodes failed due to the destruction of the nanocrystalline carbon coating during cycling. However, by increasing the carbon content to ∼60% volume percent in the monolith, capacity retention was substantially stabilized even for anodes with very high silicon loadings. These stabilized electrodes exhibited volumetric capacities as high as ∼1000 mA h/ml and retained over 725 mA h/ml by cycle 100. © 2017 American Vacuum Society.
1917 a57194697486 Laughlin K. p725 False Journal 354 Carbon monolith scaffolding for high volumetric capacity silicon Li-ion battery anodes A nanoporous carbon monolith structure has been developed for use as a scaffold for silicon anodes for lithium batteries. This scaffold was fabricated by coating vertically aligned carbon nanotubes in a highly conformal coating of nanocrystalline carbon, applied via atmospheric pressure chemical vapor deposition. The coating increases the mechanical stability of the nanotube structure, which provides electrically conductive pathways through the anode. Silicon anodes were fabricated with the monoliths by low pressure chemical vapor infiltration of silicon. This platform allows the carbon and silicon volume fractions to be independently varied in the anode. Anodes with a low silicon content (less than 5% by volume) showed high stability in cycling against lithium with a capacity retention of 89.7% between cycles 2 and 185. Anodes with a high silicon content (∼25% by volume) showed poor capacity retention when the carbon content was low (<40% by volume), and transmission electron microscopy analysis indicated that the anodes failed due to the destruction of the nanocrystalline carbon coating during cycling. However, by increasing the carbon content to ∼60% volume percent in the monolith, capacity retention was substantially stabilized even for anodes with very high silicon loadings. These stabilized electrodes exhibited volumetric capacities as high as ∼1000 mA h/ml and retained over 725 mA h/ml by cycle 100. © 2017 American Vacuum Society.
1918 a57194141209 Danforth E.M. p726 True Journal 355 Strategies employed and lessons learned by commercial construction companies during economic recession and recovery The purpose of this research was to identify strategies used and lessons learned by western U.S. commercial construction companies during the great recession (2007-2009). The experience gained by companies who weather an economic downturn must be absorbed into the corporate structure in a meaningful way if that knowledge is to be accessible for future recessions. This study focused on identifying and better understanding the specific approaches that commercial construction companies employed to weather the great recession and the corresponding lessons learned. A stratified purposeful sampling survey was conducted across 15 different commercial construction companies and included 57 participants in various management roles. This paper provides a comprehensive list of 124 different strategies or lessons learned across six principal categories: (1) contracting, (2) risk management, (3) cost-control, (4) human resources, (5) financial, and (6) investment related responses. This paper also provides recommendations for commercial construction companies to consider during various economic cycles on the basis of the lessons learned during this recession and recovery. © 2017 American Society of Civil Engineers.
1919 a55376424100 Suvorov A. p727 False Conference 308 Whole genome phylogenetic tree reconstruction using colored de bruijn graphs We present kleuren, a novel assembly-free method to reconstruct phylogenetic trees using the Colored de Bruijn Graph. kleuren works by constructing the Colored de Bruijn Graph and then traversing it, finding bubble structures in the graph that provide phylogenetic signal. The bubbles are then aligned and concatenated to form a supermatrix, from which a phylogenetic tree is inferred. We introduce the algorithms that kleuren uses to accomplish this task, and show its performance on reconstructing the phylogenetic tree of 12 Drosophila species. kleuren reconstructed the established phylogenetic tree accurately, and is a viable tool for phylogenetic tree reconstruction using whole genome sequences. Software package available at: https://github.com/Colelyman/kleuren. © 2017 IEEE.
1919 a55376424100 Suvorov A. p728 False Conference 309 Genome polymorphism detection through relaxed de bruijn graph construction Comparing genomes to identify polymorphisms is a difficult task, especially beyond single nucleotide poly-morphisms. Polymorphism detection is important in disease association studies as well as in phylogenetic tree reconstruc-tion. We present a method for identifying polymorphisms in genomes by using a modified version de Bruijn graphs, data structures widely used in genome assembly from Next-Generation Sequencing. Using our method, we are able to identify polymorphisms that exist within a genome as well as well as see graph structures that form in the de Bruijn graph for particular types of polymorphisms (translocations, etc.) © 2017 IEEE.
1920 a7006440923 Crandall K.A. p727 False Conference 308 Whole genome phylogenetic tree reconstruction using colored de bruijn graphs We present kleuren, a novel assembly-free method to reconstruct phylogenetic trees using the Colored de Bruijn Graph. kleuren works by constructing the Colored de Bruijn Graph and then traversing it, finding bubble structures in the graph that provide phylogenetic signal. The bubbles are then aligned and concatenated to form a supermatrix, from which a phylogenetic tree is inferred. We introduce the algorithms that kleuren uses to accomplish this task, and show its performance on reconstructing the phylogenetic tree of 12 Drosophila species. kleuren reconstructed the established phylogenetic tree accurately, and is a viable tool for phylogenetic tree reconstruction using whole genome sequences. Software package available at: https://github.com/Colelyman/kleuren. © 2017 IEEE.
1920 a7006440923 Crandall K.A. p728 False Conference 309 Genome polymorphism detection through relaxed de bruijn graph construction Comparing genomes to identify polymorphisms is a difficult task, especially beyond single nucleotide poly-morphisms. Polymorphism detection is important in disease association studies as well as in phylogenetic tree reconstruc-tion. We present a method for identifying polymorphisms in genomes by using a modified version de Bruijn graphs, data structures widely used in genome assembly from Next-Generation Sequencing. Using our method, we are able to identify polymorphisms that exist within a genome as well as well as see graph structures that form in the de Bruijn graph for particular types of polymorphisms (translocations, etc.) © 2017 IEEE.
1921 a14057706900 Bybee S.M. p727 False Conference 308 Whole genome phylogenetic tree reconstruction using colored de bruijn graphs We present kleuren, a novel assembly-free method to reconstruct phylogenetic trees using the Colored de Bruijn Graph. kleuren works by constructing the Colored de Bruijn Graph and then traversing it, finding bubble structures in the graph that provide phylogenetic signal. The bubbles are then aligned and concatenated to form a supermatrix, from which a phylogenetic tree is inferred. We introduce the algorithms that kleuren uses to accomplish this task, and show its performance on reconstructing the phylogenetic tree of 12 Drosophila species. kleuren reconstructed the established phylogenetic tree accurately, and is a viable tool for phylogenetic tree reconstruction using whole genome sequences. Software package available at: https://github.com/Colelyman/kleuren. © 2017 IEEE.
1921 a14057706900 Bybee S.M. p728 False Conference 309 Genome polymorphism detection through relaxed de bruijn graph construction Comparing genomes to identify polymorphisms is a difficult task, especially beyond single nucleotide poly-morphisms. Polymorphism detection is important in disease association studies as well as in phylogenetic tree reconstruc-tion. We present a method for identifying polymorphisms in genomes by using a modified version de Bruijn graphs, data structures widely used in genome assembly from Next-Generation Sequencing. Using our method, we are able to identify polymorphisms that exist within a genome as well as well as see graph structures that form in the de Bruijn graph for particular types of polymorphisms (translocations, etc.) © 2017 IEEE.
1922 a57195317234 Hurst W. p729 True Conference 310 Cooperation induction in two player bertand markets with linear demand We present a two player gradient play differential game in a producer market with quadratic payoff as a model of behavior in a competitive environment and show that the Nash equilibrium is not efficient. An algorithm is then presented which uses side payments to induce cooperation between firms, and rules for side payment strategies are shown. The stability of the new system at a reasonable equilibrium is proved, and it is shown that all participants are at least as well off as they would be at the non-cooperative equilibrium. Numerical examples show the existence of a reasonable equilibrium and that the basin of attraction of that equilibrium appears to cover all reasonable initial conditions. © 2017 American Automatic Control Council (AACC).
1923 a7102534973 Parkinson A.R. p730 True Conference 311 Student perceptions and attitudes towards a required vs. An optional course in leadership For almost ten years, the majority of students in the College of Engineering and Technology at Brigham Young University have been required to take a sophomore level leadership foundations course focused on leadership principles, ethics, and global issues. The course is part of an overall leadership framework whereby students are introduced to the importance of leadership as freshmen, learn foundational leadership principles as sophomores, and practice these principles as juniors and seniors. The leadership foundations course is required for graduation by 7 of 10 programs within the College of Engineering and Technology. Students external to the college also participate in the course as it fulfills two general education requirements for graduation. As a result, the college teaches approximately 12 sections each academic year averaging 60-80 students per section. Approximately 10-15% of student course participants are external to the college. In this paper a survey is presented of 163 students initially enrolled in the leadership foundations course regarding their perceptions and attitudes towards leadership. Results include a comparison of students who are required to take the course and those for whom it is optional. No statistically significant difference was observed between the two groups of students except for their expectation regarding workload. The engineering and technology students expected the leadership foundations course to be easier, relative to their other classes, than the nonengineering and technology group. In general, both sets of students had high expectations for the course and expressed positive attitudes towards learning about leadership. For example, students in both groups indicated they felt learning about leadership was somewhat more important than learning the skills of their discipline. © American Society for Engineering Education, 2017.
1924 a57195962821 Patrick B. p733 True Conference 314 Cross platform usability: Evaluating computing tasks performed on multiple platforms Evaluating the usability of software across various computing hardware, including desktop computers, laptops, tablets, and smartphones, is becoming increasingly important as our need to complete computing tasks on various computing platforms becomes more commonplace in our daily lives. This shift in computing expectations focuses on the ability to compute horizontally, performing the same tasks within different computing environments, as opposed to vertically, performing different tasks in the same computing environment. In this paper, we propose a method by which the usability of a given piece of software can be comparatively analyzed across all hardware platforms on which it is available. This methodology is based on the Majrashi and Hamilton's twelve factors of usability and has been extended to include specific applications and metrics for the following computing platforms: desktop computers, laptops, tablets, smartphones. These metrics focus on collecting quantitative data about the usability of each platform. This quantitative data contrasts with recent studies which focus extensively on qualitative data regarding the user experience. Combining these two types of studies will allow researchers to capture a more comprehensive picture of software usability across computing platforms. The methodology has been validated by performing an initial study using the tasks and performance metrics across each of the defined computing platforms. The results from these initial tests have allowed us to make improvements to the testing methodology as well as some hypotheses for further testing. This proposed methodology, when used in conjunction with qualitative research, can provide a reliable approach for cross-platform usability analysis. Some considerations for educational design of cross platform methodology are discussed. © American Society for Engineering Education, 2017.
1925 a6507659000 Helps R.G. p733 False Conference 314 Cross platform usability: Evaluating computing tasks performed on multiple platforms Evaluating the usability of software across various computing hardware, including desktop computers, laptops, tablets, and smartphones, is becoming increasingly important as our need to complete computing tasks on various computing platforms becomes more commonplace in our daily lives. This shift in computing expectations focuses on the ability to compute horizontally, performing the same tasks within different computing environments, as opposed to vertically, performing different tasks in the same computing environment. In this paper, we propose a method by which the usability of a given piece of software can be comparatively analyzed across all hardware platforms on which it is available. This methodology is based on the Majrashi and Hamilton's twelve factors of usability and has been extended to include specific applications and metrics for the following computing platforms: desktop computers, laptops, tablets, smartphones. These metrics focus on collecting quantitative data about the usability of each platform. This quantitative data contrasts with recent studies which focus extensively on qualitative data regarding the user experience. Combining these two types of studies will allow researchers to capture a more comprehensive picture of software usability across computing platforms. The methodology has been validated by performing an initial study using the tasks and performance metrics across each of the defined computing platforms. The results from these initial tests have allowed us to make improvements to the testing methodology as well as some hypotheses for further testing. This proposed methodology, when used in conjunction with qualitative research, can provide a reliable approach for cross-platform usability analysis. Some considerations for educational design of cross platform methodology are discussed. © American Society for Engineering Education, 2017.
1926 a57195962037 Sutton M. p734 False Conference 315 Sustainable water filters in southern Peru [No abstract available]
1927 a57195964820 Hasler E. p734 False Conference 315 Sustainable water filters in southern Peru [No abstract available]
1928 a57195961036 Williams J.L. p734 False Conference 315 Sustainable water filters in southern Peru [No abstract available]
1929 a57195964763 Irvin J.J. p734 False Conference 315 Sustainable water filters in southern Peru [No abstract available]
1930 a57195961251 Hirt J.R. p734 False Conference 315 Sustainable water filters in southern Peru [No abstract available]
1931 a55672496100 Ziegenfuss D.H. p737 False Conference 318 A model workshop for helping new faculty engage students in the STEM Classroom In May 2016 a workshop entitled "Engaging Students in the STEM Classroom" was presented to faculty at Southern Utah University. Although not exclusive to new faculty, the target audience and predominant attendees, were new faculty from the science, technology, engineering, and math (STEM) disciplines on campus. The three-day workshop focused on basic principles of effective learning and teaching, aligning learning outcomes to assessments and teaching activities, methods for active learning, and strategies for effective classroom presentation. The workshop curriculum was centered around the following goals: 1) promoting broader awareness of alternative teaching strategies for STEM classrooms, 2) increasing faculty comfort level in using alternative teaching strategies, 3) increasing adoption of active learning and other evidence-based pedagogies, 4) building a campus community dedicated to improving teaching, and 5) increasing multi-disciplinary collaborations amongst faculty attendees. The purpose of this paper is to provide an example of a model workshop designed to help new faculty engage students in STEM disciplines, and includes the planning, implementation, and assessment of this workshop. The paper begins by introducing the development of the workshop, including the logic model and assessment plan, the curriculum outline, and preparation processes. The paper also explores the implementation lessons learned. Finally, this paper includes the assessment results of the effectiveness of the workshop in meeting the workshop goals. This includes a preand post-workshop comparison of the participant's attitudes regarding evidence based pedagogies and their perceived competency in using them. This paper is useful for engineering educators in developing teaching expertise, researchers interested in faculty attitudes and perceived competency in using alternate teaching strategies, and faculty and administrators planning to create professional development opportunities to help faculty of all levels become more proficient in evidence-based pedagogies. This paper also serves as an example of a model workshop to develop interdisciplinary communities of educational practice, as well as strengthen the abilities of a new faculty in establishing an engaging and effective classroom. © American Society for Engineering Education, 2017.
1932 a35413539100 Roberts M.W. p737 False Conference 318 A model workshop for helping new faculty engage students in the STEM Classroom In May 2016 a workshop entitled "Engaging Students in the STEM Classroom" was presented to faculty at Southern Utah University. Although not exclusive to new faculty, the target audience and predominant attendees, were new faculty from the science, technology, engineering, and math (STEM) disciplines on campus. The three-day workshop focused on basic principles of effective learning and teaching, aligning learning outcomes to assessments and teaching activities, methods for active learning, and strategies for effective classroom presentation. The workshop curriculum was centered around the following goals: 1) promoting broader awareness of alternative teaching strategies for STEM classrooms, 2) increasing faculty comfort level in using alternative teaching strategies, 3) increasing adoption of active learning and other evidence-based pedagogies, 4) building a campus community dedicated to improving teaching, and 5) increasing multi-disciplinary collaborations amongst faculty attendees. The purpose of this paper is to provide an example of a model workshop designed to help new faculty engage students in STEM disciplines, and includes the planning, implementation, and assessment of this workshop. The paper begins by introducing the development of the workshop, including the logic model and assessment plan, the curriculum outline, and preparation processes. The paper also explores the implementation lessons learned. Finally, this paper includes the assessment results of the effectiveness of the workshop in meeting the workshop goals. This includes a preand post-workshop comparison of the participant's attitudes regarding evidence based pedagogies and their perceived competency in using them. This paper is useful for engineering educators in developing teaching expertise, researchers interested in faculty attitudes and perceived competency in using alternate teaching strategies, and faculty and administrators planning to create professional development opportunities to help faculty of all levels become more proficient in evidence-based pedagogies. This paper also serves as an example of a model workshop to develop interdisciplinary communities of educational practice, as well as strengthen the abilities of a new faculty in establishing an engaging and effective classroom. © American Society for Engineering Education, 2017.
1933 a57190806425 Fuentes D.S. p738 False Conference 319 Investigating engineering students' understandings of social and ethical responsibility: Coding framework and initial findings [No abstract available]
1934 a36536647200 Claussen S. p738 False Conference 319 Investigating engineering students' understandings of social and ethical responsibility: Coding framework and initial findings [No abstract available]
1935 a57198919773 Martínez A. p739 True Journal 356 Analytical fragility curves for non-skewed highway bridges in Chile Recent earthquakes in Chile and worldwide have caused significant economic losses due to the damage on the road bridge network. To conduct seismic risk assessment studies and to improve resilience of bridges, seismic vulnerability studies are required. The main objective of this study is to construct fragility curves of typical non-skewed highway bridges in Chile. The fragility curves are obtained from an incremental dynamic analysis of a two-dimensional model of the bent cap of a two-span simply supported underpass. As most bridges are constructed with seismic tie-down bars, their constitutive behavior was obtained experimentally. A total of five seismic bar specimens were tested to characterize their cyclic behavior in bridges with and without transverse diaphragms. The incremental dynamic analysis was performed with the two horizontal components of seven seismic records obtained from the Mw 8.8, 2010 Chile earthquake. Additionally, a parametric study is conducted to assess the seismic behavior of bridges with different configurations of seismic bars, with lateral stoppers, and with varying length of the transverse seat width. Results from this study reveal that seismic bars have a limited contribution to the seismic performance of the studied bridge, especially when lateral stoppers are incorporated. Additionally, the transverse seat width is found to be critical to reduce the collapse probability of the superstructure. The provided fragility curves may be used for seismic risk assessment and to evaluate possible improvements in seismic bridge design codes. © 2017 Elsevier Ltd
1936 a54787829800 Hube M.A. p739 False Journal 356 Analytical fragility curves for non-skewed highway bridges in Chile Recent earthquakes in Chile and worldwide have caused significant economic losses due to the damage on the road bridge network. To conduct seismic risk assessment studies and to improve resilience of bridges, seismic vulnerability studies are required. The main objective of this study is to construct fragility curves of typical non-skewed highway bridges in Chile. The fragility curves are obtained from an incremental dynamic analysis of a two-dimensional model of the bent cap of a two-span simply supported underpass. As most bridges are constructed with seismic tie-down bars, their constitutive behavior was obtained experimentally. A total of five seismic bar specimens were tested to characterize their cyclic behavior in bridges with and without transverse diaphragms. The incremental dynamic analysis was performed with the two horizontal components of seven seismic records obtained from the Mw 8.8, 2010 Chile earthquake. Additionally, a parametric study is conducted to assess the seismic behavior of bridges with different configurations of seismic bars, with lateral stoppers, and with varying length of the transverse seat width. Results from this study reveal that seismic bars have a limited contribution to the seismic performance of the studied bridge, especially when lateral stoppers are incorporated. Additionally, the transverse seat width is found to be critical to reduce the collapse probability of the superstructure. The provided fragility curves may be used for seismic risk assessment and to evaluate possible improvements in seismic bridge design codes. © 2017 Elsevier Ltd
1937 a56672834700 Staves D.R. p741 True Journal 352 Associative CAD references in the neutral parametric canonical form Due to the multiplicity of computer-aided engineering applications used in industry, interoperability between programs has become increasingly important. A 1999 study by the National Institute for Standards and Technology (NIST) estimated that inadequate interoperability between the original engineering manufacturers (OEM) and their suppliers cost the US automotive industry over $1 billion per year, with the majority spent fixing data after translations. The Neutral Parametric Canonical Form (NPCF) prototype standard developed by the BYU Site of the NSF Center for e-Design offers a solution to this problem by enabling real-time collaboration between heterogeneous systems while preserving design intent. The NPCF is implemented within a SQL database and defines the schema both for neutral features and for the parameters defining the inter-feature relationships and associations. © 2016 CAD Solutions, LLC.
1938 a6603625990 Red W.E. p741 False Journal 352 Associative CAD references in the neutral parametric canonical form Due to the multiplicity of computer-aided engineering applications used in industry, interoperability between programs has become increasingly important. A 1999 study by the National Institute for Standards and Technology (NIST) estimated that inadequate interoperability between the original engineering manufacturers (OEM) and their suppliers cost the US automotive industry over $1 billion per year, with the majority spent fixing data after translations. The Neutral Parametric Canonical Form (NPCF) prototype standard developed by the BYU Site of the NSF Center for e-Design offers a solution to this problem by enabling real-time collaboration between heterogeneous systems while preserving design intent. The NPCF is implemented within a SQL database and defines the schema both for neutral features and for the parameters defining the inter-feature relationships and associations. © 2016 CAD Solutions, LLC.
1939 a57193008289 Zhang W. p742 True Journal 357 Design of low-power ultra-high voltage gain differential cascode stages The conventional cascode circuit has long been used as the basis for the differential input stage to an op amp. The voltage gain of this stage can be maximised by operating the MOS devices in the moderate inversion region rather than the strong inversion region. In so doing, the voltage gains of the differential stage can reach values of over 120 dB and the power dissipation is minimised due to the low currents required. Harmonic distortion is also minimised by moderate inversion operation. Although the composite cascode or self-cascode has been successfully used as an op-amp differential stage, the conventional cascode differential circuit offers additional advantages and is compared to the composite cascode differential circuit in this work. A design procedure is also reported in this work for low-power, high voltage gain differential stages. © 2017 Informa UK Limited, trading as Taylor & Francis Group.
1940 a57192816311 Renouard J. p743 False Journal 358 Village Drill: A Case Study in Engineering for Global Development with Five Years of Data Post Market-Introduction This paper presents a case study in engineering for global development. It introduces the Village Drill, which is an engineered product that has - 5 years after its introduction to the market - enabled hundreds of thousands of people across 15 countries and three continents to have access to clean water. The Village Drill creates a 15 cm (6 in) borehole as deep as 76 m (250 ft) to reach groundwater suitable for drinking. The case study presents facts for the actual development and sustaining and are unaltered for the purpose of publication. This approach provides the reader with a realistic view of the development time, testing conditions, fundraising, and the work needed to sustain the drill through 5 years of sales and distribution. The purpose of the case study is to provide sufficient and frank data about a real project so as to promote discussion, critique, and other evaluations that will lead to new developments that inspire and inform successful engineering for global development. As part of the case, the paper describes six fundamental items: the product, the customer, the impact, the manufacturing, the delivery, and the revenue model of the drill. Copyright © 2017 by ASME.
1941 a55550262000 Wang N. p744 True Journal 359 Simulation-based coefficients for adjusting climate impact on energy consumption of commercial buildings This paper presents a new technique for and the results of normalizing building energy consumption to enable a fair comparison among various types of buildings located near different weather stations across the United States. The method was developed for the U.S. Building Energy Asset Score, a whole-building energy efficiency rating system focusing on building envelope, mechanical systems, and lighting systems. The Asset Score is based on simulated energy use under standard operating conditions. Existing weather normalization methods such as those based on heating and cooling degrees days are not robust enough to adjust all climatic factors such as humidity and solar radiation. In this work, over 1000 sets of climate coefficients were developed to separately adjust building heating, cooling, and fan energy use at each weather station in the United States. This paper also presents a robust, standardized weather station mapping based on climate similarity rather than choosing the closest weather station. This proposed simulated-based climate adjustment was validated through testing on several hundreds of thousands of modeled buildings. Results indicated the developed climate coefficients can adjust the climate variations to enable a fair comparison of building energy efficiency. © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.
1942 a36167063600 Makhmalbaf A. p744 False Journal 359 Simulation-based coefficients for adjusting climate impact on energy consumption of commercial buildings This paper presents a new technique for and the results of normalizing building energy consumption to enable a fair comparison among various types of buildings located near different weather stations across the United States. The method was developed for the U.S. Building Energy Asset Score, a whole-building energy efficiency rating system focusing on building envelope, mechanical systems, and lighting systems. The Asset Score is based on simulated energy use under standard operating conditions. Existing weather normalization methods such as those based on heating and cooling degrees days are not robust enough to adjust all climatic factors such as humidity and solar radiation. In this work, over 1000 sets of climate coefficients were developed to separately adjust building heating, cooling, and fan energy use at each weather station in the United States. This paper also presents a robust, standardized weather station mapping based on climate similarity rather than choosing the closest weather station. This proposed simulated-based climate adjustment was validated through testing on several hundreds of thousands of modeled buildings. Results indicated the developed climate coefficients can adjust the climate variations to enable a fair comparison of building energy efficiency. © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.
1943 a55550264900 Srivastava V. p744 False Journal 359 Simulation-based coefficients for adjusting climate impact on energy consumption of commercial buildings This paper presents a new technique for and the results of normalizing building energy consumption to enable a fair comparison among various types of buildings located near different weather stations across the United States. The method was developed for the U.S. Building Energy Asset Score, a whole-building energy efficiency rating system focusing on building envelope, mechanical systems, and lighting systems. The Asset Score is based on simulated energy use under standard operating conditions. Existing weather normalization methods such as those based on heating and cooling degrees days are not robust enough to adjust all climatic factors such as humidity and solar radiation. In this work, over 1000 sets of climate coefficients were developed to separately adjust building heating, cooling, and fan energy use at each weather station in the United States. This paper also presents a robust, standardized weather station mapping based on climate similarity rather than choosing the closest weather station. This proposed simulated-based climate adjustment was validated through testing on several hundreds of thousands of modeled buildings. Results indicated the developed climate coefficients can adjust the climate variations to enable a fair comparison of building energy efficiency. © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.
1944 a7006420570 Hathaway J.E. p744 False Journal 359 Simulation-based coefficients for adjusting climate impact on energy consumption of commercial buildings This paper presents a new technique for and the results of normalizing building energy consumption to enable a fair comparison among various types of buildings located near different weather stations across the United States. The method was developed for the U.S. Building Energy Asset Score, a whole-building energy efficiency rating system focusing on building envelope, mechanical systems, and lighting systems. The Asset Score is based on simulated energy use under standard operating conditions. Existing weather normalization methods such as those based on heating and cooling degrees days are not robust enough to adjust all climatic factors such as humidity and solar radiation. In this work, over 1000 sets of climate coefficients were developed to separately adjust building heating, cooling, and fan energy use at each weather station in the United States. This paper also presents a robust, standardized weather station mapping based on climate similarity rather than choosing the closest weather station. This proposed simulated-based climate adjustment was validated through testing on several hundreds of thousands of modeled buildings. Results indicated the developed climate coefficients can adjust the climate variations to enable a fair comparison of building energy efficiency. © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.
1945 a57192156100 Lorenzo G. p745 True Journal 360 Hierarchically refined and coarsened splines for moving interface problems, with particular application to phase-field models of prostate tumor growth Moving interface problems are ubiquitous in science and engineering. To develop an accurate and efficient methodology for this class of problems, we present algorithms for local h-adaptivity of hierarchical B-splines to be utilized in isogeometric analysis. We extend Bézier projection, an efficient quadrature-free local projection technique, to the hierarchical setting. In this case, extraction operators may not be invertible. To address this issue we develop a multi-level reconstruction operator which maintains the locality properties of the projection. We also introduce a balance parameter to control the overlap of hierarchical functions leading to improved numerical conditioning. We apply our algorithms to the simulation of localized prostate cancer growth. We model this disease using the phase-field method and a set of diffusion–reaction equations to account for the dynamics of nutrients and a key biomarker termed Prostate Specific Antigen. Our results include examples on simple 2D and 3D domains and a more compelling tissue-scale, patient-specific simulation, which is run over a prostate anatomy extracted from medical images. Our methods for local h-adaptivity efficiently capture the evolving interface between the tumor and the neighboring healthy tissue with remarkable accuracy in all cases. © 2017 Elsevier B.V.
1946 a36675881600 Tew K. p745 False Journal 360 Hierarchically refined and coarsened splines for moving interface problems, with particular application to phase-field models of prostate tumor growth Moving interface problems are ubiquitous in science and engineering. To develop an accurate and efficient methodology for this class of problems, we present algorithms for local h-adaptivity of hierarchical B-splines to be utilized in isogeometric analysis. We extend Bézier projection, an efficient quadrature-free local projection technique, to the hierarchical setting. In this case, extraction operators may not be invertible. To address this issue we develop a multi-level reconstruction operator which maintains the locality properties of the projection. We also introduce a balance parameter to control the overlap of hierarchical functions leading to improved numerical conditioning. We apply our algorithms to the simulation of localized prostate cancer growth. We model this disease using the phase-field method and a set of diffusion–reaction equations to account for the dynamics of nutrients and a key biomarker termed Prostate Specific Antigen. Our results include examples on simple 2D and 3D domains and a more compelling tissue-scale, patient-specific simulation, which is run over a prostate anatomy extracted from medical images. Our methods for local h-adaptivity efficiently capture the evolving interface between the tumor and the neighboring healthy tissue with remarkable accuracy in all cases. © 2017 Elsevier B.V.
1947 a35366248300 Gomez H. p745 False Journal 360 Hierarchically refined and coarsened splines for moving interface problems, with particular application to phase-field models of prostate tumor growth Moving interface problems are ubiquitous in science and engineering. To develop an accurate and efficient methodology for this class of problems, we present algorithms for local h-adaptivity of hierarchical B-splines to be utilized in isogeometric analysis. We extend Bézier projection, an efficient quadrature-free local projection technique, to the hierarchical setting. In this case, extraction operators may not be invertible. To address this issue we develop a multi-level reconstruction operator which maintains the locality properties of the projection. We also introduce a balance parameter to control the overlap of hierarchical functions leading to improved numerical conditioning. We apply our algorithms to the simulation of localized prostate cancer growth. We model this disease using the phase-field method and a set of diffusion–reaction equations to account for the dynamics of nutrients and a key biomarker termed Prostate Specific Antigen. Our results include examples on simple 2D and 3D domains and a more compelling tissue-scale, patient-specific simulation, which is run over a prostate anatomy extracted from medical images. Our methods for local h-adaptivity efficiently capture the evolving interface between the tumor and the neighboring healthy tissue with remarkable accuracy in all cases. © 2017 Elsevier B.V.
1948 a57193845336 Kleinbaum S. p746 False Journal 361 Enabling Dissimilar Material Joining Using Friction Stir Scribe Technology One challenge in adapting welding processes to dissimilar material joining is the diversity of melting temperatures of the different materials. Although the use of mechanical fasteners and adhesives have mostly paved the way for near-term implementation of dissimilar material systems, these processes only accentuate the need for low-cost welding processes capable of impartially joining dissimilar material components regardless of alloy, properties, or melting temperature. Friction stir scribe technology was developed to overcome the challenges of joining dissimilar material components where melting temperatures vary greatly, and properties and/or chemistry are not compatible with more traditional welding processes. Although the friction stir scribe process is capable of joining dissimilar metals and metal/polymer systems, a more detailed evaluation of several aluminum/steel joints is presented herein to demonstrate the ability to both chemically and mechanically join dissimilar materials. © 2017, The Minerals, Metals & Materials Society.
1949 a57193533805 Boettcher E. p746 False Journal 361 Enabling Dissimilar Material Joining Using Friction Stir Scribe Technology One challenge in adapting welding processes to dissimilar material joining is the diversity of melting temperatures of the different materials. Although the use of mechanical fasteners and adhesives have mostly paved the way for near-term implementation of dissimilar material systems, these processes only accentuate the need for low-cost welding processes capable of impartially joining dissimilar material components regardless of alloy, properties, or melting temperature. Friction stir scribe technology was developed to overcome the challenges of joining dissimilar material components where melting temperatures vary greatly, and properties and/or chemistry are not compatible with more traditional welding processes. Although the friction stir scribe process is capable of joining dissimilar metals and metal/polymer systems, a more detailed evaluation of several aluminum/steel joints is presented herein to demonstrate the ability to both chemically and mechanically join dissimilar materials. © 2017, The Minerals, Metals & Materials Society.
1949 a57193533805 Boettcher E. p887 False Journal 412 Joining Dissimilar Material Using Friction Stir Scribe Technique The ability to effectively join materials with vastly different melting points, like aluminum to steel, and polymer composites to metals, has been one of the roadblocks to realizing multi-material components for lightweighting efforts. The friction stir scribe (FSS) technique is a promising method that produces continuous overlap joints between materials with vastly different melting regimes and high-temperature flow characteristics. FSS uses an offset cutting tool at the tip of the friction stir welding pin to create an in situ mechanical interlock between material interfaces. With investments from the U.S. Department of Energy Vehicle Technologies Office and several automotive manufacturers and suppliers, Pacific Northwest National Laboratory is developing the FSS process and has demonstrated the viability of joining several material combinations. Details of welding trials, unique challenges, and mitigation strategies in different material combinations will be discussed. Joint characterization, including mechanical tests and joint performance, will also be presented. © 2017, The Minerals, Metals & Materials Society.
1950 a23983490300 Ruokolainen R. p746 False Journal 361 Enabling Dissimilar Material Joining Using Friction Stir Scribe Technology One challenge in adapting welding processes to dissimilar material joining is the diversity of melting temperatures of the different materials. Although the use of mechanical fasteners and adhesives have mostly paved the way for near-term implementation of dissimilar material systems, these processes only accentuate the need for low-cost welding processes capable of impartially joining dissimilar material components regardless of alloy, properties, or melting temperature. Friction stir scribe technology was developed to overcome the challenges of joining dissimilar material components where melting temperatures vary greatly, and properties and/or chemistry are not compatible with more traditional welding processes. Although the friction stir scribe process is capable of joining dissimilar metals and metal/polymer systems, a more detailed evaluation of several aluminum/steel joints is presented herein to demonstrate the ability to both chemically and mechanically join dissimilar materials. © 2017, The Minerals, Metals & Materials Society.
1950 a23983490300 Ruokolainen R. p887 False Journal 412 Joining Dissimilar Material Using Friction Stir Scribe Technique The ability to effectively join materials with vastly different melting points, like aluminum to steel, and polymer composites to metals, has been one of the roadblocks to realizing multi-material components for lightweighting efforts. The friction stir scribe (FSS) technique is a promising method that produces continuous overlap joints between materials with vastly different melting regimes and high-temperature flow characteristics. FSS uses an offset cutting tool at the tip of the friction stir welding pin to create an in situ mechanical interlock between material interfaces. With investments from the U.S. Department of Energy Vehicle Technologies Office and several automotive manufacturers and suppliers, Pacific Northwest National Laboratory is developing the FSS process and has demonstrated the viability of joining several material combinations. Details of welding trials, unique challenges, and mitigation strategies in different material combinations will be discussed. Joint characterization, including mechanical tests and joint performance, will also be presented. © 2017, The Minerals, Metals & Materials Society.
1951 a26323686000 Lee M.-G. p748 False Journal 362 An RVE procedure for micromechanical prediction of mechanical behavior of dual-phase steel A “bottom-up” representative volume element (RVE) for a dual phase steel was constructed based on measured microstructural properties (“microproperties”). This differs from the common procedure of inferring hypothetical microproperties by fitting to macroscopic behavior using an assumed micro-to-macrolaw. The bottom-up approach allows the assessment of the law itself by comparing RVE-predicted mechanical behavior with independent macroscopic measurements, thus revealing the nature of the controlling micromechanisms. An RVE for DP980 steel was constructed using actual microproperties. Finite element (FE) simulations of elastic-plastic transitions were compared with independent loading-unloading-loading and compression-tension experiments. Constitutive models of three types were utilized: 1) a standard continuum model, 2) a standard Crystal Plasticity (CP) model, and 3) a SuperDislocation (SD) model similar to CP but including the elastic interactions of discrete dislocations. These comparisons led to following conclusions: 1) While a constitutive model that ignores elastic interaction of defects can be fit to macroscopic or microscopic behavior, it cannot represent both accurately, 2) Elastic interactions among dislocations are the predominant source of nonlinearity in the nominally-elastic region (i.e. at stresses below the standard yield stress), and 3) Continuum stress inhomogeneity arising from the hard martensite / soft ferrite microstructure has a minor role in the observed transitional nonlinearity in the absence of discrete dislocation interactions. © 2017 Elsevier B.V.
1952 a57194162490 Hammon S. p749 False Journal 363 Mitigating Water Absorption in Waveguides Made from Unannealed PECVD SiO2 Water absorption was studied in two types of waveguides made from unannealed plasma enhanced chemical vapor deposition (PECVD) SiO2. Standard rib anti-resonant reflecting optical waveguides (ARROWs) were fabricated with thin films of different intrinsic stress and indices of refraction. Buried ARROWs (bARROWs) with low and high refractive index differences between the core and cladding regions were also fabricated from the same types of PECVD films. All waveguides were subjected to a heated, high humidity environment and their optical throughput was tested over time. Due to water absorption in the SiO2 films, the optical throughput of all of the ARROWs decreased with time spent in the wet environment. The ARROWs with the lowest stress SiO2 had the slowest rate of throughput change. High index difference bARROWs showed no decrease in optical throughput after 40 days in the wet environment and are presented as a solution for environmentally stable waveguides made from unannealed PECVD SiO2. © 2017 IEEE.
1952 a57194162490 Hammon S. p839 True Conference 366 Preserving optical confinement in unannealed PECVD SiO2 waveguides Rib and buried channel waveguides (BCWs) made of unannealed PECVD SiO2 were studied after exposure to high humidity. Low stressed rib waveguides had lower optical throughput change, while high index difference BCWs were practically unaffected. © 2017 OSA.
1953 a57194158491 Zacheu G. p749 False Journal 363 Mitigating Water Absorption in Waveguides Made from Unannealed PECVD SiO2 Water absorption was studied in two types of waveguides made from unannealed plasma enhanced chemical vapor deposition (PECVD) SiO2. Standard rib anti-resonant reflecting optical waveguides (ARROWs) were fabricated with thin films of different intrinsic stress and indices of refraction. Buried ARROWs (bARROWs) with low and high refractive index differences between the core and cladding regions were also fabricated from the same types of PECVD films. All waveguides were subjected to a heated, high humidity environment and their optical throughput was tested over time. Due to water absorption in the SiO2 films, the optical throughput of all of the ARROWs decreased with time spent in the wet environment. The ARROWs with the lowest stress SiO2 had the slowest rate of throughput change. High index difference bARROWs showed no decrease in optical throughput after 40 days in the wet environment and are presented as a solution for environmentally stable waveguides made from unannealed PECVD SiO2. © 2017 IEEE.
1953 a57194158491 Zacheu G. p839 False Conference 366 Preserving optical confinement in unannealed PECVD SiO2 waveguides Rib and buried channel waveguides (BCWs) made of unannealed PECVD SiO2 were studied after exposure to high humidity. Low stressed rib waveguides had lower optical throughput change, while high index difference BCWs were practically unaffected. © 2017 OSA.
1954 a35182844400 Du K. p750 True Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
1955 a57217654846 Cai H. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
1955 a57217654846 Cai H. p860 False Journal 402 Optofluidic bioanalysis: Fundamentals and applications Over the past decade, optofluidics has established itself as a new and dynamic research field for exciting developments at the interface of photonics, microfluidics, and the life sciences. The strong desire for developing miniaturized bioanalytic devices and instruments, in particular, has led to novel and powerful approaches to integrating optical elements and biological fluids on the same chip-scale system. Here, we review the state-of-the-art in optofluidic research with emphasis on applications in bioanalysis and a focus on waveguide-based approaches that represent the most advanced level of integration between optics and fluidics. We discuss recent work in photonically reconfigurable devices and various application areas. We show how optofluidic approaches have been pushing the performance limits in bioanalysis, e.g. in terms of sensitivity and portability, satisfying many of the key requirements for point-of-care devices. This illustrates how the requirements for bianalysis instruments are increasingly being met by the symbiotic integration of novel photonic capabilities in a miniaturized system. © 2017, Holger Schmidt et al.
1956 a57192893058 Park M. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
1957 a55544941800 Alfson K.J. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
1958 a7202812767 Griffiths A. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
1959 a6603907334 Carrion R. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
1960 a7103123753 Mathies R.A. p750 False Journal 364 Multiplexed efficient on-chip sample preparation and sensitive amplification-free detection of Ebola virus An automated microfluidic sample preparation multiplexer (SPM) has been developed and evaluated for Ebola virus detection. Metered air bubbles controlled by microvalves are used to improve bead-solution mixing thereby enhancing the hybridization of the target Ebola virus RNA with capture probes bound to the beads. The method uses thermally stable 4-formyl benzamide functionalized (4FB) magnetic beads rather than streptavidin coated beads with a high density of capture probes to improve the target capture efficiency. Exploiting an on-chip concentration protocol in the SPM and the single molecule detection capability of the antiresonant reflecting optical waveguide (ARROW) biosensor chip, a detection limit of 0.021 pfu/mL for clinical samples is achieved without target amplification. This RNA target capture efficiency is two orders of magnitude higher than previous results using streptavidin beads and the limit of detection (LOD) improves 10×. The wide dynamic range of this technique covers the whole clinically applicable concentration range. In addition, the current sample preparation time is ~1 h which is eight times faster than previous work. This multiplexed, miniaturized sample preparation microdevice establishes a key technology that intended to develop next generation point-of-care (POC) detection system. © 2017 Elsevier B.V.
1961 a55945072200 Prince D. p751 True Journal 365 Semi-empirical Model for Fire Spread in Shrubs with Spatially-Defined Fuel Elements and Flames A semi-empirical model was developed which forms shrub geometries from distinct fuel elements (e.g. leaves) and describes flame spread from element to element. Ignition, flame growth and flame decay patterns were based on combustion data of single leaves. Extension of the model to various heating conditions was achieved by scaling the flame growth parameters using physics-based heat transfer models. The resulting model offers a novel approach to examine fire spread and to explicitly describe both distinct fuel elements and fire behavior. This approach balances computational speed and modeling detail while providing a unique perspective into fire spread phenomena. Comparisons of the tuned model to fire spread behavior measured in an open-roofed wind tunnel benchmarked the model’s ability to simulate fire spread in manzanita shrubs. © 2017, Springer Science+Business Media New York.
1961 a55945072200 Prince D. p801 False Conference 337 Semi-empirical model for fire spread in chamise and big sagebrush shrubs with spatially-defined fuel elements and flames Current operational fire spread models are mostly based on experimental results from dead, low moisture fuel beds and thus do not perform well when modeling fire behavior in live shrubs. A previously-developed semi-empirical shrub combustion model was improved and expanded to treat live chamise and big sagebrush. Fire spread in live chamise and big sagebrush shrubs was measured in an open-roofed wind tunnel, which was used as the basis to develop the current model. Shrub geometry was modeled by coupling a Lindenmayer-systems (L-systems) approach with terrestrial LiDAR scan data. Wind speed was held constant at 1.4 m/s. Species specific correlations for physical properties and combustion characteristics of individual fuel element were incorporate in this model. Modeling results compared well with measured time-dependent fire behavior. Variations in local fuel density affected flame spread more than the overall fuel bed density. This model is an innovative approach to simulate shrub combustion via flame propagation at individual fuel element scale with a fairly low computational cost. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
1962 a55944583700 Shen C. p751 False Journal 365 Semi-empirical Model for Fire Spread in Shrubs with Spatially-Defined Fuel Elements and Flames A semi-empirical model was developed which forms shrub geometries from distinct fuel elements (e.g. leaves) and describes flame spread from element to element. Ignition, flame growth and flame decay patterns were based on combustion data of single leaves. Extension of the model to various heating conditions was achieved by scaling the flame growth parameters using physics-based heat transfer models. The resulting model offers a novel approach to examine fire spread and to explicitly describe both distinct fuel elements and fire behavior. This approach balances computational speed and modeling detail while providing a unique perspective into fire spread phenomena. Comparisons of the tuned model to fire spread behavior measured in an open-roofed wind tunnel benchmarked the model’s ability to simulate fire spread in manzanita shrubs. © 2017, Springer Science+Business Media New York.
1962 a55944583700 Shen C. p801 True Conference 337 Semi-empirical model for fire spread in chamise and big sagebrush shrubs with spatially-defined fuel elements and flames Current operational fire spread models are mostly based on experimental results from dead, low moisture fuel beds and thus do not perform well when modeling fire behavior in live shrubs. A previously-developed semi-empirical shrub combustion model was improved and expanded to treat live chamise and big sagebrush. Fire spread in live chamise and big sagebrush shrubs was measured in an open-roofed wind tunnel, which was used as the basis to develop the current model. Shrub geometry was modeled by coupling a Lindenmayer-systems (L-systems) approach with terrestrial LiDAR scan data. Wind speed was held constant at 1.4 m/s. Species specific correlations for physical properties and combustion characteristics of individual fuel element were incorporate in this model. Modeling results compared well with measured time-dependent fire behavior. Variations in local fuel density affected flame spread more than the overall fuel bed density. This model is an innovative approach to simulate shrub combustion via flame propagation at individual fuel element scale with a fairly low computational cost. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
1963 a35099253600 Parent J.R. p752 False Journal 366 Using vegetation management and LiDAR-derived tree height data to improve outage predictions for electric utilities The interaction of severe weather, overhead electric infrastructure and surrounding vegetation contributes to power outages. Given that 90% of storm outages in Connecticut are tree-related, accurate modeling of power outages before a storm arrives could result in improved pre-staging of crews and equipment resulting in improved electric reliability. The authors have generated a light detection and ranging (LiDAR) data product that provides a 1-m resolution measurement of vegetation that is tall enough to strike overhead distribution powerlines, called “ProxPix”. These data, along with other vegetation management (e.g. tree trimming) and infrastructure data were evaluated for their improvement an outage prediction model over eastern Connecticut during Hurricane Sandy. A random forest model utilizing a repeated balanced sampling (RBS) approach with 10,000 iterations was used to evaluate which model forcing data accurately predicted the occurrence of a power outage in a 0.5 km grid cell. The authors found that models inputted with infrastructure, vegetation management, ProxPix, performed up to 5–13% better than simpler models depending on model evaluation criteria and input data; and that the model forced with utility infrastructure and ProxPix had the best overall performance. The ProxPix data created for this study have application to other research topics such as prioritizing areas for vegetation management near utilities and providing data on potential tree threats to roads, railways, or other infrastructure networks. © 2017 Elsevier B.V.
1964 a56364369100 Qi C. p755 True Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1965 a57202367046 Li Y. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1966 a57193409777 Badger P. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1967 a57193401477 Yu H. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1968 a56896749800 You Z. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1969 a55877167500 Yan X. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1970 a56247393100 Liu W. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1971 a7404963860 Shi Y. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1972 a37105487900 Xia T. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1973 a7403361614 Dong J. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1974 a52663627000 Huang C. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1975 a14321763900 Du Y. p755 False Journal 368 Pathology-targeted cell delivery via injectable micro-scaffold capsule mediated by endogenous TGase Targeted cell delivery to lesion sites via minimally invasive approach remains an unmet need in regenerative medicine to endow satisfactory therapeutic efficacy and minimized side-effects. Here, we rationally designed a pathology-targeted cell delivery strategy leveraging injectable micro-scaffolds as cell-loading capsule and endogenous tissue transglutaminase (TGase) at lesion site as adhesive. Up-regulated TGase post-liver injury catalyzed chemical bonding between the glutamine and lysine residues on liver surface and micro-scaffolds both ex vivo and in vivo, facilitating sufficient adhesion on the pathological liver. Upon intraperitoneal injection, Mesenchymal Stem Cell-loaded capsules, exhibiting cell protection from shear-induced damage and post-transplantation anoikis, adhered to the CCl4-treated liver with a hundred-fold improvement in targeting efficiency (70.72%) compared to free-cell injection, which dramatically improved mice survival (33.3% vs. 0% for free-cell therapy) even with low-dosage treatment. This unique and widely-applicable cell delivery mechanism and strategy hold great promise for transforming cell therapy for refractory diseases. © 2017 The Author(s)
1976 a57195340095 Mishra R.K. p756 False Journal 361 Microstructure Correlation with Formability for Biaxial Stretching of Magnesium Alloy AZ31B at Mildly Elevated Temperatures Magnesium AZ31B sheets of 2 mm thickness were stretch formed with a 101.6-mm-diameter punch at temperatures from 25°C to 150°C, in 25°C increments. Surface strains were measured with a digital image correlation method. The punch height versus load curve was found to be the same for temperatures of 25°C and for 50°C, whereas at 75°C and above, the load for a given punch height started to decrease, indicating a potential change in deformation mechanism. Electron backscatter diffraction was used to quantify features of the microstructure in the tested specimens. In particular, the gradual decrease in twinning activity as a result of easier thermally activated slip with increasing temperatures is quantified across this range. Moreover, twin activity was found to predominantly involve the formation of {10 1 ¯ 1 } compression twins that rapidly transform to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
1976 a57195340095 Mishra R.K. p884 False Conference 397 Formability of magnesium alloy AZ31B from room temperature to 125, °C under biaxial tension Magnesium AZ31B sheets of 2, mm thickness were stretch formed using a 101.6, mm diameter punch at room temperature and subsequent increments from 25 to 125, °C. Surface strains were measured using a digital image correlation method in order to ensure that biaxial stretching was achieved. The punch height versus load curve was found to be the same for temperatures of 25 and for 50, °C, while at 75, °C the load for a given punch height was less. This difference seems to indicate a change in deformation mechanism between 50 and 75, °C. Electron Backscatter Diffraction (EBSD) was used to quantify features of the microstructure in the as-received and the strained specimens. Rather than a sudden transition from twinning to slip at low temperatures, it appears that twinning gradually decreases and slip activity increases as temperatures rise across the range from 25 to 125, °C. This confirms recent predictions found in the literature. The twin activity predominantly involves the formation of compression twins which rapidly transform further to create secondary twins for easier strain accommodation. © 2017, The Minerals, Metals & Materials Society.
1977 a57193099661 Embley J.S. p757 False Journal 369 Tuning Ferritin's band gap through mixed metal oxide nanoparticle formation This study uses the formation of a mixed metal oxide inside ferritin to tune the band gap energy of the ferritin mineral. The mixed metal oxide is composed of both Co and Mn, and is formed by reacting aqueous Co2+ with MnO4in the presence of apoferritin. Altering the ratio between the two reactants allowed for controlled tuning of the band gap energies. All minerals formed were indirect band gap materials, with indirect band gap energies ranging from 0.52 to 1.30 eV. The direct transitions were also measured, with energy values ranging from 2.71 to 3.11 eV. Tuning the band gap energies of these samples changes the wavelengths absorbed by each mineral, increasing ferritin's potential in solar-energy harvesting. Additionally, the success of using MnO4 in ferritin mineral formation opens the possibility for new mixed metal oxide cores inside ferritin. © 2017 IOP Publishing Ltd.
1977 a57193099661 Embley J.S. p758 False Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
1978 a57194047820 Henrichsen A.M. p757 False Journal 369 Tuning Ferritin's band gap through mixed metal oxide nanoparticle formation This study uses the formation of a mixed metal oxide inside ferritin to tune the band gap energy of the ferritin mineral. The mixed metal oxide is composed of both Co and Mn, and is formed by reacting aqueous Co2+ with MnO4in the presence of apoferritin. Altering the ratio between the two reactants allowed for controlled tuning of the band gap energies. All minerals formed were indirect band gap materials, with indirect band gap energies ranging from 0.52 to 1.30 eV. The direct transitions were also measured, with energy values ranging from 2.71 to 3.11 eV. Tuning the band gap energies of these samples changes the wavelengths absorbed by each mineral, increasing ferritin's potential in solar-energy harvesting. Additionally, the success of using MnO4 in ferritin mineral formation opens the possibility for new mixed metal oxide cores inside ferritin. © 2017 IOP Publishing Ltd.
1978 a57194047820 Henrichsen A.M. p758 False Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
1979 a55938156500 Smith T.J. p758 False Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
1980 a57194061052 Maxfield J.H. p758 False Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
1981 a56080900100 Erickson S.D. p758 False Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
1982 a57196655805 Buck D.C. p758 False Journal 369 Permanganate-based synthesis of manganese oxide nanoparticles in ferritin This paper investigates the comproportionation reaction of MnII with as a route for manganese oxide nanoparticle synthesis in the protein ferritin. We report that serves as the electron acceptor and reacts with MnII in the presence of apoferritin to form manganese oxide cores inside the protein shell. Manganese loading into ferritin was studied under acidic, neutral, and basic conditions and the ratios of MnII and permanganate were varied at each pH. The manganese-containing ferritin samples were characterized by transmission electron microscopy, UV/Vis absorption, and by measuring the band gap energies for each sample. Manganese cores were deposited inside ferritin under both the acidic and basic conditions. All resulting manganese ferritin samples were found to be indirect band gap materials with band gap energies ranging from 1.01 to 1.34 eV. An increased UV/Vis absorption around 370 nm was observed for samples formed under acidic conditions, suggestive of MnO2 formation inside ferritin. © 2017 IOP Publishing Ltd.
1983 a15831070600 Bowman K.E. p759 True Journal 352 Pseudo-singleton pattern and agnostic business layer for multi-engineer, synchronous, heterogeneous CAD Product development processes are currently highly serial workflows that prevent needed cycle time reduction. Multi-user synchronous CAD is already improving the parallelization of these workflows and the next step is to facilitate multi-user synchronous heterogeneous CAD. This paper proposes a pseudo-singleton design pattern and a class signature which are necessary in the business logic layer of an application architecture that affects multi-user synchronous collaboration across heterogeneous CAD clients. © 2016 CAD Solutions, LLC.
1984 a35615891900 Jensen C.G. p759 False Journal 352 Pseudo-singleton pattern and agnostic business layer for multi-engineer, synchronous, heterogeneous CAD Product development processes are currently highly serial workflows that prevent needed cycle time reduction. Multi-user synchronous CAD is already improving the parallelization of these workflows and the next step is to facilitate multi-user synchronous heterogeneous CAD. This paper proposes a pseudo-singleton design pattern and a class signature which are necessary in the business logic layer of an application architecture that affects multi-user synchronous collaboration across heterogeneous CAD clients. © 2016 CAD Solutions, LLC.
1985 a12646129300 Xing C. p760 True Journal 370 Thermal characterization of natural and synthetic spider silks by both the 3ω and transient electrothermal methods Thermal conductivity, thermal diffusivity, and volumetric heat capacity of three spider silks are measured in this paper as a benchmark for further studies. These silks include the major and minor ampullate silks of the Nephila clavipes spider, and a synthetic spider silk fiber made from recombinant dragline silk proteins purified from transgenic goats’ milk. Two complementary measurement techniques are employed in the thermal characterization of these microscale single fibers for self-verification. One is the transient electrothermal technique (TET) and the other is the 3ω method. Experimental measurements indicate that thermal properties of the dragline silk are very close to those of the minor ampullate silk, whereas the ones for the synthetic silk are much lower due in part to its low crystallinity. The directly measured thermal conductivity, thermal diffusivity, and volumetric heat capacity of the major and minor ampullate silks are 1.2–1.26 W m− 1 K− 1, 5.7–6 × 10− 7 m2 s− 1, and 2–2.17 MJm− 3 K− 1, respectively. The thermal conductivity and thermal diffusivity of the as-spun synthetic silk are 0.24 W m− 1 K− 1 and 1.6 × 10− 7 m2 s− 1 respectively. As part of this study, a detailed comparison of the TET and 3ω methods is provided showing the complementary nature of the techniques and illustrating the strengths and weaknesses of each. © 2017 Elsevier Ltd
1986 a36933855300 Jensen C. p760 False Journal 370 Thermal characterization of natural and synthetic spider silks by both the 3ω and transient electrothermal methods Thermal conductivity, thermal diffusivity, and volumetric heat capacity of three spider silks are measured in this paper as a benchmark for further studies. These silks include the major and minor ampullate silks of the Nephila clavipes spider, and a synthetic spider silk fiber made from recombinant dragline silk proteins purified from transgenic goats’ milk. Two complementary measurement techniques are employed in the thermal characterization of these microscale single fibers for self-verification. One is the transient electrothermal technique (TET) and the other is the 3ω method. Experimental measurements indicate that thermal properties of the dragline silk are very close to those of the minor ampullate silk, whereas the ones for the synthetic silk are much lower due in part to its low crystallinity. The directly measured thermal conductivity, thermal diffusivity, and volumetric heat capacity of the major and minor ampullate silks are 1.2–1.26 W m− 1 K− 1, 5.7–6 × 10− 7 m2 s− 1, and 2–2.17 MJm− 3 K− 1, respectively. The thermal conductivity and thermal diffusivity of the as-spun synthetic silk are 0.24 W m− 1 K− 1 and 1.6 × 10− 7 m2 s− 1 respectively. As part of this study, a detailed comparison of the TET and 3ω methods is provided showing the complementary nature of the techniques and illustrating the strengths and weaknesses of each. © 2017 Elsevier Ltd
1987 a55812858700 Copeland C.G. p760 False Journal 370 Thermal characterization of natural and synthetic spider silks by both the 3ω and transient electrothermal methods Thermal conductivity, thermal diffusivity, and volumetric heat capacity of three spider silks are measured in this paper as a benchmark for further studies. These silks include the major and minor ampullate silks of the Nephila clavipes spider, and a synthetic spider silk fiber made from recombinant dragline silk proteins purified from transgenic goats’ milk. Two complementary measurement techniques are employed in the thermal characterization of these microscale single fibers for self-verification. One is the transient electrothermal technique (TET) and the other is the 3ω method. Experimental measurements indicate that thermal properties of the dragline silk are very close to those of the minor ampullate silk, whereas the ones for the synthetic silk are much lower due in part to its low crystallinity. The directly measured thermal conductivity, thermal diffusivity, and volumetric heat capacity of the major and minor ampullate silks are 1.2–1.26 W m− 1 K− 1, 5.7–6 × 10− 7 m2 s− 1, and 2–2.17 MJm− 3 K− 1, respectively. The thermal conductivity and thermal diffusivity of the as-spun synthetic silk are 0.24 W m− 1 K− 1 and 1.6 × 10− 7 m2 s− 1 respectively. As part of this study, a detailed comparison of the TET and 3ω methods is provided showing the complementary nature of the techniques and illustrating the strengths and weaknesses of each. © 2017 Elsevier Ltd
1988 a57203178543 Lewis R.V. p760 False Journal 370 Thermal characterization of natural and synthetic spider silks by both the 3ω and transient electrothermal methods Thermal conductivity, thermal diffusivity, and volumetric heat capacity of three spider silks are measured in this paper as a benchmark for further studies. These silks include the major and minor ampullate silks of the Nephila clavipes spider, and a synthetic spider silk fiber made from recombinant dragline silk proteins purified from transgenic goats’ milk. Two complementary measurement techniques are employed in the thermal characterization of these microscale single fibers for self-verification. One is the transient electrothermal technique (TET) and the other is the 3ω method. Experimental measurements indicate that thermal properties of the dragline silk are very close to those of the minor ampullate silk, whereas the ones for the synthetic silk are much lower due in part to its low crystallinity. The directly measured thermal conductivity, thermal diffusivity, and volumetric heat capacity of the major and minor ampullate silks are 1.2–1.26 W m− 1 K− 1, 5.7–6 × 10− 7 m2 s− 1, and 2–2.17 MJm− 3 K− 1, respectively. The thermal conductivity and thermal diffusivity of the as-spun synthetic silk are 0.24 W m− 1 K− 1 and 1.6 × 10− 7 m2 s− 1 respectively. As part of this study, a detailed comparison of the TET and 3ω methods is provided showing the complementary nature of the techniques and illustrating the strengths and weaknesses of each. © 2017 Elsevier Ltd
1989 a7403131979 Hamada M.S. p763 True Journal 372 Planning and Analyzing Experiments with Models that Distinguish Between Replicates and Repeats A commonly used model to analyze experiments with normal responses does not distinguish between replicates and repeats. The same problem arises with binary and count responses where we can use a generalized linear model. In this article, we propose using models that explicitly allow for two sources of variation, that due to replicates and that due to repeats. In addition, for experiments carried out on high-volume, existing processes, there are often large amounts of data, collected in different ways, that are available to aid in the planning and analysis of the experiment. We demonstrate the value of using these available data with two detailed examples. We finish with a brief summary and raise some further issues. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
1990 a7103186661 Steiner S.H. p763 False Journal 372 Planning and Analyzing Experiments with Models that Distinguish Between Replicates and Repeats A commonly used model to analyze experiments with normal responses does not distinguish between replicates and repeats. The same problem arises with binary and count responses where we can use a generalized linear model. In this article, we propose using models that explicitly allow for two sources of variation, that due to replicates and that due to repeats. In addition, for experiments carried out on high-volume, existing processes, there are often large amounts of data, collected in different ways, that are available to aid in the planning and analysis of the experiment. We demonstrate the value of using these available data with two detailed examples. We finish with a brief summary and raise some further issues. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
1991 a7202711709 MacKay R.J. p763 False Journal 372 Planning and Analyzing Experiments with Models that Distinguish Between Replicates and Repeats A commonly used model to analyze experiments with normal responses does not distinguish between replicates and repeats. The same problem arises with binary and count responses where we can use a generalized linear model. In this article, we propose using models that explicitly allow for two sources of variation, that due to replicates and that due to repeats. In addition, for experiments carried out on high-volume, existing processes, there are often large amounts of data, collected in different ways, that are available to aid in the planning and analysis of the experiment. We demonstrate the value of using these available data with two detailed examples. We finish with a brief summary and raise some further issues. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
1992 a39862017300 Reese C.S. p763 False Journal 372 Planning and Analyzing Experiments with Models that Distinguish Between Replicates and Repeats A commonly used model to analyze experiments with normal responses does not distinguish between replicates and repeats. The same problem arises with binary and count responses where we can use a generalized linear model. In this article, we propose using models that explicitly allow for two sources of variation, that due to replicates and that due to repeats. In addition, for experiments carried out on high-volume, existing processes, there are often large amounts of data, collected in different ways, that are available to aid in the planning and analysis of the experiment. We demonstrate the value of using these available data with two detailed examples. We finish with a brief summary and raise some further issues. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
1993 a57194015684 Willoughby D. p764 False Journal 373 A Geometrically Exact Isogeometric Blended Shell: Formulation, Benchmarking, and Automotive Application We present a geometrically exact isogeometric blended shell formulation. In other words, all geometric quantities appearing in the blended theory are evaluated exactly and no approximations are employed. The blended approach allows higher-order shell theories, like Kirchhoff-Love, to be combined with Reissner-Mindlin shell formulations, which have rotational degrees of freedom. In this way, rotations can be employed only where needed to simplify shell modeling such as at kinks and intersections. Away from these regions shear locking free formulations can be employed to improve robustness, accuracy, and efficiency. We compare our approach to standard shell elements commonly used in industry on several benchmarks to explore the behavior of the element. We then model an inner car hood to demonstrate our ability to handle complex CAD geometry in a simple manner without geometry cleanup and mesh generation steps. This shell element forms the basis of the newly developed Isogeometrx structural solver. © 2017 SAE International.
1994 a57194006378 El-Essawi M. p764 False Journal 373 A Geometrically Exact Isogeometric Blended Shell: Formulation, Benchmarking, and Automotive Application We present a geometrically exact isogeometric blended shell formulation. In other words, all geometric quantities appearing in the blended theory are evaluated exactly and no approximations are employed. The blended approach allows higher-order shell theories, like Kirchhoff-Love, to be combined with Reissner-Mindlin shell formulations, which have rotational degrees of freedom. In this way, rotations can be employed only where needed to simplify shell modeling such as at kinks and intersections. Away from these regions shear locking free formulations can be employed to improve robustness, accuracy, and efficiency. We compare our approach to standard shell elements commonly used in industry on several benchmarks to explore the behavior of the element. We then model an inner car hood to demonstrate our ability to handle complex CAD geometry in a simple manner without geometry cleanup and mesh generation steps. This shell element forms the basis of the newly developed Isogeometrx structural solver. © 2017 SAE International.
1995 a35316779800 Baskaran R. p764 False Journal 373 A Geometrically Exact Isogeometric Blended Shell: Formulation, Benchmarking, and Automotive Application We present a geometrically exact isogeometric blended shell formulation. In other words, all geometric quantities appearing in the blended theory are evaluated exactly and no approximations are employed. The blended approach allows higher-order shell theories, like Kirchhoff-Love, to be combined with Reissner-Mindlin shell formulations, which have rotational degrees of freedom. In this way, rotations can be employed only where needed to simplify shell modeling such as at kinks and intersections. Away from these regions shear locking free formulations can be employed to improve robustness, accuracy, and efficiency. We compare our approach to standard shell elements commonly used in industry on several benchmarks to explore the behavior of the element. We then model an inner car hood to demonstrate our ability to handle complex CAD geometry in a simple manner without geometry cleanup and mesh generation steps. This shell element forms the basis of the newly developed Isogeometrx structural solver. © 2017 SAE International.
1996 a6508342170 Alanoly J. p764 False Journal 373 A Geometrically Exact Isogeometric Blended Shell: Formulation, Benchmarking, and Automotive Application We present a geometrically exact isogeometric blended shell formulation. In other words, all geometric quantities appearing in the blended theory are evaluated exactly and no approximations are employed. The blended approach allows higher-order shell theories, like Kirchhoff-Love, to be combined with Reissner-Mindlin shell formulations, which have rotational degrees of freedom. In this way, rotations can be employed only where needed to simplify shell modeling such as at kinks and intersections. Away from these regions shear locking free formulations can be employed to improve robustness, accuracy, and efficiency. We compare our approach to standard shell elements commonly used in industry on several benchmarks to explore the behavior of the element. We then model an inner car hood to demonstrate our ability to handle complex CAD geometry in a simple manner without geometry cleanup and mesh generation steps. This shell element forms the basis of the newly developed Isogeometrx structural solver. © 2017 SAE International.
1997 a57189227384 McDonald S.J. p766 True Conference 322 Haptic Shape-Based Management of Robot Teams in Cordon and Patrol There is a growing need to develop effective interaction methods that enable a single operator to manage a team of multiple robots. This paper presents a novel approach that involves treating the team as a moldable volume, in which deformations of the volume correspond to changes in team shape. The team possesses a level of autonomy that allows the team to travel to and surround buildings of interest in a patrol and cordon scenario. During surround mode, the operator explores or manipulates the team shape to create desired formations around a building. A spacing interaction method also allows the operator to adjust how robots are spaced within the current shape. Separate haptic feedback is developed for each method to allow the operator to "feel" the shape or spacing manipulation. During travel mode, the operator chooses desired travel locations and receives feedback to help identify how and where the team travels. Results from a user study suggest that haptic feedback significantly improves operator performance in a reconnaissance task when task demand is higher, but may slightly increase operator workload. In the context of the experimental setup, these results suggest that haptic feedback may contribute to heads-up control of a team of autonomous robots. There were no significant differences in levels of situation awareness due to haptic feedback in this study. © 2017 ACM.
1998 a19639917400 Colton M.B. p766 False Conference 322 Haptic Shape-Based Management of Robot Teams in Cordon and Patrol There is a growing need to develop effective interaction methods that enable a single operator to manage a team of multiple robots. This paper presents a novel approach that involves treating the team as a moldable volume, in which deformations of the volume correspond to changes in team shape. The team possesses a level of autonomy that allows the team to travel to and surround buildings of interest in a patrol and cordon scenario. During surround mode, the operator explores or manipulates the team shape to create desired formations around a building. A spacing interaction method also allows the operator to adjust how robots are spaced within the current shape. Separate haptic feedback is developed for each method to allow the operator to "feel" the shape or spacing manipulation. During travel mode, the operator chooses desired travel locations and receives feedback to help identify how and where the team travels. Results from a user study suggest that haptic feedback significantly improves operator performance in a reconnaissance task when task demand is higher, but may slightly increase operator workload. In the context of the experimental setup, these results suggest that haptic feedback may contribute to heads-up control of a team of autonomous robots. There were no significant differences in levels of situation awareness due to haptic feedback in this study. © 2017 ACM.
1999 a57189219942 Alder C.K. p766 False Conference 322 Haptic Shape-Based Management of Robot Teams in Cordon and Patrol There is a growing need to develop effective interaction methods that enable a single operator to manage a team of multiple robots. This paper presents a novel approach that involves treating the team as a moldable volume, in which deformations of the volume correspond to changes in team shape. The team possesses a level of autonomy that allows the team to travel to and surround buildings of interest in a patrol and cordon scenario. During surround mode, the operator explores or manipulates the team shape to create desired formations around a building. A spacing interaction method also allows the operator to adjust how robots are spaced within the current shape. Separate haptic feedback is developed for each method to allow the operator to "feel" the shape or spacing manipulation. During travel mode, the operator chooses desired travel locations and receives feedback to help identify how and where the team travels. Results from a user study suggest that haptic feedback significantly improves operator performance in a reconnaissance task when task demand is higher, but may slightly increase operator workload. In the context of the experimental setup, these results suggest that haptic feedback may contribute to heads-up control of a team of autonomous robots. There were no significant differences in levels of situation awareness due to haptic feedback in this study. © 2017 ACM.
2000 a57193266780 Penner J.F. p767 True Journal 374 Ground-based 3D radar imaging of trees using a 2D synthetic aperture Motivated by the desire to gain insight into the details of conventional airborne synthetic aperture radar (SAR) imaging of trees, a ground-based SAR system designed for short-range three-dimensional (3D) radar imaging is developed using a two-dimensional (2D) synthetic aperture. The heart of the system is a compact linear frequency modulation-continuous wave (LFM-CW) radar, a custom two-dimensional scan mechanism, and a three-dimensional time-domain backprojection algorithm that generates three-dimensional backscatter images at an over-sampled resolution of 10 cm by 10 cm by 10 cm. The backprojection algorithm is formulated directly in spatial coordinates. A new method for estimating and compensating for signal attenuation within the canopy is used that exploits the backprojection image formation approach. Several three-dimensional C-band backscatter images of different individual trees of multiple species are generated from data collected for trees both in isolation and near buildings. The trees imaged in this study are about 10 m in height. The transformation of the three-dimensional images to airborne SAR images is described and a sample result provided. © 2017 by the authors; licensee MDPI, Basel, Switzerland.
2001 a56941526100 Eaton A.N. p768 False Journal 375 Overview of estimation methods for industrial dynamic systems Measurement technology is advancing in the oil and gas industry. Factors such as wireless transmitters, reduced cost of measurement technology, and increased regulations that require active monitoring tend to increase the number of available measurements. There is a clear opportunity to distill the recent flood of measurements into relevant and actionable information. Common methods to do this include a filtered bias update, implicit dynamic feedback, Kalman filtering, and moving horizon estimation. The purpose of these techniques is to validate measurements and align imperfect mathematical models to the actual process. Additionally, they can determine a best-estimate of the current state of the process and any potential disturbances. These methods allow potential improvements in earlier detection of disturbances, process equipment faults, and improved state estimates for optimization and control. © 2015, Springer Science+Business Media New York.
2001 a56941526100 Eaton A.N. p859 False Conference 381 Automatic model calibration for drilling automation Physics-based hydraulic models are essential for proceeding to a high level of automation in drilling. Mathematical models can facilitate process understanding and problem detection, and determine appropriate actions in case of mismatch between model and data. Furthermore, calculations may replace measurements where and when the latter are not available, as normally occurs during connections or when instruments or signal transmissions fail. However, advanced hydraulic models rely on a large set of inputs, such as pipe and wellbore geometry, various tuning parameters and fluid properties. The models are therefore time-consuming and difficult to configure in the field, where third-party experts may be needed at each well, to properly initiate the automation system and adjust it during the drilling process. Although the methods described in this paper are relevant to any critical drilling operation, they are applied to Managed Pressure Drilling (MPD) as a widely deployed example of drilling automation. In MPD, hydraulic models predict downhole conditions and determine the requisite choke pressure for automatic adjustment. A new method for automatic configuration of key model parameters simplifies the tedious job of setting up the model and ensures that the automation system remains tuned to the well, even without onsite model tuning expertise. The proposed scheme is based on a simple method for separating inaccuracies due to co-linearity in frictional pressure losses and static mud weight. The search for optimal correction factors is based on a sequence of small oscillations of pump rate that can be applied during drilling without interrupting the operation. A massively parallel computing architecture improves the speed of the calibration algorithm proportional to the number of available CPU cores. A set of hydraulic model instances runs in parallel, allowing for efficient testing of changes in input signals within ranges of uncertainty. A method for selecting a subset of the best models that more accurately represent a given well is proposed. Computer simulations demonstrate how the novel calibration scheme allows automatic tuning of the friction factor and density correction factor, giving accurate prediction of the bottom hole pressure (BHP). The tuning scheme is run with a parallel architecture to demonstrate that correct values of unknown configuration parameters can be automatically determined sufficiently fast for real-time drilling control or as an advisory tool. The deployment of automation systems in drilling is hampered by the need for dedicated expert personnel to maintain systems that could have reduced the personnel needed on the rig. The proposed automated physics-based model tuning contributes to removing this roadblock, aiming at making automation systems a more cost-efficient option for drilling operations. Copyright 2017, Society of Petroleum Engineers.
2002 a56710953300 George M.W. p769 True Journal 376 Reservoir sustainability and sediment management Despite mounting demand for a more sustainable worldwide water supply system, available reservoir capacity is relentlessly diminishing due to sedimentation. Neither sustainable reservoir life spans nor intergenerational equity is achieved through conventional cost-benefit analyses (CBAs), which render all benefits and costs projected to occur more than several decades into a project as negligible. Consequently, future costs, including dam decommissioning or retrofitting with sediment management facilities, would be regarded as nonfactors in an analysis. CBAs have also historically failed to account for infrastructure and environmental impacts of sedimentation over time. Alternatives to the traditional application of the CBA do exist, however, such as dam owners instituting retirement funds or insurance policies, beneficiaries paying for rehabilitation or maintenance, and economists incorporating infrastructure damages and potentially logistic discount rates into their analyses. A brief case study of Gavins Point Dam shows that available information on damages due to a lack of sediment management account for 70% of the actual construction cost and would likely exceed construction costs if all damage information were available. By integrating these alternatives, economic analyses for reservoirs will be more accurate, reservoir life spans will be more sustainable, profits will be extended indefinitely, and the economic burdens placed on future generations will be lessened. © 2016 American Society of Civil Engineers.
2003 a7005883030 Huffaker R. p769 False Journal 376 Reservoir sustainability and sediment management Despite mounting demand for a more sustainable worldwide water supply system, available reservoir capacity is relentlessly diminishing due to sedimentation. Neither sustainable reservoir life spans nor intergenerational equity is achieved through conventional cost-benefit analyses (CBAs), which render all benefits and costs projected to occur more than several decades into a project as negligible. Consequently, future costs, including dam decommissioning or retrofitting with sediment management facilities, would be regarded as nonfactors in an analysis. CBAs have also historically failed to account for infrastructure and environmental impacts of sedimentation over time. Alternatives to the traditional application of the CBA do exist, however, such as dam owners instituting retirement funds or insurance policies, beneficiaries paying for rehabilitation or maintenance, and economists incorporating infrastructure damages and potentially logistic discount rates into their analyses. A brief case study of Gavins Point Dam shows that available information on damages due to a lack of sediment management account for 70% of the actual construction cost and would likely exceed construction costs if all damage information were available. By integrating these alternatives, economic analyses for reservoirs will be more accurate, reservoir life spans will be more sustainable, profits will be extended indefinitely, and the economic burdens placed on future generations will be lessened. © 2016 American Society of Civil Engineers.
2004 a55194109800 Sun G. p771 True Journal 378 Evaluation of stochastic particle dispersion modeling in turbulent round jets ODT (one-dimensional turbulence) simulations of particle-carrier gas interactions are performed in the jet flow configuration. Particles with different diameters are injected onto the centerline of a turbulent air jet. The particles are passive and do not impact the fluid phase. Their radial dispersion and axial velocities are obtained as functions of axial position. The time and length scales of the jet are varied through control of the jet exit velocity and nozzle diameter. Dispersion data at long times of flight for the nozzle diameter (7 mm), particle diameters (60 and 90 µm), and Reynolds numbers (10, 000–30, 000) are analyzed to obtain the Lagrangian particle dispersivity. Flow statistics of the ODT particle model are compared to experimental measurements. It is shown that the particle tracking method is capable of yielding Lagrangian prediction of the dispersive transport of particles in a round jet. In this paper, three particle-eddy interaction models (Type-I, -C, and -IC) are presented to examine the details of particle dispersion and particle-eddy interaction in jet flow. © 2016 Elsevier Ltd
2005 a7004834766 Hewson J.C. p771 False Journal 378 Evaluation of stochastic particle dispersion modeling in turbulent round jets ODT (one-dimensional turbulence) simulations of particle-carrier gas interactions are performed in the jet flow configuration. Particles with different diameters are injected onto the centerline of a turbulent air jet. The particles are passive and do not impact the fluid phase. Their radial dispersion and axial velocities are obtained as functions of axial position. The time and length scales of the jet are varied through control of the jet exit velocity and nozzle diameter. Dispersion data at long times of flight for the nozzle diameter (7 mm), particle diameters (60 and 90 µm), and Reynolds numbers (10, 000–30, 000) are analyzed to obtain the Lagrangian particle dispersivity. Flow statistics of the ODT particle model are compared to experimental measurements. It is shown that the particle tracking method is capable of yielding Lagrangian prediction of the dispersive transport of particles in a round jet. In this paper, three particle-eddy interaction models (Type-I, -C, and -IC) are presented to examine the details of particle dispersion and particle-eddy interaction in jet flow. © 2016 Elsevier Ltd
2006 a57192106462 Kim J.-R. p772 True Journal 379 Effect of tool geometry and process parameters on mechanical properties of friction stir spot welded dissimilar aluminum alloys The effects of tool geometry and process parameters on the mechanical properties of friction stir spot welded (FSSW) dissimilar aluminum alloys are experimentally investigated. Two tools with different shoulder profiles, concave and convex, were considered. Two typical automotive aluminum alloys were selected for FSSW, thus resulting in two different material combinations for each shoulder profile. The experimental results showed that the two shoulder profiles caused significant differences in the axial force, the mixing of materials, and the mechanical properties of the joint. The sensitivity of joint strength to the variation of the tool rotation speed and the plunge speed was also quite dependent on the shoulder profile. The experimental result shows that the change of joint strength can be quite significant. © 2017, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.
2007 a56012868500 Jeong Y.-H. p772 False Journal 379 Effect of tool geometry and process parameters on mechanical properties of friction stir spot welded dissimilar aluminum alloys The effects of tool geometry and process parameters on the mechanical properties of friction stir spot welded (FSSW) dissimilar aluminum alloys are experimentally investigated. Two tools with different shoulder profiles, concave and convex, were considered. Two typical automotive aluminum alloys were selected for FSSW, thus resulting in two different material combinations for each shoulder profile. The experimental results showed that the two shoulder profiles caused significant differences in the axial force, the mixing of materials, and the mechanical properties of the joint. The sensitivity of joint strength to the variation of the tool rotation speed and the plunge speed was also quite dependent on the shoulder profile. The experimental result shows that the change of joint strength can be quite significant. © 2017, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg.
2008 a57190189579 He J. p773 True Journal 380 Nonparametric Tree-Based Predictive Modeling of Storm Outages on an Electric Distribution Network This article compares two nonparametric tree-based models, quantile regression forests (QRF) and Bayesian additive regression trees (BART), for predicting storm outages on an electric distribution network in Connecticut, USA. We evaluated point estimates and prediction intervals of outage predictions for both models using high-resolution weather, infrastructure, and land use data for 89 storm events (including hurricanes, blizzards, and thunderstorms). We found that spatially BART predicted more accurate point estimates than QRF. However, QRF produced better prediction intervals for high spatial resolutions (2-km grid cells and towns), while BART predictions aggregated to coarser resolutions (divisions and service territory) more effectively. We also found that the predictive accuracy was dependent on the season (e.g., tree-leaf condition, storm characteristics), and that the predictions were most accurate for winter storms. Given the merits of each individual model, we suggest that BART and QRF be implemented together to show the complete picture of a storm's potential impact on the electric distribution network, which would allow for a utility to make better decisions about allocating prestorm resources. © 2016 Society for Risk Analysis
2009 a8372868700 Astitha M. p773 False Journal 380 Nonparametric Tree-Based Predictive Modeling of Storm Outages on an Electric Distribution Network This article compares two nonparametric tree-based models, quantile regression forests (QRF) and Bayesian additive regression trees (BART), for predicting storm outages on an electric distribution network in Connecticut, USA. We evaluated point estimates and prediction intervals of outage predictions for both models using high-resolution weather, infrastructure, and land use data for 89 storm events (including hurricanes, blizzards, and thunderstorms). We found that spatially BART predicted more accurate point estimates than QRF. However, QRF produced better prediction intervals for high spatial resolutions (2-km grid cells and towns), while BART predictions aggregated to coarser resolutions (divisions and service territory) more effectively. We also found that the predictive accuracy was dependent on the season (e.g., tree-leaf condition, storm characteristics), and that the predictions were most accurate for winter storms. Given the merits of each individual model, we suggest that BART and QRF be implemented together to show the complete picture of a storm's potential impact on the electric distribution network, which would allow for a utility to make better decisions about allocating prestorm resources. © 2016 Society for Risk Analysis
2010 a55946345200 Frediani M.E.B. p773 False Journal 380 Nonparametric Tree-Based Predictive Modeling of Storm Outages on an Electric Distribution Network This article compares two nonparametric tree-based models, quantile regression forests (QRF) and Bayesian additive regression trees (BART), for predicting storm outages on an electric distribution network in Connecticut, USA. We evaluated point estimates and prediction intervals of outage predictions for both models using high-resolution weather, infrastructure, and land use data for 89 storm events (including hurricanes, blizzards, and thunderstorms). We found that spatially BART predicted more accurate point estimates than QRF. However, QRF produced better prediction intervals for high spatial resolutions (2-km grid cells and towns), while BART predictions aggregated to coarser resolutions (divisions and service territory) more effectively. We also found that the predictive accuracy was dependent on the season (e.g., tree-leaf condition, storm characteristics), and that the predictions were most accurate for winter storms. Given the merits of each individual model, we suggest that BART and QRF be implemented together to show the complete picture of a storm's potential impact on the electric distribution network, which would allow for a utility to make better decisions about allocating prestorm resources. © 2016 Society for Risk Analysis
2011 a55574195279 Rose M.A. p774 True Journal 381 Status of elementary teacher development: Preparing elementary teachers to deliver technology and engineering experiences For over a century, teacher preparation programs (TPPs) have experienced peaks and valleys in preparing preservice teachers to deliver technology and engineering (TE) experiences in elementary classrooms. Calls to integrate engineering concepts into elementary education (Katehi, Pearson, & Feder, 2009; Kimmel, Carpinelli, Curr-Alexander, & Rockland, 2006)—especially as it relates to the Next Generation Science Standards (NGSS; NGSS Lead States, 2013) and science, technology, engineering and mathematics (STEM) education—compels TE teacher educators to evaluate their curricular programs relative to elementary education. To assist teacher educators in this selfassessment, the Teacher Preparation Committee of the Council on Technology and Engineering Teacher Education undertook a mixed methods study, the purpose of which was to identify and characterize the models of teacher preparation programs that prepared preservice elementary teachers to deliver TE experiences in elementary classrooms. © 2017, Virginia Polytechnic Institute. All Right Reserved.
2012 a56608873500 Carter V. p774 False Journal 381 Status of elementary teacher development: Preparing elementary teachers to deliver technology and engineering experiences For over a century, teacher preparation programs (TPPs) have experienced peaks and valleys in preparing preservice teachers to deliver technology and engineering (TE) experiences in elementary classrooms. Calls to integrate engineering concepts into elementary education (Katehi, Pearson, & Feder, 2009; Kimmel, Carpinelli, Curr-Alexander, & Rockland, 2006)—especially as it relates to the Next Generation Science Standards (NGSS; NGSS Lead States, 2013) and science, technology, engineering and mathematics (STEM) education—compels TE teacher educators to evaluate their curricular programs relative to elementary education. To assist teacher educators in this selfassessment, the Teacher Preparation Committee of the Council on Technology and Engineering Teacher Education undertook a mixed methods study, the purpose of which was to identify and characterize the models of teacher preparation programs that prepared preservice elementary teachers to deliver TE experiences in elementary classrooms. © 2017, Virginia Polytechnic Institute. All Right Reserved.
2013 a56608333500 Brown J. p774 False Journal 381 Status of elementary teacher development: Preparing elementary teachers to deliver technology and engineering experiences For over a century, teacher preparation programs (TPPs) have experienced peaks and valleys in preparing preservice teachers to deliver technology and engineering (TE) experiences in elementary classrooms. Calls to integrate engineering concepts into elementary education (Katehi, Pearson, & Feder, 2009; Kimmel, Carpinelli, Curr-Alexander, & Rockland, 2006)—especially as it relates to the Next Generation Science Standards (NGSS; NGSS Lead States, 2013) and science, technology, engineering and mathematics (STEM) education—compels TE teacher educators to evaluate their curricular programs relative to elementary education. To assist teacher educators in this selfassessment, the Teacher Preparation Committee of the Council on Technology and Engineering Teacher Education undertook a mixed methods study, the purpose of which was to identify and characterize the models of teacher preparation programs that prepared preservice elementary teachers to deliver TE experiences in elementary classrooms. © 2017, Virginia Polytechnic Institute. All Right Reserved.
2014 a7004980415 Shumway S. p774 False Journal 381 Status of elementary teacher development: Preparing elementary teachers to deliver technology and engineering experiences For over a century, teacher preparation programs (TPPs) have experienced peaks and valleys in preparing preservice teachers to deliver technology and engineering (TE) experiences in elementary classrooms. Calls to integrate engineering concepts into elementary education (Katehi, Pearson, & Feder, 2009; Kimmel, Carpinelli, Curr-Alexander, & Rockland, 2006)—especially as it relates to the Next Generation Science Standards (NGSS; NGSS Lead States, 2013) and science, technology, engineering and mathematics (STEM) education—compels TE teacher educators to evaluate their curricular programs relative to elementary education. To assist teacher educators in this selfassessment, the Teacher Preparation Committee of the Council on Technology and Engineering Teacher Education undertook a mixed methods study, the purpose of which was to identify and characterize the models of teacher preparation programs that prepared preservice elementary teachers to deliver TE experiences in elementary classrooms. © 2017, Virginia Polytechnic Institute. All Right Reserved.
2015 a6506269903 Vermeltfoort A.T. p775 False Journal 382 Strength, behavior, and failure mode of hollow concrete masonry constructed with mortars of different strengths This study reports the failure modes of hollow concrete masonry prisms, taking into account the block and mortar stress-strain behavior. An extensive and detailed experimental program has been conducted on three-block high stack-bonded prisms, built using a combination of one hollow block type and three mortars with different strengths. Based on the results of the experiments, masonry failure was assessed. The main conclusion of this is that the mortar in all cases governs the masonry failure mechanism. The ratio between the masonry and block moduli of elasticity, which can be used as a measure of loss of stiffness, indicates that masonry built with a strong mortar behaves almost as a homogenous material. The typical failure mode observed during testing for this type of masonry was due to tensile stresses developed in the block. A crack developed at and propagated instantly through the block face until reaching the mortar bed joint; the crack then propagated through the head joint causing a localized split at the interface between block and mortar. For masonry built with two different weak mortars, as the stress/strength ratio increased, the ratio between the masonry and mortar moduli of elasticity decreased to 0.32 and 0.55, for the weak and the weaker mortar respectively. The observed failure mode, however, was independent of how weak the mortar was since, for both cases, the masonry failed due to localized mortar crushing. Another conclusion from the study presented herein is that a robust and reliable prediction of the masonry compressive strength requires the use of the nonlinear stress-strain relationship of the component materials. © 2016 Elsevier Ltd
2016 a23134948300 Martens D.R.W. p775 False Journal 382 Strength, behavior, and failure mode of hollow concrete masonry constructed with mortars of different strengths This study reports the failure modes of hollow concrete masonry prisms, taking into account the block and mortar stress-strain behavior. An extensive and detailed experimental program has been conducted on three-block high stack-bonded prisms, built using a combination of one hollow block type and three mortars with different strengths. Based on the results of the experiments, masonry failure was assessed. The main conclusion of this is that the mortar in all cases governs the masonry failure mechanism. The ratio between the masonry and block moduli of elasticity, which can be used as a measure of loss of stiffness, indicates that masonry built with a strong mortar behaves almost as a homogenous material. The typical failure mode observed during testing for this type of masonry was due to tensile stresses developed in the block. A crack developed at and propagated instantly through the block face until reaching the mortar bed joint; the crack then propagated through the head joint causing a localized split at the interface between block and mortar. For masonry built with two different weak mortars, as the stress/strength ratio increased, the ratio between the masonry and mortar moduli of elasticity decreased to 0.32 and 0.55, for the weak and the weaker mortar respectively. The observed failure mode, however, was independent of how weak the mortar was since, for both cases, the masonry failed due to localized mortar crushing. Another conclusion from the study presented herein is that a robust and reliable prediction of the masonry compressive strength requires the use of the nonlinear stress-strain relationship of the component materials. © 2016 Elsevier Ltd
2017 a7004615647 Lourenço P.B. p775 False Journal 382 Strength, behavior, and failure mode of hollow concrete masonry constructed with mortars of different strengths This study reports the failure modes of hollow concrete masonry prisms, taking into account the block and mortar stress-strain behavior. An extensive and detailed experimental program has been conducted on three-block high stack-bonded prisms, built using a combination of one hollow block type and three mortars with different strengths. Based on the results of the experiments, masonry failure was assessed. The main conclusion of this is that the mortar in all cases governs the masonry failure mechanism. The ratio between the masonry and block moduli of elasticity, which can be used as a measure of loss of stiffness, indicates that masonry built with a strong mortar behaves almost as a homogenous material. The typical failure mode observed during testing for this type of masonry was due to tensile stresses developed in the block. A crack developed at and propagated instantly through the block face until reaching the mortar bed joint; the crack then propagated through the head joint causing a localized split at the interface between block and mortar. For masonry built with two different weak mortars, as the stress/strength ratio increased, the ratio between the masonry and mortar moduli of elasticity decreased to 0.32 and 0.55, for the weak and the weaker mortar respectively. The observed failure mode, however, was independent of how weak the mortar was since, for both cases, the masonry failed due to localized mortar crushing. Another conclusion from the study presented herein is that a robust and reliable prediction of the masonry compressive strength requires the use of the nonlinear stress-strain relationship of the component materials. © 2016 Elsevier Ltd
2018 a23973526000 Ni R. p776 False Journal 383 Three-dimensional microscopic light field particle image velocimetry A microscopic particle image velocimetry (μPIV) technique is developed based on light field microscopy and is applied to flow through a microchannel containing a backward-facing step. The only hardware difference from a conventional μPIV setup is the placement of a microlens array at the intermediate image plane of the microscope. The method combines this optical hardware alteration with post-capture computation to enable 3D reconstruction of particle fields. From these particle fields, we measure three-component velocity fields, but find that accurate velocity measurements are limited to the two in-plane components at discrete depths through the volume (i.e., 2C-3D). Results are compared with a computational fluid dynamics simulation. © 2017, Springer-Verlag Berlin Heidelberg.
2019 a56369566500 Pendlebury J. p776 False Journal 383 Three-dimensional microscopic light field particle image velocimetry A microscopic particle image velocimetry (μPIV) technique is developed based on light field microscopy and is applied to flow through a microchannel containing a backward-facing step. The only hardware difference from a conventional μPIV setup is the placement of a microlens array at the intermediate image plane of the microscope. The method combines this optical hardware alteration with post-capture computation to enable 3D reconstruction of particle fields. From these particle fields, we measure three-component velocity fields, but find that accurate velocity measurements are limited to the two in-plane components at discrete depths through the volume (i.e., 2C-3D). Results are compared with a computational fluid dynamics simulation. © 2017, Springer-Verlag Berlin Heidelberg.
2020 a57193265581 McEwen B. p776 False Journal 383 Three-dimensional microscopic light field particle image velocimetry A microscopic particle image velocimetry (μPIV) technique is developed based on light field microscopy and is applied to flow through a microchannel containing a backward-facing step. The only hardware difference from a conventional μPIV setup is the placement of a microlens array at the intermediate image plane of the microscope. The method combines this optical hardware alteration with post-capture computation to enable 3D reconstruction of particle fields. From these particle fields, we measure three-component velocity fields, but find that accurate velocity measurements are limited to the two in-plane components at discrete depths through the volume (i.e., 2C-3D). Results are compared with a computational fluid dynamics simulation. © 2017, Springer-Verlag Berlin Heidelberg.
2021 a24921842300 Liarte D.B. p777 True Journal 384 Theoretical estimates of maximum fields in superconducting resonant radio frequency cavities: Stability theory, disorder, and laminates Theoretical limits to the performance of superconductors in high magnetic fields parallel to their surfaces are of key relevance to current and future accelerating cavities, especially those made of new higher-T c materials such as Nb3Sn, NbN, and MgB2. Indeed, beyond the so-called superheating field , flux will spontaneously penetrate even a perfect superconducting surface and ruin the performance. We present intuitive arguments and simple estimates for , and combine them with our previous rigorous calculations, which we summarize. We briefly discuss experimental measurements of the superheating field, comparing to our estimates. We explore the effects of materials anisotropy and the danger of disorder in nucleating vortex entry. Will we need to control surface orientation in the layered compound MgB2? Can we estimate theoretically whether dirt and defects make these new materials fundamentally more challenging to optimize than niobium? Finally, we discuss and analyze recent proposals to use thin superconducting layers or laminates to enhance the performance of superconducting cavities. Flux entering a laminate can lead to so-called pancake vortices; we consider the physics of the dislocation motion and potential re-annihilation or stabilization of these vortices after their entry. © 2017 IOP Publishing Ltd.
2022 a55034648400 Posen S. p777 False Journal 384 Theoretical estimates of maximum fields in superconducting resonant radio frequency cavities: Stability theory, disorder, and laminates Theoretical limits to the performance of superconductors in high magnetic fields parallel to their surfaces are of key relevance to current and future accelerating cavities, especially those made of new higher-T c materials such as Nb3Sn, NbN, and MgB2. Indeed, beyond the so-called superheating field , flux will spontaneously penetrate even a perfect superconducting surface and ruin the performance. We present intuitive arguments and simple estimates for , and combine them with our previous rigorous calculations, which we summarize. We briefly discuss experimental measurements of the superheating field, comparing to our estimates. We explore the effects of materials anisotropy and the danger of disorder in nucleating vortex entry. Will we need to control surface orientation in the layered compound MgB2? Can we estimate theoretically whether dirt and defects make these new materials fundamentally more challenging to optimize than niobium? Finally, we discuss and analyze recent proposals to use thin superconducting layers or laminates to enhance the performance of superconducting cavities. Flux entering a laminate can lead to so-called pancake vortices; we consider the physics of the dislocation motion and potential re-annihilation or stabilization of these vortices after their entry. © 2017 IOP Publishing Ltd.
2023 a25222495900 Catelani G. p777 False Journal 384 Theoretical estimates of maximum fields in superconducting resonant radio frequency cavities: Stability theory, disorder, and laminates Theoretical limits to the performance of superconductors in high magnetic fields parallel to their surfaces are of key relevance to current and future accelerating cavities, especially those made of new higher-T c materials such as Nb3Sn, NbN, and MgB2. Indeed, beyond the so-called superheating field , flux will spontaneously penetrate even a perfect superconducting surface and ruin the performance. We present intuitive arguments and simple estimates for , and combine them with our previous rigorous calculations, which we summarize. We briefly discuss experimental measurements of the superheating field, comparing to our estimates. We explore the effects of materials anisotropy and the danger of disorder in nucleating vortex entry. Will we need to control surface orientation in the layered compound MgB2? Can we estimate theoretically whether dirt and defects make these new materials fundamentally more challenging to optimize than niobium? Finally, we discuss and analyze recent proposals to use thin superconducting layers or laminates to enhance the performance of superconducting cavities. Flux entering a laminate can lead to so-called pancake vortices; we consider the physics of the dislocation motion and potential re-annihilation or stabilization of these vortices after their entry. © 2017 IOP Publishing Ltd.
2024 a6601987763 Liepe M. p777 False Journal 384 Theoretical estimates of maximum fields in superconducting resonant radio frequency cavities: Stability theory, disorder, and laminates Theoretical limits to the performance of superconductors in high magnetic fields parallel to their surfaces are of key relevance to current and future accelerating cavities, especially those made of new higher-T c materials such as Nb3Sn, NbN, and MgB2. Indeed, beyond the so-called superheating field , flux will spontaneously penetrate even a perfect superconducting surface and ruin the performance. We present intuitive arguments and simple estimates for , and combine them with our previous rigorous calculations, which we summarize. We briefly discuss experimental measurements of the superheating field, comparing to our estimates. We explore the effects of materials anisotropy and the danger of disorder in nucleating vortex entry. Will we need to control surface orientation in the layered compound MgB2? Can we estimate theoretically whether dirt and defects make these new materials fundamentally more challenging to optimize than niobium? Finally, we discuss and analyze recent proposals to use thin superconducting layers or laminates to enhance the performance of superconducting cavities. Flux entering a laminate can lead to so-called pancake vortices; we consider the physics of the dislocation motion and potential re-annihilation or stabilization of these vortices after their entry. © 2017 IOP Publishing Ltd.
2025 a7004441442 Sethna J.P. p777 False Journal 384 Theoretical estimates of maximum fields in superconducting resonant radio frequency cavities: Stability theory, disorder, and laminates Theoretical limits to the performance of superconductors in high magnetic fields parallel to their surfaces are of key relevance to current and future accelerating cavities, especially those made of new higher-T c materials such as Nb3Sn, NbN, and MgB2. Indeed, beyond the so-called superheating field , flux will spontaneously penetrate even a perfect superconducting surface and ruin the performance. We present intuitive arguments and simple estimates for , and combine them with our previous rigorous calculations, which we summarize. We briefly discuss experimental measurements of the superheating field, comparing to our estimates. We explore the effects of materials anisotropy and the danger of disorder in nucleating vortex entry. Will we need to control surface orientation in the layered compound MgB2? Can we estimate theoretically whether dirt and defects make these new materials fundamentally more challenging to optimize than niobium? Finally, we discuss and analyze recent proposals to use thin superconducting layers or laminates to enhance the performance of superconducting cavities. Flux entering a laminate can lead to so-called pancake vortices; we consider the physics of the dislocation motion and potential re-annihilation or stabilization of these vortices after their entry. © 2017 IOP Publishing Ltd.
2026 a57190000029 McCall A.J. p780 True Journal 386 Structural analysis and optimization of tall buildings connected with skybridges and atria Multi-level skybridges and atria between tall buildings make possible a new urban paradigm that has the potential to dramatically reduce resource consumption, air pollution, and traffic accidents. Structural analysis and optimization methods and results are presented for tall buildings connected with roller or hinge-skybridges at multiple levels and atria between buildings. Generic building systems were studied with controlled factors such as number of buildings, equal-height vs. variable-height, skybridge connection type, site seismicity and wind intensity, and presence/absence of skybridges and atria. The 48 optimization problems held all other factors constant such as building width, shape, configuration, and spacing. A simplified lateral load analysis model is described which makes optimization of large systems possible. The simplified lateral load analysis model was compared to a finite element model for accuracy. An optimization strategy was developed involving gradient and evolutionary algorithms. Results show that atria and hinge-connected skybridges reduced the total structural volume by as much as 10 %. © 2016, Springer-Verlag Berlin Heidelberg.
2027 a55953141600 Balling R.J. p780 False Journal 386 Structural analysis and optimization of tall buildings connected with skybridges and atria Multi-level skybridges and atria between tall buildings make possible a new urban paradigm that has the potential to dramatically reduce resource consumption, air pollution, and traffic accidents. Structural analysis and optimization methods and results are presented for tall buildings connected with roller or hinge-skybridges at multiple levels and atria between buildings. Generic building systems were studied with controlled factors such as number of buildings, equal-height vs. variable-height, skybridge connection type, site seismicity and wind intensity, and presence/absence of skybridges and atria. The 48 optimization problems held all other factors constant such as building width, shape, configuration, and spacing. A simplified lateral load analysis model is described which makes optimization of large systems possible. The simplified lateral load analysis model was compared to a finite element model for accuracy. An optimization strategy was developed involving gradient and evolutionary algorithms. Results show that atria and hinge-connected skybridges reduced the total structural volume by as much as 10 %. © 2016, Springer-Verlag Berlin Heidelberg.
2028 a51461758000 Niedfeldt P.C. p781 True Journal 350 Comparison and Analysis of Recursive-RANSAC for Multiple Target Tracking In both simulated and real experiments, the recursive random sample consensus (R-RANSAC) algorithm has shown promise as an efficient multiple target tracking (MTT) filter. In this paper, we introduce a generalized and modular framework for the R-RANSAC algorithm, analyze the sensitivity of the R-RANSAC tuning parameters, and compare R-RANSAC to five well-known MTT algorithms. We show that R-RANSAC offers a unique balance between low computational complexity, excellent track continuity, and good performance in cluttered environments. © 1965-2011 IEEE.
2029 a56825569600 Ingersoll K. p781 False Journal 350 Comparison and Analysis of Recursive-RANSAC for Multiple Target Tracking In both simulated and real experiments, the recursive random sample consensus (R-RANSAC) algorithm has shown promise as an efficient multiple target tracking (MTT) filter. In this paper, we introduce a generalized and modular framework for the R-RANSAC algorithm, analyze the sensitivity of the R-RANSAC tuning parameters, and compare R-RANSAC to five well-known MTT algorithms. We show that R-RANSAC offers a unique balance between low computational complexity, excellent track continuity, and good performance in cluttered environments. © 1965-2011 IEEE.
2030 a7005903021 Archibald J.L. p782 False Journal 346 Light splitting with imperfect wave plates We discuss the use of wave plates with arbitrary retardances, in conjunction with a linear polarizer, to split linearly polarized light into two linearly polarized beams with an arbitrary splitting fraction. We show that for non-ideal wave plates, a much broader range of splitting ratios is typically possible when a pair of wave plates, rather than a single wave plate, is used. We discuss the maximum range of splitting fractions possible with one or two wave plates as a function of the wave plate retardances, and how to align the wave plates to achieve the maximum splitting range possible when simply rotating one of the wave plates while keeping the other one fixed. We also briefly discuss an alignment-free polarization rotator constructed from a pair of half-wave plates. © 2017 Optical Society of America.
2031 a12808778700 Ames D.P. p783 False Journal 387 Comprehensive and quality-controlled bedload transport database The processes involved in bed-load sediment transport are complex and difficult to quantify. Field measurements provide insight and a chance to improve predictive methods. A comprehensive database is described that contains more than 15,000 observations from nearly 500 data sets of bed-load sediment transport. Observations are compiled from published sources, author responses to queries, and personal visits to offices. Each entry has been checked twice for accuracy against the original data and converted to a common set of units. The database contains sections for sample descriptions, discharge and transport data, channel and bankfull characteristics, surface and subsurface grain size distributions, and, where possible, stream classification descriptors. Discharges range from far below to several times bankfull values. The database is freely available to the public and may be accessed via direct download and through WaterML based web services from the BYU World Water Data Sediment Transport Database portal at http://worldwater.byu.edu/app/index.php/sediment. The intent of this database is to provide useful data to researchers as they continue to investigate bed-load transport processes. Data can be added to the database by contacting the authors. © 2016 American Society of Civil Engineers.
2032 a36240601900 Khoshniat A. p784 True Journal 388 Active Integrated Antenna Supporting Linear and Circular Polarizations A patch antenna and class B power amplifier are integrated for size reduction and high power added efficiency (PAE) through harmonic suppression. Harmonic suppressing slits are etched on the patch such that both linear and circular polarizations are supported. The mechanism of the slits is explained, and both components are characterized and examined for performance validation. Measured results show that the harmonic suppression leads to up to 5% improvement in PAE and that the antenna's radiation pattern is not disturbed by the added harmonic suppressing slits for all supported polarizations. © 2016 IEEE.
2033 a57189030360 Yekan T. p784 False Journal 388 Active Integrated Antenna Supporting Linear and Circular Polarizations A patch antenna and class B power amplifier are integrated for size reduction and high power added efficiency (PAE) through harmonic suppression. Harmonic suppressing slits are etched on the patch such that both linear and circular polarizations are supported. The mechanism of the slits is explained, and both components are characterized and examined for performance validation. Measured results show that the harmonic suppression leads to up to 5% improvement in PAE and that the antenna's radiation pattern is not disturbed by the added harmonic suppressing slits for all supported polarizations. © 2016 IEEE.
2034 a16027856900 Baktur R. p784 False Journal 388 Active Integrated Antenna Supporting Linear and Circular Polarizations A patch antenna and class B power amplifier are integrated for size reduction and high power added efficiency (PAE) through harmonic suppression. Harmonic suppressing slits are etched on the patch such that both linear and circular polarizations are supported. The mechanism of the slits is explained, and both components are characterized and examined for performance validation. Measured results show that the harmonic suppression leads to up to 5% improvement in PAE and that the antenna's radiation pattern is not disturbed by the added harmonic suppressing slits for all supported polarizations. © 2016 IEEE.
2035 a35213554500 Johnson M.A. p785 False Journal 389 Stability of Viscous St. Venant Roll Waves: From Onset to Infinite Froude Number Limit We study the spectral stability of roll wave solutions of the viscous St. Venant equations modeling inclined shallow water flow, both at onset in the small Froude number or “weakly unstable” limit F→ 2 + and for general values of the Froude number F, including the limit F→ + ∞. In the former, F→ 2 +, limit, the shallow water equations are formally approximated by a Korteweg-de Vries/Kuramoto–Sivashinsky (KdV–KS) equation that is a singular perturbation of the standard Korteweg-de Vries (KdV) equation modeling horizontal shallow water flow. Our main analytical result is to rigorously validate this formal limit, showing that stability as F→ 2 + is equivalent to stability of the corresponding KdV–KS waves in the KdV limit. Together with recent results obtained for KdV–KS by Johnson–Noble–Rodrigues–Zumbrun and Barker, this gives not only the first rigorous verification of stability for any single viscous St. Venant roll wave, but a complete classification of stability in the weakly unstable limit. In the remainder of the paper, we investigate numerically and analytically the evolution of the stability diagram as Froude number increases to infinity. Notably, we find transition at around F= 2.3 from weakly unstable to different, large-F behavior, with stability determined by simple power-law relations. The latter stability criteria are potentially useful in hydraulic engineering applications, for which typically 2.5 ≤ F≤ 6.0. © 2016, Springer Science+Business Media New York.
2036 a23012861700 Noble P. p785 False Journal 389 Stability of Viscous St. Venant Roll Waves: From Onset to Infinite Froude Number Limit We study the spectral stability of roll wave solutions of the viscous St. Venant equations modeling inclined shallow water flow, both at onset in the small Froude number or “weakly unstable” limit F→ 2 + and for general values of the Froude number F, including the limit F→ + ∞. In the former, F→ 2 +, limit, the shallow water equations are formally approximated by a Korteweg-de Vries/Kuramoto–Sivashinsky (KdV–KS) equation that is a singular perturbation of the standard Korteweg-de Vries (KdV) equation modeling horizontal shallow water flow. Our main analytical result is to rigorously validate this formal limit, showing that stability as F→ 2 + is equivalent to stability of the corresponding KdV–KS waves in the KdV limit. Together with recent results obtained for KdV–KS by Johnson–Noble–Rodrigues–Zumbrun and Barker, this gives not only the first rigorous verification of stability for any single viscous St. Venant roll wave, but a complete classification of stability in the weakly unstable limit. In the remainder of the paper, we investigate numerically and analytically the evolution of the stability diagram as Froude number increases to infinity. Notably, we find transition at around F= 2.3 from weakly unstable to different, large-F behavior, with stability determined by simple power-law relations. The latter stability criteria are potentially useful in hydraulic engineering applications, for which typically 2.5 ≤ F≤ 6.0. © 2016, Springer Science+Business Media New York.
2037 a55444802600 Rodrigues L.M. p785 False Journal 389 Stability of Viscous St. Venant Roll Waves: From Onset to Infinite Froude Number Limit We study the spectral stability of roll wave solutions of the viscous St. Venant equations modeling inclined shallow water flow, both at onset in the small Froude number or “weakly unstable” limit F→ 2 + and for general values of the Froude number F, including the limit F→ + ∞. In the former, F→ 2 +, limit, the shallow water equations are formally approximated by a Korteweg-de Vries/Kuramoto–Sivashinsky (KdV–KS) equation that is a singular perturbation of the standard Korteweg-de Vries (KdV) equation modeling horizontal shallow water flow. Our main analytical result is to rigorously validate this formal limit, showing that stability as F→ 2 + is equivalent to stability of the corresponding KdV–KS waves in the KdV limit. Together with recent results obtained for KdV–KS by Johnson–Noble–Rodrigues–Zumbrun and Barker, this gives not only the first rigorous verification of stability for any single viscous St. Venant roll wave, but a complete classification of stability in the weakly unstable limit. In the remainder of the paper, we investigate numerically and analytically the evolution of the stability diagram as Froude number increases to infinity. Notably, we find transition at around F= 2.3 from weakly unstable to different, large-F behavior, with stability determined by simple power-law relations. The latter stability criteria are potentially useful in hydraulic engineering applications, for which typically 2.5 ≤ F≤ 6.0. © 2016, Springer Science+Business Media New York.
2038 a55326050200 Ozcelik D. p786 False Conference 323 MMI waveguide based multispectral detection of nucleic acids for analysis of drug-resistant bacteria A multi-mode interference waveguide is used for creating distinct temporal fluorescence patterns at multiple excitation wavelengths. This allows for identification of bacterial nucleic acids labeled with molecular beacons in two colors. © 2016 IEEE.
2038 a55326050200 Ozcelik D. p840 True Conference 367 Multimodal multiplexing of single-virus detection using multi-mode interference waveguides Multi-mode interference waveguides are used to implement simultaneous spectral and spatial multiplex fluorescence analysis in liquid-core waveguide channels. A six-times multiplex identification of single influenza viruses is demonstrated with two excitation colors and threechannels. © 2017 OSA.
2038 a55326050200 Ozcelik D. p860 True Journal 402 Optofluidic bioanalysis: Fundamentals and applications Over the past decade, optofluidics has established itself as a new and dynamic research field for exciting developments at the interface of photonics, microfluidics, and the life sciences. The strong desire for developing miniaturized bioanalytic devices and instruments, in particular, has led to novel and powerful approaches to integrating optical elements and biological fluids on the same chip-scale system. Here, we review the state-of-the-art in optofluidic research with emphasis on applications in bioanalysis and a focus on waveguide-based approaches that represent the most advanced level of integration between optics and fluidics. We discuss recent work in photonically reconfigurable devices and various application areas. We show how optofluidic approaches have been pushing the performance limits in bioanalysis, e.g. in terms of sensitivity and portability, satisfying many of the key requirements for point-of-care devices. This illustrates how the requirements for bianalysis instruments are increasingly being met by the symbiotic integration of novel photonic capabilities in a miniaturized system. © 2017, Holger Schmidt et al.
2039 a57212184217 Rahman M. p787 True Conference 324 Design and characterization of integrated 2D ABEL trap Design and characterization of a chip-based electro-optic single-particle trap with feedback-based confinement in two dimensions is demonstrated. Improvements over 1D confinement and integration of nanopores for gated delivery of individual nanoparticles are discussed. © 2016 IEEE.
2039 a57212184217 Rahman M. p841 True Conference 368 Single particle fluorescence analysis on demand on electro-optofluidic chip with gated particle delivery Electronic feedback enables introduction of single microbeads and DNA molecules into a liquid-core waveguide through a micro/nanopore. Subsequent fluorescence detection from a controlled number of individual particles is demonstrated, enabling single particle analysis on demand. © 2017 OSA.
2040 a57189292901 Duffield M.O. p788 True Conference 325 A well clear recommendation for small UAS in high-density, ADS-B-enabled airspace With the growing popularity of small unmanned aircraft systems (UAS), there is a significant need to enable small UAS to detect and avoid collisions with both manned and unmanned aircraft. The capabilities of ADS-B make it an attractive sensor for detect and avoid (DAA), but it is susceptible to frequency congestion. This paper quantitatively analyzes the frequency limitations of 978 MHz ADS-B. It then uses these limitations to make a recommendation for well clear in ADS-B-equipped airspace that has a high density of small UAS operations. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2041 a36137344800 Laycock R.G. p789 True Conference 326 Formation of deposits from heavy fuel oil ash in an Accelerated Deposition Facility at temperatures up to 1206°C Some industrial gas turbines are currently being fired directly using heavy fuel oil, which contains a small percentage of inorganic material that can lead to fouling and corrosion of turbine components. Deposits of heavy fuel oil ash were created in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University under gas turbine-related conditions. Ash was produced by burning heavy fuel oil in a downward-fired combustor and collecting the ash from the exhaust stream. The mass mean ash particle diameter from these tests was 33 microns. This ash was then introduced into the TADF and entrained in a hot gas flow that varied from 1088 to 1206°C. The gas and particle velocity was accelerated to over 200 m/s in these tests. This particle-laden hot gas stream then impinged on a nickel base superalloy metal coupon approximately 3 cm in diameter, and an ash deposit formed on the coupon. Sulfur dioxide was introduced to the system to achieve 1.1 mol% SO2 in the exhaust stream in order to simulate SO2 levels in turbines currently burning heavy fuel oil. The ash deposits were collected, and the capture efficiency, surface roughness, and deposit composition were measured. The deposits were then washed with deionized water, dried, and underwent the same analysis. It was found that, as the gas temperature increased, there was no effect on capture efficiency and the post-wash roughness of the samples decreased. Washing aided in the removal of sulfur, magnesium, potassium, and calcium. Copyright © 2017 ASME.
2042 a55486520500 Fernelius M.H. p790 True Conference 327 Predicting efficiency of a turbine driven by pulsing flow One of the challenges of integrating pressure gain combustion into a gas turbine engine is that a turbine driven by pulsing flow experiences a decrease in efficiency. Computational fluid dynamic simulations validated with experiments showed that pulse amplitude is the driving factor for decreased turbine efficiency and not the pulsing frequency. A quadratic correlation between turbine efficiency and corrected pulse amplitude is presented. Incidence variation is shown to cause the change in turbine efficiency and a correlation between corrected incidence and corrected amplitude is shown to predict turbine efficiency. Copyright © 2017 ASME.
2043 a56950317400 Wilding P.R. p791 True Conference 328 Mixed-integer multi-objective optimization applied to the PCS design of the I 2S-LWR [No abstract available]
2044 a15521557600 Memmott M.J. p791 False Conference 328 Mixed-integer multi-objective optimization applied to the PCS design of the I 2S-LWR [No abstract available]
2045 a57209397116 O’Neill M. p793 True Conference 330 TrustBase: An architecture to repair and strengthen certificate-based authentication The current state of certificate-based authentication is messy, with broken authentication in applications and proxies, along with serious flaws in the CA system. To solve these problems, we design TrustBase, an architecture that provides certificate-based authentication as an operating system service, with system administrator control over authentication policy. TrustBase transparently enforces best practices for certificate validation on all applications, while also providing a variety of authentication services to strengthen the CA system. We describe a research prototype of TrustBase for Linux, which uses a loadable kernel module to intercept traffic in the socket layer, then consults a userspace policy engine to evaluate certificate validity using a variety of plugins. We evaluate the security of TrustBase, including a threat analysis, application coverage, and hardening of the Linux prototype. We also describe prototypes of TrustBase for Android and Windows, illustrating the generality of our approach. We show that TrustBase has negligible overhead and universal compatibility with applications. We demonstrate its utility by describing eight authentication services that extend CA hardening to all applications. © 2017 by The USENIX Association. All Rights Reserved.
2046 a57212209717 Bunker D. p793 False Conference 330 TrustBase: An architecture to repair and strengthen certificate-based authentication The current state of certificate-based authentication is messy, with broken authentication in applications and proxies, along with serious flaws in the CA system. To solve these problems, we design TrustBase, an architecture that provides certificate-based authentication as an operating system service, with system administrator control over authentication policy. TrustBase transparently enforces best practices for certificate validation on all applications, while also providing a variety of authentication services to strengthen the CA system. We describe a research prototype of TrustBase for Linux, which uses a loadable kernel module to intercept traffic in the socket layer, then consults a userspace policy engine to evaluate certificate validity using a variety of plugins. We evaluate the security of TrustBase, including a threat analysis, application coverage, and hardening of the Linux prototype. We also describe prototypes of TrustBase for Android and Windows, illustrating the generality of our approach. We show that TrustBase has negligible overhead and universal compatibility with applications. We demonstrate its utility by describing eight authentication services that extend CA hardening to all applications. © 2017 by The USENIX Association. All Rights Reserved.
2047 a57191997521 Hendershot T. p793 False Conference 330 TrustBase: An architecture to repair and strengthen certificate-based authentication The current state of certificate-based authentication is messy, with broken authentication in applications and proxies, along with serious flaws in the CA system. To solve these problems, we design TrustBase, an architecture that provides certificate-based authentication as an operating system service, with system administrator control over authentication policy. TrustBase transparently enforces best practices for certificate validation on all applications, while also providing a variety of authentication services to strengthen the CA system. We describe a research prototype of TrustBase for Linux, which uses a loadable kernel module to intercept traffic in the socket layer, then consults a userspace policy engine to evaluate certificate validity using a variety of plugins. We evaluate the security of TrustBase, including a threat analysis, application coverage, and hardening of the Linux prototype. We also describe prototypes of TrustBase for Android and Windows, illustrating the generality of our approach. We show that TrustBase has negligible overhead and universal compatibility with applications. We demonstrate its utility by describing eight authentication services that extend CA hardening to all applications. © 2017 by The USENIX Association. All Rights Reserved.
2048 a57200659857 Richard F.R.Y. p795 True Conference 332 Introducing second-Year students to concept-Based projects for increased success in third-Year sponsored projects To increase the performance and decrease the stress of students in a third-year externally sponsored project experience, second-year industrial design students are introduced to a critical performance skill for the third year experience - clarifying a broad conceptual topic and making it usable for an effective design exploration. The educational goal is for students to gain confidence in their ability to gather insights through interviews, observations, and participatory experiences; simplify this data down to a handful of experience drivers; and use these drivers to create a framework that provides new insight for the more mature design exploration required in the third-year studios. The introduction of this skill earlier than immediately necessary brings tradeoffs. Disconnected from an actual sponsored project, the importance of the skill is not completely evident to the second-year students. However, in course evaluations, students comment that introducing the skill and practicing it earlier than required, helps their initial third-year product studio performance and decrease stress. This paper reports on the introductory project, the simplified process of taking observations and building a driver-based framework, and highlights some of the difficulties and successes in working with students toward this goal.
2049 a57200641848 Briscoe T. p797 False Conference 334 Design education and the new culture of design centric intellectual property This paper addresses the relevance of integrating intellectual property (IP) rights studies within contemporary industrial design studio courses. As recently as 2014, an article on design and IP argues that “recent legal and cultural evolutions within the United States Intellectual Property system”… “do not favour student inventors and hinder their ability to protect their creative work” and students would be better served using their resources on more fruitful pursuits. However, IP culture surrounding Design Patents/Design Rights has substantially changed in the last decade and it is time for this position to be readdressed. This paper reviews the reframing of Brigham Young University’s third-year industrial design studio course to include training on IP. It appraises the current state of IP training in design schools and how design related IP has markedly shifted in recent years. It outlines basic IP exercises and introduces case studies for the four the primary types of IP: Copyrights, Trademarks, Design and Utility Patents. Students are exposed to two opposing mindsets regarding IP: the traditional position that views IP as a defensive tool to build a fence around an individual’s rights; and more importantly, how to use IP as a collaborative bridge between other market players enabling meaningful market offerings.
2050 a57117361200 Stark C.G. p798 True Conference 335 Integrating a multidisciplinary design methods mindset into classroom practice Sanders and Stappers (2013) propose a new interpretation of design disciplines that is not delineated by traditional fields such as industrial design, graphic design, or architecture, but by themes focusing on “people in the context of their lives” such as design for sustainability and design for well-being. Howell, Stark, et al (2016) teaches that multiple design fields May be employed in tandem to explore human centered design projects. This mindset allows for more holistic design solutions. When students are introduced to this framework, they are opened up to more flexibility in their design process and potential solutions. This paper outlines an industrial design student’s self-directed thesis project on encouraging self-compassionate thought patterns. We will examine how the process was affected by viewing the project as a multidisciplinary design field challenge instead of a traditional form, color and material-driven industrial design challenge. Importantly, the paper will discuss how research and design methods from industrial design, graphic design, interaction design, storytelling, and psychological science played into the creation of a meaningful designed project and experience. The paper concludes with several suggestions for integrating multidisciplinary design methods into classroom practice.
2051 a57192010162 Willett K. p799 True Conference 336 Using local invasive species and flora to manufacture collagen based biodegradable plastic tableware This paper explains how we designed, developed and tested a locally sourced; environmentally sensitive, biodegradable collagen plastic. It discusses the creation of simple moulds for manufacturing tableware and the accompanying workshop proving the viability of both the process and product. Tests were conducted using commercially available collagen materials to understand its attributes. A unique formulation was developed from hides of local agricultural vermin and powders derived from invasive flora. Plaster and concrete moulds were created for the manufacture of simple tableware. A workshop occurred were 12 participants tested the quality of the plastic, the robustness of the moulds, the simplicity of the manufacturing process and the aesthetics of the tableware. Finally, four of the bowls were successfully tested for bio-degradability and fully degraded within 12 weeks of contact with soil. The workshop demonstrated the success of all aspects of the process and how this development process could be used in emerging communities globally to encourage local manufacture of sustainable products.
2052 a57214281810 Hill J.C. p800 True Journal 390 Extension of the QuikSCAT Sea Ice Extent Data Set with OSCAT Data The Ku-band Oceansat-2 Scatterometer (OSCAT) is very similar to the Quick Scatterometer (QuikSCAT), which operated from 1999 to 2009. OSCAT continues the Ku-band scatterometer data record through 2014 with an overlap of 19 days with QuikSCAT's mission in 2009. This letter discusses a particular climate application of the time series for sea ice extent observation. In this letter, a QuikSCAT sea ice extent algorithm is modified for OSCAT. Gaps in OSCAT data are accounted for and filled in to support sea ice extent mapping. The OSCAT sea ice extent data are validated with QuikSCAT and Special Sensor Microwave/Imager sea ice extent data. © 2004-2012 IEEE.
2053 a55945088000 Fletcher M.E. p801 False Conference 337 Semi-empirical model for fire spread in chamise and big sagebrush shrubs with spatially-defined fuel elements and flames Current operational fire spread models are mostly based on experimental results from dead, low moisture fuel beds and thus do not perform well when modeling fire behavior in live shrubs. A previously-developed semi-empirical shrub combustion model was improved and expanded to treat live chamise and big sagebrush. Fire spread in live chamise and big sagebrush shrubs was measured in an open-roofed wind tunnel, which was used as the basis to develop the current model. Shrub geometry was modeled by coupling a Lindenmayer-systems (L-systems) approach with terrestrial LiDAR scan data. Wind speed was held constant at 1.4 m/s. Species specific correlations for physical properties and combustion characteristics of individual fuel element were incorporate in this model. Modeling results compared well with measured time-dependent fire behavior. Variations in local fuel density affected flame spread more than the overall fuel bed density. This model is an innovative approach to simulate shrub combustion via flame propagation at individual fuel element scale with a fairly low computational cost. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
2054 a57202648414 Rhamati M. p802 True Conference 338 Investigation of merging flames in horizontal and vertical geometries One of the main needs for accurate shrub combustion modeling is the complicated flame growth pattern due to merging of flames from multiple leaves and small branches. The interactions of neighboring flames have only been studied using regularly spaced fuel sources located on a horizontal plane. Flames in a burning shrub or tree merge to form large flames from fuel arrangements, which are not described by horizontal plane geometries. A careful study of flame interactions from fuels in three-dimensional arrangements is a necessary step in strengthening operational field models in complex fuel structures. The purpose of this research is to imitate the flame merging of the solid fuels in different geometries in order to describe fire behavior in complex fuel structures, such as trees or shrubs. Ceramic felt soaked in n-heptane were used as a fuel source to conduct flame-merging experiments. Flame characteristics such as flame length and flame width were measured for both single and merged flames. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
2055 a57188753800 Richards A.P. p803 True Conference 339 A comprehensive model for predicting elemental composition of coal pyrolysis products Large-scale coal combustion simulations depend highly on the accuracy and utility of the physical submodels used to describe the various physical behaviors of the system. Coal combustion simulations depend on the particle physics to predict product compositions, temperatures, energy outputs, and other useful information. The focus of this paper is to improve the accuracy of devolatilization submodels, to be used in conjunction with other particle physics models. Many large simulations today rely on inaccurate assumptions about particle compositions, including that the volatiles that are released during pyrolysis are of the same elemental composition as the char particle. Another common assumption is that the char particle can be approximated by pure carbon. These assumptions will lead to inaccuracies in the overall simulation. There are many factors that influence pyrolysis product composition, including parent coal composition, pyrolysis conditions (including particle temperature history and heating rate), and others. All of these factors are incorporated into the correlations to predict the elemental composition of the major pyrolysis products, including coal tar, char, and light gases. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
2056 a57202642302 Shutt T. p803 False Conference 339 A comprehensive model for predicting elemental composition of coal pyrolysis products Large-scale coal combustion simulations depend highly on the accuracy and utility of the physical submodels used to describe the various physical behaviors of the system. Coal combustion simulations depend on the particle physics to predict product compositions, temperatures, energy outputs, and other useful information. The focus of this paper is to improve the accuracy of devolatilization submodels, to be used in conjunction with other particle physics models. Many large simulations today rely on inaccurate assumptions about particle compositions, including that the volatiles that are released during pyrolysis are of the same elemental composition as the char particle. Another common assumption is that the char particle can be approximated by pure carbon. These assumptions will lead to inaccuracies in the overall simulation. There are many factors that influence pyrolysis product composition, including parent coal composition, pyrolysis conditions (including particle temperature history and heating rate), and others. All of these factors are incorporated into the correlations to predict the elemental composition of the major pyrolysis products, including coal tar, char, and light gases. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
2057 a57191474405 Buckmiller E. p805 False Journal 391 Re-epithelialization of whole porcine kidneys with renal epithelial cells Decellularized porcine kidneys were recellularized with renal epithelial cells by three methods: perfusion through the vasculature under high pressure, perfusion through the ureter under high pressure, or perfusion through the ureter under moderate vacuum. Histology, scanning electron microscopy, confocal microscopy, and magnetic resonance imaging were used to assess vasculature preservation and the distribution of cells throughout the kidneys. Cells were detected in the magnetic resonance imaging by labeling them with iron oxide. Perfusion of cells through the ureter under moderate vacuum (40 mmHg) produced the most uniform distribution of cells throughout the kidneys. © 2017, © The Author(s) 2017.
2058 a57191477766 Schaumann L. p805 False Journal 391 Re-epithelialization of whole porcine kidneys with renal epithelial cells Decellularized porcine kidneys were recellularized with renal epithelial cells by three methods: perfusion through the vasculature under high pressure, perfusion through the ureter under high pressure, or perfusion through the ureter under moderate vacuum. Histology, scanning electron microscopy, confocal microscopy, and magnetic resonance imaging were used to assess vasculature preservation and the distribution of cells throughout the kidneys. Cells were detected in the magnetic resonance imaging by labeling them with iron oxide. Perfusion of cells through the ureter under moderate vacuum (40 mmHg) produced the most uniform distribution of cells throughout the kidneys. © 2017, © The Author(s) 2017.
2059 a57205589719 Wang H. p805 False Journal 391 Re-epithelialization of whole porcine kidneys with renal epithelial cells Decellularized porcine kidneys were recellularized with renal epithelial cells by three methods: perfusion through the vasculature under high pressure, perfusion through the ureter under high pressure, or perfusion through the ureter under moderate vacuum. Histology, scanning electron microscopy, confocal microscopy, and magnetic resonance imaging were used to assess vasculature preservation and the distribution of cells throughout the kidneys. Cells were detected in the magnetic resonance imaging by labeling them with iron oxide. Perfusion of cells through the ureter under moderate vacuum (40 mmHg) produced the most uniform distribution of cells throughout the kidneys. © 2017, © The Author(s) 2017.
2060 a8725937600 Wisco J. p805 False Journal 391 Re-epithelialization of whole porcine kidneys with renal epithelial cells Decellularized porcine kidneys were recellularized with renal epithelial cells by three methods: perfusion through the vasculature under high pressure, perfusion through the ureter under high pressure, or perfusion through the ureter under moderate vacuum. Histology, scanning electron microscopy, confocal microscopy, and magnetic resonance imaging were used to assess vasculature preservation and the distribution of cells throughout the kidneys. Cells were detected in the magnetic resonance imaging by labeling them with iron oxide. Perfusion of cells through the ureter under moderate vacuum (40 mmHg) produced the most uniform distribution of cells throughout the kidneys. © 2017, © The Author(s) 2017.
2061 a57125618000 Nash C. p807 False Conference 342 On if-to-baseband translation and resampling in sampled-data receivers This paper summarizes the design of a discrete-time quadrature downconversion and resampling processor that operates on samples of a 70 MHz IF signal. The unique properties of discrete-time processing-aliasing due to resampling bandpass signals and polyphase filter decompositions- are applied to create a low-complexity approach that does not require any arithmetic operations at the IF sample rate. The required tasks are performed in two stages: a downsample-by-2 operation followed by a more traditional resampler based on a polyphase filterbank.
2061 a57125618000 Nash C. p886 False Conference 398 A summary of data-aided equalizer experiments at edwards AFB This paper summarizes the analysis of bit error rate data captured during flight tests designed to compare data-aided equalizers with SOQPSK-TG to unequalized and currently available blind, adaptive equalizers with SOQPSK-TG. The number of bit errors, on a second-by-second basis, are analyzed. The results are different for each test point. Given the uncertain behavior of the preamble detector for the data-aided equalizer and the differing channel conditions between the data-aided equalizer channel and the conventional serial streaming telemetry channel, we are unable to draw any firm comparative conclusions.
2062 a57195419580 Rahmati M. p809 False Conference 344 Analysis of pyrolysis products from live shrub fuels Approximately 6 million acres per year are burned by prescribed fire shrublands in the southeastern United States. Burning the understory every 2-4 years prevents fires from spreading to the canopy. However, combustion of live shrubs is not well understood, and has been shown to differ from combustion of dead biomass fuels. The purpose of this study is to investigate pyrolysis products from live shrub fuels. The pyrolysis products constitute the fuel for the gaseous flames in a fire. Amounts of pyrolyzed species depend on heating rate, temperature, fuel type, and fuel properties. In order to provide pyrolysis conditions and oxygen-free environment, a flat-flame burner (FFB) was designed and operated in a fuel-rich mode. Hot and cold traps were used to separate low and high molecular weight (tars) pyrolysis products and then analyzed in two different GC-MS systems. The data obtained help focus modeling efforts for combustion of live shrubs. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
2062 a57195419580 Rahmati M. p810 False Conference 345 Pyrolysis of live vegetation at slow heating rates Wildland fire is an important component of many American ecosystems. Wildland fires can have necessary ecological influences in many North American ecosystems or can dangerously affect life, property and natural resources. These hazards decrease with the proper application of controlled burning. Controlled burning destroys smaller plants and also decreases combustible materials and the potential for ignition and fire propagation in the fuel bed. Fuel bed pyrolysis and ignition determine fire ignition and propagation rates in both wildland fires and prescribed burning, but the details of solid fuel reaction under wildland fire conditions remain poorly understood. The purpose of this study is to provide fundamental information about pyrolysis of live shrub fuels at slow heating rates. A programmable heater apparatus was used to study the pyrolysis products of three different kind of live shrubs from forests of the Southeastern United States. Low and high molecular weight pyrolysis products were collected in a cold trap and then analyzed using GC-MS.
2062 a57195419580 Rahmati M. p812 True Conference 347 Investigation of merging flames in Horizontal and vertical Geometries One of the main needs for accurate shrub combustion modeling is the complicated flame growth pattern due to merging of flames from multiple leaves and small branches. A careful study of flame interactions from fuels in three-dimensional arrangements is a necessary step in strengthening operational field models in complex fuel structures. The purpose of this research is to imitate the flame merging of the solid fuels in different geometries in order to describe fire behavior in complex fuel structures, such as trees or shrubs. Ceramic felts soaked in n-heptane were used as a fuel source to conduct flame-merging experiments. Flame characteristics such as flame length and flame width were measured for both single and merged flames. Our data shows that by altering the separation distance between felts in both vertical and horizontal directions, flame area, height and width vary to a large extent. The region of flame merging is mapped in both the horizontal and vertical directions. These data are being used to develop flame-merging correlations as a function of flame spacing, similar to correlations that have been developed for multiple flames in the horizontal plane.
2063 a57200206650 Howarth J. p810 False Conference 345 Pyrolysis of live vegetation at slow heating rates Wildland fire is an important component of many American ecosystems. Wildland fires can have necessary ecological influences in many North American ecosystems or can dangerously affect life, property and natural resources. These hazards decrease with the proper application of controlled burning. Controlled burning destroys smaller plants and also decreases combustible materials and the potential for ignition and fire propagation in the fuel bed. Fuel bed pyrolysis and ignition determine fire ignition and propagation rates in both wildland fires and prescribed burning, but the details of solid fuel reaction under wildland fire conditions remain poorly understood. The purpose of this study is to provide fundamental information about pyrolysis of live shrub fuels at slow heating rates. A programmable heater apparatus was used to study the pyrolysis products of three different kind of live shrubs from forests of the Southeastern United States. Low and high molecular weight pyrolysis products were collected in a cold trap and then analyzed using GC-MS.
2064 a57200203866 DeYoung J. p810 False Conference 345 Pyrolysis of live vegetation at slow heating rates Wildland fire is an important component of many American ecosystems. Wildland fires can have necessary ecological influences in many North American ecosystems or can dangerously affect life, property and natural resources. These hazards decrease with the proper application of controlled burning. Controlled burning destroys smaller plants and also decreases combustible materials and the potential for ignition and fire propagation in the fuel bed. Fuel bed pyrolysis and ignition determine fire ignition and propagation rates in both wildland fires and prescribed burning, but the details of solid fuel reaction under wildland fire conditions remain poorly understood. The purpose of this study is to provide fundamental information about pyrolysis of live shrub fuels at slow heating rates. A programmable heater apparatus was used to study the pyrolysis products of three different kind of live shrubs from forests of the Southeastern United States. Low and high molecular weight pyrolysis products were collected in a cold trap and then analyzed using GC-MS.
2065 a57200201882 Hosler T. p811 True Conference 346 Impact of particle properties on radiative heat flux in an oxy-coal reactor A sensitivity study testing the significance of particle size, scattering phase functions, and distribution in oxy-coal combustion was conducted. Literature review suggests that particle size and number density play a more critical role in determination of radiative properties than the complex index of refraction. Radiative data was produced from numerical experiments using one of two particle distribution profiles (narrow or wide). A comparison of highly forward scattering cases for two particle sizes (25μm vs. 75μm) revealed a significant difference in incident heat flux maximum (25%). This difference was observed in both profiles examined. It was also generally observed that as particle size increases the difference between incident heat flux for forward and backward scattering decreases. No significant difference was observed between the large diffuse sphere and no scattering cases, suggesting that accurate modelling of larger particle size distributions can be achieved while neglecting scattering and phase functions. This result agrees with current practice in industry for air - coal mixtures. However, data suggests that phase function/scattering coefficient influence becomes more and more important with increasingly fine particle size.
2066 a57200201106 Harper C. p812 False Conference 347 Investigation of merging flames in Horizontal and vertical Geometries One of the main needs for accurate shrub combustion modeling is the complicated flame growth pattern due to merging of flames from multiple leaves and small branches. A careful study of flame interactions from fuels in three-dimensional arrangements is a necessary step in strengthening operational field models in complex fuel structures. The purpose of this research is to imitate the flame merging of the solid fuels in different geometries in order to describe fire behavior in complex fuel structures, such as trees or shrubs. Ceramic felts soaked in n-heptane were used as a fuel source to conduct flame-merging experiments. Flame characteristics such as flame length and flame width were measured for both single and merged flames. Our data shows that by altering the separation distance between felts in both vertical and horizontal directions, flame area, height and width vary to a large extent. The region of flame merging is mapped in both the horizontal and vertical directions. These data are being used to develop flame-merging correlations as a function of flame spacing, similar to correlations that have been developed for multiple flames in the horizontal plane.
2067 a57200819002 Butler M. p812 False Conference 347 Investigation of merging flames in Horizontal and vertical Geometries One of the main needs for accurate shrub combustion modeling is the complicated flame growth pattern due to merging of flames from multiple leaves and small branches. A careful study of flame interactions from fuels in three-dimensional arrangements is a necessary step in strengthening operational field models in complex fuel structures. The purpose of this research is to imitate the flame merging of the solid fuels in different geometries in order to describe fire behavior in complex fuel structures, such as trees or shrubs. Ceramic felts soaked in n-heptane were used as a fuel source to conduct flame-merging experiments. Flame characteristics such as flame length and flame width were measured for both single and merged flames. Our data shows that by altering the separation distance between felts in both vertical and horizontal directions, flame area, height and width vary to a large extent. The region of flame merging is mapped in both the horizontal and vertical directions. These data are being used to develop flame-merging correlations as a function of flame spacing, similar to correlations that have been developed for multiple flames in the horizontal plane.
2068 a57200201511 Williams T. p814 True Conference 349 A fast-running simulation tool for axisymmetric oxy-coal combustors FENICS (Flame Equilibrium Numeric Iterative Calculation Software) is a code developed to be a fast running tool for use in designing axisymmetric, oxy-coal furnaces. The code calculates gas temperature and composition, wall heat flux, and wall and refractory temperatures using 1D, equilibrium chemistry and a 3D discrete ordinates radiation solver. Chemistry and temperature calculations are made for a discrete number of axial zones wherein the temperature and species composition are assumed to be uniform. Radiation calculations are performed on a finer grid and assume gray gases. The code was validated by comparing to experimental data obtained from the L1500 Multifuel Furnace. The experimental data were taken from a single oxy-coal combustion experiment with flue gas recirculation run at a firing rate of 880kW and an air-fuel ratio of 3.6. FENICS was able to qualitatively match the wall flux and temperature profiles quite well. The major exception to this being that peak flux cannot accurately be predicted due the assumptions utilized 'smearing' the flame. Quantitatively, FENICS showed good agreement with the data. Wall temperatures were accurate to within 150K (13%) while total wall radiative heat loss was within 4%. FENICS was also used to evaluate temperatue and flux profiles for a new pilot-scale oxy-coal reactor.
2069 a57189243866 Allen J.T. p816 True Conference 351 Designing for power transfer across fold-lines in mechanisms with origami-like movement using surrogate folds As mechanisms with origami-like movement increase in popularity, there is a need for conducting electrical power across folds. This need could potentially be filled by the use of surrogate folds. Surrogate folds are a localized reduction in stiffness in a given direction allowing the material to function like a fold. Current methods for conducting across folds are reviewed along with current opportunities. A framework for designing conductive surrogate folds that can be adapted to fit specific applications is presented. Equations for calculating the resistance in single surrogate folds as well as arrays are given. Prototypes of several conductive joints are presented and discussed. The framework is then followed in the designing and manufacturing of a conductive origami-inspired mechanism. Copyright © 2017 ASME.
2070 a57197765649 Hirschi E. p819 False Conference 354 A simple starting point for designing for and/or assessing the social impact of products In this paper we present a starting point for designing for and/or assessing the social impact of engineered products. The starting point is a set of tables comprising products, their general functional characteristics, and the accompanying social impacts. We have constructed these tables by first extracting a set of social impact categories from the literature, then 65 products were qualitatively reviewed to find their social impact. The resulting product impact tables can be used at either the beginning of the product development process to decide what social impact to design for and discover product functions that lead to it, or later to qualitatively assess the social impact of a product being designed and/or to assess the impact of an existing product. © 2017 ASME.
2071 a57195290099 Sperry R. p820 True Conference 355 Impact of computational mesh on CFD combustion predictions This study has examined the impact of cell type and mesh refinement on predicted combustion results. Mesh refinement in regions of high velocity gradients was shown to be the most critical factor in achieving realistic simulation results. In Case 5 where mesh refinement was focused near the geometric shapes of the cooling tubes and burner tile, insufficient mesh refinement existed in the fuel-air mixing zones around and above the burner to accurately predict fuel jet penetration and fuel-air mixing, resulting in inaccurate predictions for flame shape and heat flux profiles at the cooling tubes. Differences in predicted incident flux, total heat transfer and flame shape between the highest levels of mesh refinement (~2 million cells) between the structured trimmed-cell mesh and the unstructured polyhedral mesh were minimal. At lower mesh levels of 1 million cells, there were slightly greater discrepancies between the structured trimmed-cell mesh and the unstructured polyhedral mesh, particularly with respect to the flame shape and upper furnace flux profile predicted in Case 3. Interestingly, the differences in thermal efficiency and total heat transfer were greater between Case 2 and Case 1 (2 million versus 1 million cells) than between Case 2 and Case 5 (2 million versus 1 million cells with poor refinement). This trend was also observed with Case 4 and Case 3. This suggests both cell count and local mesh refinement are important to achieving accurate combustion predictions, but that there is minimal difference between the results with differing mesh types as long as the cell count and refinement are sufficient to represent the expected jet mixing behavior. These results also suggest that while the flame shape does impact the boundary flux profile as expected, the impact on thermal efficiency may be less well correlated. Thus, total heat transfer results should not be used to assess flame shape behavior; boundary flux profiles provided better correlation to flame shape.
2072 a57191918589 Stoddard A. p823 True Journal 393 A Hybrid Approach to FPGA Configuration Scrubbing This paper describes a FPGA configuration scrubbing approach for Xilinx 7-Series FPGAs that combines the high-speed internal scrubbing available within these devices with an external scrubber. The internal scrubbing unit continuously monitors the frames of the FPGA configuration memory and corrects single-bit frame errors and is used to detect multi-bit frame errors. Multi-bit upsets are repaired by means of a secondary scrubbing mechanism that is primarily external to the FPGA fabric. This Xilinx 7-Series hybrid configuration scrubbing architecture scans 25,636,224 bits of the XC7Z020 device in several microseconds and detects upsets within 8 ms and then corrects most multi-cell upsets in under an additional 6 ms. This configuration scrubber was validated with configuration fault injection and neutron radiation testing. © 2016 IEEE.
2073 a57191921086 Gruwell A. p823 False Journal 393 A Hybrid Approach to FPGA Configuration Scrubbing This paper describes a FPGA configuration scrubbing approach for Xilinx 7-Series FPGAs that combines the high-speed internal scrubbing available within these devices with an external scrubber. The internal scrubbing unit continuously monitors the frames of the FPGA configuration memory and corrects single-bit frame errors and is used to detect multi-bit frame errors. Multi-bit upsets are repaired by means of a secondary scrubbing mechanism that is primarily external to the FPGA fabric. This Xilinx 7-Series hybrid configuration scrubbing architecture scans 25,636,224 bits of the XC7Z020 device in several microseconds and detects upsets within 8 ms and then corrects most multi-cell upsets in under an additional 6 ms. This configuration scrubber was validated with configuration fault injection and neutron radiation testing. © 2016 IEEE.
2074 a57191923986 Zabriskie P. p823 False Journal 393 A Hybrid Approach to FPGA Configuration Scrubbing This paper describes a FPGA configuration scrubbing approach for Xilinx 7-Series FPGAs that combines the high-speed internal scrubbing available within these devices with an external scrubber. The internal scrubbing unit continuously monitors the frames of the FPGA configuration memory and corrects single-bit frame errors and is used to detect multi-bit frame errors. Multi-bit upsets are repaired by means of a secondary scrubbing mechanism that is primarily external to the FPGA fabric. This Xilinx 7-Series hybrid configuration scrubbing architecture scans 25,636,224 bits of the XC7Z020 device in several microseconds and detects upsets within 8 ms and then corrects most multi-cell upsets in under an additional 6 ms. This configuration scrubber was validated with configuration fault injection and neutron radiation testing. © 2016 IEEE.
2075 a7004848095 Turley R.S. p826 False Conference 356 Adding EUV reflectance to aluminum-coated mirrors for space-based observation Protective layers on aluminum mirror surfaces which can be removed via the use of atomic hydrogen or hydrogen plasmas at the point of use in space may allow an expansion of broad-band mirrors into the EUV. LUVOIR (large, UV-optical-IR telescope) is a potential NASA flagship space-based observatory of the 2020's or 30's. It would utilize the largest mirrors ever flown1. Their reflective coating will almost certainly be aluminum, since such telescopes would profit from truly broad-band mirrors. To achieve reflectance over the broadest band, the top surface of such aluminum mirrors, however, needs to be bare, without the oxide layers that naturally form in air. This will open the 11 to 15 eV band. Since thin aluminum films are largely transparent between 15 and 70 eV an EUV mirror under the aluminum could make EUV bands such as 30.4 nm available for space-based astrophysics without sacrificing mirror IR, visible and UV reflectance. The local space environment for the observatory is sufficiently oxygen-free that the surface should remain bare for decades. We discuss protecting as-deposited aluminum mirrors with robust, oxygenimpenetrable, barrier layers applied in vacuo to the aluminum immediately after deposition and before air contact. The goal is that the barrier could also be cleanly, and relatively easily, removed once the mirror is in space. We propose hydrogen atoms as the means for removing the overcoat, since they can be expected to meet the criteria that the means is gentle enough to not roughen the mirror surface, and does not redeposit material on the mirror or other spacecraft components. We have investigated both organic and inorganic (such as, a-Si) hydrogen-removable films that can be applied to the aluminum immediately after its deposition have been investigated. We also examined the REVAP technique, using Cd and Zn. Agglomeration limited their effectiveness as barrier layers. That and dealing with the reevaporated atoms may limit their utility as barrier materials. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
2076 a57196471974 Thomas S.M. p826 False Conference 356 Adding EUV reflectance to aluminum-coated mirrors for space-based observation Protective layers on aluminum mirror surfaces which can be removed via the use of atomic hydrogen or hydrogen plasmas at the point of use in space may allow an expansion of broad-band mirrors into the EUV. LUVOIR (large, UV-optical-IR telescope) is a potential NASA flagship space-based observatory of the 2020's or 30's. It would utilize the largest mirrors ever flown1. Their reflective coating will almost certainly be aluminum, since such telescopes would profit from truly broad-band mirrors. To achieve reflectance over the broadest band, the top surface of such aluminum mirrors, however, needs to be bare, without the oxide layers that naturally form in air. This will open the 11 to 15 eV band. Since thin aluminum films are largely transparent between 15 and 70 eV an EUV mirror under the aluminum could make EUV bands such as 30.4 nm available for space-based astrophysics without sacrificing mirror IR, visible and UV reflectance. The local space environment for the observatory is sufficiently oxygen-free that the surface should remain bare for decades. We discuss protecting as-deposited aluminum mirrors with robust, oxygenimpenetrable, barrier layers applied in vacuo to the aluminum immediately after deposition and before air contact. The goal is that the barrier could also be cleanly, and relatively easily, removed once the mirror is in space. We propose hydrogen atoms as the means for removing the overcoat, since they can be expected to meet the criteria that the means is gentle enough to not roughen the mirror surface, and does not redeposit material on the mirror or other spacecraft components. We have investigated both organic and inorganic (such as, a-Si) hydrogen-removable films that can be applied to the aluminum immediately after its deposition have been investigated. We also examined the REVAP technique, using Cd and Zn. Agglomeration limited their effectiveness as barrier layers. That and dealing with the reevaporated atoms may limit their utility as barrier materials. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
2077 a57196475822 Willett S.G. p826 False Conference 356 Adding EUV reflectance to aluminum-coated mirrors for space-based observation Protective layers on aluminum mirror surfaces which can be removed via the use of atomic hydrogen or hydrogen plasmas at the point of use in space may allow an expansion of broad-band mirrors into the EUV. LUVOIR (large, UV-optical-IR telescope) is a potential NASA flagship space-based observatory of the 2020's or 30's. It would utilize the largest mirrors ever flown1. Their reflective coating will almost certainly be aluminum, since such telescopes would profit from truly broad-band mirrors. To achieve reflectance over the broadest band, the top surface of such aluminum mirrors, however, needs to be bare, without the oxide layers that naturally form in air. This will open the 11 to 15 eV band. Since thin aluminum films are largely transparent between 15 and 70 eV an EUV mirror under the aluminum could make EUV bands such as 30.4 nm available for space-based astrophysics without sacrificing mirror IR, visible and UV reflectance. The local space environment for the observatory is sufficiently oxygen-free that the surface should remain bare for decades. We discuss protecting as-deposited aluminum mirrors with robust, oxygenimpenetrable, barrier layers applied in vacuo to the aluminum immediately after deposition and before air contact. The goal is that the barrier could also be cleanly, and relatively easily, removed once the mirror is in space. We propose hydrogen atoms as the means for removing the overcoat, since they can be expected to meet the criteria that the means is gentle enough to not roughen the mirror surface, and does not redeposit material on the mirror or other spacecraft components. We have investigated both organic and inorganic (such as, a-Si) hydrogen-removable films that can be applied to the aluminum immediately after its deposition have been investigated. We also examined the REVAP technique, using Cd and Zn. Agglomeration limited their effectiveness as barrier layers. That and dealing with the reevaporated atoms may limit their utility as barrier materials. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
2078 a57196468765 Greenburg M.J. p826 False Conference 356 Adding EUV reflectance to aluminum-coated mirrors for space-based observation Protective layers on aluminum mirror surfaces which can be removed via the use of atomic hydrogen or hydrogen plasmas at the point of use in space may allow an expansion of broad-band mirrors into the EUV. LUVOIR (large, UV-optical-IR telescope) is a potential NASA flagship space-based observatory of the 2020's or 30's. It would utilize the largest mirrors ever flown1. Their reflective coating will almost certainly be aluminum, since such telescopes would profit from truly broad-band mirrors. To achieve reflectance over the broadest band, the top surface of such aluminum mirrors, however, needs to be bare, without the oxide layers that naturally form in air. This will open the 11 to 15 eV band. Since thin aluminum films are largely transparent between 15 and 70 eV an EUV mirror under the aluminum could make EUV bands such as 30.4 nm available for space-based astrophysics without sacrificing mirror IR, visible and UV reflectance. The local space environment for the observatory is sufficiently oxygen-free that the surface should remain bare for decades. We discuss protecting as-deposited aluminum mirrors with robust, oxygenimpenetrable, barrier layers applied in vacuo to the aluminum immediately after deposition and before air contact. The goal is that the barrier could also be cleanly, and relatively easily, removed once the mirror is in space. We propose hydrogen atoms as the means for removing the overcoat, since they can be expected to meet the criteria that the means is gentle enough to not roughen the mirror surface, and does not redeposit material on the mirror or other spacecraft components. We have investigated both organic and inorganic (such as, a-Si) hydrogen-removable films that can be applied to the aluminum immediately after its deposition have been investigated. We also examined the REVAP technique, using Cd and Zn. Agglomeration limited their effectiveness as barrier layers. That and dealing with the reevaporated atoms may limit their utility as barrier materials. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
2079 a57192318731 Perry S.B. p826 False Conference 356 Adding EUV reflectance to aluminum-coated mirrors for space-based observation Protective layers on aluminum mirror surfaces which can be removed via the use of atomic hydrogen or hydrogen plasmas at the point of use in space may allow an expansion of broad-band mirrors into the EUV. LUVOIR (large, UV-optical-IR telescope) is a potential NASA flagship space-based observatory of the 2020's or 30's. It would utilize the largest mirrors ever flown1. Their reflective coating will almost certainly be aluminum, since such telescopes would profit from truly broad-band mirrors. To achieve reflectance over the broadest band, the top surface of such aluminum mirrors, however, needs to be bare, without the oxide layers that naturally form in air. This will open the 11 to 15 eV band. Since thin aluminum films are largely transparent between 15 and 70 eV an EUV mirror under the aluminum could make EUV bands such as 30.4 nm available for space-based astrophysics without sacrificing mirror IR, visible and UV reflectance. The local space environment for the observatory is sufficiently oxygen-free that the surface should remain bare for decades. We discuss protecting as-deposited aluminum mirrors with robust, oxygenimpenetrable, barrier layers applied in vacuo to the aluminum immediately after deposition and before air contact. The goal is that the barrier could also be cleanly, and relatively easily, removed once the mirror is in space. We propose hydrogen atoms as the means for removing the overcoat, since they can be expected to meet the criteria that the means is gentle enough to not roughen the mirror surface, and does not redeposit material on the mirror or other spacecraft components. We have investigated both organic and inorganic (such as, a-Si) hydrogen-removable films that can be applied to the aluminum immediately after its deposition have been investigated. We also examined the REVAP technique, using Cd and Zn. Agglomeration limited their effectiveness as barrier layers. That and dealing with the reevaporated atoms may limit their utility as barrier materials. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
2080 a55660173800 McClelland H.G. p828 True Conference 357 Small aircraft flight encounters database for UAS sense and avoid Hardware and software technologies that enable unmanned aircraft systems (UAS) to reliably sense and avoid (SAA) other aircraft are critical to the safe operation of UAS beyond an operator's line of sight. For small UAS, the need is especially critical because of the clutter and the air-traffic density at low altitudes where they operate. For the community of researchers who are developing SAA technology for small UAS, there is a critical need for a rich, openly-accessible compendium of encounter data with which to develop, test, and evaluate SAA algorithms. In this paper we introduce a publicly available database of small UAS encounter data, the small aircraft flight encounter (SAFE) database, with an initial deposit of 11 flight encounters. In these encounters two target aircraft, a fixed-wing and a multi-rotor are imaged by a separate fixed-wing aircraft carrying two high-definition video cameras and a unique radar unit. The data contain ground-truth navigation estimates for both the target and imaging aircraft. The target aircraft are observed in the video footage but not in the radar imagery; continuing efforts include tuning and refinement of the radar parameters and expansion of the SAFE database to support small UAS SAA technology development. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2081 a57193903292 Kang C.K. p828 False Conference 357 Small aircraft flight encounters database for UAS sense and avoid Hardware and software technologies that enable unmanned aircraft systems (UAS) to reliably sense and avoid (SAA) other aircraft are critical to the safe operation of UAS beyond an operator's line of sight. For small UAS, the need is especially critical because of the clutter and the air-traffic density at low altitudes where they operate. For the community of researchers who are developing SAA technology for small UAS, there is a critical need for a rich, openly-accessible compendium of encounter data with which to develop, test, and evaluate SAA algorithms. In this paper we introduce a publicly available database of small UAS encounter data, the small aircraft flight encounter (SAFE) database, with an initial deposit of 11 flight encounters. In these encounters two target aircraft, a fixed-wing and a multi-rotor are imaged by a separate fixed-wing aircraft carrying two high-definition video cameras and a unique radar unit. The data contain ground-truth navigation estimates for both the target and imaging aircraft. The target aircraft are observed in the video footage but not in the radar imagery; continuing efforts include tuning and refinement of the radar parameters and expansion of the SAFE database to support small UAS SAA technology development. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2082 a6701876192 Woolsey C.A. p828 False Conference 357 Small aircraft flight encounters database for UAS sense and avoid Hardware and software technologies that enable unmanned aircraft systems (UAS) to reliably sense and avoid (SAA) other aircraft are critical to the safe operation of UAS beyond an operator's line of sight. For small UAS, the need is especially critical because of the clutter and the air-traffic density at low altitudes where they operate. For the community of researchers who are developing SAA technology for small UAS, there is a critical need for a rich, openly-accessible compendium of encounter data with which to develop, test, and evaluate SAA algorithms. In this paper we introduce a publicly available database of small UAS encounter data, the small aircraft flight encounter (SAFE) database, with an initial deposit of 11 flight encounters. In these encounters two target aircraft, a fixed-wing and a multi-rotor are imaged by a separate fixed-wing aircraft carrying two high-definition video cameras and a unique radar unit. The data contain ground-truth navigation estimates for both the target and imaging aircraft. The target aircraft are observed in the video footage but not in the radar imagery; continuing efforts include tuning and refinement of the radar parameters and expansion of the SAFE database to support small UAS SAA technology development. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2083 a57193902758 Roberts A.K. p828 False Conference 357 Small aircraft flight encounters database for UAS sense and avoid Hardware and software technologies that enable unmanned aircraft systems (UAS) to reliably sense and avoid (SAA) other aircraft are critical to the safe operation of UAS beyond an operator's line of sight. For small UAS, the need is especially critical because of the clutter and the air-traffic density at low altitudes where they operate. For the community of researchers who are developing SAA technology for small UAS, there is a critical need for a rich, openly-accessible compendium of encounter data with which to develop, test, and evaluate SAA algorithms. In this paper we introduce a publicly available database of small UAS encounter data, the small aircraft flight encounter (SAFE) database, with an initial deposit of 11 flight encounters. In these encounters two target aircraft, a fixed-wing and a multi-rotor are imaged by a separate fixed-wing aircraft carrying two high-definition video cameras and a unique radar unit. The data contain ground-truth navigation estimates for both the target and imaging aircraft. The target aircraft are observed in the video footage but not in the radar imagery; continuing efforts include tuning and refinement of the radar parameters and expansion of the SAFE database to support small UAS SAA technology development. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2084 a57193895552 Buck D. p828 False Conference 357 Small aircraft flight encounters database for UAS sense and avoid Hardware and software technologies that enable unmanned aircraft systems (UAS) to reliably sense and avoid (SAA) other aircraft are critical to the safe operation of UAS beyond an operator's line of sight. For small UAS, the need is especially critical because of the clutter and the air-traffic density at low altitudes where they operate. For the community of researchers who are developing SAA technology for small UAS, there is a critical need for a rich, openly-accessible compendium of encounter data with which to develop, test, and evaluate SAA algorithms. In this paper we introduce a publicly available database of small UAS encounter data, the small aircraft flight encounter (SAFE) database, with an initial deposit of 11 flight encounters. In these encounters two target aircraft, a fixed-wing and a multi-rotor are imaged by a separate fixed-wing aircraft carrying two high-definition video cameras and a unique radar unit. The data contain ground-truth navigation estimates for both the target and imaging aircraft. The target aircraft are observed in the video footage but not in the radar imagery; continuing efforts include tuning and refinement of the radar parameters and expansion of the SAFE database to support small UAS SAA technology development. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2085 a57193900229 Cheney T. p828 False Conference 357 Small aircraft flight encounters database for UAS sense and avoid Hardware and software technologies that enable unmanned aircraft systems (UAS) to reliably sense and avoid (SAA) other aircraft are critical to the safe operation of UAS beyond an operator's line of sight. For small UAS, the need is especially critical because of the clutter and the air-traffic density at low altitudes where they operate. For the community of researchers who are developing SAA technology for small UAS, there is a critical need for a rich, openly-accessible compendium of encounter data with which to develop, test, and evaluate SAA algorithms. In this paper we introduce a publicly available database of small UAS encounter data, the small aircraft flight encounter (SAFE) database, with an initial deposit of 11 flight encounters. In these encounters two target aircraft, a fixed-wing and a multi-rotor are imaged by a separate fixed-wing aircraft carrying two high-definition video cameras and a unique radar unit. The data contain ground-truth navigation estimates for both the target and imaging aircraft. The target aircraft are observed in the video footage but not in the radar imagery; continuing efforts include tuning and refinement of the radar parameters and expansion of the SAFE database to support small UAS SAA technology development. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2086 a57208928114 Frustaci J.B. p829 True Journal 396 Implementing highway safety manual life-cycle benefit–cost analysis of safety improvements The Highway Safety Manual (HSM) lists four methods for determining the change in crash severity in order of reliability. The life-cycle benefit– cost analysis currently used by the Utah Department of Transportation is similar to the least reliable method. To provide a tool to perform the most reliable method defined by the HSM—the predictive method— this research developed a spreadsheet-based tool to allow department engineers to perform life-cycle benefit–cost analyses for the 11 roadway segment types included in the HSM. The tool can be used to analyze the cost-effectiveness of safety-related improvements identified by the Utah crash prediction model, which was previously developed to identify safety hot spots on the state highway system. The concept and the spreadsheet layout are presented by using the rural two-lane, two-way highway spreadsheet as an example. Then a case of a rural two-lane, two-way highway with two selected countermeasures is presented to demonstrate the use of this spreadsheet to compare their benefit–cost ratios. One important aspect associated with life-cycle benefit–cost analyses of safety-related improvements is the cost of implementing such improvements. Safety-related improvements are often included in larger construction contracts and such costs vary significantly, depending on the way they are included in the larger contracts. Hence, construction costs of safety-related improvements—such as initial cost, periodic rehabilitation cost, and annual maintenance costs—must be prepared outside this spreadsheet by the user. © 2017, SAGE Publications Ltd. All rights reserved.
2087 a55354928800 Heath D. p830 True Conference 358 Semantic style creation Visual style transfer involves combining the content of one image with the style of another, and recent work has produced some compelling results. This paper proposes a related task that requires additional system intelligence and autonomy-that of style creation. Rather than using the style of an existing source image, the goal is to have the system autonomously create a rendering style based on a simple (text-based) semantic description. Results demonstrate the system's ability to autonomously create interesting, semantically appropriate styles that can be applied for image rendering. © 2017, Association for the Advancement of Artificial Intelligence (www.aaai.org). All rights reserved.
2088 a57195720669 Ngo K. p831 False Conference 359 Implementation of lean practices among finishing contractors in the US Many parties to the construction process have implemented lean construction practices to improve efficiency within their respective scopes of work. Academics have researched a wide range of these applications in an effort to assess barriers, benefits, and other associated impacts. One area of construction that is currently under-represented in lean literature is finishing contractors. The purpose of this paper was to assess lean implementation by finishing contractors in the US. 33% of the sample of contractors specializing in the finishing methods reported implementation of some level of lean practices. For those attempting lean, the most common tool being utilized was Last Planner System. The same group reported that implementation was driven by a desire to improve efficiency by cutting costs and reducing schedules. Non-practicing respondents indicated that the primary barrier to implementation was a lack of knowledge in the area.
2089 a57195718233 Thameem M. p832 True Conference 360 Delivery methods and social network analysis of unethical behavior in the construction industry The construction industry accounts for about one-third of gross capital formation and is ranked as one of the most corrupt. It is a multifaceted industry with unregulated transactions in which illicit behavior can be difficult to detect. The effects of corruption go beyond demoralization associated with bribery, it can lead to substandard quality of infrastructure and insufficient funds available for project maintenance. There are a multitude of reasons identified as possible causes for unethical conduct. A few researchers cited corruption as a result of an unethical decision. Prior research concerning corruption in construction has called for several main strategies: enhanced transparency, ethical codes, project governance, and audit and information technology. However, strategies to combat corruption may not be sufficient. This research first presents an overview of unethical conduct in the industry. Then it examines the ethics in the industry followed by types of relationships and their structure which may be conducive to unethical conduct within the framework of different delivery methods. Finally, an argument is made regarding the importance of strength of relationships in curbing unethical conduct.
2090 a57190859038 Peterson M.W. p833 True Conference 361 Fourier descriptors for improved analysis of distortion transfer and generation For fan/compressor design, quantifying distortion transfer and generation bladerow by bladerow through a fan/compressor is important to understand the flow physics and predict performance. What is needed are descriptors capable of describing distortion profiles with both high and low distortion content and account for the reshaping of distortion profiles. Four key parameters were identified as desirable to quantitatively capture distortion transfer, generation and effects on performance: distortion magnitude, shape, severity and phase. A set of distortion descriptors based on Fourier analysis are shown to quantitatively capture distortion magnitude, shape and phase change across bladerows. These Fourier descriptors are modal amplitude, total amplitude, and phase shift. When used together, these Fourier descriptors can be used to qualitatively describe any conceivable profile shape for any parameter. Copyright © 2017 ASME.
2091 a57203222139 Webber T. p834 False Conference 362 Improved bottomhole pressure control with wired drillpipe and physics-based models Wired Drillpipe (WDP) technology provides two-way and high speed measurements from bottom hole and along-string sensors. The data offered by WDP technology has maximum benefit when applied in an automation system or as a real-time advisory tool. Improved control is demonstrated for Managed Pressure Drilling (MPD) with the use of high-speed telemetry and physics-based models. Stabilizing and minimizing pressure within an acceptable bound leads to higher and more consistent Rate of Penetration (ROP). MPD control is challenging due to tight pressure windows and the nonlinearity of the choke and pump response on Bottom Hole Pressure (BHP). This work demonstrates a new Hammerstein-Wiener nonlinear model predictive controller for BHP regulation in drilling. Hammerstein-Wiener models employ input and output static nonlinear blocks before and after linear dynamics blocks and thereby simplify the controller design. The control performance is evaluated in scenarios such as drilling, pipe connections, and kick attenuation. A physics-based drilling simulator, WeMod, is used for model identification and control performance evaluation. The control performance of the new nonlinear controller is compared to conventional controllers in various scenarios. Because of the interconnected multivariable and nonlinear nature of the drilling operation, conventional controllers show severe limitations. In a first scenario, the performance of set point tracking during normal drilling operation is compared. By changing the set point of the BHP, the conventional controller manipulates only the choke valve opening while the nonlinear controller moves choke valve opening, mud pump, and back pressure pump simultaneously. In a second scenario, a pipe connection of a typical drillpipe stand is demonstrated. The conventional controller is not able to regulate the BHP by adjusting the choke valve only. Although a linear version of the controller is able to exploit multivariable relationships, absence of the nonlinear relationships results in severe oscillation when the operational range is shifted outside of the training region. The nonlinear controller maintains a BHP within ±1 bar of the requested set point. A third scenario investigates the kick attenuation performance of conventional and nonlinear control algorithms. The nonlinear controller attenuates the kick within well control conditions, without requiring a well shut-in procedure. Recent advances in drilling simulators and the reliability of the WDP data highway have enabled tighter BHP control. This study presents a robust method to control BHP by applying Hammerstein-Wiener models in an efficient model predictive controller. The proposed methods have been validated in the downstream industry, but are applied for the first time to drilling with nonlinear control functionality. The multivariable control adjusts three main manipulated variables in MPD simultaneously. Copyright © 2017, SPE/IADC Drilling Conference and Exhibition.
2092 a56156055700 Shishavan R.A. p834 False Conference 362 Improved bottomhole pressure control with wired drillpipe and physics-based models Wired Drillpipe (WDP) technology provides two-way and high speed measurements from bottom hole and along-string sensors. The data offered by WDP technology has maximum benefit when applied in an automation system or as a real-time advisory tool. Improved control is demonstrated for Managed Pressure Drilling (MPD) with the use of high-speed telemetry and physics-based models. Stabilizing and minimizing pressure within an acceptable bound leads to higher and more consistent Rate of Penetration (ROP). MPD control is challenging due to tight pressure windows and the nonlinearity of the choke and pump response on Bottom Hole Pressure (BHP). This work demonstrates a new Hammerstein-Wiener nonlinear model predictive controller for BHP regulation in drilling. Hammerstein-Wiener models employ input and output static nonlinear blocks before and after linear dynamics blocks and thereby simplify the controller design. The control performance is evaluated in scenarios such as drilling, pipe connections, and kick attenuation. A physics-based drilling simulator, WeMod, is used for model identification and control performance evaluation. The control performance of the new nonlinear controller is compared to conventional controllers in various scenarios. Because of the interconnected multivariable and nonlinear nature of the drilling operation, conventional controllers show severe limitations. In a first scenario, the performance of set point tracking during normal drilling operation is compared. By changing the set point of the BHP, the conventional controller manipulates only the choke valve opening while the nonlinear controller moves choke valve opening, mud pump, and back pressure pump simultaneously. In a second scenario, a pipe connection of a typical drillpipe stand is demonstrated. The conventional controller is not able to regulate the BHP by adjusting the choke valve only. Although a linear version of the controller is able to exploit multivariable relationships, absence of the nonlinear relationships results in severe oscillation when the operational range is shifted outside of the training region. The nonlinear controller maintains a BHP within ±1 bar of the requested set point. A third scenario investigates the kick attenuation performance of conventional and nonlinear control algorithms. The nonlinear controller attenuates the kick within well control conditions, without requiring a well shut-in procedure. Recent advances in drilling simulators and the reliability of the WDP data highway have enabled tighter BHP control. This study presents a robust method to control BHP by applying Hammerstein-Wiener models in an efficient model predictive controller. The proposed methods have been validated in the downstream industry, but are applied for the first time to drilling with nonlinear control functionality. The multivariable control adjusts three main manipulated variables in MPD simultaneously. Copyright © 2017, SPE/IADC Drilling Conference and Exhibition.
2093 a57200576069 Sayre A. p835 True Conference 363 Field testing of Cryogenic Carbon Capture Sustainable Energy Solutions has been developing Cryogenic Carbon Capture™(CCC) since 2008. In that time two processes have been developed, the External Cooling Loop and Compressed Flue Gas Cryogenic Carbon Capture processes (CCC ECL™ and CCC CFG™ respectively). The CCC ECL™ process has been scaled up to a 1 TPD CO2 system. In this process the flue gas is cooled by an external refrigerant loop. SES has tested CCC ECL™ on real flue gas slip streams from subbituminous coal, bituminous coal, biomass, natural gas, shredded tires, and municipal waste fuels at field sites that include utility power stations, heating plants, cement kilns, and pilot-scale research reactors. The CO2 concentrations from these tests ranged from 5 to 22% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at a modest rate. The CCC CFG™ process has been scaled up to a.25 ton per day system. This system has been tested on real flue gas streams including subbituminous coal, bituminous coal and natural gas at field sites that include utility power stations, heating plants, and pilot-scale research reactors. CO2 concentrations for these tests ranged from 5 to 15% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at 90+%. Hg capture was also verified and the resulting effluent from CCC CFG™ was below a lppt concentration. This paper will focus on discussion of the capabilities of CCC, the results of field testing and the future steps surrounding the development of this technology. Copyright 2017, Carbon Management Technology Conference.
2094 a10540655600 Frankman D. p835 False Conference 363 Field testing of Cryogenic Carbon Capture Sustainable Energy Solutions has been developing Cryogenic Carbon Capture™(CCC) since 2008. In that time two processes have been developed, the External Cooling Loop and Compressed Flue Gas Cryogenic Carbon Capture processes (CCC ECL™ and CCC CFG™ respectively). The CCC ECL™ process has been scaled up to a 1 TPD CO2 system. In this process the flue gas is cooled by an external refrigerant loop. SES has tested CCC ECL™ on real flue gas slip streams from subbituminous coal, bituminous coal, biomass, natural gas, shredded tires, and municipal waste fuels at field sites that include utility power stations, heating plants, cement kilns, and pilot-scale research reactors. The CO2 concentrations from these tests ranged from 5 to 22% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at a modest rate. The CCC CFG™ process has been scaled up to a.25 ton per day system. This system has been tested on real flue gas streams including subbituminous coal, bituminous coal and natural gas at field sites that include utility power stations, heating plants, and pilot-scale research reactors. CO2 concentrations for these tests ranged from 5 to 15% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at 90+%. Hg capture was also verified and the resulting effluent from CCC CFG™ was below a lppt concentration. This paper will focus on discussion of the capabilities of CCC, the results of field testing and the future steps surrounding the development of this technology. Copyright 2017, Carbon Management Technology Conference.
2095 a36924577900 Baxter A. p835 False Conference 363 Field testing of Cryogenic Carbon Capture Sustainable Energy Solutions has been developing Cryogenic Carbon Capture™(CCC) since 2008. In that time two processes have been developed, the External Cooling Loop and Compressed Flue Gas Cryogenic Carbon Capture processes (CCC ECL™ and CCC CFG™ respectively). The CCC ECL™ process has been scaled up to a 1 TPD CO2 system. In this process the flue gas is cooled by an external refrigerant loop. SES has tested CCC ECL™ on real flue gas slip streams from subbituminous coal, bituminous coal, biomass, natural gas, shredded tires, and municipal waste fuels at field sites that include utility power stations, heating plants, cement kilns, and pilot-scale research reactors. The CO2 concentrations from these tests ranged from 5 to 22% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at a modest rate. The CCC CFG™ process has been scaled up to a.25 ton per day system. This system has been tested on real flue gas streams including subbituminous coal, bituminous coal and natural gas at field sites that include utility power stations, heating plants, and pilot-scale research reactors. CO2 concentrations for these tests ranged from 5 to 15% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at 90+%. Hg capture was also verified and the resulting effluent from CCC CFG™ was below a lppt concentration. This paper will focus on discussion of the capabilities of CCC, the results of field testing and the future steps surrounding the development of this technology. Copyright 2017, Carbon Management Technology Conference.
2096 a55541477400 Stitt K. p835 False Conference 363 Field testing of Cryogenic Carbon Capture Sustainable Energy Solutions has been developing Cryogenic Carbon Capture™(CCC) since 2008. In that time two processes have been developed, the External Cooling Loop and Compressed Flue Gas Cryogenic Carbon Capture processes (CCC ECL™ and CCC CFG™ respectively). The CCC ECL™ process has been scaled up to a 1 TPD CO2 system. In this process the flue gas is cooled by an external refrigerant loop. SES has tested CCC ECL™ on real flue gas slip streams from subbituminous coal, bituminous coal, biomass, natural gas, shredded tires, and municipal waste fuels at field sites that include utility power stations, heating plants, cement kilns, and pilot-scale research reactors. The CO2 concentrations from these tests ranged from 5 to 22% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at a modest rate. The CCC CFG™ process has been scaled up to a.25 ton per day system. This system has been tested on real flue gas streams including subbituminous coal, bituminous coal and natural gas at field sites that include utility power stations, heating plants, and pilot-scale research reactors. CO2 concentrations for these tests ranged from 5 to 15% on a dry basis. CO2 capture ranged from 95-99+% during these tests. Several other condensable species were also captured including NO2, SO2 and PMxx at 95+%. NO was also captured at 90+%. Hg capture was also verified and the resulting effluent from CCC CFG™ was below a lppt concentration. This paper will focus on discussion of the capabilities of CCC, the results of field testing and the future steps surrounding the development of this technology. Copyright 2017, Carbon Management Technology Conference.
2097 a56559677100 Ekstrom L.T. p838 False Conference 365 Probabilistic Lateral Spread Evaluation for Long, Linear Infrastructure Using Performance-Based Reference Parameter Maps The design of long, linear infrastructure such as pipelines, levees, roads, and canals can be challenging in areas of moderate to high seismicity due to numerous seismic and geologic hazards that can be encountered along proposed alignments. One of the most challenging earthquake-related hazards in the design of large infrastructure is liquefaction-induced lateral spread displacement. This paper presents a new simplified probabilistic approach to estimate lateral spread displacements at targeted return periods across large geographic areas using performance-based lateral spread displacement reference parameter maps and (if available) site-specific geotechnical information. The approach is demonstrated on a hypothetical pipeline extending from Rock Springs, Wyoming, to West Bountiful, Utah, in the United States. Advantages and limitations of the proposed approach are discussed. The results of the demonstrative calculation show how the approach can be used to identify areas where additional geotechnical investigations might be needed, and how probabilistic lateral spread displacements can be easily predicted along numerous proposed alignments of the pipeline once geotechnical subsurface investigation and ground surveys become available. © 2017 ASCE.
2098 a57194576753 He J. p838 False Conference 365 Probabilistic Lateral Spread Evaluation for Long, Linear Infrastructure Using Performance-Based Reference Parameter Maps The design of long, linear infrastructure such as pipelines, levees, roads, and canals can be challenging in areas of moderate to high seismicity due to numerous seismic and geologic hazards that can be encountered along proposed alignments. One of the most challenging earthquake-related hazards in the design of large infrastructure is liquefaction-induced lateral spread displacement. This paper presents a new simplified probabilistic approach to estimate lateral spread displacements at targeted return periods across large geographic areas using performance-based lateral spread displacement reference parameter maps and (if available) site-specific geotechnical information. The approach is demonstrated on a hypothetical pipeline extending from Rock Springs, Wyoming, to West Bountiful, Utah, in the United States. Advantages and limitations of the proposed approach are discussed. The results of the demonstrative calculation show how the approach can be used to identify areas where additional geotechnical investigations might be needed, and how probabilistic lateral spread displacements can be easily predicted along numerous proposed alignments of the pipeline once geotechnical subsurface investigation and ground surveys become available. © 2017 ASCE.
2099 a57213582934 Harrington M. p841 False Conference 368 Single particle fluorescence analysis on demand on electro-optofluidic chip with gated particle delivery Electronic feedback enables introduction of single microbeads and DNA molecules into a liquid-core waveguide through a micro/nanopore. Subsequent fluorescence detection from a controlled number of individual particles is demonstrated, enabling single particle analysis on demand. © 2017 OSA.
2100 a24824356000 Kochenderfer M.J. p842 False Journal 397 Efficient feature descriptor for unmanned aerial vehicle ground moving object tracking A synthetic basis (SYBA) feature descriptor was used to perform frame-to-frame feature matching for frame differencing. The SYBAfeature descriptor is a robust algorithm that performs well with different degrees of image variation including: illumination, blurring, rotation, and perspective variations. The first step in detecting moving objects is to find the absolute difference between two image frames. To find the difference, the homography that describes the geometric relationship between the two frames is calculated using matched image feature points. The homography is then used to transform and align the images accurately. The transformed images are then used to calculate the absolute difference of the two images. It is then visually apparent where objects have moved or changed between the two images. Frame-to-frame object movement can be approximated to a linear process making the Kalman filter algorithm the best option. Once an object is lost, its corresponding track is deleted along with its corresponding motion model. During tracking, an object may be occluded by other objects in the scene. The MOT metric is designed to evaluate the performance of an object tracker by considering the tracking continuity, distance error for each path, and the reliability of detection. Thus, only the position of the object is considered in generating the MOT metric. The results demonstrate the effectiveness and robustness of the method and prove that the SYBA descriptor works well with various image deformations.
2101 a56559765400 Fredrickson A. p843 True Conference 369 Passive force-deflection behavior of geosynthetic-reinforced soil backfill based on large-scale tests A correct understanding of passive force-deflection response is important for lateral load evaluations of bridges during extreme events such as earthquakes and during in-service conditions resulting from thermal expansion and contraction of the superstructure. The goal of this study was to better understand this behavior for abutments backfilled with both gravel and geosynthetic reinforced soil (GRS). Large-scale testing was performed with non-skewed and 30° skewed abutment configurations. Two tests were performed at each skew angle, one with gravel backfill and one with GRS backfill. The test abutment backwall was 3.35 m wide, non-skewed, and 1.68 m high and loaded laterally into the backfill. Both backfills exhibited greater passive resistance than sand backfills owing to increased internal friction angle and unit weight. Skew angle reduced the passive force in both cases by about 40%. The GRS backfills had reduced initial stiffness and only reached 79% to 87% of the passive force developed by the unreinforced gravel backfill. This reduction was considered to be a result of reduced interface friction at the geotextile-backwall interface due to wrapping. Reduced stiffness may be favorable for abutment configurations because it allows thermal movement without developing excessive induced stresses in the bridge superstructure. © ASCE.
2102 a23009691800 Nicks J. p843 False Conference 369 Passive force-deflection behavior of geosynthetic-reinforced soil backfill based on large-scale tests A correct understanding of passive force-deflection response is important for lateral load evaluations of bridges during extreme events such as earthquakes and during in-service conditions resulting from thermal expansion and contraction of the superstructure. The goal of this study was to better understand this behavior for abutments backfilled with both gravel and geosynthetic reinforced soil (GRS). Large-scale testing was performed with non-skewed and 30° skewed abutment configurations. Two tests were performed at each skew angle, one with gravel backfill and one with GRS backfill. The test abutment backwall was 3.35 m wide, non-skewed, and 1.68 m high and loaded laterally into the backfill. Both backfills exhibited greater passive resistance than sand backfills owing to increased internal friction angle and unit weight. Skew angle reduced the passive force in both cases by about 40%. The GRS backfills had reduced initial stiffness and only reached 79% to 87% of the passive force developed by the unreinforced gravel backfill. This reduction was considered to be a result of reduced interface friction at the geotextile-backwall interface due to wrapping. Reduced stiffness may be favorable for abutment configurations because it allows thermal movement without developing excessive induced stresses in the bridge superstructure. © ASCE.
2103 a57191416025 Mojica J.L. p844 True Journal 398 Optimal combined long-term facility design and short-term operational strategy for CHP capacity investments This work presents a detailed case study for the optimization of the expansion of a district energy system evaluating the investment decision timing, type of capacity expansion, and fine-scale operational modes. The study develops an optimization framework to find the investment schedule over 30 years with options of investing in traditional heating sources (boilers) or a next-generation combined heat and power (CHP) plant that provides heat and electricity. In district energy systems, the selected capacity and type of system is dependent on demand-side requirements, energy prices, and environmental costs. This work formulates capacity planning over a time horizon as a dynamic optimal control problem considering both operational modes and capital investment decisions. The initial plant is modified by the dynamic optimization throughout the 30 years to maximize profitability. The combined optimal controller and capital investment planner solves a large scale mixed integer nonlinear programming problem to provide the timing and size of the capacity investment (30 year outlook) and also guidance on the mode of operation (1 h time intervals). The optimizer meets optimal economic, environmental, and regulatory constraints with the suggested design and operational guidance with daily cyclical load following of heat and electricity demand. © 2016 Elsevier Ltd
2104 a57192545746 Petersen D. p844 False Journal 398 Optimal combined long-term facility design and short-term operational strategy for CHP capacity investments This work presents a detailed case study for the optimization of the expansion of a district energy system evaluating the investment decision timing, type of capacity expansion, and fine-scale operational modes. The study develops an optimization framework to find the investment schedule over 30 years with options of investing in traditional heating sources (boilers) or a next-generation combined heat and power (CHP) plant that provides heat and electricity. In district energy systems, the selected capacity and type of system is dependent on demand-side requirements, energy prices, and environmental costs. This work formulates capacity planning over a time horizon as a dynamic optimal control problem considering both operational modes and capital investment decisions. The initial plant is modified by the dynamic optimization throughout the 30 years to maximize profitability. The combined optimal controller and capital investment planner solves a large scale mixed integer nonlinear programming problem to provide the timing and size of the capacity investment (30 year outlook) and also guidance on the mode of operation (1 h time intervals). The optimizer meets optimal economic, environmental, and regulatory constraints with the suggested design and operational guidance with daily cyclical load following of heat and electricity demand. © 2016 Elsevier Ltd
2105 a57192573362 Hansen B. p844 False Journal 398 Optimal combined long-term facility design and short-term operational strategy for CHP capacity investments This work presents a detailed case study for the optimization of the expansion of a district energy system evaluating the investment decision timing, type of capacity expansion, and fine-scale operational modes. The study develops an optimization framework to find the investment schedule over 30 years with options of investing in traditional heating sources (boilers) or a next-generation combined heat and power (CHP) plant that provides heat and electricity. In district energy systems, the selected capacity and type of system is dependent on demand-side requirements, energy prices, and environmental costs. This work formulates capacity planning over a time horizon as a dynamic optimal control problem considering both operational modes and capital investment decisions. The initial plant is modified by the dynamic optimization throughout the 30 years to maximize profitability. The combined optimal controller and capital investment planner solves a large scale mixed integer nonlinear programming problem to provide the timing and size of the capacity investment (30 year outlook) and also guidance on the mode of operation (1 h time intervals). The optimizer meets optimal economic, environmental, and regulatory constraints with the suggested design and operational guidance with daily cyclical load following of heat and electricity demand. © 2016 Elsevier Ltd
2106 a6701925700 Jellen E.N. p845 True Journal 399 Oat improvement and innovation using wild genetic resources (poaceae, Avena spp.): Elevating “oats” to a new level and stature Common oat (Avena sativa, 2n = 6x = 42) has been steadily declining in harvested acreage across much of its traditional cultivation range, in spite of the crop’s tremendous health benefits. Wild and primitive domesticated genetic resources in Avena - including taxa at lower ploidy levels - represent esoteric opportunities to produce novel, innovative oat crops and products to stem this tide. Creative approaches for exploiting these resources will first require deconvolution of cryptic genotypic variation in exotic and elite germplasm. Through access to this knowledge, which is rapidly being accumulated by genome scientists, oat breeders will be able to refine improvement processes involving wide hybridization and introgression for a variety of traits, both single-gene and complex; domestication of wild and improvement of primitive domesticated taxa, especially the highly variable and stress-tolerant A-genome diploids; and creation of novel synthetic polyploids. © 2016 by Taylor & Francis Group, LLC.
2107 a56299790500 Jackson E.W. p845 False Journal 399 Oat improvement and innovation using wild genetic resources (poaceae, Avena spp.): Elevating “oats” to a new level and stature Common oat (Avena sativa, 2n = 6x = 42) has been steadily declining in harvested acreage across much of its traditional cultivation range, in spite of the crop’s tremendous health benefits. Wild and primitive domesticated genetic resources in Avena - including taxa at lower ploidy levels - represent esoteric opportunities to produce novel, innovative oat crops and products to stem this tide. Creative approaches for exploiting these resources will first require deconvolution of cryptic genotypic variation in exotic and elite germplasm. Through access to this knowledge, which is rapidly being accumulated by genome scientists, oat breeders will be able to refine improvement processes involving wide hybridization and introgression for a variety of traits, both single-gene and complex; domestication of wild and improvement of primitive domesticated taxa, especially the highly variable and stress-tolerant A-genome diploids; and creation of novel synthetic polyploids. © 2016 by Taylor & Francis Group, LLC.
2108 a7003959730 Maughan P.J. p845 False Journal 399 Oat improvement and innovation using wild genetic resources (poaceae, Avena spp.): Elevating “oats” to a new level and stature Common oat (Avena sativa, 2n = 6x = 42) has been steadily declining in harvested acreage across much of its traditional cultivation range, in spite of the crop’s tremendous health benefits. Wild and primitive domesticated genetic resources in Avena - including taxa at lower ploidy levels - represent esoteric opportunities to produce novel, innovative oat crops and products to stem this tide. Creative approaches for exploiting these resources will first require deconvolution of cryptic genotypic variation in exotic and elite germplasm. Through access to this knowledge, which is rapidly being accumulated by genome scientists, oat breeders will be able to refine improvement processes involving wide hybridization and introgression for a variety of traits, both single-gene and complex; domestication of wild and improvement of primitive domesticated taxa, especially the highly variable and stress-tolerant A-genome diploids; and creation of novel synthetic polyploids. © 2016 by Taylor & Francis Group, LLC.
2109 a57201704300 Wang Y. p846 True Conference 370 Ash deposition during advanced oxy-coal combustion using minimum recycled flue gas Research on oxy-coal combustion has heretofore primarily focused on retrofit, or near retrofit, applications, where flame temperatures or heat transfer profiles under oxy-firing are similar to those under air firing. These profiles are modulated using recycled flue gas that acts as the diluent normally served by nitrogen during air firing. The large amounts of recycled flue gas (RFG) required leads to efficiency losses, making the economics of this process less attractive. Oxy-coal combustion economics can be improved in advanced oxy-combustion processes that may involve zero or minimal RFG and possibly high combustion pressures. This paper addresses effects of high combustion temperatures resulting from minimal RFG, on ash aerosol formation and ash deposition mechanisms. Issues related to ash deposition play important roles in being able to predict overall boiler performance. Effects of high pressure will be reported in future work. A 100kW downfired laboratory combustor is used to compare ash aerosol formation and deposition under two conditions: 1) using 27% O2 in the inlet oxidant gas (denoted as OXY27), representing first generation oxy-combustion (heat transfer conditions similar to air firing for retrofit); 2) with 70% O2 in the inlet oxidant gas (denoted as OXY70), representing advanced oxy-combustion where the RFG is used only to transport the coal, not to modulate flame temperatures. The ash aerosol particle size distributions and its size segregated composition were determined using on-line electric mobility/light scattering analyzers and low pressure impactors, respectively. Their relationship to ash deposition rates as determined using a specially designed deposition probe was explored. The data show that, compared to the retrofit conditions of OXY27, the advanced oxy-coal combustion in OXY70 produce much higher concentrations of submicron particles due to increased mineral vaporization at the high flame temperature and the decreased flue gas flow rate. This appeared to lead to significant increases in deposition rates. Changes in the supermicron particle concentration were in line with those expected by the lower flue gas alone, suggesting that mineral fragmentation is not greatly affected by temperature. Deposition rates of both inside and outside deposits, as defined in earlier work, are interpreted in the light of recently developed hypotheses that point to the importance of the submicron particle ash concentration. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
2110 a57171695300 Fry A. p846 False Conference 370 Ash deposition during advanced oxy-coal combustion using minimum recycled flue gas Research on oxy-coal combustion has heretofore primarily focused on retrofit, or near retrofit, applications, where flame temperatures or heat transfer profiles under oxy-firing are similar to those under air firing. These profiles are modulated using recycled flue gas that acts as the diluent normally served by nitrogen during air firing. The large amounts of recycled flue gas (RFG) required leads to efficiency losses, making the economics of this process less attractive. Oxy-coal combustion economics can be improved in advanced oxy-combustion processes that may involve zero or minimal RFG and possibly high combustion pressures. This paper addresses effects of high combustion temperatures resulting from minimal RFG, on ash aerosol formation and ash deposition mechanisms. Issues related to ash deposition play important roles in being able to predict overall boiler performance. Effects of high pressure will be reported in future work. A 100kW downfired laboratory combustor is used to compare ash aerosol formation and deposition under two conditions: 1) using 27% O2 in the inlet oxidant gas (denoted as OXY27), representing first generation oxy-combustion (heat transfer conditions similar to air firing for retrofit); 2) with 70% O2 in the inlet oxidant gas (denoted as OXY70), representing advanced oxy-combustion where the RFG is used only to transport the coal, not to modulate flame temperatures. The ash aerosol particle size distributions and its size segregated composition were determined using on-line electric mobility/light scattering analyzers and low pressure impactors, respectively. Their relationship to ash deposition rates as determined using a specially designed deposition probe was explored. The data show that, compared to the retrofit conditions of OXY27, the advanced oxy-coal combustion in OXY70 produce much higher concentrations of submicron particles due to increased mineral vaporization at the high flame temperature and the decreased flue gas flow rate. This appeared to lead to significant increases in deposition rates. Changes in the supermicron particle concentration were in line with those expected by the lower flue gas alone, suggesting that mineral fragmentation is not greatly affected by temperature. Deposition rates of both inside and outside deposits, as defined in earlier work, are interpreted in the light of recently developed hypotheses that point to the importance of the submicron particle ash concentration. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
2111 a7101671848 Wendt J.O.L. p846 False Conference 370 Ash deposition during advanced oxy-coal combustion using minimum recycled flue gas Research on oxy-coal combustion has heretofore primarily focused on retrofit, or near retrofit, applications, where flame temperatures or heat transfer profiles under oxy-firing are similar to those under air firing. These profiles are modulated using recycled flue gas that acts as the diluent normally served by nitrogen during air firing. The large amounts of recycled flue gas (RFG) required leads to efficiency losses, making the economics of this process less attractive. Oxy-coal combustion economics can be improved in advanced oxy-combustion processes that may involve zero or minimal RFG and possibly high combustion pressures. This paper addresses effects of high combustion temperatures resulting from minimal RFG, on ash aerosol formation and ash deposition mechanisms. Issues related to ash deposition play important roles in being able to predict overall boiler performance. Effects of high pressure will be reported in future work. A 100kW downfired laboratory combustor is used to compare ash aerosol formation and deposition under two conditions: 1) using 27% O2 in the inlet oxidant gas (denoted as OXY27), representing first generation oxy-combustion (heat transfer conditions similar to air firing for retrofit); 2) with 70% O2 in the inlet oxidant gas (denoted as OXY70), representing advanced oxy-combustion where the RFG is used only to transport the coal, not to modulate flame temperatures. The ash aerosol particle size distributions and its size segregated composition were determined using on-line electric mobility/light scattering analyzers and low pressure impactors, respectively. Their relationship to ash deposition rates as determined using a specially designed deposition probe was explored. The data show that, compared to the retrofit conditions of OXY27, the advanced oxy-coal combustion in OXY70 produce much higher concentrations of submicron particles due to increased mineral vaporization at the high flame temperature and the decreased flue gas flow rate. This appeared to lead to significant increases in deposition rates. Changes in the supermicron particle concentration were in line with those expected by the lower flue gas alone, suggesting that mineral fragmentation is not greatly affected by temperature. Deposition rates of both inside and outside deposits, as defined in earlier work, are interpreted in the light of recently developed hypotheses that point to the importance of the submicron particle ash concentration. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
2112 a57200204063 Hopkins E. p849 False Conference 373 Modeling soot formation from solid complex fuels While the phenomena of soot formation in gaseous flames is well studied and understood, extension of the fundamental mechanisms to systems containing complex solid fuels can introduce large uncertainties and inaccuracies. In this study, we have developed a detailed physicsbased model for predicting the evolution of soot particles formed in systems containing complexsolid fuels such as wood or coal. This detailed physics-based model includes two particle-size distributions: that for soot particles and for soot precursor molecules. Sub-models for precursor creation, growth, and thermal cracking are included along with soot particle nucleation, coagulation, surface growth, aggregation, oxidation, and gasification. Validation work is presented comparing experimental results for a coal flame and biomass gasifier against model predicted values for soot concentrations and size distributions. The full detailed model can be computationally expensive when incorporated into CFD simulations; therefore, model simplifications are explored and presented in this work along with some preliminary work of applying particle formation physics to wildfire simulations.
2113 a56559548600 Holland T. p850 True Conference 374 Modeling effects of annealing on coal char reactivity to O2 and CO2 based on preparation conditions Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive CFD simulations are valuable tools in evaluating and deploying oxy-fuel and other carbon capture technologies either as retrofit technologies or for new construction. However, accurate predictive combustor simulations require physically realistic submodels with low computational requirements. A recent sensitivity analysis of a detailed char conversion model (Char Conversion Kinetics (CCK)) found thermal annealing to be an extremely sensitive submodel. In the present work, further analysis of the previous annealing model revealed significant disagreement with numerous data sets from experiments performed after that annealing model was developed. The annealing model was accordingly extended to reflect experimentally observed reactivity loss due to thermal annealing of a variety of coals in diverse char preparation conditions. The model extension was informed by a Bayesian calibration analysis. Additionally, because oxy-fuel conditions include extraordinarily high levels of CO2, development of a first-ever CO2 reactivity loss model due to annealing is presented.
2113 a56559548600 Holland T. p871 True Conference 391 A comprehensive model of single particle pulverized coal combustion extended to oxy-coal conditions Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive CFD simulations are valuable tools in evaluating and deploying oxy-fuel and other carbon capture technologies either as retrofit technologies or for new construction. However, accurate predictive simulations require physically realistic submodels with low computational requirements. In particular, comprehensive char oxidation and gasification models have been developed that describe multiple reaction and diffusion processes. This work extends a comprehensive char conversion code (CCK), which treats surface oxidation and gasification reactions as well as the processes such as film diffusion, pore diffusion, ash encapsulation, and annealing. In this work several submodels in the CCK code were updated with more realistic physics or otherwise extended to function in oxycoal conditions. Improved submodels include the annealing model, the swelling model, the mode of burning parameter, and the kinetic model, as well as the addition of the Chemical Percolation Devolatilization (CPD) model. Results of the char combustion model are compared to oxy-coal data, and further compared to parallel data sets near conventional conditions. © 2017 Eastern States Section of the Combustion Institute. All rights reserved.
2114 a57200200833 Billings B. p851 True Conference 375 Modeling the coanda effect with FDS and STARCCM+ to predict the effect of fires on slopes for implications of wildland firefighter safety The Coanda effect is the behavior of a fluid flowing next to a solid surface which creates a change in pressure, thereby causing the fluid to attach to the surface. Little is known concerning the Coanda effect as it pertains to flame attachment in relation to wildfires. There is a need for improvement in the correlations between fire behavior on or near a slope and fire safety zones. An understanding of this effect could lead to more reliable guidelines for the establishment of firefighter safety zones, which are regions in wildfire areas that have been determined as safe for the survival of the firefighter. This paper discusses the ability of two commercial computational fluid dynamics (CFD) codes (Fire Dynamics Simulator (FDS) and STAR-CCM+) to model the results of actual flame experiments near barren slopes. Simulation results were compared to measured values of flame attachment length and radiative and convective heat fluxes. Pressure and temperature gradient measurements along the slope are reported. Proper modeling of small-scale experiments with such software packages can lead to more confidence in large scale simulations and eventual development of firefighter safety zones in wildfires.
2115 a57200207993 Roberts M. p851 False Conference 375 Modeling the coanda effect with FDS and STARCCM+ to predict the effect of fires on slopes for implications of wildland firefighter safety The Coanda effect is the behavior of a fluid flowing next to a solid surface which creates a change in pressure, thereby causing the fluid to attach to the surface. Little is known concerning the Coanda effect as it pertains to flame attachment in relation to wildfires. There is a need for improvement in the correlations between fire behavior on or near a slope and fire safety zones. An understanding of this effect could lead to more reliable guidelines for the establishment of firefighter safety zones, which are regions in wildfire areas that have been determined as safe for the survival of the firefighter. This paper discusses the ability of two commercial computational fluid dynamics (CFD) codes (Fire Dynamics Simulator (FDS) and STAR-CCM+) to model the results of actual flame experiments near barren slopes. Simulation results were compared to measured values of flame attachment length and radiative and convective heat fluxes. Pressure and temperature gradient measurements along the slope are reported. Proper modeling of small-scale experiments with such software packages can lead to more confidence in large scale simulations and eventual development of firefighter safety zones in wildfires.
2116 a56748981000 Tolman S.S. p852 True Conference 376 Elastic energy absorption of origami-based corrugations The mechanical properties of origami tessellations may provide innovative new designs for energy absorbing applications. The elastic energy absorbing properties of a particular tesselation, the Miura-ori, is investigated. Analytical models for the kinematics and force-deflection of a unit cell based on two different modes of elastic energy absorption are derived. The force-deflection model is developed based on the application of compliant mechanism theory and virtual work analysis. The models are verified through comparison with published results for similar models, analysis using commercial kinematics software and comparison to physical testing. Physical prototypes are used to determine values stiffness terms. The analytical models are used to explore the effects of the key geometrical parameters of the tessellation. This work lays a foundation for the use of origami-based corrugations in elastic energy absorption applications. Copyright © 2017 ASME.
2117 a56577146500 Ma F. p853 False Conference 377 A framework for energy-based kinetostatic modeling of compliant mechanisms Although energy-based methods have advantages over the Newtonian methods for kinetostatic modeling, the geometric nonlinearities inherent in deflections of compliant mechanisms preclude most of the energy-based theorems. Castigliano's first theorem and the Crotti-Engesser theorem, which don't require the problem being solved to be linear, are selected to construct the energy-based kinetostatic modeling framework for compliant mechanisms in this work. Utilization of these two theorems requires explicitly formulating the strain energy in terms of deflections and the complementary strain energy in terms of loads, which are derived based on the beam constraint model. The kinetostatic modeling of two compliant mechanisms are provided to demonstrate the effectiveness of using Castigliano's first theorem and the Crotti-Engesser theorem with the explicit formulations in this framework. Future work will be focused on incorporating use of the principle of minimum strain energy and the principle of minimum complementary strain energy. Copyright © 2017 ASME.
2118 a57188764210 Bai R. p853 False Conference 377 A framework for energy-based kinetostatic modeling of compliant mechanisms Although energy-based methods have advantages over the Newtonian methods for kinetostatic modeling, the geometric nonlinearities inherent in deflections of compliant mechanisms preclude most of the energy-based theorems. Castigliano's first theorem and the Crotti-Engesser theorem, which don't require the problem being solved to be linear, are selected to construct the energy-based kinetostatic modeling framework for compliant mechanisms in this work. Utilization of these two theorems requires explicitly formulating the strain energy in terms of deflections and the complementary strain energy in terms of loads, which are derived based on the beam constraint model. The kinetostatic modeling of two compliant mechanisms are provided to demonstrate the effectiveness of using Castigliano's first theorem and the Crotti-Engesser theorem with the explicit formulations in this framework. Future work will be focused on incorporating use of the principle of minimum strain energy and the principle of minimum complementary strain energy. Copyright © 2017 ASME.
2119 a55632390400 Nevers D.R. p857 True Journal 400 Engineering radical polymer electrodes for electrochemical energy storage In principle a wide range of organic materials can store energy in the form of reversible redox conversions of stable radicals. Such chemistry holds great promise for energy storage applications due to high theoretical capacities, high rate capabilities, intrinsic structural tunability, and the possibility of low-cost “green” syntheses from renewable sources. There have been steady improvements in the design of organic radical polymers, in which radicals are incorporated into the backbone and/or as pendant groups. This review highlights opportunities for improved redox molecule and polymer design along with the key challenges (e.g., transport phenomena, solubility, and reaction mechanisms) to transitioning known organic radicals into high-performance electrodes. Ultimately, organic-based batteries are still a nascent field with many open questions. Further advances in molecular design, electrode engineering, and device architecture will be required for these systems to reach their full potential and meet the diverse and increasing demands for energy storage. © 2017 Elsevier B.V.
2120 a35489877400 Brushett F.R. p857 False Journal 400 Engineering radical polymer electrodes for electrochemical energy storage In principle a wide range of organic materials can store energy in the form of reversible redox conversions of stable radicals. Such chemistry holds great promise for energy storage applications due to high theoretical capacities, high rate capabilities, intrinsic structural tunability, and the possibility of low-cost “green” syntheses from renewable sources. There have been steady improvements in the design of organic radical polymers, in which radicals are incorporated into the backbone and/or as pendant groups. This review highlights opportunities for improved redox molecule and polymer design along with the key challenges (e.g., transport phenomena, solubility, and reaction mechanisms) to transitioning known organic radicals into high-performance electrodes. Ultimately, organic-based batteries are still a nascent field with many open questions. Further advances in molecular design, electrode engineering, and device architecture will be required for these systems to reach their full potential and meet the diverse and increasing demands for energy storage. © 2017 Elsevier B.V.
2121 a57203030537 Wheeler D.R. p857 False Journal 400 Engineering radical polymer electrodes for electrochemical energy storage In principle a wide range of organic materials can store energy in the form of reversible redox conversions of stable radicals. Such chemistry holds great promise for energy storage applications due to high theoretical capacities, high rate capabilities, intrinsic structural tunability, and the possibility of low-cost “green” syntheses from renewable sources. There have been steady improvements in the design of organic radical polymers, in which radicals are incorporated into the backbone and/or as pendant groups. This review highlights opportunities for improved redox molecule and polymer design along with the key challenges (e.g., transport phenomena, solubility, and reaction mechanisms) to transitioning known organic radicals into high-performance electrodes. Ultimately, organic-based batteries are still a nascent field with many open questions. Further advances in molecular design, electrode engineering, and device architecture will be required for these systems to reach their full potential and meet the diverse and increasing demands for energy storage. © 2017 Elsevier B.V.
2122 a56800225200 Marr K.M. p858 False Journal 401 Improving sensitivity of electrochemical sensors with convective transport in free-standing, carbon nanotube structures High-aspect-ratio, porous membrane of vertically-aligned carbon nanotubes (CNTs) were developed through a templated microfabrication approach for electrochemical sensing. Nanostructured platinum (Pt) catalyst was deposited onto the CNTs with a facile, electroless deposition method, resulting in a Pt-nanowire-coated, CNT sensor (PN-CNT). Convective mass transfer enhancement was shown to improve PN-CNT sensor performance in the non‐enzymatic, amperometric sensing of hydrogen peroxide (H2O2). In particular, convective enhancement was achieved through the use of high surface area to fluid volume structures and concentration boundary layer confinement in a channel. Stir speed and sensor orientation especially influenced the measured current in stirred environments for sensors with through-channel diameters of 16 μm. Through-flow sensing produced drastically higher signals than stirred sensing with over 90% of the H2O2being oxidized as it passed through the PN-CNT sensor, even for low concentrations in the range of 50 nM to 500 μM. This effective utilization of the analyte in detection demonstrates the utility of exploiting convection in electrochemical sensing. For through‐flow at 100 μL s−1, a sensitivity of 24,300 μA mM−1 cm−2was achieved based on the frontal projected area (871 μA mM−1cm−2based on the nominal microchannel surface area), with a 0.03 μM limit of detection and a linear sensing range of 0.03–500 μM. © 2017 Elsevier B.V.
2123 a37052385600 Leake K.D. p860 False Journal 402 Optofluidic bioanalysis: Fundamentals and applications Over the past decade, optofluidics has established itself as a new and dynamic research field for exciting developments at the interface of photonics, microfluidics, and the life sciences. The strong desire for developing miniaturized bioanalytic devices and instruments, in particular, has led to novel and powerful approaches to integrating optical elements and biological fluids on the same chip-scale system. Here, we review the state-of-the-art in optofluidic research with emphasis on applications in bioanalysis and a focus on waveguide-based approaches that represent the most advanced level of integration between optics and fluidics. We discuss recent work in photonically reconfigurable devices and various application areas. We show how optofluidic approaches have been pushing the performance limits in bioanalysis, e.g. in terms of sensitivity and portability, satisfying many of the key requirements for point-of-care devices. This illustrates how the requirements for bianalysis instruments are increasingly being met by the symbiotic integration of novel photonic capabilities in a miniaturized system. © 2017, Holger Schmidt et al.
2124 a13410345300 Gallagher H.L. p861 False Conference 382 Acoustic shock formation in noise propagation during ground run-up operations of military aircraft A distinctive feature of many propagating, high-amplitude jet noise waveforms is the presence of acoustic shocks. Metrics indicative of shock presence, specifically the skewness of the time derivative of the waveform, the average steepening factor, and a new wavelet-based metric called the shock energy fraction (SEF), are used to quantify the strength and prevalence of acoustic shocks within waveforms recorded 10-305 m from a tethered military aircraft. The derivative skewness is more sensitive to the presence of the largest and steepest shocks, while the ASF and SEF tend to emphasize aggregate behavior of the entire waveform. These metrics are applied at engine conditions ranging from 50% to 150% engine thrust request, over a wide range of angles and distances, to assess the growth and decay of shock waves. The responses of these metrics point to significant shock formation occurring through nonlinear propagation out to 76 m from the microphone array reference position. Although these strongest shocks decay, the metrics point to continued nonlinear propagation in the far-field, out to 305 m. Many of these features are accurately characterized using a nonlinear propagation scheme based on the Burgers equation, but this scheme fails to account for multipath interference and significant atmospheric effects over the long propagation distances, resulting in an overestimation of nonlinearity metrics. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2125 a55693760600 Harker B.M. p863 True Conference 384 Beamforming-based wavepacket model for noise environment predictions of tactical aircraft Jet noise consists of extended, partially correlated sources such that a single-wavepacket source representation is inadequate. A multiple-wavepacket (MWP) model provides an analytical framework for jet-noise-like radiation to simulate jet noise field levels as well as the corresponding spatial coherence properties within the field. Here, a beamforming method with regularization is applied to noise measured by a linear array near a high-performance military aircraft. Beamforming results are decomposed into a reduced-order MWP model and the predicted radiation is validated in terms of level and coherence properties using benchmark measurements. Sound levels and coherence lengths generated by the beamforming results show good agreement with benchmark measurements over a range of frequencies that contribute significantly to the overall radiation. The MWP model is shown to predict full-scale specific features such as multilobe directivity patterns, and the addition of an uncorrelated distribution (UD) model adequately predicts the sideline radiation that is otherwise difficult to reproduce from wavepacket radiation. The MWP model predicted radiation characteristics are an improvement over single-wavepacket models, which do not incorporate spatiotemporal features of the radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2126 a57194853790 Cook M.R. p864 False Conference 385 Characterization of supersonic laboratory-scale jet noise with vector acoustic intensity A new method for the calculation of vector acoustic intensity from pressure microphone measurements has been applied to the aeroacoustic source characterization of an unheated, Mach 1.8 laboratory-scale jet. Because of the ability to unwrap the phase of the transfer functions between microphone pairs in the measurement of a radiating, broadband source, physically meaningful near-field intensity vectors are calculated up to the maximum analysis frequency of 32 kHz. The new intensity method is used to obtain a detailed description of the sound energy flow near the jet. The resulting intensity vectors have been used with a ray-tracing technique to identify the dominant source region over a broad range of frequencies. Additional aeroacoustics analyses provide insight into the frequency-dependent characteristics of jet noise radiation, including the nature of the hydrodynamic field and the transition between the principal lobe and sideline radiation. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2127 a35578275000 McKinley R.L. p865 False Conference 386 Preliminary investigation of multilobe fighter jet noise sources using acoustical holography An understanding of jet noise source mechanisms can facilitate targeted noise reduction efforts. This understanding has been enhanced with acoustic imaging technologies, such as near-field acoustical holography (NAH). In this study, multisource statistically optimized NAH (M-SONAH) was used to image the sound field near a tethered F-35 aircraft at multiple frequencies. A linear microphone array, placed along the ground, spanned the length of the jet exhaust plume. A multisource model of the sound field was included in the algorithm to incorporate the effects of the ground reflection on the measurement. Narrowband reconstructions elucidated fine details of the radiation patterns, such as multilobe radiation patterns (which may supersede “dual-lobe” patterns shown in previous studies), and broadband shock-associated noise. [Work supported by F-35 JPO.] © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2128 a26658095100 Gonzalez-Juez E.D. p866 True Conference 387 Effect of the turbulence modeling in large-eddy simulations of nonpremixed flames undergoing extinction and reignition Simulating practical combustion systems requires the approximation of the interaction between turbulence, molecular transport and chemical reactions. Turbulent combustion models are used for this purpose, but their behavior is difficult to anticipate based on their mathematical formulations, making the use of numerical experimentation necessary. Therefore, the present work explores the effect of three turbulent-combustion models, two eddy-viscosity models, and their parameters on a combustion problem which is notoriously difficult to model: flame extinction and reignition. For this purpose, two types of temporal jets are considered, and direct-numerical-simulation results are compared qualitatively with those from large-eddy simulations. © 2017 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
2129 a56362659400 Dasgupta A. p866 False Conference 387 Effect of the turbulence modeling in large-eddy simulations of nonpremixed flames undergoing extinction and reignition Simulating practical combustion systems requires the approximation of the interaction between turbulence, molecular transport and chemical reactions. Turbulent combustion models are used for this purpose, but their behavior is difficult to anticipate based on their mathematical formulations, making the use of numerical experimentation necessary. Therefore, the present work explores the effect of three turbulent-combustion models, two eddy-viscosity models, and their parameters on a combustion problem which is notoriously difficult to model: flame extinction and reignition. For this purpose, two types of temporal jets are considered, and direct-numerical-simulation results are compared qualitatively with those from large-eddy simulations. © 2017 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
2130 a57193867023 Arshad S. p866 False Conference 387 Effect of the turbulence modeling in large-eddy simulations of nonpremixed flames undergoing extinction and reignition Simulating practical combustion systems requires the approximation of the interaction between turbulence, molecular transport and chemical reactions. Turbulent combustion models are used for this purpose, but their behavior is difficult to anticipate based on their mathematical formulations, making the use of numerical experimentation necessary. Therefore, the present work explores the effect of three turbulent-combustion models, two eddy-viscosity models, and their parameters on a combustion problem which is notoriously difficult to model: flame extinction and reignition. For this purpose, two types of temporal jets are considered, and direct-numerical-simulation results are compared qualitatively with those from large-eddy simulations. © 2017 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
2131 a56913378600 Skousen D.J. p867 True Conference 388 Exploration of carbon-filled carbon nanotube vascular stents The purpose of this research was to design, fabricate, and test coronary stent designs composed of carbon-infiltrated carbon nanotubes (CI-CNTs). Coronary stents currently have two major complications: restenosis and thrombosis. CI-CNT stents may provide improved clinical outcomes for both of these issues. Multiple stent design concepts were generated, evaluated, and two stent designs were selected: one with a semi-auxetic nature, and one designed for maximum force. These designs were further developed and optimized using analytical tools along with finite element analysis. Planar versions of the stent designs were manufactured and mechanically tested to verify performance. The performance of the cylindrical stent configurations was analyzed using finite element modeling. A sample cylindrical stent was also fabricated. This research demonstrates that feasible coronary stent designs can be manufactured from CI-CNTs. However, a major challenge for CI-CNT stent designs is meeting the design requirement of sufficient radial force. © Springer International Publishing Switzerland 2017.
2132 a56086163900 Jones K.N. p867 False Conference 388 Exploration of carbon-filled carbon nanotube vascular stents The purpose of this research was to design, fabricate, and test coronary stent designs composed of carbon-infiltrated carbon nanotubes (CI-CNTs). Coronary stents currently have two major complications: restenosis and thrombosis. CI-CNT stents may provide improved clinical outcomes for both of these issues. Multiple stent design concepts were generated, evaluated, and two stent designs were selected: one with a semi-auxetic nature, and one designed for maximum force. These designs were further developed and optimized using analytical tools along with finite element analysis. Planar versions of the stent designs were manufactured and mechanically tested to verify performance. The performance of the cylindrical stent configurations was analyzed using finite element modeling. A sample cylindrical stent was also fabricated. This research demonstrates that feasible coronary stent designs can be manufactured from CI-CNTs. However, a major challenge for CI-CNT stent designs is meeting the design requirement of sufficient radial force. © Springer International Publishing Switzerland 2017.
2133 a57191407630 Kowalski T. p867 False Conference 388 Exploration of carbon-filled carbon nanotube vascular stents The purpose of this research was to design, fabricate, and test coronary stent designs composed of carbon-infiltrated carbon nanotubes (CI-CNTs). Coronary stents currently have two major complications: restenosis and thrombosis. CI-CNT stents may provide improved clinical outcomes for both of these issues. Multiple stent design concepts were generated, evaluated, and two stent designs were selected: one with a semi-auxetic nature, and one designed for maximum force. These designs were further developed and optimized using analytical tools along with finite element analysis. Planar versions of the stent designs were manufactured and mechanically tested to verify performance. The performance of the cylindrical stent configurations was analyzed using finite element modeling. A sample cylindrical stent was also fabricated. This research demonstrates that feasible coronary stent designs can be manufactured from CI-CNTs. However, a major challenge for CI-CNT stent designs is meeting the design requirement of sufficient radial force. © Springer International Publishing Switzerland 2017.
2134 a57201909948 Tiwari R. p868 True Conference 389 Effect of leader placement on robotic swarm control Human control of a robotic swarm entails selecting a few influential leaders who can steer the collective efficiently and robustly. However, a clear measure of influence with respect to leader position is not adequately studied. Studies with animal systems have shown that leaders who exert strong couplings may be located in front, where they provide energy benefits, or in the middle, where they can be seen by a larger section of the group. In this paper, we systematically vary number of leaders and leader positions in simulated robotic swarms of two different sizes, and assess their effect on steering effectiveness and energy expenditure. In particular, we analyze the effect of placing leaders in the front, middle, and periphery, on the time to converge and lateral acceleration of a swarm of robotic agents as it performs a single turn to reach the desired goal direction. Our results show that swarms with leaders in the middle and periphery take less time to converge than swarms with leaders in the front, while the lateral acceleration between the three placement strategies is not different. We also find that the time to converge towards the goal direction reduces with the increase in percentage of leaders in the swarm, although this value decays slowly beyond the percentage of leaders at 30%. As the swarm size is increased, we find that the leaders in the periphery become less effective in reducing the time to converge. Finally, closer analysis of leader placement and coverage reveals that front leaders within the swarm tend to expand their coverage and move towards the center as the maneuver is performed. Results from this study are expected to inform leader placement strategies towards more effective human swarm interaction systems. © Copyright 2017, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.
2135 a35344727500 Jain P. p868 False Conference 389 Effect of leader placement on robotic swarm control Human control of a robotic swarm entails selecting a few influential leaders who can steer the collective efficiently and robustly. However, a clear measure of influence with respect to leader position is not adequately studied. Studies with animal systems have shown that leaders who exert strong couplings may be located in front, where they provide energy benefits, or in the middle, where they can be seen by a larger section of the group. In this paper, we systematically vary number of leaders and leader positions in simulated robotic swarms of two different sizes, and assess their effect on steering effectiveness and energy expenditure. In particular, we analyze the effect of placing leaders in the front, middle, and periphery, on the time to converge and lateral acceleration of a swarm of robotic agents as it performs a single turn to reach the desired goal direction. Our results show that swarms with leaders in the middle and periphery take less time to converge than swarms with leaders in the front, while the lateral acceleration between the three placement strategies is not different. We also find that the time to converge towards the goal direction reduces with the increase in percentage of leaders in the swarm, although this value decays slowly beyond the percentage of leaders at 30%. As the swarm size is increased, we find that the leaders in the periphery become less effective in reducing the time to converge. Finally, closer analysis of leader placement and coverage reveals that front leaders within the swarm tend to expand their coverage and move towards the center as the maneuver is performed. Results from this study are expected to inform leader placement strategies towards more effective human swarm interaction systems. © Copyright 2017, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.
2136 a35408719100 Butail S. p868 False Conference 389 Effect of leader placement on robotic swarm control Human control of a robotic swarm entails selecting a few influential leaders who can steer the collective efficiently and robustly. However, a clear measure of influence with respect to leader position is not adequately studied. Studies with animal systems have shown that leaders who exert strong couplings may be located in front, where they provide energy benefits, or in the middle, where they can be seen by a larger section of the group. In this paper, we systematically vary number of leaders and leader positions in simulated robotic swarms of two different sizes, and assess their effect on steering effectiveness and energy expenditure. In particular, we analyze the effect of placing leaders in the front, middle, and periphery, on the time to converge and lateral acceleration of a swarm of robotic agents as it performs a single turn to reach the desired goal direction. Our results show that swarms with leaders in the middle and periphery take less time to converge than swarms with leaders in the front, while the lateral acceleration between the three placement strategies is not different. We also find that the time to converge towards the goal direction reduces with the increase in percentage of leaders in the swarm, although this value decays slowly beyond the percentage of leaders at 30%. As the swarm size is increased, we find that the leaders in the periphery become less effective in reducing the time to converge. Finally, closer analysis of leader placement and coverage reveals that front leaders within the swarm tend to expand their coverage and move towards the center as the maneuver is performed. Results from this study are expected to inform leader placement strategies towards more effective human swarm interaction systems. © Copyright 2017, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.
2137 a55807632000 Baliyarasimhuni S.P. p868 False Conference 389 Effect of leader placement on robotic swarm control Human control of a robotic swarm entails selecting a few influential leaders who can steer the collective efficiently and robustly. However, a clear measure of influence with respect to leader position is not adequately studied. Studies with animal systems have shown that leaders who exert strong couplings may be located in front, where they provide energy benefits, or in the middle, where they can be seen by a larger section of the group. In this paper, we systematically vary number of leaders and leader positions in simulated robotic swarms of two different sizes, and assess their effect on steering effectiveness and energy expenditure. In particular, we analyze the effect of placing leaders in the front, middle, and periphery, on the time to converge and lateral acceleration of a swarm of robotic agents as it performs a single turn to reach the desired goal direction. Our results show that swarms with leaders in the middle and periphery take less time to converge than swarms with leaders in the front, while the lateral acceleration between the three placement strategies is not different. We also find that the time to converge towards the goal direction reduces with the increase in percentage of leaders in the swarm, although this value decays slowly beyond the percentage of leaders at 30%. As the swarm size is increased, we find that the leaders in the periphery become less effective in reducing the time to converge. Finally, closer analysis of leader placement and coverage reveals that front leaders within the swarm tend to expand their coverage and move towards the center as the maneuver is performed. Results from this study are expected to inform leader placement strategies towards more effective human swarm interaction systems. © Copyright 2017, International Foundation for Autonomous Agents and Multiagent Systems (www.ifaamas.org). All rights reserved.
2138 a57194116428 Scott E. p869 False Conference 390 Geofoam inclusions for reducing passive force on bridge abutments based on large-scale tests To decrease lateral earth pressures on structures, a zone of compressible material or an "inclusion" can be used as a barrier to decrease lateral earth pressures on structures. The compressible material is typically expanded polystyrene or geofoam. Little guidance is available on the development of passive force with an inclusion. To explore this issue, large-scale passive force tests were conducted with and without a geofoam inclusion acting as a barrier between the backfill soil and a simulated bridge abutment. The presence of the geofoam inclusion reduced the passive force by 70% relative to the sand backfill alone. Although the measured force and failure geometry appeared to conform to a log-spiral mechanism when only sand backfill was used, the geofoam inclusion transforms the failure geometry to a Rankine failure mechanism. This suggests that the geofoam acted to reduce the interface friction between the wall and the backfill sand thereby reducing the passive resistance. © ASCE.
2139 a55932655400 Marsh A. p869 False Conference 390 Geofoam inclusions for reducing passive force on bridge abutments based on large-scale tests To decrease lateral earth pressures on structures, a zone of compressible material or an "inclusion" can be used as a barrier to decrease lateral earth pressures on structures. The compressible material is typically expanded polystyrene or geofoam. Little guidance is available on the development of passive force with an inclusion. To explore this issue, large-scale passive force tests were conducted with and without a geofoam inclusion acting as a barrier between the backfill soil and a simulated bridge abutment. The presence of the geofoam inclusion reduced the passive force by 70% relative to the sand backfill alone. Although the measured force and failure geometry appeared to conform to a log-spiral mechanism when only sand backfill was used, the geofoam inclusion transforms the failure geometry to a Rankine failure mechanism. This suggests that the geofoam acted to reduce the interface friction between the wall and the backfill sand thereby reducing the passive resistance. © ASCE.
2140 a6701753933 Jüttler B. p870 True Journal 403 Isogeometric design and analysis [No abstract available]
2141 a55722439300 Qian X. p870 False Journal 403 Isogeometric design and analysis [No abstract available]
2142 a6507743831 Barker E.I. p872 True Journal 404 Predicting Lap Shear Strength for Friction Stir Scribe Joining of Dissimilar Materials Friction stir scribe technology has been developed to join materials with vastly different properties, most importantly different melting regimes. Specifically lighter, lower temperature materials such as aluminum or magnesium can be joined to higher temperature materials such as steel and titanium. The scribe portion of the modified friction stir welding pin tool creates in situ mechanical interlocks at the material interface. This mechanical interlocking, or hook-like interface morphology, has shown promising joint strength. However, this morphology can vary along a weld length and is sensitive to joining and tooling parameters. The current work seeks to determine the sensitivity of joint strength to the morphology of the hook interface and predict joint strength based on key morphology parameters. Key morphology features of the hooks extracted from joined samples are varied to quantify their impact on simulated lap shear strength. Predictable joint strength is key to wide spread use of this technique. © 2017, The Minerals, Metals & Materials Society.
2143 a8624941100 Sun X. p872 False Journal 404 Predicting Lap Shear Strength for Friction Stir Scribe Joining of Dissimilar Materials Friction stir scribe technology has been developed to join materials with vastly different properties, most importantly different melting regimes. Specifically lighter, lower temperature materials such as aluminum or magnesium can be joined to higher temperature materials such as steel and titanium. The scribe portion of the modified friction stir welding pin tool creates in situ mechanical interlocks at the material interface. This mechanical interlocking, or hook-like interface morphology, has shown promising joint strength. However, this morphology can vary along a weld length and is sensitive to joining and tooling parameters. The current work seeks to determine the sensitivity of joint strength to the morphology of the hook interface and predict joint strength based on key morphology parameters. Key morphology features of the hooks extracted from joined samples are varied to quantify their impact on simulated lap shear strength. Predictable joint strength is key to wide spread use of this technique. © 2017, The Minerals, Metals & Materials Society.
2144 a57202394793 Harris R. p875 True Journal 406 Waves of destruction in the East Indies: The Wichmann catalogue of earthquakes and tsunami in the Indonesian region from 1538 to 1877 The two volumes of Arthur Wichmann's Die Erdbeben Des Indischen Archipels [The Earthquakes of the Indian Archipelago] (1918 and 1922) document 61 regional earthquakes and 36 tsunamis between 1538 and 1877 in the Indonesian region. The largest and best documented are the events of 1770 and 1859 in the Molucca Sea region, of 1629, 1774 and 1852 in the Banda Sea region, the 1820 event in Makassar, the 1857 event in Dili, Timor, the 1815 event in Bali and Lombok, the events of 1699, 1771, 1780, 1815, 1848 and 1852 in Java, and the events of 1797, 1818, 1833 and 1861 in Sumatra. Most of these events caused damage over a broad region, and are associated with years of temporal and spatial clustering of earthquakes. The earthquakes left many cities in 'rubble heaps'. Some events spawned tsunamis with run-up heights >15 m that swept many coastal villages away. 2004 marked the recurrence of some of these events in western Indonesia. However, there has not been a major shallow earthquake (M ≥ 8) in Java and eastern Indonesia for the past 160 years. During this time of relative quiescence, enough tectonic strain energy has accumulated across several active faults to cause major earthquake and tsunami events, such as those documented in the historical records presented here. The disaster potential of these events is much greater now than in the past due to exponential growth in population and urbanization in areas destroyed by past events. © 2017 The Author(s).
2145 a56587519900 Major J. p875 False Journal 406 Waves of destruction in the East Indies: The Wichmann catalogue of earthquakes and tsunami in the Indonesian region from 1538 to 1877 The two volumes of Arthur Wichmann's Die Erdbeben Des Indischen Archipels [The Earthquakes of the Indian Archipelago] (1918 and 1922) document 61 regional earthquakes and 36 tsunamis between 1538 and 1877 in the Indonesian region. The largest and best documented are the events of 1770 and 1859 in the Molucca Sea region, of 1629, 1774 and 1852 in the Banda Sea region, the 1820 event in Makassar, the 1857 event in Dili, Timor, the 1815 event in Bali and Lombok, the events of 1699, 1771, 1780, 1815, 1848 and 1852 in Java, and the events of 1797, 1818, 1833 and 1861 in Sumatra. Most of these events caused damage over a broad region, and are associated with years of temporal and spatial clustering of earthquakes. The earthquakes left many cities in 'rubble heaps'. Some events spawned tsunamis with run-up heights >15 m that swept many coastal villages away. 2004 marked the recurrence of some of these events in western Indonesia. However, there has not been a major shallow earthquake (M ≥ 8) in Java and eastern Indonesia for the past 160 years. During this time of relative quiescence, enough tectonic strain energy has accumulated across several active faults to cause major earthquake and tsunami events, such as those documented in the historical records presented here. The disaster potential of these events is much greater now than in the past due to exponential growth in population and urbanization in areas destroyed by past events. © 2017 The Author(s).
2146 a12797217700 Zentner L. p876 True Journal 407 Preface [No abstract available]
2147 a6602247507 Corves B. p876 False Journal 407 Preface [No abstract available]
2148 a25628175700 Lovasz E.-C. p876 False Journal 407 Preface [No abstract available]
2149 a57209165874 Nguyen T. p879 False Conference 395 The use of unmanned aerial vehicles and structures from motion to measure the volume change at a deep dynamic compaction site A small unmanned aerial vehicle (sUAV) is used with structure from motion (SfM) computer vision (Marr and Nishihara 1978; Snavely et al. 2008) to measure the amount of settlement that is induced by deep dynamic compaction at a site of a new casino near Lake Havasu City, AZ. Details of the project and field operations are provided, and comparisons are made between induced settlement measurements from traditional techniques and induced settlement measurements from the new sUAV/SfM approach. Results of the study show that the sUAV/SfM approach estimates an average induced settlement of 38 cm across the site, which straddles within 2.5 cm of the average induced settlements that were measured with other traditional techniques. Additionally, the sUAV/SfM technique is shown to provide significant detail of the distribution of induced settlements across the site. This distribution of settlements could be indicative of the distribution of subsurface soils that were more affected by the DDC such as looser or cleaner sands. Implications of the findings of this study are briefly discussed. © ASCE.
2150 a7202842875 Shao L. p879 False Conference 395 The use of unmanned aerial vehicles and structures from motion to measure the volume change at a deep dynamic compaction site A small unmanned aerial vehicle (sUAV) is used with structure from motion (SfM) computer vision (Marr and Nishihara 1978; Snavely et al. 2008) to measure the amount of settlement that is induced by deep dynamic compaction at a site of a new casino near Lake Havasu City, AZ. Details of the project and field operations are provided, and comparisons are made between induced settlement measurements from traditional techniques and induced settlement measurements from the new sUAV/SfM approach. Results of the study show that the sUAV/SfM approach estimates an average induced settlement of 38 cm across the site, which straddles within 2.5 cm of the average induced settlements that were measured with other traditional techniques. Additionally, the sUAV/SfM technique is shown to provide significant detail of the distribution of induced settlements across the site. This distribution of settlements could be indicative of the distribution of subsurface soils that were more affected by the DDC such as looser or cleaner sands. Implications of the findings of this study are briefly discussed. © ASCE.
2151 a57193807582 Bender C. p879 False Conference 395 The use of unmanned aerial vehicles and structures from motion to measure the volume change at a deep dynamic compaction site A small unmanned aerial vehicle (sUAV) is used with structure from motion (SfM) computer vision (Marr and Nishihara 1978; Snavely et al. 2008) to measure the amount of settlement that is induced by deep dynamic compaction at a site of a new casino near Lake Havasu City, AZ. Details of the project and field operations are provided, and comparisons are made between induced settlement measurements from traditional techniques and induced settlement measurements from the new sUAV/SfM approach. Results of the study show that the sUAV/SfM approach estimates an average induced settlement of 38 cm across the site, which straddles within 2.5 cm of the average induced settlements that were measured with other traditional techniques. Additionally, the sUAV/SfM technique is shown to provide significant detail of the distribution of induced settlements across the site. This distribution of settlements could be indicative of the distribution of subsurface soils that were more affected by the DDC such as looser or cleaner sands. Implications of the findings of this study are briefly discussed. © ASCE.
2152 a57194008450 Wolfe D. p879 False Conference 395 The use of unmanned aerial vehicles and structures from motion to measure the volume change at a deep dynamic compaction site A small unmanned aerial vehicle (sUAV) is used with structure from motion (SfM) computer vision (Marr and Nishihara 1978; Snavely et al. 2008) to measure the amount of settlement that is induced by deep dynamic compaction at a site of a new casino near Lake Havasu City, AZ. Details of the project and field operations are provided, and comparisons are made between induced settlement measurements from traditional techniques and induced settlement measurements from the new sUAV/SfM approach. Results of the study show that the sUAV/SfM approach estimates an average induced settlement of 38 cm across the site, which straddles within 2.5 cm of the average induced settlements that were measured with other traditional techniques. Additionally, the sUAV/SfM technique is shown to provide significant detail of the distribution of induced settlements across the site. This distribution of settlements could be indicative of the distribution of subsurface soils that were more affected by the DDC such as looser or cleaner sands. Implications of the findings of this study are briefly discussed. © ASCE.
2153 a57193811936 Reimschiissel B. p879 False Conference 395 The use of unmanned aerial vehicles and structures from motion to measure the volume change at a deep dynamic compaction site A small unmanned aerial vehicle (sUAV) is used with structure from motion (SfM) computer vision (Marr and Nishihara 1978; Snavely et al. 2008) to measure the amount of settlement that is induced by deep dynamic compaction at a site of a new casino near Lake Havasu City, AZ. Details of the project and field operations are provided, and comparisons are made between induced settlement measurements from traditional techniques and induced settlement measurements from the new sUAV/SfM approach. Results of the study show that the sUAV/SfM approach estimates an average induced settlement of 38 cm across the site, which straddles within 2.5 cm of the average induced settlements that were measured with other traditional techniques. Additionally, the sUAV/SfM technique is shown to provide significant detail of the distribution of induced settlements across the site. This distribution of settlements could be indicative of the distribution of subsurface soils that were more affected by the DDC such as looser or cleaner sands. Implications of the findings of this study are briefly discussed. © ASCE.
2154 a26538762200 Sabau S. p880 True Journal 408 Optimal Distributed Control for Platooning via Sparse Coprime Factorizations We introduce a novel distributed control architecture for heterogeneous platoons of linear time-invariant autonomous vehicles. Our approach is based on a generalization of the concept of leader-follower controllers for which we provide a Youla-like parameterization, while the sparsity constraints are imposed on the controller's left coprime factors, outlining a new concept of structural constraints in distributed control. The proposed scheme is amenable to optimal controller design via norm based costs, it guarantees string stability and eliminates the accordion effect from the behavior of the platoon. We also introduce a synchronization mechanism for the exact compensation of the time delays induced by the wireless communications. © 1963-2012 IEEE.
2155 a7003702751 Oara C. p880 False Journal 408 Optimal Distributed Control for Platooning via Sparse Coprime Factorizations We introduce a novel distributed control architecture for heterogeneous platoons of linear time-invariant autonomous vehicles. Our approach is based on a generalization of the concept of leader-follower controllers for which we provide a Youla-like parameterization, while the sparsity constraints are imposed on the controller's left coprime factors, outlining a new concept of structural constraints in distributed control. The proposed scheme is amenable to optimal controller design via norm based costs, it guarantees string stability and eliminates the accordion effect from the behavior of the platoon. We also introduce a synchronization mechanism for the exact compensation of the time delays induced by the wireless communications. © 1963-2012 IEEE.
2156 a9636293200 Jadbabaie A. p880 False Journal 408 Optimal Distributed Control for Platooning via Sparse Coprime Factorizations We introduce a novel distributed control architecture for heterogeneous platoons of linear time-invariant autonomous vehicles. Our approach is based on a generalization of the concept of leader-follower controllers for which we provide a Youla-like parameterization, while the sparsity constraints are imposed on the controller's left coprime factors, outlining a new concept of structural constraints in distributed control. The proposed scheme is amenable to optimal controller design via norm based costs, it guarantees string stability and eliminates the accordion effect from the behavior of the platoon. We also introduce a synchronization mechanism for the exact compensation of the time delays induced by the wireless communications. © 1963-2012 IEEE.
2157 a57202040530 Mancini S. p881 False Conference 396 Highly compressible origami bellows for microgravity drilling-debris containment The design and testing of an origami-based bellows for microgravity drilling is described. The potential benefits of an origami-based solution created an opportunity for application on NASA’s Asteroid Redirect Mission (ARM) to protect sensitive parts from debris. Origami-based bellows were designed to fit spatial limitations and meet needed compression ratios. Designs have demonstrated high mass reductions, improved stroke length, greatly decreased stowed volume, improved flexibility, and reduced reaction forces in comparison with traditional metal bellows. A nylon-reinforced polyvinyl fluoride based bellows with an aramid fiber stitched seam is well suited for debris containment in space conditions. Various epoxies maintained an adequate bond with polyvinyl fluoride below expected environmental temperature for bellows mounting. Asymmetric compression of the bellows occurs at extreme low temperatures and is preventable by balancing stiffness within the structure. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2158 a23006267900 Parness A. p881 False Conference 396 Highly compressible origami bellows for microgravity drilling-debris containment The design and testing of an origami-based bellows for microgravity drilling is described. The potential benefits of an origami-based solution created an opportunity for application on NASA’s Asteroid Redirect Mission (ARM) to protect sensitive parts from debris. Origami-based bellows were designed to fit spatial limitations and meet needed compression ratios. Designs have demonstrated high mass reductions, improved stroke length, greatly decreased stowed volume, improved flexibility, and reduced reaction forces in comparison with traditional metal bellows. A nylon-reinforced polyvinyl fluoride based bellows with an aramid fiber stitched seam is well suited for debris containment in space conditions. Various epoxies maintained an adequate bond with polyvinyl fluoride below expected environmental temperature for bellows mounting. Asymmetric compression of the bellows occurs at extreme low temperatures and is preventable by balancing stiffness within the structure. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
2159 a7004002400 Chee P.W. p882 True Journal 409 Interspecific hybridization for upland cotton improvement Interspecific hybridization has been central to the evolution, domestication, and improvement of Upland cotton, the cultivated form of Gossypium hirsutum. As the world’s most important fiber crop species, Gossypium hirsutum belongs to the allotetraploid Gossypium clade that consists of six additional species. The lint fiber evolved only once in the history of Gossypium, in the ancestor diploid A-genome species, and this trait was passed on to the allopolyploid species when the A-genome united in a common nucleus with a D-genome from the other ancestor that produced no lint fibers. The domestication history of G. hirsutum involved the collection and use of lint fibers by indigenous people for the purpose of making strings and other textile products; hence, spinnable lint fibers were likely to have evolved under domestication. The geographical distribution of G. hirsutum overlaps with G. barbadense and G. mustelinum, and gene flow among these species has been documented. Therefore, the introgression of novel alleles into G. hirsutum possibly contributed to greater ecological adaptation in colonizing new habitats and providing important sources of genetic variation for artificial selection in the early domestication efforts. In modern Upland cotton, numerous germplasm lines have been developed from crossing with G. barbadense. However, reproductive barriers such as reduced fertility, segregation distortion, and hybrid breakdown are often observed in later generation hybrids between G. hirsutum and the other polyploid species, complicating the task of introgressing new, stably inherited allelic variation from inter specific hybridization. Recent efforts in molecular genetic research have provided insights into the location and effects of QTLs from wild species that are associated with traits important to cotton production. These and future research efforts will undoubtedly provide the tools that can be utilized by plant breeders to access novel genes from wild and domesticated allotetraploid Gossypium for Upland cotton improvement. © 2016 by Taylor & Francis Group, LLC.
2160 a7202361029 Paterson A.H. p882 False Journal 409 Interspecific hybridization for upland cotton improvement Interspecific hybridization has been central to the evolution, domestication, and improvement of Upland cotton, the cultivated form of Gossypium hirsutum. As the world’s most important fiber crop species, Gossypium hirsutum belongs to the allotetraploid Gossypium clade that consists of six additional species. The lint fiber evolved only once in the history of Gossypium, in the ancestor diploid A-genome species, and this trait was passed on to the allopolyploid species when the A-genome united in a common nucleus with a D-genome from the other ancestor that produced no lint fibers. The domestication history of G. hirsutum involved the collection and use of lint fibers by indigenous people for the purpose of making strings and other textile products; hence, spinnable lint fibers were likely to have evolved under domestication. The geographical distribution of G. hirsutum overlaps with G. barbadense and G. mustelinum, and gene flow among these species has been documented. Therefore, the introgression of novel alleles into G. hirsutum possibly contributed to greater ecological adaptation in colonizing new habitats and providing important sources of genetic variation for artificial selection in the early domestication efforts. In modern Upland cotton, numerous germplasm lines have been developed from crossing with G. barbadense. However, reproductive barriers such as reduced fertility, segregation distortion, and hybrid breakdown are often observed in later generation hybrids between G. hirsutum and the other polyploid species, complicating the task of introgressing new, stably inherited allelic variation from inter specific hybridization. Recent efforts in molecular genetic research have provided insights into the location and effects of QTLs from wild species that are associated with traits important to cotton production. These and future research efforts will undoubtedly provide the tools that can be utilized by plant breeders to access novel genes from wild and domesticated allotetraploid Gossypium for Upland cotton improvement. © 2016 by Taylor & Francis Group, LLC.
2161 a7007170899 Udall J.A. p882 False Journal 409 Interspecific hybridization for upland cotton improvement Interspecific hybridization has been central to the evolution, domestication, and improvement of Upland cotton, the cultivated form of Gossypium hirsutum. As the world’s most important fiber crop species, Gossypium hirsutum belongs to the allotetraploid Gossypium clade that consists of six additional species. The lint fiber evolved only once in the history of Gossypium, in the ancestor diploid A-genome species, and this trait was passed on to the allopolyploid species when the A-genome united in a common nucleus with a D-genome from the other ancestor that produced no lint fibers. The domestication history of G. hirsutum involved the collection and use of lint fibers by indigenous people for the purpose of making strings and other textile products; hence, spinnable lint fibers were likely to have evolved under domestication. The geographical distribution of G. hirsutum overlaps with G. barbadense and G. mustelinum, and gene flow among these species has been documented. Therefore, the introgression of novel alleles into G. hirsutum possibly contributed to greater ecological adaptation in colonizing new habitats and providing important sources of genetic variation for artificial selection in the early domestication efforts. In modern Upland cotton, numerous germplasm lines have been developed from crossing with G. barbadense. However, reproductive barriers such as reduced fertility, segregation distortion, and hybrid breakdown are often observed in later generation hybrids between G. hirsutum and the other polyploid species, complicating the task of introgressing new, stably inherited allelic variation from inter specific hybridization. Recent efforts in molecular genetic research have provided insights into the location and effects of QTLs from wild species that are associated with traits important to cotton production. These and future research efforts will undoubtedly provide the tools that can be utilized by plant breeders to access novel genes from wild and domesticated allotetraploid Gossypium for Upland cotton improvement. © 2016 by Taylor & Francis Group, LLC.
2162 a7005725911 Wendel J.F. p882 False Journal 409 Interspecific hybridization for upland cotton improvement Interspecific hybridization has been central to the evolution, domestication, and improvement of Upland cotton, the cultivated form of Gossypium hirsutum. As the world’s most important fiber crop species, Gossypium hirsutum belongs to the allotetraploid Gossypium clade that consists of six additional species. The lint fiber evolved only once in the history of Gossypium, in the ancestor diploid A-genome species, and this trait was passed on to the allopolyploid species when the A-genome united in a common nucleus with a D-genome from the other ancestor that produced no lint fibers. The domestication history of G. hirsutum involved the collection and use of lint fibers by indigenous people for the purpose of making strings and other textile products; hence, spinnable lint fibers were likely to have evolved under domestication. The geographical distribution of G. hirsutum overlaps with G. barbadense and G. mustelinum, and gene flow among these species has been documented. Therefore, the introgression of novel alleles into G. hirsutum possibly contributed to greater ecological adaptation in colonizing new habitats and providing important sources of genetic variation for artificial selection in the early domestication efforts. In modern Upland cotton, numerous germplasm lines have been developed from crossing with G. barbadense. However, reproductive barriers such as reduced fertility, segregation distortion, and hybrid breakdown are often observed in later generation hybrids between G. hirsutum and the other polyploid species, complicating the task of introgressing new, stably inherited allelic variation from inter specific hybridization. Recent efforts in molecular genetic research have provided insights into the location and effects of QTLs from wild species that are associated with traits important to cotton production. These and future research efforts will undoubtedly provide the tools that can be utilized by plant breeders to access novel genes from wild and domesticated allotetraploid Gossypium for Upland cotton improvement. © 2016 by Taylor & Francis Group, LLC.
2163 a56024800300 Liu L. p883 False Journal 410 Thermophysical properties of thin fibers via photothermal quantum dot fluorescence spectral shape-based thermometry To improve predictions of composite behavior under thermal loads, there is a need to measure the axial thermophysical properties of thin fibers. Current methods to accomplish this have prohibitively long lead times due to extensive sample preparation. This work details the use of quantum dots thermomarkers to measure the surface temperature of thin fibers in a non-contact manner and determine the fibers’ thermal diffusivity. Neural networks are trained on extracting the temperature of a sample from fluorescence spectra in calibrated, steady-state conditions, based on different spectral features such as peak intensity and peak wavelength. The trained neural networks are then used to reconstruct the evolution of the surface temperature in transient heating experiments. In order to determine the thermal properties of a thin fiber, modulated laser heating is applied and an FFT-based method is used to extract the phase and amplitude response of the temperature field at the modulation frequency. The spatiotemporal dependence of the fluorescence signal, obtained by scanning the distance between the excitation and detection laser spots and varying the frequency response due to an axial scan and a frequency scan, is then curve-fit to the resulting decay curves by a photothermal model in order to determine the thermal diffusivity of the fiber. The measured thermal diffusivity (3.3 ± 0.8 × 10−7 m2 s−1) of a synthetic spider silk fiber by the current method has similar properties to other synthetic silk fibers, and demonstrates the ability of the current method to more rapidly measure thermophysical properties of thin fibers. © 2017 Elsevier Ltd
2164 a57203269936 Glorieux C. p883 False Journal 410 Thermophysical properties of thin fibers via photothermal quantum dot fluorescence spectral shape-based thermometry To improve predictions of composite behavior under thermal loads, there is a need to measure the axial thermophysical properties of thin fibers. Current methods to accomplish this have prohibitively long lead times due to extensive sample preparation. This work details the use of quantum dots thermomarkers to measure the surface temperature of thin fibers in a non-contact manner and determine the fibers’ thermal diffusivity. Neural networks are trained on extracting the temperature of a sample from fluorescence spectra in calibrated, steady-state conditions, based on different spectral features such as peak intensity and peak wavelength. The trained neural networks are then used to reconstruct the evolution of the surface temperature in transient heating experiments. In order to determine the thermal properties of a thin fiber, modulated laser heating is applied and an FFT-based method is used to extract the phase and amplitude response of the temperature field at the modulation frequency. The spatiotemporal dependence of the fluorescence signal, obtained by scanning the distance between the excitation and detection laser spots and varying the frequency response due to an axial scan and a frequency scan, is then curve-fit to the resulting decay curves by a photothermal model in order to determine the thermal diffusivity of the fiber. The measured thermal diffusivity (3.3 ± 0.8 × 10−7 m2 s−1) of a synthetic spider silk fiber by the current method has similar properties to other synthetic silk fibers, and demonstrates the ability of the current method to more rapidly measure thermophysical properties of thin fibers. © 2017 Elsevier Ltd
2165 a57192908187 Ravert J. p886 False Conference 398 A summary of data-aided equalizer experiments at edwards AFB This paper summarizes the analysis of bit error rate data captured during flight tests designed to compare data-aided equalizers with SOQPSK-TG to unequalized and currently available blind, adaptive equalizers with SOQPSK-TG. The number of bit errors, on a second-by-second basis, are analyzed. The results are different for each test point. Given the uncertain behavior of the preamble detector for the data-aided equalizer and the differing channel conditions between the data-aided equalizer channel and the conventional serial streaming telemetry channel, we are unable to draw any firm comparative conclusions.
2166 a6603263001 Cole-Rhodes A. p886 False Conference 398 A summary of data-aided equalizer experiments at edwards AFB This paper summarizes the analysis of bit error rate data captured during flight tests designed to compare data-aided equalizers with SOQPSK-TG to unequalized and currently available blind, adaptive equalizers with SOQPSK-TG. The number of bit errors, on a second-by-second basis, are analyzed. The results are different for each test point. Given the uncertain behavior of the preamble detector for the data-aided equalizer and the differing channel conditions between the data-aided equalizer channel and the conventional serial streaming telemetry channel, we are unable to draw any firm comparative conclusions.
2167 a26325009000 Moazzami F. p886 False Conference 398 A summary of data-aided equalizer experiments at edwards AFB This paper summarizes the analysis of bit error rate data captured during flight tests designed to compare data-aided equalizers with SOQPSK-TG to unequalized and currently available blind, adaptive equalizers with SOQPSK-TG. The number of bit errors, on a second-by-second basis, are analyzed. The results are different for each test point. Given the uncertain behavior of the preamble detector for the data-aided equalizer and the differing channel conditions between the data-aided equalizer channel and the conventional serial streaming telemetry channel, we are unable to draw any firm comparative conclusions.
2168 a57200730646 Busuttil P. p887 False Journal 412 Joining Dissimilar Material Using Friction Stir Scribe Technique The ability to effectively join materials with vastly different melting points, like aluminum to steel, and polymer composites to metals, has been one of the roadblocks to realizing multi-material components for lightweighting efforts. The friction stir scribe (FSS) technique is a promising method that produces continuous overlap joints between materials with vastly different melting regimes and high-temperature flow characteristics. FSS uses an offset cutting tool at the tip of the friction stir welding pin to create an in situ mechanical interlock between material interfaces. With investments from the U.S. Department of Energy Vehicle Technologies Office and several automotive manufacturers and suppliers, Pacific Northwest National Laboratory is developing the FSS process and has demonstrated the viability of joining several material combinations. Details of welding trials, unique challenges, and mitigation strategies in different material combinations will be discussed. Joint characterization, including mechanical tests and joint performance, will also be presented. © 2017, The Minerals, Metals & Materials Society.
2169 a56316070300 Yuan Y. p888 True Journal 413 A minimal realization technique for the dynamical structure function of a class of LTI systems The dynamical structure function of a linear time invariant (LTI) system reveals causal dependencies among manifest variables without specifying any particular relationships among the unmeasured states of the system. As such, it is a useful representation for complex networks where a coarse description of global system structure is desired without detailing the intricacies of a full state realization. In this paper, we consider the problem of finding a minimal state realization for a given dynamical structure function. Interestingly, some dynamical structure functions require uncontrollable modes in their state realizations to deliver the desired input-output behavior while respecting a specified system structure. As a result, the minimal order necessary to realize a particular dynamical structure function may be greater than that necessary to realize its associated transfer function. Although finding a minimal realization for a given dynamical structure function is difficult in general, we present a straightforward procedure here that works for a simplified class of systems. © 2014 IEEE.
2170 a37057761700 Rai A. p888 False Journal 413 A minimal realization technique for the dynamical structure function of a class of LTI systems The dynamical structure function of a linear time invariant (LTI) system reveals causal dependencies among manifest variables without specifying any particular relationships among the unmeasured states of the system. As such, it is a useful representation for complex networks where a coarse description of global system structure is desired without detailing the intricacies of a full state realization. In this paper, we consider the problem of finding a minimal state realization for a given dynamical structure function. Interestingly, some dynamical structure functions require uncontrollable modes in their state realizations to deliver the desired input-output behavior while respecting a specified system structure. As a result, the minimal order necessary to realize a particular dynamical structure function may be greater than that necessary to realize its associated transfer function. Although finding a minimal realization for a given dynamical structure function is difficult in general, we present a straightforward procedure here that works for a simplified class of systems. © 2014 IEEE.
2171 a16053936800 Stan G.-B. p888 False Journal 413 A minimal realization technique for the dynamical structure function of a class of LTI systems The dynamical structure function of a linear time invariant (LTI) system reveals causal dependencies among manifest variables without specifying any particular relationships among the unmeasured states of the system. As such, it is a useful representation for complex networks where a coarse description of global system structure is desired without detailing the intricacies of a full state realization. In this paper, we consider the problem of finding a minimal state realization for a given dynamical structure function. Interestingly, some dynamical structure functions require uncontrollable modes in their state realizations to deliver the desired input-output behavior while respecting a specified system structure. As a result, the minimal order necessary to realize a particular dynamical structure function may be greater than that necessary to realize its associated transfer function. Although finding a minimal realization for a given dynamical structure function is difficult in general, we present a straightforward procedure here that works for a simplified class of systems. © 2014 IEEE.
2172 a56830082600 Goncalves J. p888 False Journal 413 A minimal realization technique for the dynamical structure function of a class of LTI systems The dynamical structure function of a linear time invariant (LTI) system reveals causal dependencies among manifest variables without specifying any particular relationships among the unmeasured states of the system. As such, it is a useful representation for complex networks where a coarse description of global system structure is desired without detailing the intricacies of a full state realization. In this paper, we consider the problem of finding a minimal state realization for a given dynamical structure function. Interestingly, some dynamical structure functions require uncontrollable modes in their state realizations to deliver the desired input-output behavior while respecting a specified system structure. As a result, the minimal order necessary to realize a particular dynamical structure function may be greater than that necessary to realize its associated transfer function. Although finding a minimal realization for a given dynamical structure function is difficult in general, we present a straightforward procedure here that works for a simplified class of systems. © 2014 IEEE.
2173 a7401698226 Allen B.L. p889 False Journal 414 Dryland agriculture in north america Areas of North America with high density dryland farming include the Canadian Prairies, U.S. and Mexican Great Plains, and the inland pacific northwest of the U.S, with wheat (Tritcum aestivum L.) being the dominant crop. Dryland farming is less dense but important in nearly every state in the western U.S and in northern and central Mexico. In addition to wheat, North American dryland farming is important for the production of maize (Zea maize L.), sorghum (Sorghum bicolor L.), pulses, and oilseeds. The traditional and still prevalent cropping system is a two-year rotation of wheat and summer fallow. In this traditional practice, shallow tillage is used during fallow periods to control weeds and help store moisture in the soil. Sustainability of this practice is limited by soil degradation and erosion and poor water use efficiency. Where adopted, no-till practices improve precipitation storage and use efficiency, which has led to crop intensification and diversification and improvements in soil properties. This chapter highlights some current issues for dryland cropping in North America including integrated pest management for herbicide resistant weeds, diversification of crop rotations, soil carbon dynamics and residue management, and the application of models to aid decision making. Sustaining the dryland cropping systems of North America depends on research and application of practices that reverse past soil degradation, increase cropping system diversity, and apply integrated pest management strategies. Both experimental and modelling approaches are needed to address these challenges. © Springer International Publishing AG 2016.
2174 a8702836000 Anapalli S. p889 False Journal 414 Dryland agriculture in north america Areas of North America with high density dryland farming include the Canadian Prairies, U.S. and Mexican Great Plains, and the inland pacific northwest of the U.S, with wheat (Tritcum aestivum L.) being the dominant crop. Dryland farming is less dense but important in nearly every state in the western U.S and in northern and central Mexico. In addition to wheat, North American dryland farming is important for the production of maize (Zea maize L.), sorghum (Sorghum bicolor L.), pulses, and oilseeds. The traditional and still prevalent cropping system is a two-year rotation of wheat and summer fallow. In this traditional practice, shallow tillage is used during fallow periods to control weeds and help store moisture in the soil. Sustainability of this practice is limited by soil degradation and erosion and poor water use efficiency. Where adopted, no-till practices improve precipitation storage and use efficiency, which has led to crop intensification and diversification and improvements in soil properties. This chapter highlights some current issues for dryland cropping in North America including integrated pest management for herbicide resistant weeds, diversification of crop rotations, soil carbon dynamics and residue management, and the application of models to aid decision making. Sustaining the dryland cropping systems of North America depends on research and application of practices that reverse past soil degradation, increase cropping system diversity, and apply integrated pest management strategies. Both experimental and modelling approaches are needed to address these challenges. © Springer International Publishing AG 2016.
2175 a7005306331 Blackshaw R.E. p889 False Journal 414 Dryland agriculture in north america Areas of North America with high density dryland farming include the Canadian Prairies, U.S. and Mexican Great Plains, and the inland pacific northwest of the U.S, with wheat (Tritcum aestivum L.) being the dominant crop. Dryland farming is less dense but important in nearly every state in the western U.S and in northern and central Mexico. In addition to wheat, North American dryland farming is important for the production of maize (Zea maize L.), sorghum (Sorghum bicolor L.), pulses, and oilseeds. The traditional and still prevalent cropping system is a two-year rotation of wheat and summer fallow. In this traditional practice, shallow tillage is used during fallow periods to control weeds and help store moisture in the soil. Sustainability of this practice is limited by soil degradation and erosion and poor water use efficiency. Where adopted, no-till practices improve precipitation storage and use efficiency, which has led to crop intensification and diversification and improvements in soil properties. This chapter highlights some current issues for dryland cropping in North America including integrated pest management for herbicide resistant weeds, diversification of crop rotations, soil carbon dynamics and residue management, and the application of models to aid decision making. Sustaining the dryland cropping systems of North America depends on research and application of practices that reverse past soil degradation, increase cropping system diversity, and apply integrated pest management strategies. Both experimental and modelling approaches are needed to address these challenges. © Springer International Publishing AG 2016.
2176 a7102554886 Lyon D.J. p889 False Journal 414 Dryland agriculture in north america Areas of North America with high density dryland farming include the Canadian Prairies, U.S. and Mexican Great Plains, and the inland pacific northwest of the U.S, with wheat (Tritcum aestivum L.) being the dominant crop. Dryland farming is less dense but important in nearly every state in the western U.S and in northern and central Mexico. In addition to wheat, North American dryland farming is important for the production of maize (Zea maize L.), sorghum (Sorghum bicolor L.), pulses, and oilseeds. The traditional and still prevalent cropping system is a two-year rotation of wheat and summer fallow. In this traditional practice, shallow tillage is used during fallow periods to control weeds and help store moisture in the soil. Sustainability of this practice is limited by soil degradation and erosion and poor water use efficiency. Where adopted, no-till practices improve precipitation storage and use efficiency, which has led to crop intensification and diversification and improvements in soil properties. This chapter highlights some current issues for dryland cropping in North America including integrated pest management for herbicide resistant weeds, diversification of crop rotations, soil carbon dynamics and residue management, and the application of models to aid decision making. Sustaining the dryland cropping systems of North America depends on research and application of practices that reverse past soil degradation, increase cropping system diversity, and apply integrated pest management strategies. Both experimental and modelling approaches are needed to address these challenges. © Springer International Publishing AG 2016.
2177 a35854537900 Machado S. p889 False Journal 414 Dryland agriculture in north america Areas of North America with high density dryland farming include the Canadian Prairies, U.S. and Mexican Great Plains, and the inland pacific northwest of the U.S, with wheat (Tritcum aestivum L.) being the dominant crop. Dryland farming is less dense but important in nearly every state in the western U.S and in northern and central Mexico. In addition to wheat, North American dryland farming is important for the production of maize (Zea maize L.), sorghum (Sorghum bicolor L.), pulses, and oilseeds. The traditional and still prevalent cropping system is a two-year rotation of wheat and summer fallow. In this traditional practice, shallow tillage is used during fallow periods to control weeds and help store moisture in the soil. Sustainability of this practice is limited by soil degradation and erosion and poor water use efficiency. Where adopted, no-till practices improve precipitation storage and use efficiency, which has led to crop intensification and diversification and improvements in soil properties. This chapter highlights some current issues for dryland cropping in North America including integrated pest management for herbicide resistant weeds, diversification of crop rotations, soil carbon dynamics and residue management, and the application of models to aid decision making. Sustaining the dryland cropping systems of North America depends on research and application of practices that reverse past soil degradation, increase cropping system diversity, and apply integrated pest management strategies. Both experimental and modelling approaches are needed to address these challenges. © Springer International Publishing AG 2016.